January 1983 $2.49 V 2 Issue #268 Amateur Radio’s Technical Journal A Wayne Green Publication 9 Projects to Build and Use! More “Fun” Rigs Page 48 Better Breadboards Page 52 Autodialer Spectacular Page 40 Blockbuster SSB Rig! Page 12 BBC: Queen of the Airwaves Page 68 1982 40/80m, 160m Contest Results 3 age 103 Pulse King—100 Action Machine for 20 ^“| Are home-brew rigs a lost art? Noi vet' Here an SMi transceiver you can build WB5IPM 12 An Alarming Procedure IN I This false-proof repeater emergen- cv alert won t tie up expensive equipment WA1LCF,K1FNX 24 Trimming the Fat from ATV Why use 3 MHz when S(X) kHz will do? WB6FHD proposes a way WB6FHD 32 The Forgetful Autodialer Puzzle |\l Even Sherlock couldn't ligure out how to make an autodialer that re programs with no hardware changes Elementary. sa\s dear Bane W7BBX 40 My Own Silver Mine Fyl for W1FLP reclaiming silver from — photographic fixer is cheap, ea^v and profitable King Midas should have had it so good W1FLP 46 Fun-Equipment Revisited [\J Here are higher-band versions of the ever-popular Fun-Mitter and Fun-Amp They are based on the Fun-Philosophy cheap and simple WA0RBR 48 The Ultimate Breadboard 1 here used to be two qvles of proto¬ types—rat’s nest and cramped Now there i' a third style —simple NbBW 52 Beating the Untraceable Buzz l\! Man-made interference doesn i have to destroy reception. Nut when you usp WIGV’s buzz-brat- mg antennas W1GV/4 56 The Care and Feeding of Optoelectronics |\ I There are many wavs to make these 1 devices earn their keep Here is one K iVDB 62 International Success Story: The BBC From its li.itlc-rv of transmitters llu BBC fires a daily salvo of news and entertain¬ ment around the world Nn commer¬ cials, either Peterson 68 Active-Filter Design Made Easy r TA Using this BASIC program, ii you don I like the design, then scrap il Ml \[>u lose i» a few seconds WD4HPC 78 The Cornerstone of Equipment Failure: Heat Damage The proper heat 'ink will preserve tran¬ sistors I earn how to keep your cir< uitrv from resembling a core meltdown Shamburger 84 Your (anuary Home-Brew Project |V1 No frills —just a solid SSB ex- citer for I IF Who says hams don't build anymore? VI7|)OD 92 King of the Pulse Generators lyl One shot or a train TT | or CMOS this generator will fit the bill It s just what vour test bench always wanted V\ A3R|S 100 Repeater Controller—126 Never Say Die—6 Satellites—101 Contests—102 Reader Service—114 Social Events—115 Letters —116 Circuits—124 Review—126 RTTY Loop—130 Fun! —132 Corrections—134 DX—138 Awards—140 New Products—142 Ham Help—144 Dealer Directory —162 Propagation—162 Manuscripts Contributions in the form of manu¬ scripts with drawings and/or photo¬ graphs are welcome and will be con¬ sidered for possible publication. We can assume no responsibility for loss or damage to any material. Please enclose a stamped, self-addressed envelope with each submission. Pay ment for the use of any unsolicited materia) will be made upon accep¬ tance. All contributions should be di¬ rected to the 73 editorial offices. ‘How to Write for 73" guidelines are available upon request Editorial Offices: Pina Street Peterborough NH 03456 Phone: 603 924-9471 Advertising Offices: Elm Street Peterborough NH 03456 Phone: 603-924-7138 Circulation Offices: Elm Street Peterborough NH 03456 Phone: 603924-9471 Subscription Rates In the United States and Possessions: One Year <12 issues) $25.00 Two Years (24 issues) $36.00 Three Years (38 issues) $53.00 Elsewhere: Canada and Mexico—$27.97/1 year on¬ ly, U.S. funds. Foreign surface mall—$44.97/1 year only, U.S. funds drawn on U.S. bank. Foreign air mall—please inquire. To subscribe, renew or change an address: Write to 73, Subscription Department, PO Box 931, Farmlngdale NY 11737, For renewals and changes of address, include the address label from your most recent issue ot 73. For gift sub¬ scriptions, include your name and ad¬ dress as well as those of gift reci¬ pients. Subscription problem or question: Write to 73, Subscription Department, PO Box 931, Farmlngdale NY 11737, Please include an address label. 73 Amateur Radio's Technical Journal (ISSN 0096-9010) Is published monthly by 73, Inc, a subsidiary of Wayne Green, Inc., 60 Pine Street, Peterborough NH 03458. Second class postage paid at Peterborough NH 03456 and at addition¬ al malting offices. Entire contents copy right £ 1962, Wayne Grean, Inc. AiJ rights reserved. No part of this publica¬ tion may be reprinted or otherwise repro¬ duced without written permission from the publisher. Microfilm Edition—Uni¬ versity Microfilm, Arm Arbor Ml 46108. Postmaster Send address changes to 73, Subscription Services, PO Box 931, Farmlngdale NY 11737. R-X Noise Bridge • Learn the truth about your antenna. • Find its resonant fequency. • Adjust it to your operat¬ ing frequency quickly and easily. If there is one place in your station where you cannot risk uncertain results it is in your antenna The Patomar Engineers R-X Noise Bridge teis you if your antenna is resonant or not and, if it is not. whether it is too long or too short All this in one measurement reading. And it works just as well with ham-band*only receivers as with general coverage equipment because it gives perfect null readings even when the antenna is not resonant. It gives resistance and reactance readings on dipoles, inverted Vees, quads, beams, multiband trap dipoles and verticals. No station is complete without this up-to- date instrument. Why work in the dark? Your SWR meter or your resistance noise bridge tells only half the story. Get the instrument that really works, the Palomar Engineers R-X Noise Bridge. Use it to check your antennas from 1 to 100 MHz. And use it in your shack to adjust resonant frequen¬ cies of both series and parallel tuned cir¬ cuits. Works better than a dip meter and costs a lot less. The price is $59.95 in the U.S. and Canada. Add $3.00 shipping/handling. California residents add sales tax. Hi 1 . 1 MESA Sand for FREE catalog describing the R-X Noise Bridge and our complete line of SWR Meters, Preamplifiers, Toroids, Baiuns, Tuners, VLF Conver¬ ters, loop Antennas and Keyars. Palomar Engineers Bo* 455, Escondido. CA 92025 Phone: (619) 747-3343 4 73 Magazine • January, 1983 W2NSD/1 NEVER SAY DIE editorial by Wayne Green IT’S SNOW FUN Are you going to be wasting your time the second week of January chasing some fool DXpedition around twenty me¬ ters or are you going to be out with a bunch of us on the slopes of Aspen, HTing it and having a ball? That's the low season in Aspen, so the prices are still a bargain. . and it’s right after the Winter Consumer Electronics Show in Las Vegas, if you're in the electronics industry. During the day. Chuck Martin WA1KPS (Tufts Electronics) will be leading the kamikaze group down the expert slopes, while I'll be struggling to keep up with the geriatric crowd and their walkers on the gentler slopes. It is a lot of fun to ski with fellow hams. . . keeping in touch with HTs. And it’s even more fun to get togeth- er for dinner at some of the fa* mous Aspen restaurants and talk over the ham industry. DXing, and so on. If you can get away January 8- 12, we'll be skiing out of The Limelight Hotel (again), so don’t miss the Eighth Ham Industry Winter Symposium. . .obviously an historic event. We’re expect¬ ing ham manufacturers there as well as dealers, so there should be some brisk discussions on discounts, service support, need¬ ed new products, technical ad¬ vances, and so on. THE VIEW FROM OVERSEAS With such a heavy percentage of our DX contacts going not much further than an exchange of names, locations, and, possi¬ bly, in some rare cases, a recita¬ tion of the equipment being used, not only are we failing most of the time to live up to one of the fundamental rationales for amateur radio—the develop¬ ment of international friend¬ ship—but also we are wasting an impressive technology. When is the last time you got on the air and had a half-hour con tact with someone in a relatively rare DX country? Rather than lecture you and try to make you feel guilty for maintaining the most eternal tradition of amateur radio, meaningless contacts. I'd rather go about this in a positive fash¬ ion. I recognize that one of the problems when you meet some¬ one new is to find a field of mu¬ tual interest about which to talk. Most of us are so used to our own areas that we tend to forget that though they are pedestrian to us, they might be of con¬ siderable interest to someone overseas. Sure, the chap in a small town in Germany will go to a fair in his area just as you may in yours. But there the similarity ends. While the fair I go to may offer Italian hot-sausage sandwiches with fried onions and green pep¬ pers, fruit salad, green salad in a pita-bread pouch, fried dough, french-fried onion rings, french fries, do-it-yourself ice cream sundaes, and corn on the cob, my friend in Germany will beeat- ing a wide variety of sausages, hot potato salad, grilled fish, pigs’ knuckles, shashliks, and drinking new wine or a special seasonally-produced type of beer. At French fairs, the fare is again different, but no less delicious. In order to work toward bring¬ ing amateurs together on a worldwide basis. I'd like to solic¬ it regular reports on hamming overseas via a group of corre¬ spondents. If you are living in some area of the world which should be reported on in 73.. . or if you know someone who might be interested in such. I’d like to hear from you. What I have in mind is a regu¬ lar ... perhaps monthly for many areas. . .report on any news of interest to hams around the world. I think many of us would like to know about con¬ tests which are coming up which are organized in your area. We’d like to know about new certificates. We’d like to NEW BAND APPROVED The FCC has approved use of the 10 MHz band, but amateur operation is limited ami the Commission did not release the new rule without a cautionary note According to the rule, most ol the frequencies from 10.1 to 10.15 MHz are available to hams, except tor a slice from 10 109 to 10.115 MHz. That section is stilt reserved for government use General. Advanced-, and Extra-class licensees are allowed to transmit CW and RTTY SK and AFSK) with a final input power of up to 250 W. In its decision, the Commission cited the “limited size’ 1 of the band and the “temporary nature” of the ruling The FGC’S action is valid until the Senate takes action on theWARC treaty, ieav ing present limitations open for change Although 30 meters has been a possibility Since the 1979 WARC convention, approval ot the treaty was delayed. Though the FCC previously denied an ARRL petition requesting use ot the band, the amendment did not directly address the Commission's change ol mind. “Strong interest" in the amateur community was Cited as a reason tor the deci Sion, but the Commission warned that since its action is subject to tutur# Senate decisions about the treaty, the amendment "may be effective for only a brief period " The FCC added that hams would be “ill-advised to Invest heavily in equipment which can only be used in this band —WB8JILG know about any outstanding ham conventions. We’d like to know about ham products which are made in your area. We’d like to know more about the growth of hamming, any special developments, impor¬ tant rule changes, how to get a visitor’s license, and so on. What areas? I'm open to sug¬ gestions. Perhaps we d like to hear from the U K , Germany. France. Benelux, Scandinavia, Southern Europe, the Mediterra nean area, the Mideast, India, Japan, Southeast Asia. Austra lia-New Zealand, Oceania, South America, the Carib¬ bean. . . and so on? Regular correspondents will not only be paid for the reporting work, but also will get special press passes from the maga¬ zine. special OSL cards, busi¬ ness cards, and other such doc¬ uments to help them with their reporting contacts. This would be a good medium for bringing up area problems for world discussion. It would help us know more about com¬ ing and past DXpeditions. We might be able, with such a wide¬ spread correspondent system, to develop some sort of network of ham help to meet traveling hams and make them welcome. We would be better able to keep things like local net frequencies known, repeater channels publi¬ cized, and so forth. I would love to have some correspondents from Iron Cur¬ tain countries, recognizing that they might prefer to be paid in magazine subscriptions and books rather than American cash, which can be a problem. If you have any good friends in spots around the world who you think might be able to pro¬ vide a continuing series of inter¬ esting reports, you might drop them a line with a copy of this editorial and suggest the idea. Or you could bring it up on the air. . give you something of in¬ terest to talk to them about. The prestige of being published in an international magazine can help a person substantially, sometimes. I remember when I first ran into that. It was in 1956 and I was visiting St. Thomas and Dick Spenceley KV4AA. I was the editor of CO at the time, which I didn’t think of as being of much importance. Well, I stopped by a store downtown, happened to mention Dick, and was told how important he was, doing a DX column for an inter¬ national magazine* Hmmm. It 6 73 Magazine • January, 1983 -\ STAFF PUBLISHERS DlTOR Wayne G/wi W2NSDn EXECUTIVE VICE PRESIDENT S/wrry SmylUe ASSISTANT pubusher/eoitor J ell DeTray WBflBTH MANAGING EDITOR JoMn Butnail ASST MANAGING editor S usan Pbnbnc* EDITORIAL ASSISTANTS Nancy Noyd Richatd Siev* u*weit technical editor Avery L JenHinj WB&JLG ASSISTANT TO THE PRESIDENT Mail new Smilh KAUEi ASSOCIATES Roben WBPGFE John Edwards Ki2U Bill Gcsney KE7C Sar>g«f Green Chou VP2ML Of Mart Leavey WAJAjR J H Nelson Bril Pasternak WA6ITF Peiar Stark K20AW PRODUCTION MANAGER! PUBLICATIONS Nancy Salmon ASST PRODUCTION man age ^publications Michael Murphy ADVERTISING GRAPHICS MANAGERS Scoll W Philbrick Fiona Davies Bruce Heflin Jane Preaion PRODUCTION Prances Benton Linda Drew Denzel Dyer Phil Geraci Donna Harlwell Louis Marini Dianne K. Riison Anne Rocchlo Mary Seaver Deborah Slone Theresa Verville Judl Wimberly David Wozmah PHOTOGRAPH* Thomas VlUeneuve Sandra Duhelie Laurie Jennlson Irene Vail Roben M Villeneuve TYPESETTING Sara Bedell Mane Barker Melody Bedell Michele DesRocnem Jenmler Pay Lyfln Haines Linda Locke Nancy Wilson Newman DeDbie Nullmg Karen Stewan GENERAL MANAGER Debra Wetherbee CONTROLLER Roger J Murphy ACCOUNTING MANAGER Knud Keller KV*GGr' CIRCULATION MANAGER Patricia Perrante BULK SALES MANAGER Gmnie Boudrieau 'iSOOr 343-0728 ADVERTISING 603-924 7138 Jim Gray W1XU Mgr Nancy Ciampa. Assi M^ Ross Kenyon KAlGAV Cornelia Taylor _ J sure cut a lot of ice in St. Thomas. I was sorry to hear that Dick passed away recently. . . we’ll all miss that incredible fist of his. Any serious CW operator could tell Dick instantly by the perfection of his fist. Please give me a hand with this so that we can bring ama¬ teurs worldwide together a bit. The end result will be a lot more interesting things for us to talk about. . . perhaps bringing more DX operators onto our bands. Ops in rare countries sure get sick of endless demands for in¬ stant contacts and QSL cards. I get ham magazines from the U.K.. South Africa. Malaysia. Au¬ stralia. and so on. so I have a fair idea of what is going on. . .but 99.99% of you don't have that sort of input or the resources to pay for such a wide variety of magazines. Columns devoted to Continued on page 118 QSL OF THE MONTH This month's wi nning QSL comes from a Bapt si mission in Kenya, me home ol Milton (5Z4CL- and Charlotte SZ4CM) Erm \ The design is simple and informati<--». using only two colors to achieve a sinking contrast. Few cards are as succinct as this one. tel'i-g me reader at a glance where in the world the station is locatBO. And Irom a distance. Charlotte and Milton’s calls stand out clearly, leav¬ ing no doubt that this QSL is probably the pride of many a DXer s shack Entering 73's QSL contest is easy —send your QSL. in an envelope to: Editorial Offices 73 . Peterborough NH 03456 Specify a book Irom 71 s Radio Bookshop, if your card is chosen, we'll be nappy to send me book along to you. Entries which are not m an envelope or do not specify a book will not be considered 8 73 Magazine • January. 1983 Reader Service tor facing page ** 15 Frank H. Perkins WB5IPM Box 13642 Arlington TX 76013 Action Machine for 20 Are home-brew rigs a lost art? Not yet! Here's an SSB transceiver you can build I designed and built mini'ceiver 20 to learn something about SSB trans¬ ceiver design, Several times in the course of the project I became convinced that I was learning more about SSB transceiver design than I ever wanted to know! Any¬ way, mini'ceiver has worked out and it's quite a conversa¬ tion piece on the air. You can run mini'ceiver from a lantern battery, which opens up a number of possibilities, I have made an effort to use readily-available parts and easy-to-tune circuits in mini’ceiver, so I feel you will have a good shot at making it work if you want to give it a try This article covers mini'ceiver's circuit opera¬ tion once over lightly and then, in some detail, the cir¬ cuit schematics. No math or theory here, just a shirt¬ sleeve discussion of the cir¬ cuitry and how well it seems to work. If you are game at this point, I'll then give you some hints on how to build and tune up mini'ceiver, and I'll wind up with some ideas on accessories, possible de¬ sign alternatives, and opera¬ tion If you've always want¬ ed to build a good size proj¬ ect from scratch but never quite got around to it, this article is written for you. I'll try to give you an idea of what you've been missing. Mini'ceiver Circuit Operation Let's first look at Fig 1, mini'ceiver's block diagram Mini'ceiver is a 20-meter sin¬ gle-conversion superhetero¬ dyne transceiver boiled down to the basics. A con¬ ventional 9-MHz i-f frequen¬ cy is used. In the receive mode, an incoming signal in the 14 25-14.30-MHz range is routed through the receiver antenna switch to a dual¬ gate MOSFET mixer where it is mixed with the vfo signal (vfo range is 5 250-5 300 MHz). The mixer's differ¬ ence output, at 9 MHz, is routed through the receiver side of the T/R filter switch to the four-pole crystal filter, which provides the re¬ ceiver's selectivity. The i-f output from the crystal filter is amplified by a single- stage 1C amplifier which can provide a voltage gain of up to about 1000 The output from the i-f amplifier is mixed with the 8 9985- MHz bfo in the MOSFET product detector, recover¬ ing, typically, 5 mV of audio The audio output from the product detector is am¬ plified by the low-level au¬ dio amplifier and then routed to the age amplifier and the volume control. The age amplifier further ampli¬ fies the audio to around five volts peak-to-peak and then detects this signal to devel¬ op the age control voltage Meanwhile, audio from the volume control is routed to the audio power amplifier and on to the speaker jack While in the receive mode, the transmit circuitry is dis¬ abled by switching off the + T supply voltage In the transmit mode, the + T voltage is switched on as the 4- R voltage is switched off, enabling the transmitter circuitry as the receiver circuitry drops out. Low-level speech signals from the microphone are amplified to about 1.5 volts peak-to-peak by the speech amplifier and applied to the balanced-modulator audio input. Here the audio is mixed with the bfo signal in an 1C double-balanced mod- Photo A. Mini'ceiver 20 is an SSB transceiver boiled down to the basics . 12 73 Magazine • January, 1983 Fig. 1. Mini'ceiver 20 block diagram. ulator The double-sideband output from the modulator is routed through the trans¬ mit side or the T/R filter switch to the crystal filter. The crystal filter strips off the unwanted lower side¬ band and routes the 9-MHz SSB signal to the transmit mixer. At the transmit mixer, the 9-MHz SSB signal is mixed with the vfo signal and the sum output at 14 MHz is developed in the transmit mixer's tuned out¬ put circuit. The 14-MHz SSB signal next is amplified by two MOSFET low-level transmit amplifiers to about 600 mV peak-to-peak. The driver stage boosts this signal to about 200 mW and the final amplifier to about 15 W The output from the final is sent to the antenna Since the receiver antenna switch is open in the transmit mode, the receiver mixer is protected from overload The + R and + T power- supply voltages are alter¬ nately switched on under the control of the micro¬ phone PTT switch. All in all, mini'ceiver is a simple and straightforward design T/R Voltage Switch Almost every modern SSB transceiver design incorpo¬ rates digital logic* and mini'ceiver is no exception. Refer to Fig 2, the T/R volt¬ age switch schematic. A 4093 B E CMOS quad Schmitt NAND gate is the heart of this circuit. When the PTT switch is open, -M2 V dc is applied to R1 and on through the gate intercon¬ nections to pull R3 low at pin 10. This turns on Q1 and supplies + R to most of the receiver circuitry. -FR also turns on Q4, which helps pull down the -FT voltage on a transmit-to-receive transition. Meanwhile, pin 11 is at +12 V dc and Q2, + T, and Q3 are off. When the PTT switch is closed, the input side of R1 is grounded, which first al¬ lows pin 10 to go to 12 V dc, shutting off Q1 and Q4. About 30 milliseconds later pin 11 will go low, turning on Q2 and Q3, supplying + T to the transmit circuitry and clamping +R to ground. R2 and C3 account for the time that both +R and +T are off during a receive-to- transmit or transmit-to- receive transition R1 andC2 simply form a glitch filter Schmitt inputs were chosen for reliable logic switching with the slow rise times pro¬ vided by R1-C2 and R2C3. The vfo, bfo, audio power amplifier, and the collectors of the transmitter driver and final amplifier are continu¬ ously supplied with +12 V dc from the input power jack. Cl provides dynamic filtering for operating from dry cell batteries, etc. Vfo and Bfo Fig 3 provides the vfo and bfo schematics. Well start with the latter. The bfo is a grounded-base crystal oscil¬ lator designed to work with a series-resonant 8.998500- MHz crystal. It is easily tuned ± 300 Hz, which al¬ lows you to tailor the "sound'' of the rig some¬ what It will provide a 5-V peak-to-peak output when loaded by the product de¬ tector and balanced modu¬ lator Note that it is en¬ closed in a minibox. This is a must. I first had the bfo cir¬ cuit on the receiver main board I also had about two volts of bfo in the i-f amplifi¬ er output, plus all the local AM radio stations, etc! Keep the bfo shielded from the i-f amplifier; that is sage advice. The vfo consists of a buf¬ fered Hartley oscillator de¬ signed along recently-pub¬ lished guidelines. 1 I found the vfo to be quite stable. Tuning is very fast; you may want to use a reduction drive if you don't have a steady hand. R18 allows the vfo output to be adjusted to 5 V peak-to-peak. The vfo al¬ so is built in a minibox, pri¬ marily for its own protec¬ tion. The box helps stabilize temperature and shield the vfo from other rf signals Receiver Rf Section CR3, CR4, R24, R25, R26, C28, and C29 form the re¬ ceiver antenna switch In the Fig . 2. T/R voltage switch. 73 Magazine • January, 1983 13 VFO TRANSMIT RECEIVER Fig . 3. Vfo and bio schematics. receive mode, R25 supplies rf output from the final am and might use PIN diodes, current to CR3-R24 and CR4- plifier is positive, CR3 is however. Pm not a purist R26 from + R. CR3 and CR4 reverse-biased so little sig- -“just cheap are forward-biased with nal makes it to the mixer in about 5 mA dc and appear put transformer When the rf The receiver mixer em- to small rf signals from the output from the final is neg- ploys the often-used 40673 antenna as 25-Ohm resis- ative-going, CR3 is forward- (Q8) which is adequate for tors. Receiver signals thus biased so the rf signal ap- this application. We now easily can pass through C28 pears at R25. However, CR4 come to the second diode and C29 f which are dc block- is now reverse-biased, block switch in the mini'ceiver, ing capacitors, and the ing the rf output from reach- which is used to switch sig- two forward-biased diodes ing the mixer input. nals to the crystal filter from to the input transformer of The use of this type of di- either the receiver mixer or the mixer ode switch eliminates the the double-balanced modu- When the bias to the di- need for a mechanical relay, lator, CR5 forms half the odes is removed in the trans- Purists would probably add switch; CR8(lig. 6) forms the mit mode, the diode switch some rf chokes in series other half When + R is on, opens. Notice that when the with the biasing resistors CR5 is conducting about 6 mA dc, again providing a low-loss path to small rf sig¬ nals. Meanwhile, CR8 is back-biased, isolating the balanced modulator from the receiver-mixer output and crystal-filter input R30 is the biasing resistor for CR5 R31 establishes a suit¬ able input impedance for the crystal-lattice filter The crystal-lattice filter uses four crystals, two cut for series-resonance 750 Hz below center frequency and two cut for series-resonance 750 Hz above center fre¬ quency The overall 6-dB bandwidth appears to be about 2200 Hz Unwanted sideband suppression is around 26 dB (5%) at 1000 Hz, which is OK for QRP While the filter can be built for under $30, you won t hurt my feelings if you use a commercial filter here. Remember to adjust R31 and R32 to suit the com mercia! filter's termination impedance if you decide to go this route I've always had good luck with the MCI350 i-f ampli¬ fier (IC2). It exhibits high but stable gain when properly terminated and smooth for¬ ward age action, assuming you keep the bfo signal out of it. The value of R40 and the turns ratio of L6 were chosen for high stable gain I Photo B. Typical mini’ceiver SSB voice waveform. About Photo C Output spectrum consists primarily of the funda - 1.5-W p~p output . mental and harmonics. All spurs are more than 40 dB down . 14 73 Magazine • January, 1983 Fig. 4. Receiver rf schematic. 16 73 Magazine • January, 1983 don't suggest pushing the 1C harder by raising the value of R40. You don't need the extra gain and accompany¬ ing headache. The faithful 40673 MOSFET is again in service as a product detector at Q9. Notice the heavy audio by¬ passing and decoupling. Receiver Af Section Refer to Fig. 5. An LF353 dual op amp (IC3) is used as the receiver low-level audio amplifier. R47 allows the au¬ dio gain to be trimmed out to suit. C50 and C51 help roll off the high-frequency re¬ sponse of the audio section. The LM383 audio power am¬ plifier, ICS, is somewhat of a power overkill, but it pro¬ vides low-distortion audio at normal listening levels — much better than trying to push an underrated audio section too hard. IC4 is another LF353, this time used as an age amplifi¬ er and detector I seem to get the best results with au¬ dio-derived age when the base audio frequencies are rolled off —which explains the small value of C54. R57 controls the age attack time and R58 controls the release time. Of course, changing C58 messes up both time constants, Age characteris¬ tics are quite subjective, so feel free to experiment here. You might consider age something of a luxury on a basic transceiver. On 20 meters, I don't. Speech Amp, Balanced Modulator, and Transmit Mixer Fig. 6 details the above- mentioned circuitry. Again an LF353 is used as a two- stage audio amplifier (IC6). This time it is rigged to pro¬ vide a high-impedance input to the microphone. Since high-impedance audio cir¬ cuits make me nervous, I heavily decoupled the input from rf. A 1496N double-bal¬ anced mixer (IC7) is em¬ ployed as the balanced modulator and works quite well. At least 40 dB of car¬ rier suppression is easily ob¬ tained by adjusting R77. No¬ tice the other end of the T/R filter switch (CR8) at the output of the balanced modulator After being routed through the crystal filter to do away with the lower side¬ band, our 9-MFiz SSB signal is ready to be translated to 14 MFlz. It was at this point that I started learning too much about SSB transceiver design. I won't bore you with all the mixer circuits that didn't work. Let me just say that I have seen just about every picket fence display on my spectrum an¬ alyzer that I could imagine (see "Poor Man's Spectrum Analyzer," 73, August, 1982). The biggest problem was the 3rd harmonic of the vfo at 15 MFlz. Now you can supposedly get this out with a carefully designed multi¬ pole bandpass filter, but it sort of compromises our sim- ple-to-build theme. Fortu¬ nately, there is another way. First, start with a 1496N double-balanced mixer. Next, don't drive the carrier port (pin 8) with more than 70 mV peak-to-peak of vfo signal. This leaves the mixer pretty much in "linear" op¬ eration so that not much 3rd harmonic of the vfo appears in the mixer output. (Refer to the spectrum photo, which tells the story.) Any¬ way, we now have a clean 14-MHz SSB signal, so on to the transmit amp chain. Transmit Amplifier Chain Referring to Fig. 7, we find the transmit amplifier chain uses both tuned and broad¬ band stages. Q11 and Q12 are tuned low-level amplifi¬ er stages. There is more po¬ tential gain in these stages than needed, so the turns ratio at L9 is not for imped¬ ance matching, it's to "throw away" some extra gain without lowering Q. The turns ratio at L10 pro¬ vides a suitable match be¬ tween the drain of Q11 and the 30-Ohm or so input im- Fig . 5. Receiver af schematic . pedance of the driver. The driver is the broadband stage. The same feedback that sets the broadbanding on this stage pretty much en¬ sures low-frequency stabili¬ ty, which is what I was after. It seems a little hard to find a suitable driver for HF work, but the 2N3866, which often is used in cable TV sys¬ tems, is very easy to find. Since it is a VHF transistor, feedback for the sake of sta¬ bility seems prudent in an HF driver application. LI 2 matches the output of the driver to the 5-Ohm or so input impedance of the fi¬ nal amplifier, A single pi net¬ work of rather low Q trans¬ forms the assumed 50-Ohm antenna impedance to around 35 Ohms, setting up the 1.5-W output with some room to spare. LI 6 and Cl08 form a series-resonant trap that takes care of the 2nd harmonic, which is the only offending spur. Notice that the bias to both the driver and the final amplifier are switched by +T. Despite some deliberate and unde¬ liberate attempts, Lve not managed to zing the final (probably because I have a spare). Harmonic suppres¬ sion appears to be fairly in¬ sensitive to antenna imped¬ ance, which is characteristic of series trap suppression. R99 allows you to adjust the overall gain of the amplifier chain, Mini'ceiver Construction I feel that you will have a good chance of successfully building the mini'ceiver, or your customized version of it, if you are comfortable us¬ ing a triggered oscilloscope in troubleshooting and have built several kits and scratch- built projects. Or, of course, if you can get help from a friend and/or some¬ one in your club or repeater group with the above ex¬ perience. I'm not trying to discourage anyone; I just want you to have a good chance for success if you embark on the project Building and experimenting is great fun, and I want it to stay that way for you. I believe that you can build mini'ceiver for about $200, maybe less if you have a big junk box. Parts See below for the list- Parts List Component Ref# Supplier# 4093BE 1C IC1 4 1350P 1C IC2 2,4,6,7,8 1496N 1C IC7-8 4 LF353 1C IC3-4.6 2,4,7 LM383 1C IC5 2,4,7 TIP125 DBJT Q1-2 2,4,7 2N2222 BJT Q3-4,7 2,4,6,7,8 MPF102 JFET Q5 2,4,6,8 40673 MOSFET Q6.8-10 1,2,4,6,7,8 2N3866 BJT Q12 2,7,8 MRF476 BJT Q13 8 1N914B Diode CRI-8,10 2,4,6,7,8 1N4001 Diode CR9 2,4,6,7,8 8.998500 MHz .001 % SR crystal Y1 5 8.999250 MHz .001 % SR crystal Y2,5 5 9.000750 MHz .001 % SR crystal Y3-4 5 L43-2 Coil form L2,5-7 3 L43-6 Coil form L4,8-10 3 FT-37-43 Toroid L6 3 FT-50-61 Toroid L11 3 T-50-6 Toroid LI 4-16 3 3-30 pF Var. cap.,V4" shaft C9 6 3-30 pF Var. cap., PC mount C6 6 80-300 Arco trimmer Cl 14 8 4-40 Arco trimmer C108 8 5% NPO Ceramic cap C7-8.10 Local TV supply 10% TS Ceramic cap C20,30,34 Local TV supply 43,76-77 or use silver 88,91 mica 5% 5% SM Silver mica cap C21 t 22 2,4,8 C105-107 500 pF Feedthrough cap, C15,17 1 threaded type 1 uF Low-leak cap C58 7 CU-3000A Bud minibox 2 CU-3011A Bud minibox 2 Note: Other components are garden variety V*- and Ya-W resistors, + 80,-10% 50-V ceramic capacitors, and standard electrolytic capacitors. Suppliers: 1. Alaska Microwave Labs, 4335 E 5th Street, Anchorage AK 99504; (907)-338-0340. 2. Allied Electronics, 401 E 8th Street, Fort Worth TX 76102; (817)-336-5401. 3. Amidon Associates, 12033 Otsego Street, N. Hollywood CA91607; (213)-760-4429. 4. Jameco Electronics, 1355 Shoreway Road, Belmont CA 94002; (415)-592-8097. 5. Jan Crystals, 2400 Crystal Drive, Fort Meyers FL 33906; (813)-936-2397. 6. RadioKit, Box 41 IS, Greenville NH 03048; (603)-878-1033. 7. Radio Shack. 8. Semiconductors Surplus, 2822 N 32nd Street #1, Phoenix AZ 85008; <602)-956-9423. 18 73 Magazine • January, 1983 Fig. 6. Speech^amp, balanced-modulator ; and transmit-mixer schematic. 20 73 Magazine • January, 1983 Photo D. Vfo construction detail. ing of all major parts. As I promised, the parts are read¬ ily available. You might have a little trouble finding the NPO capacitors, but many radio-TV parts houses stock them. Keep in mind that one of your best sources for parts informa¬ tion is just a CQ or two away —just don't conduct your purchases directly on the air! Chassis I built my mini'ceiver in a 12" L X 7" W X 4" H Bud CU-3011A minibox, and used two 2 3 /i" L X 2-1/8" W X 1-5/8" H Bud CU-3000A miniboxes within to house the vfo and bfo. As you can see in the construction pho¬ tos, I put the power supply, receiver, speech amp, bal¬ anced modulator, and trans¬ mitter mixer on a main board and the transmit amp chain on a smaller piggy¬ back board. This worked out successfully. However, I plan to use two cards of the same size mounted vertical¬ ly, each facing out, in the next mini'ceiver. In this case, I would put most of the transmitter circuitry on one card. If you decide on this layout, keep the speech amplifier and final rf amp at opposite ends of the trans¬ mitter board! Circuit Boards The layout of high-gain rf and audio PC boards is something of an art form. For a one-shot project, it's hard to beat the use of sin¬ gle-sided (2-ounce copper) circuit board with the cop¬ per on the component side used as a ground plane. No¬ tice that the transmit ampli¬ fier chain is built in this way. It's generally taster to dupli¬ cate a circuit using this ap¬ proach than to go through the process of lifting circuit board art, exposing resist:, etching, etc. I've outlined the ap¬ proach I like to use in an ear¬ lier article, but it's worth go¬ ing through again. If nothing else, it makes component substitutions a snap. Get some drafting vellum with a light bluel/IOth-inch grid on it. After you have gathered all the parts for a circuit, you can begin developing the board layout. Start by mulling over the schematic and inspecting the compo¬ nents. Then lay out the com¬ ponents on the grid paper and think through their in¬ terconnection. juggle the components around as needed for a neat arrange¬ ment that minimizes trace lengths and crossovers. If you think in terms of circuit strips, it makes things easier. After you have the layout and interconnection for a section of the circuit visual¬ ized, pick up the compo¬ nents and sketch in their Photo E. View of the main board which includes the receiver; speech amp , balanced modulator , and transmit mixer outlines on the vellum. Rf Coils and Transformers Show the component inter- Radjo shack currently connections underneath the mar kets a packet of magnet circuit board with dotted w j re j n three gauges: part lines. You will be surprised number 278-1345. This type how fast this goes. Remem- Q f wire can be stripped sim- ber that all ground connec- p | y wit h hot solder, so it's tions are on top. Be careful idea | for rf coi | and tra ns- to keep input and output former applications. Use the connections of high-gain rf 30-gauge wire for winding all and audio stages separated. the shielded transformers. Once the layout is com- (Jse the 22-gauge wire plete, you can tape it direct- for winding all the toroids ly to your circuit board except L6 and L14, where blank. Drill through the lay- the 26-gauge wire will be out and the circuit board easier to use. I used a small each place a component 10-uH molded choke for lead or wire goes through LI3. However, this should the board. I use about a #62 not be too critical. If you bit for most holes except 1C have trouble finding a mold- leads, where I use a #68 bit. ed choke, try 16 turns or so It's easy to enlarge holes onanFT-50-61ferritecore.lt later as needed for the big- might be a good idea to put ger component leads. a 10-Ohm resistor in series After all the holes are with this choke to avoid any drilled, lightly countersink surprise resonances, them with a 3/32" bit-ex- You will notice a number cept those which are going of bifilar windings are used, to be direct ground con- I use an electric drill to pre- nections. The countersink- twist pairs of wires to about ing keeps the leads from 6-8 turns per inch. Use an shorting out on the ground ohmmeter to figure out plane After cleaning the which wire is which after board and perhaps tin-plat- winding the bifilar coils. On ing it, you can begin instal- the shielded coils, bring the ling components. They are bifilar pairs out together at interconnected under the each end of the bifilar wind- board by their leads and/or ing and then separate and bus wire. Remember to keep tin them under the circuit connections as short as pos- board. Don't try to solder di- sible and watch input-out- rectly to the coil-form posts put routing around high-gain on these transformers. You'll stages. wind up a post short. S5 Fig . 7. Transmit-amplifier chain. 73 Magazine • January, 1983 21 Photo F. Top view of the transmit amplifier chain. Note the Photo G. Overall view of the mini'ceiver circuitry with the "stovepipe" driver heat sink. transmit amplifier card in place . The bio is housed in the small minibox in the back . You may find the vfo and bfo a little tight to construct since they have to fit in their respective mimboxes With a little patience everything will fit For the vfo, it's prob¬ ably best to etch the copper off the circuit board except around the edges. Hopeful ly, the vfo detail photo will help with the layout Heat Sinks The audio power amplifi¬ er, transmit final amplifier, and transmit driver should all have heat sinks. I made a "'stovepipe" heat sink out of copper sheet for the 2N3866 driver. Standard commer¬ cial heat sinks were used elsewhere Tune-Up Recommended test equip¬ ment for tuning up mini ceiver includes a triggered oscilloscope with at least a 20-MHz bandwidth, a multi¬ band HF transceiver, a dum¬ my load, a frequency count¬ er, and an audio oscillator Luxury items for tune-up in elude a grid-dip oscillator, an rf signal generator with a step attenuator, a two-tone oscillator, and, of course, a spectrum analyzer Power Supply and T/R Voltages You can run a mini'ceiver off a 12-V-dc, 1 -A supply. Be- 22 73 Magazine • January, 19 fore powering up the rest of the circuitry, test the T/R voltage switch tor proper ac¬ tion Check the collectors of Q1 and Q2 in each PIT switch position for proper on/off action. You did wire the microphone jack up right, didn't you? Bfo and Vfo Tune-Up Apply +12 V dc to the vfo and check for oscillation with the scope at Cl6 Fully mesh tuning capacitor C9 and adjust C6 for operation around 5.250 MHz. Unmesh C9 and confirm operation at about 5 300 MHz Set C9 about mid-range and peak L2 while looking at the vfo output Then adjust R18, clockwise from the bottom, for a 5-V peak-to-peak out put Putting the top on the vfo will change its operating frequency somewhat, so you may want to tune and try a couple of times until you get it on frequency with the top on Apply +12 V dc to the bfo and back the slug nearly out of L3 While monitoring the output of L3 with the scope, slowly run the tuning slug in until oscillation starts Peak the oscillator output You should get about a 5-V peak-to-peak output Check oscillation frequency with your counter and fine-tune the slug in L3 for operation at 8 998500 MHz The bfo must be load¬ ed with the product detec¬ tor and balanced modulator for proper operation It's a good idea to put a small hole in the top of the bfo minibox over L3 to allow for touch-up adjustment of the slug with the minibox top in place Receiver Tune-Up Run the tuning slugs in on L4, L5, and Lb so that the tops of the slugs are just slightly above the top of the shield cans. Set the volume control and R47 at mid¬ range You should now be able to hear 20-meter SSB signals on your antenna or on a 15' piece of wire stuck in the antenna jack Fire up your other HF rig into a dummy load at low output power and set its out¬ put frequency for about 14 275 MHz Tune the mini'ceiver to find the sig¬ nal Once found, monitor pin 7 on IC4 (the age output) and peak L4, L5, and L6 for maximum age output. If you see the age voltage peaking above 6 V dc during tuning, reduce your signal level a bit You can now adjust R47 to suit. Back this pot down a bit if you run into high- volume audio distortion or instability when running off dry cells Transmitter Tune-Up Hook mini'ceiver to a 50-Ohm dummy load Short the PTT input on the mike jack to ground Check the voltage across R115 It should be around 20 mV dc, which indicates a 20-mA qui¬ escent bias on Q13. If it s much off this value, replace R112 with a larger or smaller resistor as needed to bring the bias in range. Incidental¬ ly, if you have trouble find¬ ing a 1-Ohm resistor for R115, you can use a 10-Ohm resistor (200 mV dc), but short the resistor out after setting up the bias Input a single audio tone of about 8 mV peak-to-peak into the audio side of the mike jack Adjust R70 for a 1 5-V peak-to-peak audio signal at pin 1 of IC7 Hook the scope to the anode of CR8 and peak L7 You will see a waveform that looks like an AM signal with 20- 40% modulation, about 400 mV peak-to-peak. Check pin 1 of IC8 for a fairly clean 150-200-mV CW signal Look at the output of L8 and peak for a 14-MHz signal of about 150-200 mV Move the scope to the output of L10 and peak L9, L10, and R99 Adjust R99 for a lower bias voltage to Q10 and Q11 if the output of L10 is more than 500 mV peak-to-peak Check the output of Q12 at C59 for about a 5-V peak-to- peak signal Hook the scope to the output of the amplifier chain (SO-239 connecter) and peak Cl 14 This is broad tuning, so watch carefully You should have about 25 V peak-to-peak of rf output find the 2nd harmonic of mini'ceiver's output on 10 meters and tune Cl08 for a null Tuning is quite sharp, so tune carefully, Cl08 can also be tuned to peak the 2nd harmomic; be sure you tune for minimum output on 10 meters. You can use a short piece of wire for a receive antenna on your 10-meter rig since it's in the same room with mini'ceiver. Disconnect the jumper and audio oscillator from the microphone jack and plug in the mike Readjust R70 a bit, if needed, for an S5B voice signal similar to the one in Photo B Be careful not to push too hard; there is enough flat-topping out there already Operation Now the moment of truth The results you get with mini' ceiver depend heavily on your antenna system, but this is true of any station I think you will be surprised I've gotten clean audio re¬ ports (except when I tried a narrower crystal filter!) and moderate signal strength re¬ ports which is expected for QRP The fact that mini' ceiver is home-brewed does generate QSO interest Mods and Alternative Circuitry An S /rfoutput meter can be added easily if you like to watch meters jiggle. For the S-meter, monitor the age voltage which will vary from about 4 to 7 V. Add a 2:1 re¬ sistive divider across the rt output (about Ik total load) and then detect the peak rf voltage at the divider output with a diode-capacitor rf de¬ tector This should give you about 6 V peak to drive the meter. Use a toggle switch to switch modes on the meter. There is enough room left to add an 'afterburner" if you feel you need a little more power I suggest using an MRF477, which should take you easily into the 25-W range. No more lan¬ tern battery operation, though The receiver anten¬ na switch should be moved to the collector side of the matching network in this case I don't suggest this un¬ less you have already done some rf amplifier design Mini'ceiver should be fair¬ ly easy to put on other HF bands by adding the appro¬ priate crystal oscillator and another 1496 mixer to achieve a suitable vfo out¬ put range, along with adjust¬ ing L and C values as needed. From Here You can never really fin¬ ish an electronic design (or a computer program for that matter) and mini'ceiver is no exception There are many ways the design can be im¬ proved If you have an idea, try it! Experimenting is fun If you would like to ask me a question about mini'ceiver, please send an SASE 73! ■ References and Readings 1 . “Progressive Communica¬ tions Receiver,” Wes Hayward and John Lawson, QST t Novem¬ ber, 1981. 2. Solid State Design for the Radio Amateur ; Wes Hayward and Doug DeMaw, ARRL publi¬ cation. 3. Crystal Oscillator Design and Temperature Compensation, Marvin Frerking, Van Nostrand Reinhoid. 4. introduction to Radio Fre¬ quency Design, Wes Hayward, Prentice-Hall. (Excellent if you can handle higher math.) 2300 MHz VARIABLE D O W N C O N V E R T E R ANTENNA KIT . n a<z£k* "\ ^ V J2 WASHERS Y \\£\s? v 31 SPACERS \ ^ - MOUNTING BRACKET 1 R G 174 COAX T CONNECTOR • 35” ROD 6 ¥ 2 ” x 4” P.V.C. 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BOARD PRE-DR1LLED SOLDER PLATED WITH PLATED THROUGH HOLES FOR A MORE STABLE PIC¬ TURE. AS&XAJ " ... ?/57 HoTTZR*)<> 3 AWSIST9R— 2 HP 2835 Diodes 6 .001 Chip Caps. 9 Resistors 4 Prewound chokes 1 Electrolytic Cap. 1 Pre Made Probe ★ WIRED P.C. BOARD TEST¬ ED, READY TO CONNECT TO CAN WITH PROBE & CABLE CONNECTOR ATTACHED. $24.95 We will tune conver¬ ter board for $12.50 trouble shoot add..7.50 trouble shoot power supply. $12.50 plus any parts needed We will accept telephone orders for Visa & Mastercard No C.O.D. Orders TO ORDER CALL 317*291*7262 TO UKDEK CALL g00-428*3500 ELECTROniC Complete kit weighs 10 lbs. Please add sufficient postage 6254 LaPas Trail Indianapolis, Indiana 46268 RAIflBOUl o c 146 See Ltst of Advertisers on oage 114 73 Magazine • January, 1983 23 An Alarming Procedure This false-proof repeater emergency alert won't tie up expensive equipment. Melvyn C. Morris WA1LCF Michael Polimer K IFNX 140 Hampton Road Sharon MA 02067 Decoder hoard mounted in battery compartment. Fig. 1. Block diagram. T wo-meter repeaters pro¬ vide reliable communi¬ cation for relatively large areas surrounding the re¬ peater site There has long been a need for a reliable warning or alert system op¬ erating through a repeater for civil defense, RACES, emergency, and similar type requirements In particular, if this need is required in the specific area within the lo¬ cale of a repeater, then the approach described here- 24 73 Magazine • January, 1983 in will prove more than satisfactory. On the assumption that a secure alert signal must be coded in some way, it be¬ comes readily apparent that the receiver/decoder must be immune (i.e., secure) from false triggering. The problems associated with using a repeater manifest themselves through the types of signals transmitted. For example: engine whine, noise, voice characteristics, whistling, and other distor¬ tions contained in speech must not falsely trigger the alarm mechanism. The re¬ ceiver, therefore, must be of sufficient sensitivity to oper¬ ate within a given signal- strength area and contain a decoder. The repeater must be able to pass the coded signal with sufficient ampli¬ tude to activate the alarm mechanism. Additional requirements are that any operator can initiate the alarm without the necessity of a special code generator and that ex¬ isting 2-meter receivers not be pressed into service to monitor and decode the alarm signals. (A previously published article out of Can¬ ada described the use of a 2-meter transceiver with a 'listening" decoder placed in front of the speaker to re¬ ceive and decode the alarm signal. Not only does this tie up a piece of very expensive equipment—but also it im¬ plies that the user must listen to every QSO and not forget to turn up the au¬ dio volume.) Finally, and above all, the receiver and code generator must be inexpensive. With the rudimentary specifications as set forth above, a search was con¬ ducted into readily avail¬ able equipment that could be modified for the task. Af¬ ter some deliberation it was decided that a crystal-con¬ trolled FM weather radio of the type used by mariners for monitoring NOAA Fig. 2. Schematic diagram of unmodified Weatheradio. 73 Magazine • January, 1983 25 weather broadcasts that al¬ so contains the built-in de¬ coder for NOAA-broadcast weather alerts would be ideal The Radio Shack Weatheradio Alert (cata¬ logue #12-154) was selected and was used as the basis for design In the event of a weather emergency, NOAA trans¬ mits a tone (1050 Hz) which activates an alarm in the re¬ ceiver which in turn alerts the listener to activate the audio portion of the receiver and listen to the detailed weather info. (Most weath¬ er-alert receivers allow the user to deactivate the audio while still keeping the re¬ ceiver in the monitor mode.) Normally transmitted speech does not activate the system since a relatively long transmit time (seconds) is required of the coding sig¬ nal and it is believed that NOAA also notches out" 1050 Hz during non-coded transmissions Before describing the modifications and design philosophy of our alert re¬ ceiver, a cursory look at a simplified block diagram of the unmodified weather ra¬ dio is necessary (Fig. 1). The incoming rf is sup¬ plied (via a link to the ac power cord) to an rf amplifi¬ er A crystal-controlled LO drives a diode multiplier and is loosely coupled to the in¬ put of a mixer stage. The output of the mixer (455 kHz) drives a tuned i-f ampli¬ fier and discriminator which provides detected audio to the audio preamplifier and to the 1050-Hz filter In the normal listening (WX) mode the audio is boosted through the audio amplifier and drives the speaker In the monitor (or alert) mode the alarm oscillator is enabled and the output of the vol¬ ume control is disconnected from the audio amplifier and speaker Reception of a 1050-Hz tone will trigger the oscillator and the signal thus produced will be am¬ plified via the audio ampli¬ fier and sound the alert. (There are some auxiliary features which will be de¬ scribed in the discussion on modifications.) NOAA broadcasts oper¬ ate on frequencies of DECODER 162.400, 162.475, and 162.550. This is facilitated in the unmodified alarm re¬ ceiver by operating the crys¬ tal padded with either a ca¬ pacitor, an inductor, or nothing. A three-position switch on the rear of the unit is provided for this purpose Since we will be operating on a fixed frequency, this is an unnecessary feature and must be disabled (We set the switch in the H un- padded" position and epox- ied it in place.) The repeater frequency we are using is 146.865-MHz output. The rf stages must be retuned to this frequency as well as selecting a new crystal which will provide an i-f of 455 kHz when operat¬ ing in conjunction with this frequency. A crystal fre¬ quency of 16 202 MHz is used to generate 455 kHz when operating with the "central" NOAA frequency of 162.475 MHz. Working backwards, 162.475 MHz ~455 kHz = 162.02 MHz It becomes obvious then that the multiplier is operat¬ ing at a multiplication fac¬ tor of 10. At the repeater op- erating frequency of 146.865, a crystal of (146.865 -455 kHzVIO = 14.641 MHz is required for the LO (The crystal can be purchased from: Sentry Mfg. Co , Chickasha, Oklahoma: #SCM-18, HC-25case with wire leads, 15-pF load.) With this detemiined and the planned use of the 1050- Hz coding signal, we set off to modify the receiver First we applied a signal at the NOAA frequency of 162 475 MHz FM modulated with 1050 Hz (3-kHz deviation) and measured the output of the discriminator at the point where the alarm would just trigger We ob¬ served the output of the sig¬ nal generator and used this output (in microvolts) as the target sensitivity at the re¬ peater frequency On the tri¬ al unit this was observed as approximately 1 uVL Next we replaced the crystal, ob- FROM DISCRIMINATOR OUTPUT Fig. 1 Decoder subassembly schematic . Fig. 4 . Connecting the decoder board to the receiver. 26 73 Magazine * January, 1983 served that the LO was oper¬ ating, and proceeded to re¬ tune the rf and LO stages. Unable to lower the tuned frequency adequately by squeezing the inductor coils closer together, we added capacitors in parallel to the tank circuits to bring the tuning in range of the coils All the while we monitored the output of the discrimina¬ tor and tuned for maximum output of the 1050-Hz sig¬ nal, With judicious twisting Fig . 5. PC board. and squeezing of the coils we were able to match the sensitivity observed at the NOAA frequency A hastily designed 1050- Hz tone generator was im¬ plemented and the receiver was put to the test It trig¬ gered obediently in re¬ sponse to the coded sig¬ nal—as well as from alter¬ nator whine and anybody who spoke with the right quantity of 1050-Hz energy! We quickly deduced that any decoding scheme that was dependent on a single frequency was doomed to a similar fate In order to mini¬ mize the cost of the decod¬ ing circuitry; we decided against any scheme which required timing sequences We also felt that the more complicated the scheme, the larger (and more costly) the decoder would be. and we did have space limitations within the receiver The solution decided upon was to code and de¬ code a single two-tone com¬ posite signal much like that used in the Bell Touch- Tone™ system In fact, for purposes of simplicity and availability, we designed around an actual DTMF tone pair The 1050-Hz fil¬ ter/amplifier was of no fur¬ ther use; therefore, it was bypassed A small printed- circuit board containing the two tone decoders and their associated drivers was de¬ signed to fit into the backup battery compartment. (The backup battery would be glued to the receiver case using double-sided masking tape.) A detailed description of the electrical design and receiver modifications fol¬ lows. To understand how our decoder design developed, it is first necessary to under¬ stand the operation of the unmodified decoder-alarm circuit Transistors Q9 and Q10 are operated as a trig¬ gered astable multivibrator R22 and R23 keep the pair in an untriggered state by keeping Q9 off in the ab- to osciiiato* jha* (JUNCTION #11. RSI. 04, ECO) Fig. 6. Component layout If resistors marked with asterisks are not used , they must be replaced by jumpers. UNIVERSAL M-600 MULTI-MODE AND CRYPTO-DECODER — NEW — DECODES: TOR-SITOR BIT INVERSION WEATHER FORMAT NON STANDARD SHIFT The M-600 converts these Codes plus RTTY (Baudot & ASCII) to video and will drive a Serial or Parallel printer for hard copy. Baudot speeds from 60 to 132 WPM and ASCII from 110 to 1200 Baud rates. Morse reception, auto range up to 60 WPM. The M-600 has 3 fixed shifts and 1 tunable shift. Multiple scroll inhibit and un-shift on space are included along with a built-in self-test system. Isolated loop MIL-188 or RS232 and optional parallel ASCII. CONTACT US FOR FURTHER INFORMATION Phone: (614) 866-4605 $799.95 MC & VISA Accepted (shipping extra) UNIVERSAL ELECTRONICS INC. 1280 AIDA DRIVE, REYNOLDSBURG, OHIO 43068 ALL NEW H.F. 10/160 METER SOLID STATE P.L.L. TRANSCEIVER US8-LSB 4 Memories 3 Way Auto-Scan Includes New Bands 3-Step Tuning Speed IF Tune ± 1 KHZ Built-in Dual VFO CW-W CW-N 20GW. PEP(160M-12M) 100 W. PEP(IOM) Built-in Power Supply AC-120 VAC DC-13.8 V -Ground External ALC 13.5 VDC Relay JUST SLIGHTLY AHEAD 1275 N. GROVE ST. ANAHEIM, CA 92806 TO ORDER OR DLRINFO. CALL (714) 630-4541 *^318 NOTE; Price. Specifications subject to change without notice and obligation 28 73 Magazine • January, 1983 The New Standard in High Performance Repeater Control... □ FRIENDLY. POWERFUL EASY TO USE - Human engineered to be your 'assistant'' at the repeater with capability second to none. □ REMOTELY CONFIGURABLE - Change command codes, mes¬ sages. tone characteristics, tim ing. and more, remotely! Reliable storage in E 2 PROM. Call or write for detailed specifications. Manual and demonstration cassette tapes available separately. □ Room to grow: BUILT IN! - Features intelligent remote con¬ trol and meter readback. Inter¬ faces to synthesized remote bases and links. Planned soft¬ ware upgrade path. □ SUPPORT -We invented the "Computer Controlled Talking Repeater." so we know how to provide the applications assis¬ tance. and long term support so crucial to a computer based product □ BRING YOUR REPEATER SYSTEM INTO THE 80‘S - Start¬ ing at less than $1200! The RC-850 Repeater Controller! advanced com pule' controls acc 10816 Northridge Square Cupertino. CA 95014 (408)253-8085 ^ 124 sence of any external bias current. When the coded 1050-Hz signal is received and passed through the 1050-Hz twin-T filter/ampli¬ fier (Q8), it is rectified and doubled via D3, D4, and EC4. The resulting dc is ap¬ plied to the base of Q9 through R22 as a trigger cur¬ rent. The multivibrator then oscillates. Diode D6 recti¬ fies the oscillator output and feeds it back to the in¬ put of Q9, thereby main¬ taining the alarm even after the initial trigger signal is re¬ moved. Depending on the desired mode of operation as an alert receiver, this may or may not be a desirable feature. This will be dis¬ cussed later. The two-tone-decoder de¬ sign is a relatively straight¬ forward adaptation of a standard NE567 design. Two decoders are connected in parallel and drive a pair of PNP trigger amps. In order to use as much of the exist¬ ing receiver as possible, it was decided to disconnect the collectors of the multivi¬ brator transistors from the supply rail and drive each of them from the tone decod¬ ers. In this way the oscillator cannot function unless both tones are present, thereby acting as an AND gate as well as an oscillator. The PNP trigger amps (Fig. 3) pro¬ vide the necessary inversion of the 567 output as well as a convenient node to add some time delay to the de¬ coding functions. (To pre¬ vent accidental triggering, a time delay was added to the decoding spec.) Referring to Fig. 3, the output of either 567 (pin 8) goes low when the correct tone is presented to its in¬ put. This in turn provides bi¬ as current for the base of the PNP (QA or QB), but not un¬ til CA1, B1 is first discharged (providing the time delay). The LEDs in the emitters of the PNPs necessitate that the base drop an additional two diode drops (in addition to VBE) before the PNP can turn on again for time delay See List ot Advertisers on page 114 purposes. (They also add the additional feature of illumi¬ nating for test purposes.) As mentioned above, when both PNPs are on, the multivibrator can oscillate. Note: Since the 1050-Hz fil- ter/amp is disconnected, a permanently enabling bias voltage is applied to multivi¬ brator transistor Q9 through RBI on the decoder board. Potentiometers RA2 and RB2 permit tuning the tone decoders for the desired fre¬ quency. Refer to Fig. 4 for the modified schematic showing points of connec¬ tion (and disconnection). Figs. 5 and 6 show the PC layout and an assembled board, respectively. Some final comments are in order. We decided not to depend on rf coupled through the power line for our input. A banana jack was mounted on the case and connected to the rf in¬ put through a small capaci¬ tor. An inexpensive !4-wave antenna was implemented using a piece of #10 elec¬ trical wire soldered into a banana plug. Also, for the needs of the Sharon, Massachusetts, Civ¬ il Defense group for whom this receiver was designed, the latching diode (D6) was disconnected. Our philoso¬ phy is that in time of civil emergency the intent of gen¬ erating an alarm is to alert available personnel. If with¬ in the vicinity of the receiv¬ er, they will respond by switching to the audio mode and following the broadcast instructions coming over the repeater. If they are not around or available, latch¬ ing the alarm will not serve any useful purpose. This is obviously a policy decision based on individual need. One of the obvious ad¬ vantages of this system is that any DTMF tone pair can be used. Using # or * has the advantage that they are not normally used tones in a repeater with a phone patch. If, however, it is felt that using known (and easily generated) tones can cause false alarms, then any pair can be used simply by de¬ signing simple multivibrator oscillators driving speakers and holding them against the microphone of a trans¬ mitter. Only authorized per¬ sonnel would be issued coders. The first prototype was built using perfboard and placed in continuous opera¬ tion in the spring of 1980. As of this writing it has never "falsed" yet and continues to respond when needed upon adequate application (several seconds) of the cod¬ ed tone pair. The unit is self- tested merely by unplugging and replugging the ac power by virtue of the momentary- charging current to the two time-delay capacitors, CA1 and CB1, applied through the base-emitter junction of the PNP drivers. That, by the way, is why the capacitors are connected to ground and not the supply rail, and why resistors RA3 and RB3 are required (to prevent burnout of the junctions). One final comment: A more secure three-tone sys¬ tem is possible with no fur¬ ther modification of the re¬ ceiver. Merely reconnect the 1050-Hz filter/amp (dis¬ connecting the bias resistor RBI) and now a simultane¬ ous three-tone signal (of which 1050 Hz is one) is necessary to trigger the alarm. Of course a proper three-tone generator would have to be designed. Other options are available if the filter frequency is altered from 1050 Hz. We believe this design achieved our initial objec¬ tive of providing a relatively inexpensive alert receiver wth minimal modifications and additions to an existing receiver. At the same time it did not require an elaborate code-generating device. It also does not require modifi¬ cations to or need the use of other 2-meter equipment.■ 73 Magazine • January, 1983 29 Charles Leo Suggs WB6FHD 1172 No. Ardmore 4ve. Hollywood CA 90029 Trimming the Fat from ATV Why use 3 MHz when 500 kHz will do? WB6FHD proposes a way. M y colleagues of the Southern California Amateur Television Club have been asking me to sub¬ mit an extended article to 73 Magazine since my brief presentation of this con¬ cept at our monthly club meeting, July, 1980, and its subsequent publication in our August newsletter My purpose in publishing this article is to stimulate those of my radio amateur col¬ leagues blest with true sci¬ entific creativity to develop this concept into a refined state-of-the-art system of global amateur radio televi¬ sion communication. The development of a practical narrowband sys¬ tem of real television, in the true sense of the word, is of tremendous importance at this time, because every time we turn around, this or the other big commercial interest wants to lobby the FCC to give them portions of our amateur bands for their own private use, even though other amateurs in other countries still contin¬ ue to use these same fre¬ quencies. My proposal not only will result in making it possible to transmit a pic¬ ture almost similar in qual¬ ity to a commercial tele- vison station, but will do it in only one-twelfth of the usual channel bandwidth normally required. It will do this as low as six meters if we get together and peti¬ tion the FCC with a propo¬ sal for experimental nar¬ rowband television privi¬ leges on the almost disused upper three-fourths of the band. Another reason I want the experimentation to be on six meters is that occa¬ sionally there are some pretty good band openings into other countries. I want to give thanks to Al Lipkin W3AEH, whose narrowband TV article in the 1964 ATV Experimenter Anthology (by 73 Magazine) inspired me to carry his idea through the next few logical steps to the present engi¬ neering conceptualization of the entire system, all the way from camera to TV re¬ ceiver. I sincerely hope that this article will start an ava¬ lanche of contributions by other engineers —as hap¬ pened with SSTV exactly twenty years ago My profession is elec¬ tronics-concepts design en¬ gineering, but I was caught in the aerospace layoffs of 1969 and have not been ac¬ tive in it since then This means I am not up on the newest devices and tech¬ nology, and accordingly will not submit any sche¬ matics The most interesting things about this proposal are that: • The entire channel, video and sound combined, can be fitted into a band¬ width of only 500 kHz. • The video and sound sig¬ nals are generated inde¬ pendently, each crystal- controlled, both just above 10 MHz. • Using simple SSB tech¬ niques (but no balanced modulator), the lower vesti¬ gial video sideband is com¬ pletely filtered out, like an SSB signal, while retaining the carrier (for the present, but some day ?). • The signal is now hetero¬ dyned from just above 10 MHz upward in frequency to the region between 51 and 54 MHz, where the maximum video modulat¬ ing frequency will be less than one percent of the fi¬ nal transmitting carrier fre¬ quency, as with good engi¬ neering practice. • The scanning standards will be: 225 lines per frame. 4:1 interlace, 15 frames per second, 60 fields per sec¬ ond, 56.25 lines per field The horizontal deflec¬ tion frequency will be 3,375 Hz, and the vertical deflec¬ tion frequency will be 60 Hz. The synchronizing puls¬ es for the TV camera are generated by solid-state fre¬ quency divider-compara¬ tors and a phase-locked loop The master frequency for the countdown (fre¬ quency-dividing) sequence will be 13,500 Hz To obtain the horizontal sync pulses, some of the master-frequency oscillator output goes to a divide-by- four device, output, 3,375 Hz. To obtain the vertical sync pulses, some of the master-frequency oscillator output (13,500 Hz) goes to a series of divide-by devices (see Fig. 1) resulting in an output of 60 Hz This sync generator will provide the camera's modified horizon¬ tal and vertical sweep oscil¬ lator/amplifiers with the complex sync necessary to scan a 225-line, 4:1 interlace raster on the camera's vidi- con image tube. If the usual practice of ATVers is to be the case, this system will work fine, as there will be no discern¬ ible flicker if the motion in the image is not excessively rapid. We ATVers who use vidicon TV cameras know better than to either pan the camera quickly or go sud¬ denly from a bright to a HORiZ SYNC VERT sync 60 Hr FROM OUTPUT TO OUTPUT TO POWER MAUtS TV CAMERA TV CAMERA INPUT TO l*C Fig. 1. The sync-generator countdown frequency-divider chain. 32 73 Magazine • January. 1983 dimly-illuminated scene, as we get smear in the image. The reduced horizontal scan rate will increase the vidicon's light sensitivity due to the photoelectric/ photon-charge-storage prin¬ ciple, so an ordinary table lamp should suffice to light up the shack You might ask, why use only 225 lines in the image? Commercial television uses 525 lines; wouldn't the pic¬ ture have less than half the sharpness, resolution, and detail of standard TV? Be¬ lieve it or not, unless you have a huge screen and are almost sitting on the set, you probably won't even notice the difference. Have you seen how sharp the pic¬ ture is on a 14" surveil¬ lance-camera monitor TV screen, or how crisp the de¬ tail is on your living room TV set when the kids are playing with the TV game? Those security systems and the TV games have one thing in common: The im¬ ages are non-interlaced, and provide an image of on¬ ly 262,5 lines on a security monitor or on any TV set I'm sure you're all won¬ dering by now how a TV set can receive both a 525-line and 262.5-line image! Did you know that when your TV set is not receiving a sig¬ nal, it is scanning only 262.5 lines on the screen? Wheth¬ er or not you're receiving a signal, an interlaced signal or a non-interlaced signal, the TV set's scan oscillators don't change frequency. The 2:1 interlace system used in commercial televi¬ sion allows twice the num¬ ber of scanning lines (and, therefore, vertical image de¬ tail) to be scanned by the TV camera than its scan-system oscillators, actually operat¬ ing at no difference in fre¬ quency, would normally scan. Whether the camera is scanning 262.5 lines or 525 lines, the maximum video frequency in the camera output is exactly the same. A 525-line non-interlaced picture would require a hor¬ izontal deflection frequen¬ cy of twice that used for an interlaced system, and the maximum video frequency also would be twice that of an interlaced system. As for the difference between the 262.5- line picture which was discussed earlier and a 225-line picture, the differ¬ ence amounts to only 37.5 lines —slightly noticeable, yes, but only if you had a 262.5- Jine picture being dis¬ played on another TV set of the same screen size along¬ side. In practice, a 14" screen is about the largest practi¬ cal size for a 225-line TV system, and at a viewing distance of eight feet, no line structure can be re¬ solved by the eye. The 4:1 interlace system outlined in this proposal consists of transmitting four coarse- scan fields, each consisting of 56.25 lines, in 1/15 of a second, to form a complete frame of 225 interlaced scanning lines. The requirements for de¬ signing a 4:1 interlace sys¬ tem are as follows: The master frequency must end in a zero, and each divider stage downward in frequen¬ cy must also end in a zero, ail the way down to the mains-power frequency. The vertical scanning fre¬ quency must be the same as and lock to the mains-pow¬ er frequency. The horizon¬ tal scanning frequency must be 1 /4th of the master frequency, and end in the whole number five. The to¬ tal number of lines compris¬ ing a frame, when divided by four, must end in the decimal .25 in the lines-per- field count. Only a very limited num¬ ber of different 4:1 inter¬ lace line-count systems which are mathematically possible are practical for a television system of this kind, and far fewer can be constructed to work, much less work reliably, if a rela¬ tively high frequency must be divided to a far lower frequency in just one de¬ vice. This is because of these three big problems to be solved: stability, obtain- ability, and cost The following is for a 225-1 ine-per-frame system with a 3X4 aspect ratio: The horizontal deflection frequency of 3,375 Hz is de¬ rived by multiplying the rate of frames per second (15) times the line count per frame (225). If the I ine-per- frame count is divided by four, we get the line-per- field count of 56.25, as four of these interleaved fields are scanned consecutive¬ ly to form one complete frame. The usable lines and portions thereof for the im¬ age with any line-count or aspect-ratio scan system are approximately and on the average only 5/6ths of the total lines scanned, due to loss of lines during verti¬ cal retrace time, vertical and horizontal overscan on the camera image tube, and other scanning efficiency factors. To calculate the maxi¬ mum video frequency which will be produced by a television system, we first consider the aspect ratio (the ratio of height to width). In America, we use an aspect ratio of three units high to four units wide, or 3X4. Converting the 225-lines per frame to picture elements (pixels), we have 225 pixels vertical¬ ly. As we have a 3X4 as¬ pect ratio, 225 pixels is therefore only 3/4ths of what must be the horizon¬ tal pixel count; it follows that the horizontal pixel count is 300. The total num¬ ber of pixels per frame, then, is 67,500, and multi¬ plied times 15 frames per second is 1,012,500. We must now divide this large number by 2, as at this point it must be un¬ derstood that the maxi¬ mum video frequency con¬ sists of alternate black and white squares on each scan¬ ning line, a black and white pair equaling one full cy¬ cle. When the video signal is closely examined, how¬ ever, it is found that on¬ ly the black (or only the white) squares count as the maximum measured video frequency. Therefore, 1,012,500 cycles divided by 2 is 506,250, and as we only have 5/6th efficiency, it fol¬ lows that the maximum vid¬ eo frequency is 421,875 Hz. For the sake of making things slightly easier, divide the product of total pixels times "rep-rate" by 2.4. (1,012,500 divided by 2.4 is 421,875.) Using the same system to calculate the maxium video frequency of a conventional commercial TV camera, 525 pixels X 700 pixels is 367, 500 pixels x 30 frames/second is 11,025,000 divided by 2 4 is 4,593,750 Hz In commercial practice, a filter limits the maxi¬ mum video frequency to 4,000,000 Hz. As this 225- line system is incompatible with commercial television standards, it must be point¬ ed out that commercial vacuum-tube TV camera and TV sets can be modi¬ fied easily to a 225-line sys¬ tem, and what's more, I'll tell you just how to do it, too! To begin with, the verti¬ cal deflection circuits in both TV cameras and TV sets aren't touched at all, as both systems are locked to 60 Hz. The TV camera con¬ version, first of all, must have the solid-state sync- generator board installed within, along with its power source. The horizontal- sweep circuitry will have to be modified from a fre¬ quency of 15,750 Hz to 3,375 Hz. If the vidicon won't fully scan horizontal¬ ly, either more energy is re¬ quired or the associated de¬ flection coil hasn't enough inductance to give a good reactive load at this much lower deflection frequency. Magazine • January, 1983 33 Fig. 2. The rf-generator video and audio-exciter chain . Instead of the high-imped¬ ance horizontal-sweep tube, a silicon PNP transis¬ tor may have to be used, as its output impedance is low, and at 3,375 Hz it will be 'looking into" a load which will be closer to a correct impedance match. The receiver conversion will be fun. The horizontal- oscillator/amplifier circuit will continue to provide the picture tube with high volt¬ age, but that's all. The afc circuit will be disconnected from both the horizontal oscillator and the horizon¬ tal-output transformer, and the horizontal deflection coils will be disconnected from the same transformer. A solid-state horizontal-os¬ cillator/amplifier circuit will be built using the latest state-of-the-art phase- locked-loop technology to "lock the sync" even under adverse conditions of heavy QRM. As with the TV camera, a silicon PNP transistor will likely be required to direct¬ ly drive the horizontal-de¬ flection coils. The metal case of the transistor will be grounded directly to the metal chassis of the TV set (and remember, the transis¬ tor's case is the collector) and the emitter will be con¬ nected to the sawtooth- scan side of the horizontal- deflection coils. The other end of the same coils will go to the plus side of the 34 73 Magazine • January, 1983 transistor's power supply. Since both the horizontal sweep frequency and the circuit impedances are now much lower than before, the diode damper normally required in the horizontal- output circuit should not be needed. Of course, the one in the high voltage power supply will naturally re¬ main, as it is part of the "bootstrap" power supply associated with the high- voltage circuit to the pic¬ ture tube. An electron-beam squelching circuit will have to be added to put a dc volt¬ age on the picture tube's electrode which blanks out the vertical retrace lines, because when no signal is being received to cause a fully 4:1 interlaced raster to appear on the screen, the free-running deflection cir¬ cuits in the modified TV re¬ ceiver will be scanning only 56.25 lines on the picture tube. This much-reduced scan of only one field will be intensely bright and will permanently damage the phosphorescent coating on the face of the picture tube with ugly brown horizontal streaks from which little or no useful light will come. Remember, 3,375-Hz hori¬ zontal-scan frequency di¬ vided by 60 Hz vertical- scan frequency equals 56.25 lines on the picture tube! Now, on to the signal cir- 10.925 MHz AUDIO CARRIER FREQUENCY Fig . 3 . The over-coupled, double-humped-response curve of the modified 10.7-MHz i-f transformer used in the out¬ put/filter circuit of the video-modulated rf amplifier. cuits. The TV set's tuner must have the swamping re¬ sistors removed to narrow down the band-pass to around 500 kHz. The chan¬ nel 2 coils will be our con¬ cern here, as the signal coils will be centered between 51 and 54 MHz, say, 52.5 MHz. The oscillator will be modi¬ fied to tune this range, but 23 MHz above. Why 23 MHz? Only the older TV sets had an i-f that low; all modern TV sets use 40-MHz i-f amplifiers! Well, first of all, the modern i-fs are twice as broad as we need, so they'll have to go— and be replaced with some Miller (or other) bifilar- wound 20-MHz i-f trans¬ formers, with best Q at around 23 MHz. All of the swamping resistors associ¬ ated with the former i-f transformers are to be re¬ moved, of course. All of the i-fs will be tuned to the same frequency, not only for best gain, but with three i-f stages —optimum band¬ width, too. At the output of the last i-f stage, the band¬ pass should be around 500 kHz at —3 dB. If it is desired to use an intercarrier sound-recovery system, it will operate on a frequency of 450 kHz, as this is the heterodyne differ¬ ence frequency between the picture and sound car¬ rier frequencies. 455 kHz i-f transformers will tune down here easily. The sound system is NBFM with plus and minus 5-kHz devia¬ tion. Another way to re¬ cover the sound is by using a low-band FM communica¬ tions receiver made to tune below 30 MHz to the region between 22 and 24 MHz. The local oscillator should be converted from crystal control to self-excited, with the tuning control on the front panel. An afc circuit should be added to prevent drifting off center frequen- cy. Now we get to the piece de resistance , the rf genera¬ tor. A block diagram is shown in Fig. 2. The video circuit will consist of a crys- tal-controlled oscillator driving a very low-powered amplifier with an output be¬ low 100 mW. This amplifier will be grid- or cathode- modulated by a video am¬ plifier/modulator, supplied with composite negative¬ going video and sync by the modified TV camera. The output of the video-modu¬ lated amplifier will pass through a lower vestigial video-sideband filter com¬ posed of a large 10,7- MHz FM i-f transformer with overcoupled primary and secondary windings; this is in order to slightly broaden the bandpass and form the characteristic double-humped response curve. Other components of the filter include a tunable 10.7-MHz series-T rejection trap, and a few crystals —in order to put a deep, wide notch just below the video¬ carrier frequency so that the lower vestigial video sideband will be complete¬ ly filtered out The video¬ carrier crystal oscillator will operate at a frequen¬ cy of 10.475 MHz. The au¬ dio-carrier crystal oscillator will operate at a frequen¬ cy of 10.925 MHz. These two frequencies are 450 kHz apart; both are sym- metrically on opposite sides of the 10.7-MHz center fre¬ quency of the i-f trans¬ former, and both, therefore, are the same number of dBs down on the transformers response curve. The FM audio signal's rf does not pass through the same i-f transformer used in the output/filter circuit of the video-modulated rf am¬ plifier, but it will pass through a similar transform¬ er in the output of the video rf/audio rf mixer The 10.925- MHz FM audio generator will have one crystal oscil¬ lator and one afc phase- locked loop self-excited os¬ cillator, both operating on the same frequency. The time constant of the afc/ phase-lock circuit will al¬ low for FM carrier devia¬ tion. Now comes the rest of the answer to the question I'm sure all of you are ask¬ ing by now, which is: Why does he keep harping on six meters? Doesn't he know that the FCC would never allow "that sort of thing/' and hasn't he heard about the "national band-appor¬ tionment plan"? Well, I'll tell you, at the risk of sounding like some sort of rebel. First of all, about FCC — how many of you can re¬ member back when we could do anything we want¬ ed to do on those ultra- shortwave bands? I do! As for this so-called national band-appointment plan, how many of you out there really agree wholehearted¬ ly with how two meters and now 220 have been and are being chopped up into neat little slices for all of those open and closed machines? Where are those "wide open spaces" we knew in the 40s and 50s where we had megacycles to burn? I know, I know —progress! OK, fine. Two things I know: A long time ago, I read somewhere that no one has a monopoly or right to any "personal" frequen¬ cy in the "ham bands" — and I've got a box full of crystals for six and two me¬ ters and I guess a lot of them must fall across re¬ peater-band edges and out¬ puts! 'Nuff said? I think so, too, so let's get back to business. By now, at least a few of you must be wanting to say, Hey! How can a country with a different mains- power frequency than ours send us a picture with a 50-Hz vertical-deflection frequency and some cocka- mamie horizontal frequen¬ cy and we receive it? That's easy! All you have to do is remember that your TV set doesn't care what it gets —just design enough latitude into your horizon¬ tal and vertical hold con¬ trols and their phase- locked-loop circuits, and you can reach out and hold on to the "man in the moon"! Next question: How about color? Thought you'd never ask! Let's get black and white off the ground first (!) but, since you won't get any sleep unless I tell you, here goes. Yes, of course, the present American or Euro¬ pean systems can be con¬ verted to work with my sys¬ tem. The TV receiver should have many adjustments (like a scope) so that any scan system, type, and po¬ larity of sync or modulation can be received. Incidental¬ ly, I've got another, even narrower-band system of real TV which I can tell you about. It would fit into an FM channel. Of course, it wouldn't have nearly the definition or quality of what I'm offering you here. However, I'll give you one more hint. It would be like slow scan, but real TV Cheerio! M WHEN YOU NEED JUST A LITTLE MORE AUDIO The RBTMK® model 2003 audio amplifier module produces 250 mW of low THD audio. This transformerless design has a low parts count and does not require a heatsink. The model 2003 features a dc-operated volume control. Output level is selected by changing a dc voltage with an on-board pot, remote pot or micro-computer D/A interface. ► Low-Z, ac-coupled output drives speaker or headphones. ► Dc-type volume control assures hum-free operation without using shielded cable to the volume control. ► No interstage transformers or heatsinks. ► Compatible with other f4STMK M modules, such as the model 2002 sound synthesizer. ► One evening assembly using 3.6 by 1.0 inch pc board and instructions supplied. Price: $9.45 Price includes; glass-epoxv. etched, plated, drilled pc board; instruction manual; postage in U.S.A (Ohio residents add 5% sales tax). Send §1.00 for illustrated MSTtt 4 K* product catalog and refund coupon. Prohah Electronics Incorporated 34fcj£0 LAKELAND BLVD EASTLAKE OH 440*14 (ELD *151-2110 STATE-OF-THE-ART The Saturn V is a deep fringe microwave receiver for homeowners that are outside of the service area of focal pay TV stations (i e.. HBO. Showtime) !f is normally used within line of s*gnt of a trans¬ mitting tower m a 50 mile range and is simply attached to your TV antenna mast. This unit is completely ready to install including all cable and mounting hardware. It is designed to be installed by tne homeowner We accept MasterCnarge & Visa 36 73 Magazine • January, 1983 The Forgetful Autodialer Puzzle Even Sherlock couldn't figure out how to make an autodialer that reprograms with no hardware changes. Elementary , says dear Bade. Howard F. Bade W7BBX 12002 Cheviot Drive Herndon VA 22070 Photo A. 40 73 Magazine • January, 1983 A mong some autodialer designs for 2-meter mobile autopatch use, a common limitation has been a lack of program¬ ming flexibility. 1 * 2 '- 5 Al¬ though it is much easier to design and implement a di- ode-logic or PROM scheme for storing phone numbers, changing or adding a tele¬ phone number can be quite inconvenient for hard-wired systems or PROM-based designs. In this design, pro¬ gramming is done directly from the tone-encoder keyboard and allows pro¬ gramming of up to eight phone numbers. Numbers which are not programmed can be dialed directly from the keyboard in the normal manner. The primary disadvan¬ tage of a RAM-based design is the requirement to con¬ tinuously power the RAM to overcome its volatility. However, when you consid¬ er that an ample power source is available at both places in which an autodial¬ er has a real application (your car and the shack), the disadvantage is more than offset by the ability to reprogram the memories very quickly and easily. Since the circuit described here has a total continuous current drain of only about 45 mA from a 12-15-volt source, it may be connect¬ ed directly to the car bat¬ tery without fear of running it down, since cars usually do not sit idle for weeks at a time. If complete discon¬ nection is necessary, each phone number can be re¬ programmed as quickly as the phone number can be manually dialed. The RAM used was care¬ fully selected after consid¬ ering all available CMOS and bipolar memories; the logic support circuitry was then designed to meet the needs of the RAM. The most important constraints were that the RAM have bi¬ directional input/output lines and that these lines be tri-state. These requirements were necessary in order to significantly reduce the cir¬ cuit complexity and cost while still permitting the keyboard to be used manu¬ ally without affecting the stored phone numbers. Of secondary importance, it was desired that the RAM be organized 8 bits wide to allow direct interface with the seven data lines of a 3X4 keyboard matrix. The RAM selected was the Texas Instruments TMS 4036 since it met all of these requirements. Description Fig. 1 shows the com¬ plete autodialer schematic; connections to the trans¬ ceiver are shown in Fig. 2. The autodialer memory holds up to eight numbers of up to seven digits each (* and # count as digits); there¬ fore, the number actually stored may be either a stan- dard 7-digit telephone number or an autopatch ac¬ cess code of from 1 to 7 digits in length. The total number of phone numbers in memory is a function of the RAM organization, in this case 64 X 8. With selec¬ tion of a different RAM, more or fewer telephone numbers could be stored. For example, if the RAM or¬ ganization were 128 X 8, six¬ teen phone numbers could be stored. Eight 8-bit words are required to completely store each 7-digit telephone number. Inclusion of D2 and D3 drops the voltage supplied to the RAM from +5.0 volts down to about +3.5 volts. This decreases the current required by the entire auto¬ dialer from 65 mA to about 40-45 mA. Reliable data re¬ tention is maintained with this RAM as long as the Vcc pin remains above +2.8 volts dc. In addition to direct pro¬ gramming from the encod¬ er keyboard, other features of the autodialer include a speed control to vary the rate of readout, an on¬ board audio amplifier to al¬ low you to hear the tones sent to the transceiver, a visual indication to aid in both programming and readout, and a minimum number of controls. The autodialer may also be used as a "standard" tone encoder to manually dial Fig. 7. Schematic diagram . phone numbers or access three RAM address lines To program the autodial- codes which are not pro- (AO, A1, and A2), and is used er, the phone number digits grammed directly into the to select the desired phone are keyed in on the tone en- memories. number location for either coder keyboard with the autodial readout or pro- PROGRAM push-button, Operation gramming. The selected S2, held down. This action Selection of one of the phone number will then be routes the U8b output pulse eight stored phone numbers available until a new one is produced by each key- is accomplished by depress- selected; neither manual board digit depression to ing the appropriate key- operation of the keyboard the clock input of the board digit (1-8) while hold- nor autodialing the stored counter, U10. When each ing down the SELECT push- phone number will alter the digit key is depressed, LED1 button, S3. This action selection of the phone will light for about half a latches the logic state of number. second; when it goes out, 73 Magazine • January, 1983 41 DRAKE TR-33C rS ^ TONES OUT TO SPEAKER that digit has been pro¬ grammed in and the next digit may be programmed If only four digits are to be programmed (as in an ac¬ cess code), they are keyed in in the same manner Then, after the last digit has been entered, tap the DIAL push-button, Si, while keeping the PROGRAM button down. This activates the clock and steps the ad¬ dress counter, U10, through the remaining memory ad¬ dresses for the selected phone number. Whatever information may have been stored previously in the lat¬ ter part of the 8-digit memo¬ ry segment is automatically erased The LED will light up while the clock cycles through the unused digits; when it goes out (or when all the digits have been en¬ tered into the memory), re¬ lease the PROGRAM push¬ button, and the memory is ready to be a u tod i a led To read out (autodial) a phone number, simply se¬ lect the phone number you want and press the DIAL push-button, SI. LED1 will light up during the autodial¬ ing sequence; when it goes out, the number has been completely autodialed, In the manual mode, the tri-state memory data lines are always in the high-im¬ pedance OFF state; the key¬ board activates the tone en¬ coder, U3, and the encoder tones are fed directly to the transmitter mike input Since the autodialer is al¬ ways ready to dial a phone number manually (except when programming or dur¬ ing autodial readout), a sep¬ arate manual/autodial _ PAD-8 r\ switch or other control is not necessary It should be noted that this design specifically omits an automatic push- to-talk (PTT) line activation feature. While this feature is very useful for a manual- only tone encoder or an autodialer having only a PROM-based scheme for storage of phone numbers, incorporation into a key¬ board-programmable auto¬ dialer based on a RAM de¬ sign is actually undesirable, in a ROM-based scheme, the manual keyboard is used only for dialing unpro¬ grammed numbers; how¬ ever, in a keyboard-pro¬ grammable RAM-based scheme such as this one, the keyboard serves two ad¬ ditional functions —selec¬ tion of the phone number to be autodialed and pro¬ gramming of the actual dig¬ its. This also eliminates pan¬ el clutter by making addi¬ tional controls unneces¬ sary Inclusion of the auto¬ matic PTT feature on a key¬ board-programmable auto¬ dialer would activate the transmitter when selecting or programming a phone number. This is undesirable and was avoided, allowing off-the-air phone number selection, programming, and autodial readout moni¬ toring. The microphone PTT switch is used in the normal manner to key the transceiver for both speak¬ ing and for autodialing. Construction A conscious effort was made to keep the overall size of the finished auto¬ dialer to the minimum nec¬ essary, so that installation in the car would not be ham¬ pered by a bulky cabinet. A large and expensive multi¬ deck rotary switch for phone number selection was elimi¬ nated from an earlier de¬ sign, as was an internal monitor speaker The final PC board design and layout now incorporates keyboard- selection of the phone num¬ bers and still retains the on¬ board audio amplifier to permit monitoring the en¬ coder tones in the speaker of your transceiver. The requirement for bulky panel controls in an earlier project 4 has been eliminated by incorporat¬ ing the panel control func¬ tions within the logic de¬ sign. The result is a very compact unit which retains all the necessary features. A standard LMB enclosure (CR-531) was chosen, based on its small size and neat appearance, and the PC board was laid out to con¬ form to it. The PC board itself mea- sures 2 V 2 " X 5 Vi * (6.35 cm XI3.34 cm), is of top- quality commercial-grade G-10/FR^ material, is dou¬ ble-sided with plated- through holes, and contains all of the components re¬ quired except the three panel push-buttons, the in¬ put/output jack, and the LED Connection to all pan¬ el controls is eased by pro¬ viding all required logic and power signals to a central location on the PC board; a ribbon cable can then be used to interconnect the PC board with the panel con¬ trols. All panel, signal, and panel-control lines are also available at the dual, 15-pin edge-connector fingers on the PC board (0.15673.% mm spacing). By laying out the PC board in this fashion, maximum flexibility is af¬ forded for selection of any convenient-sized cabinet or, if desired, the panel con¬ trols can be remoted entire¬ ly from the autodialer PC board through an edge con¬ nector r i op- D — 1 AT x Fig . 3. Connect/on as shown for Fig. 2 Power is derived from transceiver and transceiver speaker is used for monitor. 42 73 Magazine • January, 1983 f ig. 4. Autodialer power is derived directly from car battery; transceiver speaker is used for monitor . Installation and Adjustment Autodialer interconnec¬ tions to your 2-meter trans¬ ceiver include the -M 3.6- volt supply line, tone en¬ coder output, and the audio amplifier output; these should be shielded between the autodialer and trans¬ ceiver as shown in Fig 2 The TONE jack on the rear of my Drake TR-33C was re¬ placed with an audio DIN jack Although a six-pin jack was used (tor possible fu¬ ture access to other parts of the transceiver), only the three lines mentioned above plus ground are re¬ quired by the autodialer The supply line can be run to a + 13.6-volt source separate from the trans¬ ceiver, if desired, permit¬ ting use of a standard 2-wire shielded mike case be¬ tween the autodialer and transceiver. The autodialer tone-encoder output is ex¬ tended through a short piece of RG-174/U to the transceiver microphone jack; the coax shield need not be grounded at the mike-jack end The audio amplifier, U2, is connected directly to the transceiver speaker; normal transceiver audio is not affected and this arrangement eliminates the need for a separate speaker The wire to the speaker inside the trans¬ ceiver cabinet need not be shielded. The tone encoder output can be interfaced di¬ rectly with either low-im¬ pedance microphone in¬ puts (e g., TR-33C) or with high-impedance inputs (eg., the Heath HW-2036A). Only three adjustments are necessary for proper 44 73 Magazine • January, 191 operation of the autodialer. The speed is set by R12 to give a total autodial dura¬ tion of about one second for all seven digits. The tone encoder output level into the transceiver microphone input is adjustable by R7. If a deviation meter is avail¬ able, the tone-encoder out¬ put may be set to yield a de¬ viation of about 4 5 kHz when any keyboard digit is held down Alternatively, the level may be adjusted by ear with the help of another operator on the repeater to a point which gives re¬ liable autopatch access and dialing operation but which does not sound distorted (over deviated). The last ad¬ justment is to set the audio¬ amplifier output level to give a comfortable and un¬ distorted speaker volume under road conditions. R7 is the trimmer which does this. If the external audio monitor is not desired, R5, R6, C5, C6, and U2 can be eliminated altogether Final Notes The addition of the auto- dialer described here has made a great improvement in the ease and enjoyment of using the local auto¬ patch repeaters and has certainly decreased the risk of becoming a potential traffic statistic while trying to dial a phone number Further, the ability to rapid¬ ly and conveniently pro¬ gram or reprogram phone numbers in the memories is greatly appreciated, espe¬ cially when access codes are changed periodically In addition, performance of Fig. 5. Autodialer power is derived directly from car battery: car radio speaker is used for monitor. the autodialer has been ab¬ solutely flawless through¬ out three very cold winters and hot summers, and I'm looking forward to many more years of enjoyable re¬ peater autopatch use with this autodialer The printed-circuit board for this project and a 10-page illustrated step-by- step assembly manual are available from me for $10.00 postpaid in the US 111 be happy to answer questions about the auto¬ dialer, but please indude an SASE.B References 1. Crawford, John, “An Auto¬ matic Dialer for Deluxe Mobile,” 73, January, 1976. 2. Lloyd, Bob, “Mobile Autodial¬ er,“ 73, June, 1976. 3. McEwan, Don, “A No-Hands Telephone Dialer,” 73, January, 1977. 4. Batie, Howard, “A Program¬ mable Contest Keyer,” Ham Ra¬ dio, April, 1976. Parts List. PAD-8 Cl— 50-uF, 16-V tantalum C2—50-uF, 16-V tantalum C3—.01-uF, 16-V disc ceramic C4—.01-uF, 16-V disc ceramic C5—10-uF, 10-V tantalum C6—.001-uF, 16-V disc ceramic C7—2.2-uF, 10-V tantalum C8—.01-uF, 16-V disc ceramic C9—4.7-uF, 10-V tantalum CIO—,01-uF, 16-V disc ceramic Cl 1—.01-uF, 16-V disc ceramic C12—.001-uF, 16-V disc ceramic D1-D3—1N4001 Si rectifier J1 — MAS-4/MAB-4 (two) LED—MV5023 or equivalent Y1—1.000 MHz crystal LMB CR-531 cabinet Digitran KL-0054 keyboard 1C Sockets; 8 pin—2 14 pin—8 16 pin—4 20 pin-1 #4 Hardware; V* " bolts—4 V* * bolts—4 Nuts—16 Lockwashers—16 8* 12-conductor ribbon cable S1-S3—SPST mom, push-button (normally open) U1—LM340T5, UA7805, etc. (TO-220 case) U2— LM380 (8-pin) Do not substitute U3—MC1441QP Do not substitute U4—MC14528B, CD4528B, etc. U5—MCI401 IB, CD4011B, etc. R1—12 meg, Vi W U6—TMS 4036NL Do not substitute R2—1.8k, 'A W U7—MC14012B, CD4012B, etc. R3—2.2k, W U8—MC14528B, CD4528B, etc. R4, R5—10k, 'A W U9—MC14042B, CD4042B, etc. R6—25k PC trimmer U10—MC14024B, CD4024B, etc. R7-100k PC trimmer U11 —MC14081B, CD4081B, etc. R8, R9-680k, % W U12—MCI 4001B, CD4001B, etc. R10, R11—10k, 'A W U13—MCI 4001B, CD4001B, etc. R12—25k PC trimmer U14—MC14002B, CD4002B, etc. R13, R14—3.3k, 'A W U15—MCI401 IB, CD4011B, etc. R15—10k, 'A W U16—NE555V, LM555, etc. R16, R17—680k, 'A W Don Carmody W1FLP 42 Royal Crest Drive Nashua NH 03060 My Own Silver Mine For W1FLP, reclaiming silver from photographic fixer is cheap, easy , and profitable. King Midas should have had it so good. I recently purchased a brand spanking new Az- den 2m rig. As I was install¬ ing it in the mobile, I came to the realization that my total cost was $2.50—yes, that is correct—two dollars and fifty cents! No, it was not "hot!" I paid a local dealer full list price. Knowing that many brother hams are also ama¬ teur photographers, I thought they might have an interest in how to obtain 0-50mA Fig. 1. Typical electrolysis circuit 46 73 Magazine • January, IS goodies for the shack at a relatively low cost. The se¬ cret is in silver reclamation. Silver reclamation is gen¬ erally thought to require ex¬ pensive capital equipment and in large photo labs it does, but for the amateur, the equipment can be very simple. How simple is deter¬ mined by the amount of silver-saturated solution you have, how rapidly you obtain it, and how fast you want to reclaim it. The silver-saturated solu¬ tion referred to is the photo¬ graphic fixer in every dark¬ room. The process of fixing photographic film removes the unexposed silver crystals from the film. This silver remains in solution in the fixer. The more film pro¬ cessed, the more silver in solution. With the price of silver what it is, it doesn't take much math to find the "break-even" point at which investment in capital equipment is desirable. For hams, using their in¬ nate ability to scavenge junk boxes to produce working apparatus, there is an inexpensive, easy meth¬ od to reclaim impressive amounts of silver at very low cost. The method I use is elec¬ trolysis. Basically, it is accomplished by passing a current (dc) through the so¬ lution, thereby "plating" out the silver. Industrial concerns use large contain¬ ers with large currents and constant circulation of the solution. I will not get into the math required to determine the current and voltages; the important parameter is the current density required to reclaim 90% to 98% pure silver. The current den¬ sity needed is determined by the amount of silver in solution, the surface area of the electrodes, and the lev¬ el of circulation of the solu¬ tion. A typical electrolysis circuit is shown in Fig. 1. Any dc supply can be used; regulation is not re¬ quired. A simple half-wave rectifier without filtering will do fine. The simple system I use is a 1.5-V alkaline battery, a potentiometer, a 0-50 mA dc meter, a stainless steel rod, and a carbon rod. The 1 5-V battery and the pot can be replaced by any available power supply, with an increase in the cost of silver recovery. When a dc current is passed through the solu¬ tion, the silver is plated out onto the stainless steel rod. It is important to monitor this plating process until you arrive at the correct dc current (current density) for your individual setup. The plated silver should appear white to light cream-col¬ ored. If it appears dark cream to brown, the current density is too high. A darker color means that higher amounts of contaminants are being plated out. RTTY - 50 RTTY - 100 Basic Terminal Unit Expanded Version of the Popular RTTY - 50 • 60 mA Loop Keying • PLL Demod w/2 pole filter $7Q00 • AFSK Generator " ^ • AFSK • 4 Pole Filters • 850/170 • AGC (80db) • TTL& RS232 Call or write for FREE catalog with over • 60 mA Loop $4 0000 • Loop Supply 1 Q9 65 P.C. Boards & Kits . • Auto Start COMMUNICATIONS DESIGN INC. 1105 Lehr St — West Memphis. Arkansas 72301 (501) 735-4568 OIHMUNICA TIONS SERVICE SPECIALIST ^Vccl LOW RATES REPEATERS 45 DAY WARRANTY! MARS MODS A HAM RADIO STORE THAT SPECIALIZES IN SERVICE!!! We are in the business of providing top quality repairs on all types of amateur radio equipment. A complete line of parts is Kept on hand to provide you with an extremely fast turnaround. VOTUC COMMUNICATIONS CO. PHONE 146 B RIVER AYE. GUY (412)583-2131 MASONTOWN PA 15461 N2CJW GIANT HEAVY DUTY ALL PURPOSE TARPAULINS Before Midnight Jan. 23 VIKING Ind will send any of the above size tarpaulins to any reader of this publication who reads and responds to this test before midnight Jan 23. Each tarpaulin lot (#Z-18,PVC) is constructed of high density fabric (with virgin grade ingredients, sup¬ plied by Gulf Oil Co.. Dow Chemical Co,, and Union Oil Co.) with nylon reinforced rope hems, double lock stitched hems, electronic¬ ally welded seams. 100% water proof. #4 {Vi** dia ) metal grommets set on 3 ft centers with reinforced triangular comer patches and are recommended for all heavy duty use. all yachts and sailboats, and all bulk or pallet riding materials, and will be accompanied with a LIFETIME guarantee that it must per¬ form 100% or it will be replaced free. Add S7 handling & crating for each tarp ordered. Vik¬ ing Ind. pays all shipping. Should you wish to return your tarpaulins you may do so for a’ full refund. Any letter postmarked later than Jan 23, will be returned. LIMIT: Fifty (50) tarps per address, no exceptions. Send ap¬ propriate sum together with your name & ad¬ dress to Tarp Test Dept. #124DJ, Viking Ind., 6314 Santa Monica Blvd.. L.A., CA , 90038. or for fastest service from any part of the coun¬ try call collect, before midnight 7 days a week (213) 462 1914 f Ask exchange operator for) TARP TEST H124DJ, have credit card ready 26 x 40 S89 26x55 Si 15 30x60 $145 50 x 100 $390 60x120 $547 50 x 150 $562 12 x 16 $23 16x20 $32 20x20 $36 18x24 $38 18x32 $50 20x30 $50 Reduce the current The color changes can be seen in seconds, so if it has not been dark for more than a few minutes, no harm has been done. High current densities without circulation of the solution will result in lowered purity of the plated-out silver plus a chemical change in the fixer that will reduce the amount of silver you can reclaim When the silver has built up to a thickness of be¬ tween 1/8 inch to 1/4 inch, remove the stainless steel bar holding the silver, rinse it in warm water, and let it dry To remove the silver, spread out a plastic or paper sheet, strike the plating sharply with a screwdriver, and it will crack Simply chip off the plating until it is all re¬ moved Return the stainless steel bar to the silver mine and continue. Of course, this mine is not bottomless. The fixer solution will eventually be¬ come so low in silver con¬ tent that it must be re¬ placed with fresh solution. Fresh solution, in this case, means solution that has been used to process film and is no longer useful for fixing film because it is sat¬ urated with silver There are many methods to determine the useful plating life, i e., silver con¬ tent, of the fixer The easi¬ est but least accurate is the color of the solution When it turns the color of medium strength tea, replace it. The more accurate method is to use the Kodak Silver Esti¬ mating Test Papers, cat no 1965466 When dipped in the solution, this test paper will turn from its normal yellow to some shade of brown The darker the col¬ or, the higher the silver con tent remaining in solution There is a color comparison chart on the back of the Kodak folder I generally discard the fixer at a re¬ maining silver level of 1 gram/liter To set up this simple sil¬ ver mine, I used a carbon rod from a discarded D-cell battery, a 6-inch stainless steel rod, a 1-lb. plastic margarine container, and a battery, pot, and meter as previously described. With no agitation of the solution, I maintain a current of 5 mA I have been plating out approxi¬ mately 3 ounces troy of silver per month I am blessed with the availability of 12 gallons of fixer every 12 weeks that has a silver content of approximately 10 grams/liter The amount of silver you recover per li¬ ter will depend upon its starting silver content, i e , how much film has been processed through it and the average image content of the film The effect of the film im¬ age on silver content is that a very dark image has most of the silver left in the film Conversely, a light image has had most of the silver removed The Kodak test papers can be used to deter¬ mine this silver content and, barring the probable contamination of the fixer with other chemicals, can be used as a guide to the useful life of the fixer. The above method re¬ quires monitoring but twice daily and fixer replacement when required. If you have plenty of fixer and/or want a faster recovery rate, sim¬ ply provide a means of gen¬ tle agitation I have suc¬ cessfully used an old clock motor with a plastic shaft with a V 2 -inch by 2-inch paddle connected to the sweep second-hand shaft immersed in the fixer This has yielded about an ounce a week Larger electrodes, higher currents, greater agitation, and larger solu¬ tion containers will of course increase the recov¬ ery rate. So why throw good mon¬ ey down the drain? Dig into that silver mine and buy some more ham gear.B **See List of Advertisers on page 114 73 Magazine • January, 1983 47 Fun-Equipment Revisited Here are higher-band versions of the ever-popular Fun-Mitter and Fun-Amp. They are based on the Fun-Philosophy: cheap and simple. Mtirk Oman WAlQRBR 5 28 Demes Court ft Cottim CO mm H ome-brewing is alive and well! I reached this conclusion following the response to the publica¬ tion of my series of “Fun’' home-brew gear. 14 Re¬ sponse to the simple, low- cost home-brew units has been great, indicating that hams are still building at least some of their own gear. From nearly-Novices to long-time Extras, hams have built the Fun rigs and have discovered that build¬ ing is easy, fun, and very rewarding. Many requests have been received asking for differ¬ ent band coverage of the Fun-Mitter and its compan¬ ions, This article is the re¬ sult of those requests. It describes a simple CW transmitter for 15 or 20 me¬ ters operating off 24 volts and modification of the 20-Watt Fun-Amp for opera¬ tion on the same bands. The Fun-Ceiver and Fun Oscillator are not included in this article on modifica¬ tions due to instability problems at higher frequen¬ cies Frequency stability is of prime importance with today's rigs and it is just too difficult to obtain the type of results desired on the higher frequencies and still maintain the objectives of the gear This second version of the Fun-Mitter is a five- Watt-output, crystal-con- trolled CW transmitter that uses either low-cost FT243 crystals at one-third the operating frequency or HC6U fundamental crystals on the operating frequency, If the variable crystal oscil lator (vxo) capacitor is in¬ stalled (C option), the fre¬ quency can be varied by as much as 10 kHz from the crystal frequency, using FIC6U crystals This coverage allows enough flexibility to provide plenty of frequencies with only a few crystals. Crystals are cheap, easy to obtain, re¬ liable, and very stable. They make simple transmitters easy for all of us to build! Philosophy An early objective with the Fun-Mitter and Fun-Amp was to design simple gear that was easy to build with parts that could be obtained from Radio Shack The Mark 11 versions of these rigs fol¬ low the same objective w ith only the crystal and its sock¬ et not being found at Radio Shack Other objectives: costs of less than $25 each, no tuning adjustments, and same size PC boards (2 Va " x 3 "). These objectives are con¬ tinued in the higher-band versions. A twenty-meter transmitter and amplifier can easily be built in an af¬ ternoon and put on the air J3 Fig . 1, Schematic of J 5/20-meter Fun-Mitter. Reference designators remain the same as in the original Fun-Mitter article in order to match the parts locator for the PC hoard. Capacitance values less than 1 are in uF. 48 73 Magazine • January, 1983 without adjustments. (The reader is strongly urged to review the articles on the Fun-Mitter and Fun-Amp for detailed construction and design descriptions.) Circuit The circuits remain un¬ changed from the original designs. The resonant circuit and filter values, however, must be changed to allow operation on the higher fre¬ quencies. Radio Shack rf chokes and disc ceramic ca¬ pacitors again were used The Fun-Mitter schematic is reproduced in Fig 1 The Pierce oscillator operates on the operating frequency us¬ ing either third overtone or fundamental crystals. (A third overtone is simply three times the value marked on the crystal.) For example, to operate the transmitter on 14 060 MHz, either a 14 060-MHz funda¬ mental crystal can be used or a 4 383-MHz crystal can be operated on its third overtone (This allows the use of cheaper FT243 crys¬ tals in the Fun-Mitter) Also, on fifteen meters many of the same crystals used for forty meters, when operat¬ ing on their third overtone, will provide the frequency coverage desired Fundamental mode crys¬ tals in an HC6U holder do, however, have the advan¬ tage of more frequency range when used with the vxo capacitor (C option) 1 have had several HC6U crys¬ tals, however, that do not provide a stable, clean oscil- ♦ 24V Fig. 2. Schematic of 15/20-meter Fun-Amp. I at or signal, probably due to the higher-than-normal pow¬ er used in the Fun-Mitter oscillator stage Although the FT243 will have a range of only approximately 1 kFIz with the vxo, it will provide better and more reliable operation (FT243 4 3- or 7-MHz crystals for use on twenty or fifteen third over¬ tone will not oscillate on ex¬ actly three times the marked frequency Depending on the crystal, they may be as much as 10 kFIz lower than the marked frequency Keep this in mind when ordering.) LI and C3 determine the resonant frequency of the oscillator If LI is construct¬ ed correctly, the oscillator should oscillate with no ad¬ justments A three-turn winding (L2) over LI oper¬ ates as a transformer to match the collector imped¬ ance of Q1 to the base im¬ pedance of Q2, Q3 and pro¬ vide drive. Q2 and Q3 oper¬ ate in parallel as a class C amplifier which provides good efficiency. These 2N3866 transistors, Q2 and Q3, are being pushed to their limits in the Photo A Front view of twenty-meter version of Fun-Mitter/ Fun-Amp. Fun-Mitter circuit Under some load conditions, some hams have discovered that Q2 and Q3 can be de¬ stroyed To avoid this, either reduce the supply voltage to 20 to 22 volts or increase the value of R5 and R6 to 4 to 5 Ohms Also, the 2N3866 part can be replaced with the much more rugged 2N3553. The only other components needing change are C4, C5, and L4 which, together, comprise a pi-network filter Component values are given in the Parts Lists. The Fun-Amp schematic is reproduced in Fig 2 Using the Fun-Amp on other fre¬ quencies is even easier than using the Fun-Mitter on other frequencies Only L2, L3, and C3 need to be modi¬ fied The input circuit re¬ mains c o m p I e t e I y u n Parts Lists Fun-Mitter— fib. 1 Fun-Amp— Fig. 2 C1-C10 Ceramic disc 272-xxx C1-C5 Ceramic disc 272-xxx C3 20m—47 pF Cl 570 pF (470 and 100 in par.) 15m—47 pF C3 20m—250 pF (2 47 pF in C4.C5 20m—220 pF series, 1 220 in parallel) 15m—160 pF (2 220 in se- 15m—160 pF (2 220 pF in ries, 1 47 in parallel) series, 1 47 pF in parallel) C option Broadcast variable (any C6 10/iF, 35 Vdc 272-1013 small variable with maxi* CR1 1N914 small signal 276-1122 mum capacitance of 100 to silicon 300 pF will work) LI 10 h H 273-101 J3 Phono jack 274-386 L2 20m—26 turns removed 273-101 J4 Phone jack 274-252 15m—28 turns removed 273-101 LI 20m—20 turns removed 273-101 L3 20m—24 turns removed 273-101 15m—24 turns removed 273-101 15m—26 turns removed 273-101 L2 3 turns wound over Q1 end Q1-Q3 VN67AF VMOS FET 276-2071 of LI R1,R3 150Q, y* W 271-013 L3 10 mH 273-101 R2 33Q, y 2 W 271-007 L4 20m—25 turns removed 273-101 R4 47Q, y 2 w 271-009 15m—27 turns removed 273-101 R5 47kQ, Va W 271-1342 Q1 RS-2009 276-2009 S2 DPDT toggle 275-1546 Q2 ( Q3 RS-2038 276-2038 TO-220 heat sink (3) 276-1363 R1-R4 V* Watt 271-lxxx Case 270-252 R5, R6 Each is three 10 Q, V? W Hardware 64-3012 271-001 in parallel 64-3019 SI DPDT toggle 275-1546 Wire Y1 Crystal—FT243, HC6U Coax 73 Magazine • January, 1983 49 TO *24V Photo B . /ns/de view of twenty meter version of Fun- M liter/ Fun-Amp. The coil shown connected between the crystal and C (optional) does not exist in the final version of the Fun-Mitter, changed This circuit oper¬ ates very well at 15 and 20 meters due to the excellent frequency characteristics of Q1-Q3. A detailed circuit de¬ scription is given in the Fun Amp article. Two additions have been made to the higher frequen¬ cy versions of the transmit¬ ter and amp. Fig. 3 shows a half-wave harmonic filter which reduces harmonic ra¬ diation. Also, a 10-pF capaci¬ tor (272-1013) has been add ed at the key jack ()4) to shape the keyed waveform and eliminate any key clicks. Construction Even though the Fun-Amp and Fun-Mitter are "goof proof" projects, care and thought must be put into their construction Although the fifteen- and twenty-me¬ ter versions are as simple as the earlier models, it might be helpful to review some pitfalls to watch for For best results, use of a PC board is strongly recom¬ mended. * Refer to the earli¬ er articles for the patterns and component locators The 2 Vi ” by 3* format shown in Photo B is small enough to allow mounting flexibility I would suggest that this format be followed Combining several bands, amplifier, transmitter, etc., on one board can lead to 50 73 Magazine • January, 1983 problems, particularly if you are inexperienced in home¬ brew Before building, develop a plan as to how you will load the boards, assemble the unit, and test. After the plan is developed, proceed carefully Most problems are due to misloaded parts, poorly soldered connec¬ tions (rosin-core solder is a must!), faulty components, and hasty build-and-test. Most of these problems can be avoided by developing a plan and carefully and thoughtfully following it Radio Shack rf chokes are used as inductors by remov¬ ing turns as necessary Fif¬ teen- and twenty-meter cir¬ cuits require less inductance and, therefore, the coils will have fewer turns. In con structing the coils, be sure that the exact number of turns is removed and that in¬ sulation is scraped from the end of the wire that will be resoldered to the coil form The three-turn Fun-Mitter coil (L2) that is wound over LI should be wound in the same direction as the turns of 11 Also, wind it over the end of LI that is mounted nearest Q1 The excess wire cut off when the turns are re¬ moved is excellent for wir¬ ing 12 Refer to Photo B for a view of the coils. It is best to construct a Fig. 3. Fla If-wave filter for 15/20-meter Fun-Mitter/Fun- Amp. The filter reduces any harmonic radiation to be¬ low acceptable levels. It is wired using point-to-point wiring between the antenna connector and S i. The filter provides receiver filtering by placing it before the re¬ ceiver antenna connector. Values are as follows: use 273-101 10 uH rf choke with turns removed; 272-xxx series ceramic caps. 20m 15m Ca 2 20 150(100 & 47 in parallel) Cb 440 (2 220 m parallel) 320 (100 & 220 in parallel) Cc 220 150(100 & 47 in parallel) La 2b turns removed 28 turns removed Lb 26 turns removed 28 turns removed single band in one box rath er than combining bands. This is slightly more costly due to duplication of some parts, but it eliminates switching problems com¬ pletely An advantageous modifi¬ cation to the Fun-Mitter is to allow a "spotting" function This is helpful when finding your frequency on your re¬ ceiver without transmitting on the air This is accom¬ plished by continuously ap¬ plying 24 V to the oscillator stage To do this, break the connection between LI and L3, then connect LI directly to 24 V Also, one end of R1 is removed from the circuit board and a wire from it run to the 24-V side of LI With this modification, pressing the key will produce a note in the receiver w'ith the send/receive switch set to re¬ ceive. See Fig 4 for details of the modification Crystals can be obtained very easily After deciding on either FT243 third over¬ Fig. 4. Modification to allow "spotting " of transmitter (use when using PC pattern from the February , 1981, 73) tone or HC6U fundamental, both crystals and sockets can be ordered from a sup plter such as ( W Crystals or jan Crystals. 6 Adjustment Adjusting the high-fre¬ quency Fun-Mitter and Fun Amp is just as easy as w ith the low-band versions Again by thinking carefully through the process, the rig can be set up without prob¬ lems in a short time If possible, find a VOM to use at this stage Although not absolutely necessary, it is much more helpful and educational to see what is happening during tune-up Begin by ensuring that you do indeed have a 24-V source (either lantern bat¬ teries or the Fun-Mitter pow¬ er supply). Measure the volt¬ age. With +24 V discon¬ nected, measure the resis¬ tance at the voltage-input connector to ensure that no shorts exist to ground (use Ohms scale) It is essential that a dum¬ my load be connected to the antenna connector at all times during tune-up For the Fun-Mitter/Fun-Amp combination, a dummy load capable of dissipating 20 Watts will be needed With out a load, the transistors will be destroyed quickly The final step in tune-up is to attach an ammeter and begin testing! Connect an ammeter capable of mea¬ suring at least 1.5 Amps in series in the +24 line going to the gear Set the T/R switch (Si) to transmit With the Fun-Amp switched out, the meter should read around 300 mA with the key pressed. Switching the Fun- Amp in should produce a reading of around 12 Amps with the key clown, indicat¬ ing a power input of around 30 Watts. As can be seen, there are no adjustments to be made This is one of the beauties of the gear After building the units carefully, they should work the first time with no adjustments! If trouble is encountered, check the following 1 Isolate the problem to a stage —Fun-Mitter, Fun- Amp; if Fun-Mitter, does os* cilia tor work? 2 Measure voltages at collectors and drams of transistors with T/R switch in T position (should read 24 V). 3 Check for wiring errors 4. Check soldering Operating The thrill of home-brew construction comes in the actual operation Making contacts with gear you built yourself is fun! The high-fre¬ quency Fun-Mitter and Fun- Amp easily will produce worldwide contacts. Twenty Watts on 15 or 20 meters can bring in contacts from all continents easily. With the capability of 15- through 80-meter operation with the Fun gear, WAS, WAG, and DXCC are all within reach Good luck!B References 1 ‘The Fun-Mitter—A Goof- Proof Rf Project/* 73 , February, 1981. 2. ‘The Fun-Ceiver," 73, July, 1981. 3. ‘The Fun-Oscillator/' 73, February, 1982. 4. ’The Fun-Amp/’ 73, May, 1982. 5. PC boards may be obtained from the author for $7.00 ppd. each. (For both originals and modified.) 6. CW Crystals, 570 N. Buffalo St., Marshfield MO 65106; Jan Crystals, 2400 Crystal Drive, Ft. Myers FL 33906. 1900 - 2500 MHZ KITS ARTE HR A KIT $19.95 1 PC. BOA AD PRE-DRILLEDAHD SOLDER FLOWED 3 MRf901 TRAHS 2 HR DIODES 6 CHIP CAPS *LADCE $ RESISTORS 9 PREP41RED COILS, FACTOR yWOVHD 33 WASHERS 32 SPAURS 1 3 TOOT ROD 2 RUTS 1 D*PM PIPE 2 4%EHDCAPS t MOUHTfHC BAR 1 m r CORRECTOR 1 HUT AH D DOLT Itt tt ttt _ It* Htt 0t. -#» * mm t tar am eta aar it taata tat aatatrr mtaaart POWER SUPPLY KIT $1095 1 P C. BOARD 1 POWER TRAHSE. 1 3171 ADJUSTABLE PECULATOR 1 TIRE TUHiHG POT WITH SWITCH 1 COARSE TUHm POT. 2 KH0DS 3 'f* CORRECTORS 9 POWER DIODES I Rf CHOKE 3 RESISTORS 3 DISK CAPS 1 1000 MED CAP. 1 DPDTMtm T0CSLE SWITCH j 1 LED WITH HOLDER J MAIL ORDERS ADO $5,00 FOR SHIPPING AND HAN DUNG. TRIONYX IND. INC. INDIANA RESIDENTS ADD 4% SALES TAX. 6219 COFFMAN RD. INDIANAPOLIS* IND. 46268 ^104 (317) 291-7280 (317) 291-2995 TUSA a wmou hew would of rv viewing with tussa ‘8 . . NEW WO DEL CVV- 40 , *0 CHANNEL CABLE TV CONVERTER now s 28.95« Tn« lyitam allows you to fuogtam (tout pay uwry TV it„< • * Cabte Lflitnruytn lot taping on any VCR --- wild* you watching a dilloiwni channel on you, TV Simple to install and ope late ■>. any maLu ol IV with UHL NOW AVAILABLE NEW TUNEABLE DELUX MODEL CVU1000 Wl REGARD 75 OHM UHF TAG! 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G ANAHEIM, CALIFORNIA 3?3Q6 MAIL ORDERS WELCOME PLEASE INCLUDE POSTAGE SHIPPED SAME DAT RECEIVED NO MINIMUM C HIGH PERFORMANCE PRESELECTOR-PREAMP The solution to most interference, intermod, and desense problems in AMATEUR and COMMERCIAL systems. • 40 to 1000 Mhz - tuned to your frequency ® • 5 large helical resonators ■L — — j Bm • Low noise - High overload resistance " j nnr" 1 1 ^ ^ 9 din ultimate rejection> 80 dB • FANTASTIC REJECTION! Typical rejection: Price - $69 95 bipolar w/RCA jacks ±600 Khz@144 Mhz: — 28dB Connector options: BMC $5, UHF $6, ±1.6Mhz#220 Mhz: -40dB N $10 ±5 Khz@450 Mhz -50dB SUPER HOT! GaAs Fet option $20 AUTOMATIC IDENTIFIERS • For TransLetvers and repeaters AMATEUR and COMMERCIAL • Automatic opera!ton • adjusiaWe s peed and amplitude • Small %m - easy mstaltaticm • 7 to 15 volts DC • 8 setectaPie. reprogrammable messages - each up to 2 rmn tong • Wired, tested and programmed with your message!sI Model 10-1 - $39 95 Model m ? w/1 to TO msnute timer - $59 §5 We otter a complete line ol transmitter and receiver smps and synthesizers tor amateur and commercial use. Request our tree catalog Allow $2 tm UPS stuppmg - Mastercard and VISA welcome GIB ELECTRONICS 1952 Clinton St. Buffalo, NY 14206 716-824-7936. 9 to 4 See Ltst of Adverfrsers on page f U 73 Magazine • January, 1983 51 Frank R. Fortune N6BW 2351 Nina Street Pasadena CA 91107 The Ultimate Breadboard There used to be two styles of prototypes —rat's nest and cramped. Now there is a third style—simple. T here are at least a doz¬ en different boards on the market intended for prototyping and one-of-a- kind construction projects. Most that I have used in my ham activities, in the class¬ es at Los Angeles Access, and professionally have either been lacking in flexi¬ bility and ease of construc¬ tion or are difficult to cir¬ cuit trace. Of the commonly-avail- able types, the wire-wrap board, for example, is ex¬ tremely difficult to circuit trace, especially when the component density reaches a certain point. This is com¬ plicated by the fact that components must be placed in 1C header plugs. The widely-used perf- board-type with general- purpose foil pads is much too cramped, lacks definite locations for ICs, is too dif¬ ficult to circuit trace, and is prone to solder bridges. The third common type, consisting of many small squares, works reasonably well for small projects. However, it becomes en¬ tirely too large for bigger Forming a short jumper from bare wire using a small round tool and the end of your finger. 52 73 Magazine • January, 1983 circuits. It also lacks defi¬ nite locations for compo¬ nents, especially ICs. The board shown here solves many of the prob¬ lems by combining a num¬ ber of the good features of all systems into one, all contained on a standard 4 V 2 " X 6 V 2 " 22-pin edge- connect card. The connec¬ tor may be cut off easily if it is not used. The basic features of the board are sixteen 16-pin DIP patterns for small ICs and one 40-pin pattern for larger ICs such as micropro¬ cessors, UARTs, etc. Alter¬ nately, the larger pattern will accommodate two ad¬ ditional 16-pin ICs. Two continuous power rails run throughout the board and are available on both sides of all 1C patterns. There is also a set of pads and a foil area for a 3-termi- nal tab-type regulator. On the opposite end from the edge connector are a num¬ ber of small pads for switches or indicator LEDs. Locating Components Components may be mounted on either side of the board. In some cases, #60 holes will have to be drilled in the plain pads for this. For experimenting, however, all components including the ICs are best placed on the foil side. This leaves the entire circuit in view without turning the board over. In this way, the circuit is much easier to visualize. For more permanent proj¬ ects, some of the larger components and the ICs are best placed on the non-foil side. Buses of many wires are also better on the back to keep them out of the way during testing and re¬ pair. Resistors, small capac¬ itors, and most intercon¬ necting wires should be on the foil side. A component properly formed and soldered to the board. Attaching Components The biggest mistake most first-time users of the board make is looping compo¬ nents too high Keep every¬ thing as tight against the board as possible All com¬ ponents should be pre¬ formed, with leads kept as short as possible After sol¬ dering, give the component or wire a gentle bend back and forth to relieve lead stress This is important, es¬ pecially when connecting another component to the same spot, as it will prevent the first component from moving when the solder is remelted Do not connect compo¬ nents in midair. Even if you have to tie one end of a component to an unused pad and complete the con¬ nection with a piece of wire, the final result will be much neater and less likely to be damaged by subse¬ quent handling By the same token, it is wise to use the same technique to avoid crossing components over ICs. If you have to replace the 1C at a later date, it will be much easier if you do not have to re¬ move other components. For long interconnec¬ tions, use insulated wire. For close or adjacent pads, bare tinned wire is best. To jump over a pad or rail, form the bare wire as you install it. Using a long piece, solder one end first After the solder hardens, bend the long end up at about a 45° angle Next place a small round tool, like a common nail, on the pad to be jumpered. It will be easy, then, to bend the wire down over the nail into contact with the pad to which it is to be soldered. Clip the end with small diagonal cutters and then solder. I recommend wire-wrap wire for use on the board It is available in inexpensive small rolls at most electron¬ ic parts stores It has solid conductor and heat-proof insulation. Stranded wire or wire with ordinary PVC plastic insulation is very hard to work with. You also may need to buy a little stripping tool—ordinary strippers often work poorly on wire-wrap wire. Plan Your Work It is quite a temptation, because of the ease of con¬ struction using the board, to simply grab components, wire, and solder and to be¬ gin building without plan¬ ning. Even if you are doing original design work, give the layout of the board some preliminary thought I find it invaluable to literally draw out the project in pen¬ cil. The main benefit is in re¬ ducing the number of " a c ro s s -t he -bo a r d " w i re s It s not possible to elimi¬ nate them all, but a little planning reduces the num¬ ber and makes the final board much neater and eas¬ ier to repair in the future. Conclusion For original design work, for student use, and for pro¬ ducing permanent repeater control systems, the board has become very popular in my local group Personally, I like it best for ^one-of-a- kind" projects that appear in ham magazines. Many ar¬ ticles do not contain board layouts. The board has pro¬ vided a very satisfactory and quick means to build such projects It also great¬ ly facilitates modification of published circuits to one's own needs in a form that is genuinely permanent The prototype board is available commercially from WhELECTRONICS, PO Box 5515, Pasadena CA 91107, for $6.95 (California residents add 6% sales tax). For home construction, a photographic negative is available for $4.95, The board is made of C-10 glass epoxy, drilled, and rosin- coated ■ rmsrmvrfim l rmwmvrmsl! 54 73 Magazine • January, 1983 Fig . h The better prototyping board. Beating the Untraceable Buzz Man-made interference doesn't have to destroy reception. Not when you use WIGV's buzz-beating antennas. GAP (i INCH) •—TUBING m (*J • 1 i TO RECEIVER Fig . 1. Two versions of the shielded loop . (a) A single-turn version may be constructed using tubing and heavy wire or by using coaxial cable. The value of C will have to be deter¬ mined by experimentation, although a 365-pF receiving- type variable usually will suffice, (b) A multi-turn loop is shown l Circumference of the loop should be about 0.75 wavelength in either case , although it may be considerably less if a preamplifier is used. See text 56 73 Magazine • January, 1983 Stan Gibilisco W1GV/4 PO Box 561652 Miami FL 33156 Y ou've just moved into a new apartment or a new house for rent and the landlord has given his okay to your putting up a four- band trap vertical on the roof. (Miracles do happen!) So you blithely install your new station console, trying to improve the layout still further over what you had Frequency Circumference MHz Feet Meters 1.8 78 (24) 3.5 40 (12) 7 20 (6.1) 10 14 (4.3) 14 10 (3.1) 18 8 (2-4) 21 7 (2.0) 24 6 0-8) 28 5 (1-5) Table 7. Circumference of a shielded loop for various frequencies. These c/rcum~ ferences represent 0.15 wavelength for the indicat¬ ed bands. If a preamplifier is used , the loop may be used at frequencies below that where it is 0.75 wavelength. the last time; you painstak¬ ingly solder every PL-259 onto the interconnecting cables You ground your equipment with a bus bar of 1/4-inch copper tubing run¬ ning to a cold-water pipe only three feet away You install 20 radials on the roof for each band (80 in all, and with the best stranded No. 16 wire). Finally, everything is ready to go. You turn on the receiver A solid installation, this, you proudly think to your¬ self. Not a DX killer, to be sure, but it's well built and there should be plenty of good hamming ahead. The S-meter reads a steady S9 + 20. You turn up the volume: ZZZZZZ! Up and down the band you tune. The noise limiter does no good; the pulses must be too broad ZZZZZZ! So much for 20 meters. Switch to 40 Peak up the preselector ZZZZZZ! S9 + 30. Damn Switch to 15 Peak it up. ZZZZZZ! Only S9. Oh, great! Why even try 10? Why make yourself de¬ pressed needlessly? The Search Begins The next step, of course, is to switch off everything LOOP SHIELD Fig. 2. A method of azimuth/elevation mounting that allows the shielded loop to be pointed towards the focal direction of a noise source. This kind of mount is practical only up to a certain size —about an 8-foot-diameter loop. The loop shield should be constructed from copper tubing if this kind of mounting is used. in the place except the rig. Thwack! Thwack! Thwack! One circuit breaker after another And from the shack, several rooms away, you can hear the receiver with the volume up to 3:00: ZZZZZZZ —it stops! Your heart leaps Whoops, that was the shack Thwack! ZZZZZZZ The XYL shouts, "Will you turn that thing down and stop fussing with the lights? I'm trying to watch TV and iron!" All your clocks were set to WWV from your watch, which you had to set at a friend's QTH because you can't even hear WWV at yours. Now all the clocks are out of whack since you played with the breakers. You run all over the yard, using a little, plastic 6-transistor AM radio your Aunt Jenny gave you for Christmas back in '65 and you've hardly used for any¬ thing until now. Some places the noise is louder, some places softer. But there is no logical pattern. It's everywhere, but it's cen¬ tered nowhere. You try to DF (direction find) using the ferrite loop- stick in the little radio. There is a sharp null in the direction of either the elm tree out front, or else 180 degrees opposite, from somewhere under the drive¬ way. Move into the back¬ yard It's either coming from the rising full moon or else from the base of the swing set. No power transformers of any consequence in the area The noise is constant, around the clock. You get up at 5:00 am: ZZZZZZ! You come home for lunch (actually, instead of lunch). ZZZZZZ! Your stomach growls. You'll never get rid of it. You Could Search More Oh, yes, eventually, if you search long and hard enough, you'll find it. Maybe it's an electric blanket in a neighbor's house But, then, who uses an electric blanket for 24 hours out of every day? A refrigerator? Maybe, but they don't run continuous¬ ly, unless unless there is not enough of that coolant stuff in them. Hmmm. It's not a street lamp starter, since it happens during the day. A fluores¬ cent lamp starter, maybe? Well, who leaves a fluores¬ cent lamp on for 24 hours a day? You might snoop around the neighborhood at 4:00 am or so and see if anybody has any fluores- cents on But, no, you might get arrested or mugged or something. Maybe it's a thermostat mechanism. God help you What Can You Do? Although I've made light of all this, it's not exactly funny when it happens. And sometimes you just will not, by any reasonable means, be able to locate and/or eliminate a source of man¬ made noise. If it's some¬ body's refrigerator without coolant, maybe it will burn up some day. A noisy fluo¬ rescent light starter will eventually fail and have to be replaced. Lot of good that does you now. The situation is not hope¬ less, though Noise has dif¬ ferent characteristics than signals There are ways of getting your antenna sys¬ tem to favor those single- frequency signals that you want to hear, while discour¬ aging that wide-band hash that you can't stand to hear. There are basically three methods of doing this. You can use them in combina¬ tion if necessary. They will almost always provide sig¬ nificant improvement. These methods are: 1) Shielded-loop antennas; 2) High-Q antennas; 3) Noise¬ cancelling antennas. Let's look at these one by one. Incidentally, these anten¬ nas are for receiving only. If you have a transceiver, some sort of switching de¬ vice, such as a relay, will have to be used. These an¬ tennas will all prove quite lousy for transmitting. The Shielded Loop Fig. 1 shows two types of shielded-loop antennas. Fig. 1(a) is a schematic diagram of a single-turn loop, which may be constructed from coaxial cable. The loop is tuned to resonance by ca¬ pacitor C, which may be a common 365-pF receiving- type variable available at most Radio Shack stores. It may be necessary to paral¬ lel this capacitor with a 330-pF fixed capacitor if resonance cannot be ob¬ tained with the variable by itself. The loop should have an overall circumference of about 0.15 wavelength. Es¬ sentially, it is a single-band affair. If used on a band much lower than where it is 0.15 wavelength, the anten¬ na will not pick up signals very well. If used on a much higher frequency, the an¬ tenna will pick up more noise. Nevertheless, you can probably get away with using it at half the design frequency and still get fair results. The loop may be placed on an "X" brace made out of wooden dow¬ els or 2 by 4s, taped to an in¬ side closet wall, or even put up in a tree. The "shielding" of the loop obviously is not com¬ plete. Actually, it is electro¬ static (Faraday) shielding, which shorts out the electric component of the signal while letting the magnetic part pass. For some reason, man-made noise seems to be transmitted mostly by capacitive coupling, as an electric field. But signals have both a magnetic and electric component. The re¬ sult is that the noise gets at¬ tenuated more than the sig¬ nals At Fig. 1(b), we have a multi-turn shielded anten¬ na. The overall physicakcir- cumference should still be 0.15 wavelength. The shield may be constructed out of copper or aluminum tub¬ ing. The loop should have four to six turns; too many turns will lower the Q of the antenna and this will ad¬ versely affect its noise per- 73 Magazine • January, 1983 57 Fig. 3 Effect of increasing the Q of an antenna system. (a) The antenna system has essentially no selectivity. The signal , at frequency f Q , is buried in the noise, (b) A selective circuit is used in the antenna system. The to¬ tal amount of noise (area under the curve) is smaller and this results in fewer high-order mixing products > which actually reduces the noise level at f Q . But the signal level remains un¬ changed , improving the sig- nal-to-noise ratio. formance. (Part of the noise attenuation of the shielded loop is the result of its high Q, which we will discuss lat¬ er) Several turns, however, provide for more "sensitivi¬ ty" than just one One word of warning: It is a physical contortion of considerable difficulty to find a way to get several turns through the tubing without a good deal of cussing and high blood pressure. Table 1 gives the circum¬ ference of an 0.15-wave- length loop at various fre¬ quencies, The loop may be a square, pentagon, hex¬ agon, octagon, or perfect circle The circle is geomet¬ rically best A long, skinny rectangle will not work too well. You should try to get the largest possible area for the circumference allowed, and keep it all in the same plane. 58 73 Magazine * January, 1983 Fig. 4. A ferrite loopstick antenna with multiple taps. The taps should be chosen so that C may be adjusted for resonance on each band used. See text for discussion of inductance values . A shielded loop does have a directional pattern The antenna will respond to signals in any direction ex¬ cept right along the axis. There is a sharp null in the line of the axis. The null is so sharp that signals propa¬ gated via the sky wave will never fall into it because of their multipath nature Lo¬ cal signals might possibly fall into the null; just move the antenna a little and they'll come up Of course, the noise can be nulled out if the antenna is oriented just right. This will provide even more attenuation to an already weakened foe. Nulling It Out The noise that is causing you so much frustration may originate in a single de¬ vice. but it is probably be¬ ing transmitted all over the place by the ac power lines Therefore, it may be com¬ ing from all around Howev¬ er, noise will always have a focal direction. Mathemati¬ cally, all the noise com¬ bines in such a way that it may be considered to be coming from one single di¬ rection. (It's sort of like gravity Even parts of the Earth that aren't straight un¬ der you are pulling at you, but it all averages out to a straight down force ) This axiom holds true as long as it's only one fluorescent light, thermostat, or elm tree that is responsible. If there are two independent culprits, each one will have its own focal direction, and you won't be able to null them both out at once. But chances are that there is on¬ ly one source of noise (It is just too horrible to even consider that there might be more!) Fig. 2 shows a method of mounting a shielded loop so that its null can be pointed in any direction The focal direction might even be straight overhead, so the antenna must be capable of pointing in the vertical as well as the horizontal plane. The XYL won't let you put such a contraption in the living room? Well, try the attic or the backyard, then. Or even the roof It may take some time to find the focal direction of the noise, since the antenna null is so sharp But once you've found it, there may be as much as a 20-dB drop in the noise level —and this is in addition to the im¬ provement that results from the electrostatic shielding Now you should be able to hear some sig¬ nals. Let that guy's refriger¬ ator run until it burns itself out High-Q Antennas: The Ferrite Loopstick Man-made noise differs in another way from signals The signal you want to hear is never more than 3 kHz wide on the HF bands (un¬ less you want to listen to AM shortwave music broad¬ casts, which take up about 10 kHz). The noise, howev¬ er, is hundreds or even thousands of kHz wide The higher the Q (the nar¬ rower the bandwidth) of the antenna system, the smaller the total amount of noise that gets into the receiver But that little 3-kHz signal will all be passed. This ef¬ fect is shown in Fig. 3 The less total noise that gets to the receiver front end, the less noise that will appear within that 3-kHz signal 'window," since there will be a lower level of high- order mixing products Thus, the signal-to-noise ratio will be better. The shielded-loop anten¬ na, discussed earlier, has a fairly high Q. It can be max¬ imized by using a single turn of very heavy wire in¬ side a piece of tubing, or else by using RG-8/U coax¬ ial cable for the loop sec¬ tion A preamplifier with rf tuning may be added at the receiver input with any an¬ tenna in order to increase the Q There are several commercially made units available Ameco Equip¬ ment Company (12033 Ot¬ sego Street, North Holly¬ wood CA 91607) makes one called the PT-2 that tunes 160 through 6 meters. An antenna with very high Q can be constructed using a ferrite rod. Just wind several turns of enameled copper wire on the ferrite core from the antenna in Aunt Jenny's at-last-useful AM transistor job. Ferrite sticks are available com¬ mercially from Amidon As¬ sociates (275 Hillside Ave¬ nue, Williston Park NY 11596). The coil should be tuned to resonance using a variable capacitor Fig 4 shows a multiband ferrite antenna system with multi¬ ple taps The exact number of turns that will provide reso¬ nance on the desired band using a 365-pF variable ca¬ pacitor at C will have to be found by trial and error, unless there is data includ¬ ed showing inductance vs number of turns for your particular stick Table 2 shows the values of induc¬ tance that will provide reso¬ nance with 200 pF of capac¬ itance (about the middle of the range of a 365-pF vari¬ able) at various frequen¬ cies A ferrite antenna, com¬ plete with azimuth/eleva tion mount and a built-in Frequency Inductance MHz pH 1.8 39 3.5 10 7 2.6 10 1.3 14 0.65 18 0.39 21 0.29 24 0.22 28 0.16 Table 2. Inductance re¬ quired to resonate with 200 pF of capacitance (the mid¬ dle range of a 365-pF vari¬ able) at various frequencies. This data may be used in conjunction with data pro¬ vided with commercially available ferrite rods r for the purpose of making a ferrite loopstick antenna. preamplifier, is available from Palomar Engineers (Box 455, Escondido CA 92025) at the time of writ¬ ing The ferrite loopstick is not electrostatically shield¬ ed, but it does tend to favor inductive coupling over ca¬ pacitive It is easier to work with mechanically, espe¬ cially at lower frequencies Simply orient the loopstick until a null occurs in the noise background. The null will be very sharp Need this last comment be made? Let's not take any chances. Don't try using a toroid core for this antenna. It won't work Noise-Cancelling Antennas There's still another char¬ acteristic of noise that makes it different from sig¬ nals. Oddly enough, this is the very resemblance of noise to a signal, with a unique focal direction You hear the noise on the same frequency as a given signal, the noise may be thought of as a local signal. As such, using two antennas to com¬ bine the noise in opposite phase, the noise can be "cancelled out/' Fig 5 illustrates one such system. The spacing be¬ tween the two inductively- loaded vertical dipoles need not be very great, but it should be as large as prac¬ tical without exceeding a quarter wavelength. The el¬ ements themselves may be very short. In fact, shorten¬ ing them increases the Q, which will add to the noise- reducing effectiveness. One antenna is fed 180 degrees out of phase with respect to the other. The easiest way to do this is to make the phasing lines the same length, but feed one of the antennas upside down with respect to the other. That is, if one anten¬ na has the feedline center conductor going to the top section, the other antenna should have its feedline go¬ ing to the bottom. In the plane equidistant from the two antennas, phase can¬ cellation will occur. This is a vertically-oriented plane, and by rotating the entire system through 180 de¬ grees, any focal direction can be put into the null plane. It is possible, but not like¬ ly, that a signal will arrive from a direction that lies in the same plane as the noise, once the noise has been cancelled out. Sky-wave signals, since they arrive from a varying direction (ionospheric shift), may fade more if this happens Local signals will be attenu¬ ated considerably. This particular kind of antenna is mentioned here to illustrate the third way that signals can be distin¬ guished from noise. As de¬ scribed, it will not work as well as the shielded loop or the ferrite antenna. But this scheme could conceivably be used with two shielded loops or ferrite antennas! Actually, pointing these two types of antennas at the focal direction of the noise is a means of phase cancellation But even more cancellation could be obtained by using two such antennas, both pointed at the focal direction of the noise and then combined 60 73 Magazine • January, 1983 Fig . 5. Using two antennas to obtain phase cancellation of the noise. This particular system uses two inductively- loaded vertical dipoles. This system is illustrated primarily to demonstrate the third difference between signals and noise; this antenna by itself will not work as well as a shield¬ ed loop or a ferrite antenna. so that the small amount of remaining noise from each antenna arrives at the re¬ ceiver in opposing phase Which One? In a noisy environment, probably the best choice is the shielded loop. Using a selective preamplifier, one shielded loop can be used on several bands; it should be constructed for the high¬ est band used On lower fre¬ quencies, the value of ca¬ pacitor C will have to be in¬ creased by paralleling it with fixed capacitors The preamplifier will allow re¬ ception on lower bands be¬ cause of its gain. Perhaps there is no good place to put a shielded loop with azimuth/elevation mounting, and you can't get enough noise attenuation unless the antenna can be oriented towards the focal direction of the noise. Then, the next best choice is the ferrite loopstick. It can be put right at the operating desk! The ferrite antenna will probably not be quite as effective as a shielded loop. The null will not be as well defined (though still quite sharp) and its discrimi¬ nation against electrostatic coupling will not be quite as good. But it can still be used to advantage. Conclusion Noise differs from signals in three ways: 1) Noise is transferred mostly by elec¬ trostatic coupling, but sig¬ nals are transferred by elec¬ tromagnetic fields; 2) Noise is broadbanded, but signals occupy only a small part of the spectrum; 3) Noise has a unique and usually con¬ stant focal direction at a given frequency, and it will usually be in a different fo¬ cal direction than desired signals These three differ¬ ences are taken advantage of by; 1) Faraday shielding; 2) High-Q antenna circuits; 3) Phase cancellation. These three methods of dealing with noise may be used individually or in com¬ bination. A shielded loop with azimuth/elevation mounting takes advantage of all three of the differ¬ ences between signals and noise. It has electrostatic shielding, has a high Q, and may be oriented to null out the noise A ferrite loop can be used when the shielded loop is impractical because of space limitations, either in reality or in the imagina¬ tion of an XYL or landlord Good luck! Carry on the search for the noise source by all means But at least get on the air in the mean¬ time. ■ Charles £. Heisler K3VOB 7 IS Dixie Drive Red Lion PA 17356 The Care and Feeding of Optoelectronics There are many ways to make these devices earn their keep. Here is one. C an you really see which photo-coupler interrupter believing this so far, be- want to, you can make this way the wind is blow- module This module has cause I just read it in an little black thing do some- ing with optoelectronics? two components: an in- optoelectronics manual. thing to earn its keep. For The answer to that ques- frared LED light source The H21A1 module has a instance, if you pass some- tion is yes —with a little called the emitter, and a gap in its housing. The emit- thing opaque through the help from you photo transistor called the ter is mounted on one side gap, you will interrupt the The subject of this article detector of the gap and the detector output of the emitter Do is General Electric's H21A1 I think you are safe in on the other. You may think you think that's why GE someone planned it that calls it a photo-coupler in¬ way because now, if you terrupter module? Fig. 1. The H21A1 , detector side, is not shown physically Photo A. Wind-direction indicator with the weather cov- correctly drawn here — look on top of the device for the cor- er removed ' rect pinout All resistors are 1/4 Watt; capacitors are pF. 62 73 Magazine • January, 1983 The interrupter module is just one of many types of photo couplers. To mention a few, the reflector module could be used somewhat like the interrupter module except that the light source must be bounced off a re¬ flective surface and back to the detector. There are discrete emitter and delec¬ tor units, and also a whole family of optocouplers in which the emitter and de¬ tector are sealed into one cube with no way of any¬ thing getting between them, which offer as high as 4000-volts isolation be¬ tween the input and the output I have mentioned but a few that are available (most of them cheap) And that brings me to the reason for my taking your time while you read this. My purpose is to tell you how I used an interrupter- type module in a project and to get you interested enough to think about using optoelectronics in your next project The more you know about them the more jobs you will see that they can do for you I sort of hinted at the beginning that I know how to make the H21A1 (actual¬ ly, 8 of them) tell which way the wind is blowing, so I better get to it The con¬ struction part is a mix of electronics and mechanics. The device, in case you haven't guessed, is a wind- direction indicator. As you can see in the photos, there are some ma¬ chined parts used on the model Don t let this scare you; in almost every case, there is an alternative way to fabricate the same part with hand tools I will sug¬ gest ways as we go along On the other hand, the fel¬ low with a lathe or machine shop could have a good time developing this proj¬ ect even further The model pictured here has been perfected only to the point that it works reliably in all weather experienced here in Pennsylvania, and it should continue to work for Photo B. An exploded view with the vane boom removed, many years. That is to say, don't be afraid to use the ideas and hardware avail¬ able to you The most important points to remember when planning your construction are that (1) the bearing fric¬ tion should be low enough so that a gentle breeze will have enough force on the tail of the vane to keep it headed into the wind, (2) you must devise a way of mounting it to your tower or pole, and (3) when it's all finished you must have some means of weather¬ sealing it Photo A shows the wind- direction indicator fully as¬ sembled except for the weather cover. The vane boom is 3/16 X 12-inches- long aircraft aluminum rod (I might mention at this time that all parts were made from T3 aluminum ) The tail is 1/16 X 6 inches and has just about 13 square inches of surface The vane boom is mounted to the axle or vertical shaft 2/3 of the length of the boom in front of the tail, or 1/3 of the way back of the nose. So, to balance this boom, the nose must be proportionately heavier than the tail The nose is 1 X 3 inches long and is threaded onto the boom, A 1/16-inch slit has been milled into the boom to ac¬ cept the tail, but a flat sur¬ face filed on the boom with the tail screwed to it would be just as good The nose could be epoxied to the boom if there is no thread¬ ing tool available. The axle or vertical shaft is a 1/4 X 9-inch rod with a a 3/16-inch hole drilled in it near the top to accept the vane boom A hole was drilled and tapped into the end of the shaft down through the vane boom and on into the shaft another half inch to secure the boom to the shaft Photo B is an exploded view It shows the next com¬ ponent on the way down the shaft—the top bearing weather seal. This rotates with the shaft and, together with a piece of pipe that is epoxied to the top support frame, prevents the ele¬ ments from getting into the bearing The top support frame is 4-7/16 inches deep (as viewed in Photo B) and 4-5/8 inches wide It provides a mounting surface in the back and was formed from 1/8-inch stock The back two corners were welded for strength. The inner bear- Photo C. A view of the H21A1s mounted on their fiberglass substrate and the disc interrupter tab rotating through the H21A1 gap . Mounted underneath is the PC board with the rest of the circuit components. 73 Magazine • January, 1983 63 Photo D. The eight H21 Als in a 1-1VI6" circle (measured to the center of the gap). Photo f. The electronic components mounted on what we call a "do all " PC board. The pencil is pointed at one of the ten pins used to terminate the cable coming from the read¬ out LEDs in the shack. The component at 10:00 o'clock near the shaft hole that looks like an overweight disc capacitor is the MOV. ing seal is 3/4-inch i d con¬ duit 1-1/8 inches high The outer bearing seal is 5 8- inches i d X 1-3/8 inches high The next component down the shaft is the top bearing I used ball bear¬ ings pressed into a bearing block to facilitate mount¬ ing and alignment, but a neat hole in a hunk of brass would be just as good It would then be smart to use a brass or steel shaft, be¬ cause brass and aluminum don't get along, especially out in the weather The next component down the shaft is the disc interrupter. It rotates with the shaft and is the compo¬ nent that actually tells the optoelectronics interrupter module which way the wind is blowing. (More about that later ) The disc inter¬ rupter used in this model was machined from a piece of solid round stock As seen in Photo C, it is merely a disc with a collar and set screw to secure it to the shaft, and with a right angle tab on it. An easier way to make the disc would be to use the top portion of a 64 73 Magazine • January, 1983 small soup can and epoxy a collar to the top to secure it to the shaft My disc-inter¬ rupter tab runs in a 1-11/16-inch circle and is 3/8-inch deep. The width of the tab is cut so that it covers two interrupter modules. (More about that later.) The H21A1's gap is 3/32-inch wide so I made the tab 1/16-inch thick. Photo D is a top view of the heart of the whole thing, the eight H21A1 interrupter modules mount¬ ed in their circle on a piece of fiberglass epoxy board 18-inch thick x 3-1/4 inch¬ es square This would have been a perfect situation in which to design and etch a printed circuit board At the time, however, I did not have on hand PC board ma¬ terial thick enough to do the job I think it should be at least 1/8-inch-thick stock to get the thermal and me¬ chanical stability needed As you can see in Photo E, I used a piece of Radio Shack "do all" board The leads from the H21A1s were stuck through the board and soldered first, to set the spacing be¬ tween the two boards. Then the positive bus (near the center of the board) and the negative bus (around the outside of the board) were put down After that, it's just as the schematic shows. The pencil in Photo E is pointing to the terminal pin on the negative bus. There are 10 pins on the board; two are for power (+5 V and ~5 V), and the other eight are the direction signals that are being sent down to the wind direction LED readout in the shack The male pins on the board will mate with female pins on the end of the cable go¬ ing to the shack. I tried various methods of reducing the number of conductors needed in the interconnection cable, BCD, etc., but when the smoke cleared (get it?), two runs of inexpensive 5-con- ductor TV-antenna rotor wire were found to work fine. The eight H21A1s are spaced every 45° around the circle Consequently, with the eight LEDs placed on the compass rose in the shack, you are able to de¬ termine if the wind is out of the north, northeast, east, southeast, south, south¬ west, west, or northwest merely by observing the LEDs, However, by making the disc interrupter tab wide enough to cover two adjacent interrupter mod¬ ules, two LEDs are lit. So, for example, if the south and the southeast LEDs are lit, we can assume that the wind is out of the south- southeast, or approximate¬ ly 157° Obviously, more H21A1s could be added to increase the resolution At this point, some method of reducing the number of ca¬ ble conductors between the aerial unit and the readout panel would be necessary The electronic theory is super simple. When thedisc interrupter tab interrupts the emitter light source, the photo transistor turns off, turning the 2N3904 off, hence allowing the appro¬ priate LED to light Any 5-volt power supply that can deliver at least 500 mA continuously will work The General Electric MOV is for transient voltage- spike protection. I used the Photo F. An exploded view from the front looking up at the wind-direction indicator V47ZA7 because I had them; a better choice could be made So far, there has been no need for rf suppression, but that is not to say you may not need to add a bypass capacitor or two. The next to last thing on the shaft is the 1/4-inch col¬ lar It is secured to the shaft with a set screw and rests on top of the lower bearing. It prevents the shaft from falling through. As you can see in Photo B, the collar is not in place because this is an exploded view. Photo F shows an explod¬ ed view with the 3-3/4~inch spacer screws removed from the bottom plate. You also can see the four small 3/4-inch spacers on the bot¬ tom of the bottom bearing plate. These spacers will be used to secure the weather cover All of the spacers could be substituted for with all- thread rod, and then you would use the nuts to adjust your spacing The bottom bearing and bearing block are identical to the top bearing and bearing block The weather cover is nothing more than a five¬ sided box that slides up over the lower bearing plate and butts against a cork gasket glued to the bottom side of the top sup¬ port frame (gasket or cover not pictured) A fruit or soup can of the proper size also would work for a weather cover. After the machine was fully assembled and tested, I disassembled it so that I could wash all the metal parts with dishwashing de¬ tergent. Then everything was sprayed with clear Kry- lon™, including the elec¬ tronics board but exclud¬ ing the H21A1 board Photo G is a view of the wind-direction readout panel with its eight LEDs, etc. On a sub-panel on the rear, the power-supply com¬ ponents and cable terminal blocks are located. On the right is the companion meter that I hope in the near future will indicate wind velocity (not ac Amps) My plans for this meter as they stand now are to perfect a 4-inch cup ane¬ mometer to the point that it will indicate wind velocity with the additional feature of generating 7 to 10 Watts to be used to light a small lamp or to charge the HT battery. Tune-up of this little gem is pot pie. Just mount it in the air on whatever struc¬ ture you plan to use. Point the nose of the wind vane north and by using the set screw in the disc interrupter collar, damp the tab so it is centered through the H21A1 that you have desig¬ nated north. Be sure the vane still rotates freely. Se¬ cure the weather cover in place, then go down to the shack, turn the power sup¬ ply on, and watch the LEDs blink. It is that simple. Of course, you knew it was go¬ ing to work before you put it in the air. Hi, hi! A word about finding parts and materials. If you can't get the H21A1s local¬ ly, see Reference 1 I found a shop in my area where I can buy a foot of this and an inch of that, plus getting some good advice to boot. I found this shop by talking to a fellow who is building an experimental aircraft. They use the same types of material. Perhaps you can find an experimental air¬ craft club in your area, or you can get your material where I got mine See Refer¬ ence 2. I would be very remiss if I did not implicate my collaborators in this proj¬ ect; Fred Jones K3CVM, 73 Magazine • January, 1983 65 N s Fig . 2. Here is your ready-to-use compass rose! International Success Story: The BBC From its battery of transmitters, the BBC fires a daily salvo of news and entertainment around the world. No commercials, either. Roger N. Peterson 25 Orchard Lane New Canaan CT 06840 A sk just about any short¬ wave radio listener or look at the most recent lis¬ tener-preference studies on international broadcasters, and you'll get the same an¬ Bush House , home of the BBC's External Service s, in The Strand , London. (All photos BBC copyright.) 68 73 Magazine • January, 1983 swer. The British Broadcast¬ ing Corporation (BBC) ranks number one There are a number of reasons for this popularity ranking, and I was turning them over in my mind as I walked down The Strand in London on a sunny day on my way to the BBC head¬ quarters in Bush House, near Fleet Street. Some cyn¬ ics say that the only reason for BBC popularity is that it is on the air more often and on more places on the dial than any other internation¬ al broadcaster. There is some truth to this, although the facts are not quite as above. The BBC ranks only fifth among international broadcasters for the amount of time on the air, per week The USSR is first, followed by the US (Voice of America plus Ra¬ dio Free Europe), the Re¬ public of China (Radio Pe¬ king), and West Germany (Deutsche Welle). However, from the standpoint of pro- grams in English that can be heard here in North Ameri¬ ca, the BBC does indeed lead all the others. You can hear the BBC round-the- clock in the US and Canada, and this beats such big North American broadcast¬ ers as the Voice of America, AFRTS (US Armed Forces Radio), and the popular CBC Northern Service in Canada. It also is true that BBC programs are often "all over the dial" on your re¬ ceiver. During many hours of the day, you can pick up their broadcasts on three, four, or even more different frequencies This is because of its unusually strong transmission facilities —79 transmitters, 47 of them in four different locations in Britain and 32 in eight over¬ seas relay stations, includ¬ ing the US, Canada, and the Caribbean. At certain hours, the Russians offer even more frequencies to the US listener, but only the BBC provides this multi¬ band reception for most of the twenty-four hours. While these technical ad¬ vantages give the BBC a big boost over competition, they are not the only rea¬ sons for its popularity The control room at Bush House , London i, home of the BBC External Services . World Ser¬ vice programs are broadcast 24 hours a day from these facilities in English and38 other lan¬ guages. broadcasters The BBC broadcasts more than 250 news programs a day from its headquarters in London. They are all prepared in an ultra-modern newsroom with electronic readout aids of all kinds, and with a staff that numbers over 100. It may be the world's larg¬ est newsroom and, at this news machine by BBC cor¬ respondents from all over the world and by the inter¬ national news agencies. An¬ other important source is the famous BBC Monitoring Service. This BBC Division, located at Caversham Park, some 50 miles from Lon¬ don, provides round-the- clock reports on the con¬ tents of selected broad¬ casts from foreign radio sta¬ tions This supplements the agencies' and foreign corre¬ spondents' reports. The BBC Monitoring Ser¬ vice provides a Summary of World Broadcasts every day and, in addition to sending among listeners. The great writing, certainly the most reputation for world news modern as it was complet- coverage makes the BBC ed just over a year ago. unique among international News is fed into this giant A GUIDE TO BBC WORLD NEWS BROADCASTS Time (GMT) Best Frequencies (MHz) 0000, 0200, and 0300 5.975, 6.12, 6.175, 7.325, 11.750, 15.260 0400, 0500, and 0600 5.975, 6.175, 9.510, 15.070 0700 6.175,9.510, 15.070 0800 and 0900 9.510, 15.070 1100 and 1300 6.195, 9.510, 11.775. 15.070 1600 and 1700 15.070, 15.260, 17.830, 21.710 1800 15.070,21.71 2000 6.175, 15.070 2300 5.975, 6.175, 7.325, 15.070 BBC AND THE FALKLAND ISLANDS CRISIS BBC is at its best reporting on significant news events, and the Falkland Islands crisis certainly was a good example. First of all, the regular news broadcasts generally were an hour or so ahead of the wire services or what your local radio or TV station reported. You heard it first on BBC if you tuned it in. Second, BBC has special programs to deal with current newsworthy events, and the Falkland situation was no excep¬ tion. On May 2, right after the air attack on the Argentine-held airfields on the Islands, the BBC preempted one of its most popular programs, Letter From America, for an interview with several military experts. These special programs generally come right after major news programs such as their 1100, 2000,0000, and 0200 GMT broadcasts, but they can come at any time, as the BBC thinks nothing of interrupting regular programs for something spe¬ cial. Finally, the BBC has always had a special weekly broad¬ cast to the Falklands on Sunday afternoon from 2209 to 2245 GMT on 9.915 and 12.040 MHz. I heard the one right after the Argentine invasion on April 4, and it was excellent. It included a message from the British Foreign Secretary, a review of Brit¬ ish press opinions, and even special messages to relatives. The program was very easy to receive in the Northeast, where I reside. Check it out at the above times and frequencies. 73 Magazine • January, 1983 69 A view of the antenna farm for the BBC's broadcasts to North America. The signal is loud and strong to the US. it to the BBC News Staff, most popular of these (as of supplies it on a subscription last year) are: basis to other governments, f . . news agencies and news- • Outlook- an up-to-the- papers. universities, re- minute lo ° k at people, search institutes, industrial events > a ^d opinions to- and commercial organiza- 8 ether with the latest UK tions, and private individu- news - s P orts ’ and weather l s • Twenty-Four Hours — analysis of the main news World news can be heard of the day plus reviews of in North America seventeen the British press, times a day (see box). In ad- • The World Today — ex- dition, back-up programs amines thoroughly one top- on the world events are of- ical aspect of the interna- fered daily. Some of the tional scene. SOME POPULAR BBC PROGRAMS (All Times GMT) Letter From America (Alistair Cooke) Sundays 0545, 1115, 1645, 2315 Letterbox Fridays 1415; Saturdays 2315; Sundays 0515. 2015 Look Ahead {Program Previews) Daily 0940; weekdays 1943 In The Meantime Thursdays 2120; Fridays 0150, 1115 Outlook Weekdays 1900, 1515, 0115 (Tuesday- Sat urd ay) Anything Goes Saturdays 1215; Mondays 0330, 0830 Concert Hall Sundays 1515 Top Twenty Wednesdays 1830, 2330; Thursdays (Hit Records) 1215 New Ideas Saturdays 0530, 1015, 2230; Wednesdays 1725 Good Books Saturdays 2015; Sundays 0215 Ja 2 z For The Asking Wednesdays 2130 • Commentary — back¬ ground to the news from a wide range of specialists. • Radio Newsreel — news of events as they happen, and dispatches from BBC correspondents all over the world. • New About Britain . • British Press Review — Survey of editorial opinion in the press. • Financial News— includ¬ ing news of commodity prices and significant moves in currency and stock markets. In addition to these daily reports, the BBC also offers a number of weekly review- type programs on current events and special interest subjects. Among the most popular: • Financial Review—a look back at the financial week • Business Matters —a weekly survey of commer¬ cial and financial news. • From Our Own Corre¬ spondent— BBC reporters comment on the back¬ ground to the news. • From the Weeklies —a review of the British weekly press. • Listening Post —a week¬ ly survey of comment from radio stations around the world. While the BBC has no ri¬ val for its extensive cover¬ age of news, it also leads the way in many other types of programs—sport, drama, light entertainment, and music. These can be divid¬ ed into two categories — monthly features and regu¬ lar programs. A typical month will have anywhere from 12 to 16 feature programs These range from general interest to special interest subjects. Some are only for the "in¬ tellectuals/' and others are for the "common man." In June, for example, the Queen's Birthday Parade (better known as "Trooping the Colours") is broadcast from London with all the music and pageantry you would expect. The BBC also has had weekly programs called " The Poetry of Eu¬ rope," "The Movie Moguls; ' and "Medical Hypnosis." Music is an important part of BBC programming In fact, no other interna¬ tional broadcaster comes close to providing the num¬ ber of musical programs — both classical and "Pops" — as does the BBC Every month there are eight or nine special programs mak¬ ing their bows. Regular mu¬ sic programs include "Con¬ cert Hall/' "Talking about Music," and a long-time BBC favorite, "The Plea¬ sure's Yours/' where Gor¬ don Clyde plays classical requests. Another, "Classi¬ cal Record Review/' reports on new releases Classical music is not the only thing that the BBC pro¬ vides listeners who dig in¬ struments and vocal sounds For the rock devo¬ tee, there is the weekly "John Peel" show where the host selects tracks from a newly released album and singles from the progressive rock scene in London, "jazz for the Asking" is a popular weekly request show, and "Top Twenty" lets you lis¬ ten to all the big hits. "Terry Wogan's Album Time" is a weekly show for those peo¬ ple who like the easy-listen¬ ing kind of music, and there are many more of the same on the BBC every week Another area where BBC programming leads the way is in drama. There are four regular weekly features plus specials for the partic¬ ular month. Total air time per week for this type of show is about 16 hours. A regular drama program is "Thirty Minute Theater." This often shows plays by such famous writers as Dor¬ othy L. Sayers, Terrence Rattigan, and Oscar Wilde. "Play of the Week," "Ra¬ dio Theater," and "Short Story" are other regular dra¬ ma programs. 70 73 Magazine • January, 1983 Margaret Howard hosts the very popular Letterbox' pro- Alistair Cooke is heard every Sunday on the BBC with his gram on the BBC. Hear it on Fridays at 1415, Saturdays at popular Letter From America " program. Listen to it at 0545, 2315 , or Sundays at 0515 and 2015 GMT . 1115 , 1645, or 2315 GMT . Book lovers hear the fol¬ lowing programs every week: "Book Choice," "Good Books," and "Paper¬ back Choice." For those in¬ terested in science and hob¬ bies, "Discovery" covers advanced developments in science, "New Ideas" gives you news of the latest Brit¬ ish products and inventions of particular interest to the home owner and small busi¬ nessman, "Science in Ac¬ tion" lives up to its name, and "Time Off" is a pro¬ gram devoted to hobbies, pastimes, and entertain¬ ment. Religion is not over¬ looked at the BBC, either Services broadcast from fa¬ mous English cathedrals and churches can be heard on Sundays and Mondays. Two other programs are "Report on Religion," a weekly magazine of reli¬ gious news and views, and a daily program called "Re¬ flections." Sports occupy a promi¬ nent part of the BBC weekly schedule, but a good many of these broadcasts are "very British indeed" —rug¬ by, cricket, British football — and do not have a great appeal to the average US audience. If you have any British expatriates in your area, you can get them real¬ ly excited by inviting them over to hear something like England versus Scotland in football. BBC programs are very carefully researched by sur¬ veys and opinion polls A Listener Panel (of which I am a member} is made up of 88% foreign nationals and 12% British expatriates and is asked to vote on indi¬ vidual programs and/or sub¬ jects on a regular basis. Panel voting accounts for the unusual number of dra¬ ma programs and for the addition of a new business news program ("Financial Review," mentioned above). Over 50% of the panel ap¬ parently wanted more business news Research indicates that one of the most popular BBC weekly programs is Al¬ istair Cooke's "Letter from America." Back in 1946, the BBC commissioned Cooke to deliver a series of radio talks on the subject of the USA where he had been liv¬ ing and working for more than a decade. The original plan called for thirteen weekly programs, but it has never stopped in all these years It may well be the longest-running series in ra¬ dio history. Listen to it on Sundays at 0545, 1115, 1645, or 2315 GMT. One other BBC program that continues to score high marks is "Letterbox." This is a show where several peo¬ ple simply read letters (of¬ ten complaints or sugges¬ tions for BBC programming} from listeners, and the BBC replies. On the surface, it doesn't sound very fantas¬ tic. However, the people on the show are so funny — with British wit and satire — that it has become one of the big BBC hits Hear it on Fridays at 1415, Saturdays at 2315, and Sundays at 1515 and 2015 GMT. At this point you might well be thinking about why the British go to all the trou¬ ble and expense of provid¬ ing such a wealth of pro¬ grams to the shortwave ra¬ dio listeners of the world To understand their mo¬ tives we should examine the basics of the whole BBC foundation. The letters "BBC" were first used in 1922 when the 73 Magazine • January. 1983 71 Introducing The SRT-3000 RTTY Communications Send-Receive Terminal $995.00 Introductory Price $795.00* • Built-in demodulator & AFSK modulator for 170,425.850 Hz shifts, high and low tone pairs • 60,66,75,100,132 WPM Baudot. 110,300 Baud ASCII, 5-99 WPM Morse • 1000 character text buffer with BREAK feature • Ten 80 character message memories with battery backup • Selectable display formats, 24 lines x 72 characters (2 pages), 24 lines x 36 characters (4 pages), 16 lines x 36 characters (6 pages) • Spilt screen operation • On screen status line displays a tuning bar, mode, speed, shift, tone pair, normal/reverse, USOS, WRU, SELCAL, buffer mode and buffer count • Cassette interface for long "Brag Tapes" or unattended message storage • Baudot and ASCII printer outputs • Built-in audio monitor • Built-in 110 VAC power supply • Other features—PTT control, WRU, SELCAL, sync idle, CW ID. USOS, auto¬ start, full or half dupfex. scope outputs, weight control, intercharacter spacing, reverse video, RS-232, word wrap around • Compact size only 13,3 x 10.3 x 4 inches • Made in USA. *Introductory prices good thro Feb . 28, 1983 , Optional 9” video monitor shown $149.00. Send For Free Information DCMJ EL EC TRQNICS, INC. 787 Briar Lane, Beloit, Wis. 53511 (608) 362-0410 British Broadcasting Com- \ pany was formed and when < regular daily broadcasts be- ; gan. In those days, the BBC I was a commercial organiza- 5 tion, but one that operated t under a license on condi- ! tions which would have pre- < vented it—even if it wanted 1 to —from turning broad- < casting into a moneymaker ! for the shareholders. From i the start, it placed the inter- j ests of the public above all. I The result was that the Brit- < ish developed a genuine i public service broadcasting i system, paid for by its audi- I ence through their receiv¬ ing licenses. In 1927, the 1 Company became the Brit¬ ish Broadcasting Corpora- ; tion. It is a public corpora¬ tion constituted by Royal i Charter and holding a li- < cense from the Minister re¬ sponsible for broadcasting. Thus the BBC is neither a government department nor a commercial concern The External Services, 72 73 Magazine • January, 1983 which is what we hear on our shortwave receivers, are an integral part of the BBC, operating under the same charter as the domes¬ tic service and sharing the same traditions. Unlike the domestic service (which is financed by annual "listen¬ er licenses"), the External Service is paid for by Parlia¬ mentary grants-in-aid. The government prescribes the languages which are broad¬ cast and the length of time each is on the air, but edito¬ rial control rests with the BBC External broadcasting from Great Britain began in 1932 with a service in En¬ glish A few years later, the BBC was asked by the gov¬ ernment to broadcast in other languages, the first of which was Arabic During the early days of World War II, the BBC was a con¬ stant ray of hope for the people in France and other Nazi-occupied countries I can well remember, as an airman shot down in France a few weeks before the in¬ vasion and hiding in a French farmhouse, listening to the BBC on the family ra¬ dio. The BBC used to send coded messages to the French underground during those days. Today, the External Ser¬ vices broadcast to the world in English and 38 other languages for over 100 hours every day. These programs originate mainly from the 52 studios in Bush House in London. While the British Empire is no longer the world power that it once was and no longer has all those colo¬ nies on which 'The sun nev¬ er sets/' it still has thou¬ sands of citizens and expa¬ triates living abroad. The BBC brings information and entertainment from home and helps them keep their ties to the mother country. This, of course, is a prime objective of BBC broad¬ casting overseas Naturally, the BBC is in¬ terested also in presenting its own point of view to citi¬ zens of other countries around the world. The BBC estimates that about 75 mil¬ lion adults listen regularly (once a week or more) to its External Services. The En glish broadcasts are heard by about 25 million Like all international shortwave broadcasters, BBC programs and frequen¬ cies change from month to month. How can you keep up-to-date with these con¬ stant changes? Basically there are two ways to do it — by your radio receiver and by print. The BBC has three programs which will help you keep abreast of things. First is a show called "Look Ahead" which pre¬ views programs for each day. "In the Meantime" is a program which tells you what is new in BBC pro¬ grams. And third, there is a program called "Wave¬ guide" which covers fre¬ quency changes, propaga¬ tion estimates, and other things which help you to keep tuned well to the BBC Serious listeners to the BBC will be interested in re¬ ceiving a monthly copy of "London Calling." This pub¬ lication is sent airmail from London every month, pre¬ viewing programs and giv¬ ing frequency changes so that the listener is right on top of BBC broadcasts a month ahead of time. Un¬ fortunately, this is not a free publication and the cost to subscribers in the US is $13 00 per year You can get a free sample copy, however, by writing BBC World Service, PO Box 76, Bush House, London WC2B 4PH Or, to save yourself the cost of an overseas air¬ mail stamp, direct your or¬ der to; British Broadcasting Corporation, 630 Fifth Ave¬ nue, New York NY 10019. ■ BEST BBC FREQUENCIES FOR NORTH AMERICA Time (GMT) Frequencies (MHz) 00000230 15.07, 15.26, 11.75, 7.325, 6.175, 6.12, 5.975 0230-0330 11.75, 9.60. 9.51, 7.325, 6.175, 6.12, 5.975 0330-0630 9.51.6.175, 5.975, 15.07 0630-0730 15.07, 9.51 0915-1100 11.750, 9.740, 15.07 1100-1330 21.55, 15.07, 11.75, 9.51,6.195 1300-1500 21.71, 15.07 1500-1745 21.71, 17.83, 15.40, 15.26, 15.07 1745-2000 15.07, 9.41, 12.095 2000-2100 21.56, 15.26, 15.07, 6.175 2100-0000 15.26, 15.07, 6.175 2200-0000 15.42, 11.75, 9.59, 9.51, 6.12, 15.07 2300-0000 7.325, 5.975 This chart effective summer, 1982. Some changes will take place in the fall. Reader Service for facing page ^5 — Active-Filter Design Made Easy Using this BASIC program, if you don't like the design, then scrap it. All you lose is a few seconds. B. L Taylor WD4HPC recipes, i.e., if you want my 922 Reaves Street performance, duplicate my fackson MS 39204 circuit The rest have been tutorial articles which are mathematical in nature.*- here have been many There is a section on mul- articles on active band- tiple-feedback bandpass pass filters in the electron- (MFB) filter design in the ics/amateur publications 1979 ARRL Handbook* and Most of the articles are there are at least two books Program listing. 10 REM BANDPASS BASIC 70 REM BY ft. I: » TAYi lift* UTMHPt SO REM r Oft SECOND ORDER HIM TIPLE FEEDBACK BANDPASS FILTERS 100 R.1 ~ 0 i»v ren input sen ion or i ions follow 200 PRINT*TOUR CHOICES ARE AS FOLLOWS* 210 PM N T *1 CHOOSE R1 * R3» R5 AND C“ 220 PRINT *2 CHOOSE Or 0, f AND C* ’30 PRINT *3 CHOOSE Rlr F» 0 AND C* 240 PRINT *4 SCALE FREQUENCY BY CHAN Til NO CAPACITORS* 200 PRINT *5 SCALE FREQUENCY BY CHANGING RESISTORS* 260 PRINT *6 SCALE 'IMPEDANCE OF COMPONENTS* 22<> PRINT *7 DO CALCULAT IONS FOR CASCADED SECTIONS* 280 INPUT ‘ENTER THE NUHWR CORRESPONDING TCI YOUR CHOICE* »H TOO IF HI THEN 1000 310 IF M 3 THEN 2000 VTA IF ft- 3 THEN 3000 330 IF M--4 THEN 5000 340 IF H 5 THEN 5300 350 IF H-* THEN 5600 36 O IF M ~7 THEN 6000 370 GOTO 280 999 REM DESIGN A FILTER BY SPECIFYING ALL COMPONENTS 1 000 INPUT * R1 * f R1 * * R3 * i R3. ‘ R5 * r RT;i» * C * t C 10.10 C=C ♦ 3. E-6 1020 G- . 5*R5/R t 1030 Q“ S OR UR1* R51R 3*R5>/<4*R I #R3> ) 1040 F *=0 / < A . 2832*R1 *C#0 > 1050 GOTO 4000 1999 REM DESIGN A FILTER BY SPECIFYING ALL PARAMETERS AND C 2000 I NPUT *G*!Gf *F * fF.*0* S01 *C“f C 2010 M=6.2832*F 2020 C=C*?C-6 2030 RI«O/<U« G* C> 2040 R5=2*G*RI 2050 ft ,3=R .1 *R5/ < 4*0*CI*ft 1 -R51 2060 IF 0-R3 THEN PRINT ’NOTE - NEGATIVE VALUE OF R3* 2070 GOTO 4000 2999 REM DESIGN BY SPECIFYING INPUT IMPEDANCE» OrF AND C 3000 INPUT *R1* rRl» *0* f 0 » * F * IF * * C * * C 3010 W=6.2832*F 3020 C~C*1EA 3030 G»Q/(W*Rt*C> 3040 R5a2*G*Rl 3050 R3=Rl*R5/< 4 * 0*0*R1 - R5> 3060 IF 0>R3 THEN PRINT “NOTE - NEGATIVE VALUE OF R3* 3070 GOTO 4000 3999 REM OUTPUT SECTION FOR ABOVE SEGMENTS 4000 PRINT 4010 PRINT 4020 PRINT *FOR THIS DESIGN* 4030 PRINT *R1- * IR1* * OHMS * 78 73 Magazine • January, 1983 devoted to active filter the design parameters and design.the component values are The equations used in de- interdependent. Changing signing the most common any one can lead to changes type of active bandpass fil- in others, which leads to ter—the second-order. MFB more calculations filter— can be solved nearly This is just the sort of cal- as easily as the name of the culation that is ideally suit- filter can be pronounced. ed for computer evaluation. The problem is that all of The program described in 4040 PR INT * R3- * *R3 ? * OHMS * 4050 PRINT "R5»-*tR5**0HMS* 4060 C1«C*IE6 4070 PRINT *0 * ?•€! * * MICROFARADS* 408O PRINT •F**|FS*HERT7* 4090 PRINT *0***0 4.100 PRINT *«** ?G 411.0 PRINT 411*0 PRIM! 4130 INPUT «DO YOU WISH TO CONTINUE Y OR N*JXE 4140 Y11 ~ *N * 4150 Y2$«"Y* 4160 IF X*»Y1* THEN 9999 4170 IF X$»Y2< THEN 200 4180 GOTO 4130 4«?9 REM SCALE FREQUENCY Br CHANGING CAPACITORS 5000 IF ft t 0 THEN 5030 5010 PRINT *CANNOT SCALE UNTIL VALUES ARE DETERMINED* 5020 GOTO 200 5030 INPUT ‘NEW FREQUENCY*JFO 5040 C-€*FYFO 5050 F*FO 5060 GOTO 4000 5299 REM SCALE FREQUENCY BY CHANGING RESISTORS 5300 IF PI O THEN 5010 5310 INPUT “NEW FREQUENCY*SFO 5370 D-F/FO 5330 Fl-PI YD 5 340 P3-P3LD 5350 R5-R5*D 5360 F= F 0 5 770 GO 1 11 4000 5599 REM SCALE IMPEDANCE OF ALL COMPONENTS 5S<‘*0 IF PI -0 THEN 501.0 5610 INPUT * HEW VALUE OF CAPACITOR* ?C0 5720 D~T.;>f t V 6/C 5 730 C=C0t H 6 ■>740 ffl -PLft 5/SO R3-R3/D *>760 R5~R5/D 5770 GOTO 4000 %*.**>*? PFH CASE ADE I DEN IT CAL SECTIONS 6OO0 1NPLM * HUM MANY SECOND ORDER SECTIONS**N 6*“* 1 0 TNPIII * H PER SEC I I ON" J 01 . * GAI N PER SECT I ON * S 01 >070 B -• 2 M F v P (I Oft C 2 >/N > - 1 > /Mil *01 > 0030 U1 * . 5-tD 1 . *>*SOp ( ft XU 4 > 60 4 O U 7 ,5 f D , S f 5 OR < B # It 4 > 6050 O^SUR< Ul> 5QR < U?' A060 0 - J , .0 70 PR t H f * f 01, * < N : * SEC r 1 UNS EACH OF 0~ * Nil 080 PR ! NT * * I it ! 0 f Al n I * * 0 0OVA Irl/Pi Ntt ftC* < T* I t '■ /!»'*■• PR JO i * Off KM IN or IN! system is* «t; : 11 it PF1 ft r .' ! *<. .,010 41 K WVV * NH this article was written to allow one to perform com¬ puter-aided design of sec¬ ond-order MFB filters The circuit diagram of an MFB filter is shown in Fig. 1. The labeling of the compo¬ nents is the same as that used in the program The equations for performing the design are listed in Table 1. Most general-pur¬ pose op amps can be used in the filter This program has been written in such a manner as to be as versatile as possi¬ ble. It should be helpful to the person wishing to de¬ sign a filter of specified pa¬ rameters and equally use¬ ful to the person who wishes to alter some param¬ eter or component value in an existing MFB filter de¬ sign. Take note: There are intrinsic limitations on the Q, gain, and center frequen¬ cy of MFB filters which are not discussed in this article. The reader who is unfamil¬ iar with these limitations should consult one of the references at the end of this article. The program has seven possibilities for design, as follows: 1) Specify the values for R1, R3, and R5 in Ohms and C in uF. The program will calculate Q, G (the pass- band gain), and F (the cen¬ ter frequency, in Hz). This segment is useful in check¬ ing the parameters of a fil¬ ter using the values of the available components. Sample printout YOUR CHOICES ARE AS FOLLOWS 1 CHOOSE Rl. R3r R5 AND C 2 - CHOOSE G* 0' F AN!) C 3 - CHOOSE Rl* F* 0 AND C 4 - SCALE FREQUENCY BY CHANGING CAPACITORS 5 - SCALE FREQUENCY BY CHANGING RESISTORS A - SCALE IMPEDANCE OF COMPONENTS 7 - DU CALCULATIONS FOR CASCADED SECTIONS ENTER THE NUMBER CORRESPONDING TO YOUR CHOICE? 1 Rl? 6BE 3 R3? 4.3E3 R5? 1B0E3 C? ,015 FOR THIS DESIGN Rl« 68000 OHMS R3= 4300 OHMS R5 180000 OHMS C* ,015 MICROFARADS F* 393.253 HERTZ Q« 3.3357 G* 1.32353 DO YOU WISH TO CONTINUE - Y OR N ? Y YOUR CHOICES ARE AS FOLLOWS 1 CHOOSE Rl* R3 * R5 AND C 2 - CHOOSE 0. «f F AND C 3 - CHOOSE R1, F. Q AND C 4 SCALE FREQUENCY BY CHANGING CAPACITORS 5 - SCALE FREQUENCY BY CHANGING RESISTORS 6 - SCALE IMPEDANCE OF COMPONENTS 7 - DO CALCULATIONS FOR CASCADED SECTIONS ENTER THE NUMBER CORRESPONDING TO YOUR CHOICE? 2 G? 1.33 F? 400 Q? 3.0 C? .015 2 - CHOOSE G» 0* F AND C 3 - CHOOSE Rl* F. 0 AND C 4 - SCALE FREQUENCY BY CHANGING CAPACITORS 5 - SCALE FREQUENCY BY CHANGING RESISTORS 6 - SCALE IMPEDANCE OF COMPONENTS 7 - DO CALCULATIONS FOR CASCADED SECTIONS ENTER THE NUMBER CORRESPONDING TO YOUR CHOICE? 4 NEW FREQUENCY? 600 FOR THIS DESIGN Rl* 50000 OHMS R3~ 4849.77 OHMS RS= 159155 OHMS C= .01 MICROFARADS F- 600 HERTZ 0= 3 6= 1.59155 DO YOU WISH TO CONTINUE Y OR N? Y YOUR CHOICES ARE AS FOLLOWS 1 - CHOOSE El* R3. RS AND C 2 - CHOOSE 6* 0* F AND C 3 CHOOSE Rl• F * Q AND C 4 - SCALE FREQUENCY BY CHANGING CAPACITORS 5 - SCALE FREQUENCY BY CHANGING RESISTORS 6 - SCALE IMPEDANCE OF COMPONENTS 7 - DO CALCULATIONS FOR CASCADED SECTIONS ENTER THE NUMBER CORRESPONDING TO YOUR CHOICE? 5 NEW FREQUENCY? 800 FOR THIS DESIGN Rl~ 37500 OHMS R3= 3637.33 OHMS R5* 119366 OHMS C* .01 MICROFARADS F* 800 HERTZ 0- 3 G* 1.59155 FOR THIS DESIGN Rl» 59832.5 OHMS R3* 4773.68 OHMS RS- 159155 OHMS .015 MICROFARADS F» 400 HERTZ 0» 3 B* 1.33 DO YOU WISH TO CONTINUE Y OR N? Y YOUR CHOICES ARE AS FOLLOWS 1 CHOOSE Rl* R3r RS AND C 2 - CHOOSE Gf O. F AND C 3 - CHOOSE El. Ft 0 AND C 4 SCALE FREQUENCY BY CHANGING CAPACITORS 5 - SCALE FREQUENCY BY CHANGING RESISTORS 6 - SCALE IMPEDANCE OF COMPONENTS 7 - HO CALCULATIONS FOR CASCADED SECTIONS ENTER THE NUMBER CORRESPONDING TO YOUR CHOICE? 3 Rl? 50E3 0? 3 F? 400 C? ,015 FOR THIS DESIGN Rl• 50000 OHMS R3* 4849.77 OHMS R5* 159155 a mm f> ,015 MICROFARADS F* 400 HERTZ 0= 3 G* 1.59155 DO YOU WISH TO CONTINUE Y OR N? Y YOUR CHOICES ARE AS FOLLOWS 1 * CHOOSE Rl» R3. R5 AND C DO YOU WISH TO CONTINUE - Y OR N' 8 ' Y YOUR CHOICES APE AS FOLLOWS 1 - CHOOSE Rl. R3* R5 AND C 2 - CHOOSE G» O. F AND C 3 - CHOOSE Rif Ff 0 AND C 4 SCALE FREQUENCY BY CHANGING CAPACITORS 5 - SCALE FREQUENCY «T CHANGING RESISTORS 6 - SCAl E IMPEDANCE OF COMPONENTS / - do Calculations for cascaded sections ENTER THE NUMBER CORRESPONDING TO YOUR CHOICE? 6 NEW UALUE OF CAPACITOR? .02 FOR THIS DESIGN Rl* 18750 OHMS R3~ 1818.67 OHMS 59683 OHMS C- ,02 MICROFARADS r- 800 HERTZ 0 3 G 1.59155 DO YOU WISH TO CONTINUE Y OR N? Y YOUR CHOICES ARE AS FOLLOWS 1 - CHOOSE Rl. R3» R5 AND C 2 - CHOOSE G» 0* F AND C 3 ~ CHOOSE Rl. F» Q AND C A ~ SCALE FREQUENCY BY CHANGING CAPACITORS 5 - SCALE FREQUENCY BY CHANGING RESISTORS 6 ~ SCALE IMPEDANCE OF COMPONENTS 7 - DO CALCULATIONS FOR CASCADED SECTIONS ENTER THE NUMBER CORRESPONDING TO YOUR CHOICE*? 7 HOW MANY SECOND ORDER SECTIONS? 4 a PER SECTION? 3 GAIN PER SECTION? 1.5? FOR 4 SECTIONS EACH OF Q» 3 THE TOTAL 0 IS 6,89688 THE GAIN OF THE SYSTEM IS 6,39129 73 Magazine • January, 1983 79 Fig . 7. Schematic of a secondorder, multiple-feedback band¬ pass filter ; The notation is the same as that of the program . q merit is useful if one is try- R1 = 2?tFGC ing to achieve a certain in¬ put impedance and the gain P2_ q is not too critical 2nFC(2Q ? -Gj 4) This section allows one to change the center fre- = quency of a previously de- 7 signed filter by changing the Table 1. value of the capacitors. 5) In this segment, one 2) Specify the values of can change the center fre- G, F, Q, and C. The program quency by changing the will calculate the values of value of the resistors. R1, R3, and R5< Since resis- 6) This segment scales tors are usually more read the impedance of the com ily available than capac* ponents in an MFB filter itors, this portion should be while retaining the same F, useful when the gain, Q, Q, and G One chooses the and center frequency are new value for the capaci critical to the proper opera- tors and the program cal tion of the device. culates the values of the 3) Specify the values of resistors to maintain the R1, Q, F, and C This seg- same Q, F, and G This is a useful feature if the desired values of C are not avail¬ able and substitutes must be used. 7) This section allows one to predict the net Q and G of cascaded identical MFB sections For example, three sections each of gain 2.0 and Q = 10 yield a net gam of 8.0 and a net Q of 1 96 Thus, there is a law of di¬ minishing returns for the Q of cascaded sections. An unrealistic calculation shows that 120 cascaded sections each of Q = 2.0 would yield a net Q of 263! The program has been written so that only the de¬ sired sections need he en¬ tered into the computer, in case a mass-storage device is not available The pro¬ gram should run with no dif¬ ficulty on any computer in which the BASIC has both floating-point arithmetic and string variables. Only minor modification would be needed to run the pro¬ gram on a machine that does not have string vari¬ ables This program has been run successfully on an 8K Pet. To illustrate the use of the program, a sample print¬ out has been included. It should be mentioned that several of the computer¬ generated designs were built on a breadboard and that the measured perfor¬ mance agreed very well with the theoretically predicted performance. ■ References 1. ‘Design Your Own Active Fil¬ ters.” H. M. Berlin, QST, June, 1977. 2. “Active Bandpass Filters,” T. A. Conboy, Ham Radio , De¬ cember, 1977. 3. The Radio Amateur's Hand¬ book , Fifty-sixth edition, Amer¬ ican Radio Relay League, New¬ ington CT. 4. The Active Filter Cookbook , #21168, Howard W. Sams, In¬ dianapolis IN, 1975. 5. Design of Active Filters, With Experiments, H. M. Berlin, #21359, Howard W. Sams, In¬ dianapolis IN, 1978. FILTER CASCADING ■ ALL BAND TRAP ANTENNAS!! The most cost-effective way to improve the selectivity of any receiver - old or new - is to improve its IFfiltering A Fox-Tango Cascading Kit puts a high-quality steep¬ sided 8-pote filter in series with your present filter(s), both SS8 and CW. The result is narrower Bandwidth and better Shape Factor, both of which dramatically reduce adjacent channel GRM - a necessity in today's crowded bands. CONSIDER THESE KIT FEATURES • Easy installation - 30 minute average. • No drilling, switching, alignment • 16 poles of filtering yield: Filter Shape Factor as high as 1 19 Ultimate Rejection better than lOOdB Works wonders on SSB, improves CW • Compensates for Filter insertion loss, • Complete instructions, clear diagrams, • No RX audio impairment, TX unaffected • Includes Filter and ail needed parts. • Fits all models of Senes - any letter • All Filters 8-pole - Guaranteed One Year SPECIFY KIT WANTED WHEN ORDERING YAESU FT101 S75; FT101ZD$70; FT107 S75; FT901 12 $65; FR101 $55 (filter only). KENWOOD TS520/R599 S70; TS820$70; TS830/RB20S150 (Two Filters), HEATH SB104A $60. Shipping $3 (Air $5). FL Sales Tax 5% In addition to the above, FOX-TANGO stocks a wide line of $55 SSB. CW. and AM 8-pole filters for Yaesu, Kenwood. Drake R4C and 7-iine, and Heathkit Also, special filters made to order Send specs for quote GO FOX-TANGO - TO BE SURE! Order by Mail or Telephone. 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The ONLY ANTENNA YOU WILL EVER NEED FOR ALL DESIRED BANDS - WITH ANY TRANSCEIVER - NEW - EXCLUSIVE! NO BALUNS NEEDED! 80-40-20-15-10-6 meter - 2 trap — 104 ft. with 90 ft. RG50U - connector -Model 990BUC $09.95 40-20-15-10 meter — 2 trap —54 ft. with 90 ft. RG50U - connector - Model 1001BUC_$80.95 20-15-10 meter — 2 trap— 2 6ft. with 90 ft. RG50U - connector - Model 1007BUC.$07.95 SEND FULL PRICE FOR POSTPAID INSURED. DEL. IN USA. (Canada Is $5.00 extra for postage - clerical- customs etc.)or order using VISA - MASTER CARD - AMER. EXPRESS. Give number and ex. date. Ph 1-306-236-5333 9AM - 6PM week days. We ship in 2-3 days. ALL PRICES MAY INCREASE . . SAVE - ORDER NOW! All antennas guaranteed for 1 year. 10 day money back trial H 1 returned in new condition! Made In USA. FREE INFO. AVAILABLE ONLY FROM _WESTERN ELECTRONICS_ Dept. AM_Kearney, Nebraska, 68B47 ✓SO PORT APEATER Q - - — S 179.00 assembled unit Tl* *4Channel PROM CW I Der led M100 A $99.00 assembled INSTANT REPEATER board * Works with any ANY BAND ANY MODE type radios * VOX or COR operation * 250 volt switching capability * An Instant Repeater •Complete Timer Functions • Built In Test Functions •20 Page Technical Manual Repeater (Fully tested, programmed, assembled) ^302 W-S ENGINEERING P.O. BOX 58, PINE HILL, N.J. 08021 (201-852-0269) 73 Magazine • January, 1983 The Cornerstone of Equipment Failure: Heat Damage The proper heat sink will preserve transistors. Learn how to keep your circuitry from resembling a core meltdown. Kenneth H Shamburger 1413 Glendale Greenville TX 7540? H eat is a hazard to all electronics projects. Many electronics enthusi¬ asts have experienced the displeasure of watching a prized project destroy itself with heat. Understanding heat transfer and heat-sink selection is necessary to avoid this hazard This article explains the fundamentals of heat-sink selection, which are easy to understand and apply. It begins with a review of the ways heat is transferred, ex¬ plains how to calculate the temperature inside a semi¬ conductor component, pro¬ vides an example of heat¬ sink selection, and contrib¬ utes some hints for inter¬ preting semiconductor and heat-sink thermal specifica¬ tions The Review "Heat transfer" is more accurate in describing the removal of heat than "heat flow " The word "flow" lim¬ its the possibilities we asso¬ ciate with the phenomenon to a single action—such as water flowing Heat is trans¬ ferred by three mecha¬ nisms. It is transferred by radia¬ tion as an electromagnetic wave The heat transmitted from the sun through the vacuum of space to the Earth is an example of radi¬ ation Heat is transferred by conduction when two ob jects are in contact. A sol¬ dering iron melts solder by conduction. Heat is transferred by convection when a fluid medium, such as air, moves across the surface of an ob¬ ject The air drawn through the radiator of your auto¬ mobile cools the radiator by convection When air is blown across an object, it is called forced convection But, the air surrounding a warm object will rise, caus¬ ing cooler air to replace it without the aid of a fan. When air is allowed to cir¬ culate by heating, it is called natural convection Heat is transferred from semiconductor devices by all three mechanisms, as il¬ lustrated by the transistor in Fig. 1. It is radiated from the transistor chip to the case (a) and is conducted to the case where the sub¬ strate and case are in con¬ tact (b). The heat trans¬ ferred to the case distrib¬ utes itself throughout the case by conduction and, then, is transferred to the surrounding air by convec¬ tion (c). If a heat sink is at¬ tached to the transistor, heat is transferred from the transistor case to the heat sink by conduction and to the surrounding air by con¬ vection. Also, it is radiated from the case and heat sink to objects nearby However, the amount of heat transferred by radia¬ tion is a small percentage of the heat transferred by con¬ vection For this reason, the heat transfer equations typ¬ ically used in heat-sink se¬ lection calculate only the heat transferred by natural convection. Similarly, the heat transferred by radia¬ tion from the chip to the case does not receive spe¬ cial attention in the calcu¬ lations And despite the in¬ accuracy, convenience makes us think of heat as flowing These simplifica¬ tions ease the analysis pro¬ cess. Not all heat generated in the transistor is transferred to the air. Each segment of Fig. L Heat transfer from a transistor: (a) from chip to case by radiation; (b) from chip to case by conduction; (cj from case to air by convection. 84 73 Magazine • January, 1983 « JA *fe5*c/w the path between the chip and the air resists heat flow in a manner similar to a re¬ sistor resisting current flow. The heat retained in the transistor because of this impedance causes the tem¬ perature of the chip to rise. Our goal is to determine the temperature of the transis¬ tor chip. The chances of its destruction then can be evaluated. The Fundamentals In classical physics, equations have been devel¬ oped for calculating the amount of heat transferred; they are not complicated. However, their solution de¬ pends upon parameters which are difficult to eval¬ uate in practice. For this reason, engineers have de¬ vised equations which do not use these parameters, but which make heat flow analogous to electric cur¬ rent flow. In this analogy, a heat source is analogous to a current source, thermal resistance to electrical re¬ sistance, and temperature to voltage. The equation re¬ lating them is like Ohm's Law and says that the differ- ence in temperature (volt¬ age drop) across a thermal resistance is equal to the thermal resistance multi¬ plied by the heat (current) flowing through the resis¬ tance. This thermal equiva¬ lent to Ohm's Law is ex¬ pressed by the equation T = ©P. The symbol ©, with sub¬ scripts to indicate the cir¬ cuit connections, common¬ ly represents thermal resis¬ tance For example, ©jc is the thermal resistance be¬ tween the transistor chip and its case. (The capital for junction, is used widely to represent the source of heat in semicon¬ ductor components.) Val¬ ues of thermal resistance for semiconductor compo¬ nents and heat sinks are us¬ ually obtained from their respective specifications. In an electronic compo¬ nent, heat originates as Fig. 2. Thermal circuit for a semiconductor power dissipated by the device. The thermal anal¬ ogy carries this into the electrical thermal model by making power, identified by a capital "P," equal to heat. (Sometimes the lowercase "q" is used to represent power because this symbol is used for heat in physics.) The Calculations Our goal is twofold First, we must determine the tem¬ perature of the semicon¬ ductor chip If this tempera¬ ture exceeds a safe value, we must determine the ther¬ mal specifications for a heat sink which will provide adequate transfer away from the transistor. Using the electrical thermal anal¬ ogy, the calculations in¬ volved in both tasks are similar to electric circuit calculations. A diagram for the ther¬ mal circuit of a transistor is illustrated in Fig. 2. The unique feature of this dia¬ gram is the voltage source labeled T A . This addition does not alter the validity of the model. The proper¬ ties of the theoretically per¬ fect current source (labeled P) do not allow current to flow backward through it. Since it is the only source of current in the circuit, the current flowing through the circuit equals P. The voltage source is simply a way of representing the temperature of the sur¬ rounding air (called the am¬ bient temperature). It is con¬ venient to include it so that the ambient temperature appears in Kirchoffs volt¬ age equations for the cir¬ cuit. Some people, choos¬ ing to account for T A later 9 it *es Fig. 3. Thermal circuit for a semiconductor with a heat sink. in the analysis, do not in¬ clude this source. A resistor represents the thermal resistance of each segment along the path be¬ tween the semiconductor junction and the ambient. Each segment can be identi¬ fied by the letters compris¬ ing its subscripts. Beginning at the junction, these are JC for junction-to-case and CA for case-to-ambient. The thermal analogy for Kirchoffs Voltage Law says that the temperature of a semiconductor chip is equal to the sum of the tem¬ perature drops around the remainder of the circuit. This is expressed by the equation Tj = Tjc + Tca + T a , where Tj is the semicon¬ ductor chip temperature, Tjc is the temperature drop across ©jc Tca is the tem¬ perature drop across ©ca, and T a is the ambient tem¬ perature. The values of Tjc and Tca can be calculated from the thermal equiva¬ lent of Ohm's Law. Substi¬ tuting these into the above equation, the junction tem¬ perature equation becomes T) = (©]C + ©Ca) P + T a . Many times, a manufac¬ turer specifies a value for ©j a, which is the thermal re¬ sistance between the junc¬ tion and the ambient ©| A is equal to the sum of ©jc and ©ca and may be used in the preceding equation instead. A thermal circuit which includes the thermal resis¬ tances associated with a heat sink is illustrated in Fig 3 The case-to-ambient resistance, ©ca, has been re¬ placed by two resistances, the case-to-sink resistance, ©c$, and the sink-to-ambi- ent resistance, ©s A When Fig. 4. Thermal circuit for the example without a heat sink. « cs *4a*c/w Fig. 5. Thermal circuit for the example with a heat sink. these are substituted for ©ca. the equation for the semiconductor junction temperature becomes Tj = (®|C + e c$ + ©sa)P + Ta. A heat sink is selected on the basis of its ©$a, which characterizes its ability to transfer heat into the sur¬ rounding air To determine the largest value of ©sa that will maintain a safe semi¬ conductor temperature, the equation is solved for ©$ A This yields the following equation: © SA = [(Tj-T A )/P] -(ejc + ©cs) An Example Suppose you are design¬ ing an audio amplifier You have estimated the power dissipation of the output transistor at 2 Watts. Hav¬ ing selected a transistor, you determine the relevant parameters from the tran¬ sistor data sheet These pa¬ rameters are the maximum allowable power dissipa¬ tion (P ma *), the maximum operating junction temper¬ ature (T) m ax). the junction- to-case thermal resistance (©jc), and the junction-to- ambient thermal resistance ( 0 |a) The values you found are listed below. P mdX = 10 Watts T],max = 150°C ©j C = 12.5° C/W ©,a = 65° C/W Also, you note that the Magazine • January, 1983 85 MAXIMUM RATINGS Hem 3: maximum junction operating tem¬ perature. item 4: specified thermal resistance 6 jq. Item 6: derating curves for case and am¬ bient temperatures Rating Symbol 2N6034 2N6037 2N6035 2N6038 2N6036 2N6039 Unit Collector-Emitter Vo stage v CEO 40 60 80 Vdt Collect of-Base Voltage Vcs 40 60 80 Vdc Emitter Base Voltage v eb — *>0 Vdc Collector Current - Continuous Peak *c — -4.0-— — -8 0-— Adc Base Current *8 —-too mAdc Tots! Pome. Dissipation 0 T c « ?5 {J C Derate above 25°C p o — -40-— — -* 0.32-— Watt* w/°c Total Power Dissipation T^ » 25 f, C Derate above 25°C p o — -1 5-— — -0 012-— Watt* w/°c Operating and Storage Junction Temperature Range T J- T *tg —--65 to +150-- -Sc~ THERMAL CHARACTERISTICS Characteristic Symbol Max Unit Thermal Resistance, Junction to Case ^JC 3.12 °C/W Thermal Resistance, Junction to Ambient 3ja 93 3 °C/W *lnd»catet JEDEC Registered Data Item 1 ; maximum power dissipation at specified case temperature and derating. Item 2: maximum power dissipation at specified ambient temperature and derat¬ ing. Item 5: specified thermal resistance Fig. 6. Semiconductor thermal specifications and parameters. transistor is in a TO202 (plastic) case In addition to these specified parameters, you have ascertained that the temperature of the air surrounding the transistor will not exceed 150° F (65.6° C). Good design prac¬ tice suggests that you use a value between 10 and 20 percent greater than your estimated value for this temperature, as a safety factor, which you have done (A diagram of the thermal circuit is shown in Fig 4.) Because your first con¬ cern is whether your transis¬ tor needs a heat sink, you use the value specified for Bja to calculate Tj as fol¬ lows; T, - (e, A )P + T a T, = (65)2 + 65.6 T) = 195.6° C The calculated value of Tj is greater than the specified maximum operating junc¬ tion temperature (Tj mdx ) by 45 6° C The next step is to deter¬ mine the thermal resistance required of the heat sink This is accomplished by solving the equation for e$ A after substituting the value of Tj max for Tj However, the value of one other pa¬ rameter, the case-to-sink thermal resistance, ©cs, must be determined before Metal-to-Metal Insulated Case Style Dry Lubricated Dry Lubricated TO-3 0.5 0.1 1.3 0.36 TO-66 1.5 0.5 2.3 0.9 TO-83 — 0.1 — — TO-94 — 0.1 — — TO-126 2.0 1.3 4.3 3.3 TO-127 1.6 0.8 2.6 1.8 TO-202 1.3 0.9 4.8 2.0 TO-220 1.2 1.0 3.4 1.6 Table 7. Case-to-sink thermal resistance in °C/W. 86 73 Magazine • January, 1983 this equation can be solved © cs depends upon the method used to mount the transistor It usually is pro¬ vided in a table by heat-sink manufacturers and, occa¬ sionally, semiconductor manufacturers. Table 1 lists values of ©c;s for some com¬ mon transistor case types and mounting methods After obtaining a value of 48° C/W for ©cs. the completed thermal dia¬ gram is shown in Fig. 5. ©s A is calculated as follows: e SA = ((150 - 65.6)/2] - (12.5 + 4 8) © SA — 24.9° C/W A heat sink with a ther¬ mal resistance of 24.9° C/W or less will provide ade¬ quate heat transfer. A num¬ ber of small, inexpensive heat sinks with a ©s A of 20° C/W for the TO202 case style are available You sim¬ ply select one which meets your mounting require¬ ments The Semiconductor Specs Except for saying that they are found in the manu¬ facturers' data sheets, de¬ tails of how the values for thermal resistances are ob¬ tained have not been dis¬ cussed. Yet determining these values from the speci¬ fications sometimes re¬ quires skill Familiarity with the types of data most like¬ ly to appear in the data sheet is necessary to suc¬ cess. With the aid of the data sheet appearing in Fig. 6, this data and its interpre¬ tation are described in the following paragraphs. The data sheet in Fig. 6 was chosen to illustrate common methods of speci¬ fying semiconductor ther¬ mal specifications for two reasons. First, all of the spec¬ ifications are labeled clear¬ ly and are arranged into a single, logical area of the specification This is not true of all semiconductor data sheets Often, thermal specifications, particularly for linear integrated cir¬ cuits, are placed in notes. (The entire data sheet should be read before con¬ cluding that they have been omitted ) The second rea¬ son for selecting the data sheet shown in Fig. 6 was that it contained all of the data relating to thermal specification. A typical data sheet will provide only a portion. Thermal resistance is specified by direct specifi¬ cation, by derating, and by thermal-related parame¬ ters. A manufacturer uses direct specification when he tabulates thermal resis¬ tance in data sheets. The designer simply inserts the specified values into his thermal equations Items 4 and 5 of Fig 6 illustrate di¬ rect specifications. A derating specifies how quickly the maximum pow¬ er dissipation must be de¬ creased as the case or ambi¬ ent temperature increases. A derating may be given by statement (illustrated by items 1 and 2) or by curve (illustrated by item 6). A nu¬ meric value for thermal re¬ sistance is needed for the thermal analysis. The tech¬ nique for determining a number from this kind of specification is more easily explained using an exam¬ ple The derating (item 1) indi¬ cates that the 2N6034 has a maximum power dissipa¬ tion of 40 Watts at a case temperature of 25° C It also indicates that this should be derated at 0 32 W/°C above 25° C The de¬ rating is assumed to be lin¬ ear above the specified tem¬ perature unless otherwise specified. This means that for every degree increase in case temperature, the dissi¬ pated power must be de¬ creased by 0.32 Watts An examination of the electrical thermal model in Fig. 2 causes us to conclude that the power has to be de¬ creased because junction- to-case thermal resistance is limiting heat flow from the device. Furthermore, the rate at which the power must be decreased as the temperature increases is re¬ lated to the value of this thermal resistance. Actual¬ ly, the rate of derating is the reciprocal of the thermal re¬ sistance. Thus, the junction- to-case thermal resistance for the 2N6034 can be cal¬ culated: e jC = 1/0.32 ©1C = 3.125° C/W The same technique can be applied to determine the junction-to-ambient ther¬ mal resistance from the de¬ rating in item 2. The type of thermal resis¬ tance specified is indicated by the location of the speci¬ fied temperature. The sub¬ script attached to the tem¬ perature symbol identifies this location. Frequently, a manufac¬ turer will provide a derating curve, such as the one illus¬ trated in Fig. 7, which pro¬ vides the same information in graphical form. The hori¬ zontal axis indicates tem¬ perature. In this curve, it is temperature at the case. The vertical axis is the maxi¬ mum dissipated power al¬ lowed at the indicated tem¬ perature To find the ther¬ mal resistance from a derat¬ ing curve, divide the differ¬ ence in temperature by the difference in dissipated power. From Fig. 7, the tem¬ perature changes from 25° C to 150° C, which is 125° C. The change in dissipated power over this tempera¬ ture range is from 40 Watts to 0 Watts, a difference of 40 Watts. Thus, ©jc is calcu¬ lated by dividing 125 by 40. ©1C = 125/40 ©|C = 3.215° C/W Notice (in item 6 of Fig. 6) that Motorola gave a derat¬ ing curve for both case and ambient temperatures Each curve is labeled with the appropriate tempera¬ ture. A manufacturer may not specify either a thermal re¬ sistance or a derating. How¬ ever, a knowledgeable de¬ signer can determine a de¬ rating specification from other specifications and calculate the thermal resis¬ tance from this derating. The key to determining a derating curve for a semi¬ conductor is to find two points of the curve above the temperature where it begins to slope downward. Among other parameters, the derating curve specifies the temperature above which the device can no longer be operated, that is, T),max (see Fig. 7). At this temperature, the power must be zero This is equiv¬ alent to saying that the current must equal zero in the electrical thermal cir¬ cuit (Fig. 2). Because no current is flowing in the circuit, no temperature is dropped across either ©jc or ©ca T hus, the maximum operat¬ ing temperature of the de¬ vice must equal the maxi¬ mum operating ambient temperature and the maxi¬ mum operating case tem¬ perature. When the manu¬ facturer specifies Tj max , one point on both the ambi¬ ent and the case tempera¬ ture derating curves is known. The second point on the derating curve is es¬ tablished as the tempera¬ ture where the maximum power dissipation is speci¬ fied. For example, the follow¬ ing are specified for the 2N6034 (items 1 and 3). P max = 40 Watts® T c = 25° C Tj.max =150° C The fact that this data agrees with the derating curve can be verified by comparing these two points on the derating curve la¬ beled Tc in Fig. 6, item 6. Though Motorola seems to specify P max as part of the derating specification, the appearance is created by the organization of the data sheet. The common prac¬ tice is to specify that pa¬ rameter, though no derat¬ ing is specified. Typically, the values of thermal resistance calculat¬ ed from the derating curve and from the power and temperature specifications will agree with the specified thermal resistances within a few percent. Have you cal¬ culated ©ja by the above methods to find how close¬ ly they agree to its specified value? As a designer searches for thermal specifications, he will discover that either ©ja or ©jo but not both, is specified for a number of devices. Also, these specifi¬ cations will be void of data which allows calculation of the unspecified value. This is true because manufactur¬ ers specify the parameters they believe relevant to the use of the device being specified, as they under¬ stand its application In this regard, a device may fall in¬ to one of three categories. It may have a specific function and the designer is not expected to concern himself directly with the power dissipation versus temperature relationship. For example, an SN7400 TTL quad NAND logic gate has a specific function. In this case, the manufacturer specifies the maximum temperature of operation for the device. The designer is expected to limit the am¬ bient temperature to a value such that the speci¬ fied value is not exceeded. A device may be designed for use with or without a heat sink. These devices. Magazine • January, 1983 87 the heat flow To find the thermal resistance, simply find the temperature differ¬ ence caused by the heat flowing in your thermal cir¬ cuit Then, divide the tem¬ perature difference by that power In the example where we calculated the audio output transistor dissipated 2 Watts. The curve in Fig. 8 shows a temperature differ¬ ence of 40° C at a 2-Watt power dissipation Thus, the thermal resistance is: e SA = 40/2 ©SA = 20° C/W Sometimes, the thermal re¬ sistance curve is nonlinear, meaning that e SA changes as the dissipated power in¬ creases. Thus, it will not be a straight line, as shown in Fig, 8. Usually, it is straight In either case, ihis technique determines ©$A easily All manufacturers pro¬ vide curves with essentially the same data The only dif¬ ference is the axis labeling For example, IERC labels the vertical axis on some of their data sheets "max¬ imum sink temperature rise being rated between 0.25 The Heat-Sink Specs above ambient (°C)" To and 5 Watts dissipation Values of thermal resis- avoid confusion, simply without a heat sink, usually tance for heat sinks are remember the thermal are classified as small or in- more easily determined equivalent of Ohm's Law: A termediate power devices. f rom data sheets than are temperature difference is An example is the 2N6034 those for semiconductors, caused by heat flowing Darlington used in the Thermal resistance for a through a thermal resis- above examples Both ©j A heat sink can be provided tance. and ©|c are specified for by either of two methods. One other factor must be these devices. The fj rst is by direct state- considered during heat-sink Lastly, a device may be ment, as in the case of semi- selection The thermal resis- classified for use only with conductors The second tance of a heat sink is sped- a heat sink. These are the method is by curve, as illus- fied for a specific physical high-power devices, such as trated in Fig 8 The horizon- orientation of the heat sink the 2N3055. The data man- tal axis is heat as power dis- (This is true of semiconduc- uals commonly provide on- sipated The vertical axis tors, also.) Except for heat ly the data required to de- shows the temperature dif- sinks which are designed termine the heat-sink re- ference between the heat for special applications, the quirements. sink and ambient caused by manufacturer specifies the resistance for maximum un¬ obstructed natural convec¬ tion. To understand the meaning of this, recall that natural convection depends upon heated air rising to be replaced by cooler air. A heat sink operates properly when air can circulate free¬ ly across the maximum area of every fin. This means Fig . 8. Heat-sink thermal rating curve. that it should be mounted 66 73 Magazine • January, 1983 0 12 3 4 5 DISSIPATED POWER (WATTS) I ACT| I I ■ This service will be available nationally. Lab tested & time proven modifications professionally installed in your amateur Handy-Talkie 2M, 220, 440, MH2 transceiver by Henry Radios warranty technicians {KNOWN AS “A&W PRODUCTIONS") HAVE ALL PL TONES AVAILABLE AT YOUR FINGER TIPS Outboard the dip switch! Have it neatly tnlayed into the back cover ot your Handy-Talkie making ait 32 PL Tones Selectable at a moment's notice. •25 Got your own PL? Send it to us with your Handy-Talkie unit and we do the professional Installation for you. •55 We will Install a new PL and inlay the dip switch into the back cover of your Handy-Talkie ready to operate Send us your Handy-Talkie unit and a check or money order plus S3.5G tor shipping and hand¬ ling payable to AAW PRODUCTIONS. INC. For TEMPO units the dip switch is tnlayed into the Push-to-Talk bar The TEMPO 8-15 will have the dip switch intayed into the back cover *45 We will install a NEW BATTERY BEATER in youi TEMPO S-1, S-2. S-A, S-5 READY to operate. Your New Battery Beater wilt use the same jack as Ihe charger with no new holes and regulation circuits built into unit Comes with Cigar Lighter Adapter with internal fuse CONTACT AAW PRODUCTIONS FOR SPE¬ CIAL MODIFICATIONS YOU MAY WANT TO HAVE DONE. WE SPECIALIZE IN THE TEMPO HANDY-TALKIES. WE ARE AN OFFICIAL 'TEMPO’ REPAIR STATION L WORK GUARANTEED FOR 30 DAYS SEND YOUR HANDY-TALKIE AND A CHECK OR MONEY ORDER TO jO^/SPODUCTJONS ~ mm W Cmltfomim 90405 (213) B 2 B Q310 with its fins vertical. Also, the ends should be kept clear to allow unobstructed entry of air between the fins at the bottom and exit from the top. Your mounting con¬ straints should always be considered during heat-sink selection . Summary The principles involved in heat-sink selection are now complete The thermal circuit and its electrical equivalent provide a theo¬ retical model for easy anal¬ ysis of thermal phenomena Thermal resistances for an equivalent circuit are deter¬ mined from the manufac¬ turers' data sheets. Applied to the thermal circuit, Ohm's Law and Kirchoff's Voltage Law, which are un¬ derstood by those who work with electrical cir¬ cuits, allow calculation of the semiconductor junction temperature. The calculat¬ ed temperature is com¬ pared to the maximum tem¬ perature specified by the manufacturer to determine the necessity of a heat sink If a heat sink is required, the maximum semiconductor temperature is substituted into the equations to deter¬ mine the maximum thermal resistance for a heat sink which will limit the junction temperature to a safe val¬ ue Two criteria are used to se¬ lect a heat sink Its thermal resistance must be less than the calculated maximum val¬ ue a nd its mounting must be consistent with the design er's application, Heat-sink selection using these criteria completes the process. Acknowledgements The semiconductor data contained in Fig 6 was re¬ produced from page 4-195 of the Power Device Data Manual, 1st Edition, copy¬ right 1978 by Motorola Semiconductor Products, Inc , Phoenix, Arizona Per¬ mission to print this portion of the manual was provided by Motorola, ■ Calvin McCarthy VE7DOD Box 1333 Princeton B C Canada VOX 1W0 Your January Home-Brew Project No frills—just a solid $10 SSB exciter for HF. Who says hams don't build anymore? P romises, promises. How can any SSB exciter be inexpensive when an i-f fil¬ ter is needed? I have been regaled with plans for inex¬ pensive SSB generators, but the operative paragraph usually describes how the filter was found deep in the bowels of the faithful junk box or bought for a song from an unsuspecting entre¬ preneur at the last flea mar¬ ket. I have always arrived just as the last treasure has been sold The promise of an inexpensive exciter elud¬ ed me. So what am I offering you? Another inexpensive SSB exciter. This time the operative paragraphs will describe how you can make a very satisfactory crystal i-f filter for less than $10.00 which needs no critical tun¬ ing or messy and unpredict¬ able crystal grinding. I will then describe how I used it in a 15-meter exciter This simple filter is made using four of the ubiquitous 3,58-MHz television crys¬ tals in a ladder configura¬ tion as shown in Fig. 1. If all you want is a simple i-f filter, this could be built as described by the schematic and you would be pleasant¬ ly impressed by its perfor¬ mance For those who are innovators and have other crystals which are the same in frequency, there are general design rules for making two-, three-, and four-crystal filters. Fig 2 gives the normalized ca¬ pacitance values for these. To find the actual value of —»— —tai— i pHlM r-» — : 22 k -Leo U. J Lee J Le, J Leo ji b 1 “ ] p 59p- i 7 /I p 56 pF p 7 n r 59 *f '"I 7 n P 8 2 7 m Fig. 1. A 3.58-MHz crystal-lattice SSB i-f filter with an audio bandwidth of 2 kHz and 2.2k input and output impedance. The prototype 15~meter SSB exciter. 92 73 Magazine • January, 1983 The exciter displaying the crystal filter mounted in a minibox for shielding. H te fe ic *c Hlh -Ci rti' - H r -Ilf- - 11 - ^CO ? t ; ci 2 n ? rt 7 Fig. 2. To find the actual value of the shunt capaci¬ tors, multiply the coeffi¬ cient beside each capacitor by 1/(2nfR), where f is the crystal frequency and R is the filter design impedance. each capacitor, the coeffi¬ cient beside each capacitor must be multiplied by 1/(2nfR) where f is the reso¬ nant frequency of the crystals in Hertz and R is the design input and output impedance in Ohms. For the suggested filter using the 3 58-MHz crystals, R was chosen to be 2 2k Ohms — thus 1 /(2irfR) = 20 pF. C a = .4142 X 20 pF = 8.284 pF = 8.2 pF; C, =1.82 X 20 pF = 36.40 pF = 39 pF; C 2 = 2.828 X 20 pF = 56.56 pF = 56 pF If the impedance was chosen to be 1.8k Ohms, then C 0 = 10 pF, C, = 47 pF, and C 2 = 68 pF. Thus, the impedance which is chosen to work toward is flexible, but there are a few considerations to notice As the impedance is lowered, the passband of the filter is reduced and the insertion loss will increase. On the other hand, as the im¬ pedance is increased, the passband widens but the ripple in the passband also increases. As well, the low capacitance values for higher impedances make stray capacitance more troublesome. This technique has been used by others to make •S2V r t r r *J2V J C 4 TURtfS AftOWO LI m H i m f‘ #,r to —)->BALANCED C 356 MHt -Ill- Fig. 4. Carrier oscillator . All resistors are Va Watt LI could be Miller part 46A225CPC with a 4-turn secondary added[ available from Radiokit, Box 411H, Greenville NH 03048. filters using surplus crystals in the 8-to-12-MHz ranges as well. It was stated that a design impedance of 800 to 1000 Ohms was usable at that frequency for an SSB filter. A design impedance of 1500 Ohms was usable at 5 MHz. In putting this filter into a circuit, it is imperative that it be properly terminated in its design impedance, both on the input and output. Neglecting this can give a very high passband ripple. Now, you may think, we have the filter, but there is always a need for carrier-os¬ cillator crystals. Good news! The series resonant frequency of the crystals controls the lower limit of the passband, so one more crystal identical to those used in the crystal filter will allow selection of the upper sideband How easy can it be? Listening to OSCAR 8, mode A has whet my appe¬ tite for a taste of operating through this satellite. One constraint seems to be that one should have full-duplex capabilities for the most success, but I had no VHF equipment and only one HF transceiver. I built a simple transmitting converter with five Watts output on 2 meters for one-milliwatt in¬ put on 15 meters. This gave me VHF capability. I first proposed to excite this with a CW signal; then the idea of a DSB exciter was enter¬ tained before I discovered the inexpensive crystal filter just described. I then could proceed with a full SSB exciter with an output power of one milliwatt on 15 meters. The design phi¬ losophy was very simple— I used the parts I had easily available to build a basic transmitter without bells and whistles This was done and I am happy with the results. Microphone Amplifier The microphone amplifi¬ er described in Fig. 3 must match a low-impedance dynamic microphone to a low-impedance, balanced- modulator input while in¬ creasing the microphone output of 2 mV to one volt The first stage is a common base amplifier to take ad¬ vantage of the low input im¬ pedance and high voltage gain of this configuration. This directly drives a com¬ mon emitter amplifier with adjustable feedback in the emitter to control the gain of this stage. The output stage is the common 741 operational amplifier, used for its very low output im¬ pedance which easily drives the 100-Ohm audio input of the balanced modulator. If you have other micro¬ phones, you will need dif¬ ferent amplifier circuits than this. Just remember to 73 Magazine • January, 1983 93 use a low-impedance out¬ put circuit to successful¬ ly drive the balanced modulator Carrier Oscillator The crystal-controlled Colpitts oscillator (Fig. 4) was chosen as the carrier oscillator because it is very easy to get operating and the crystal vibrates in its series resonant mode. The output is terminated in a 100-Ohm variable resistor which allows for the adjust¬ ment of the carrier level for best carrier suppression in the balanced modulator. Inductor LI was found in a Poly Paks assortment and a four-turn secondary was added. Miller part 46A225CPC also could be used for LI. Balanced Modulator This is the popular MC1496 double-balanced modulator which, when built with reasonable care, works very well (see Fig 5) The first one was built on the same PC board as the crystal filter, but the result¬ ing 30-dB carrier suppres¬ sion was disappointing With proper shielding of the carrier oscillator and crys¬ tal filter, this suppression was increased to a usable •82 V 50 dB. The balanced-modu¬ lator output is greater than is needed by the carrier mix¬ er and also greater than can be passed by the filter. With this in mind and having a need for a resistive input-fil¬ ter termination, the bal¬ anced modulator is output into a resistive pad, the value of which is chosen to give maximum linear con¬ version mixer output with¬ out limiting while retain¬ ing maximum carrier sup¬ pression. Carrier Mixer The 3 58-MHz single¬ sideband output of the crys¬ tal filter must be converted to the desired 21.5-MHz band to be usable. In order to properly terminate the filter and provide im¬ pedance conversion, an FET buffer amplifier is in¬ cluded which drives the 600-Ohm input of the TL442 balanced mixer (Fig 6). This integrated circuit was cho¬ sen as it uses few biasing components and has good carrier suppression without balancing controls If de¬ sired, the MCI4% could be used with equally good re¬ sults if the TL442 is hard to find. With this situation in mind, a carrier mixer was built using the easily found MC1496 double-balanced mixer. I had good success with it as well This mixer circuit, shown in Fig. 7, is almost identical to the bal¬ anced modulator R1, be¬ tween pins 2 and 3, was made variable, enabling me to set the gain of the stage and thus control the drive to my transmitting convert¬ er. The output was made single-ended instead of balanced, so I could use the same tuned circuit as was used for the TL442 mixer The input drive circuit was made a source follower to properly match the lower input impedance of the new circuit. The SSB drive level into the mixer is adjusted so that the maximum input does not cause the output Fig, 5. Balanced modulator All resistors are V* Watt T2:42 uH; primary— T50-2—91 turns c-t bifilar wound #34; secondary—30 turns wound over primary. X I >6000 filter FIGURE I GJ*F -M— /ft rh KEYED * 12 V _ f 0 IpF EP IOpF -)l— TL44Z | I Jl 1 X ft* from vro OUTPUT -> LINEAR AMP Fig. 6. Carrier mixer. FROM v FILTER ) 0/P rh rh T r Qi?f bb- .0l*F bb- 50* CARRIER NOLL T T a X, T .t^h to I 3*»H VARIABLE INDUCTOR I->T0 PA Fig. 7. Carrier mixer using the MC1496 double-balanced mixer. 94 73 Magazine • January, 1983 INPUT FROM CENTRE TAP OF CARRIER MIXER INDUCTOR > 9ipF 2K5PF -W- TRAP TUNED TO )4MH* X I .01 4 7K 4Tj>F ~3b 2 2K IK rb KEYED *f2V -)h X X /r\2N5t79 r x lOOfl ^820 pF All RESISTORS t/4 WATT I OUTPUT Fig. 8. Linear amplifier. 220n *12 V Fig. 9. Vfo. LI: 23 turns of #22 enameled wire close-wound on 3/8"-diameter ceramic form . 77: Primary^25 turns #34 enameled wire on Amidon toroid T25- 6; secondary — 28 turns center-tapped #34 enameled wire wound over primary. which allowed for engineer¬ ing changes at a whim (also called mistake rectifica¬ tion), and many ideas were tried as I went along. All cir¬ cuits were put on printed circuit boards as this makes for neat construction. The vfo and carrier oscillator are on single-sided board and the others are on dou¬ ble-sided board. I also put the carrier oscillator and the crystal filter in their own shielded enclosures to reduce the carrier feed¬ through, interconnecting the units with RG-174 coax¬ ial cable and audio-cable connectors. A block dia¬ gram of my exciter is shown in Fig. 10. Many parts values may be questioned, and I assure you that I would not argue for their absolute value. My choice has been controlled very much by availability. I had some 1-uH variable in¬ ductors bought from Digi¬ tal Research Corporation of Texas, a bag of assorted in¬ ductors and chokes from Poly Paks, some dipped- mica capacitors removed from surplus boards, and assorted resistors. to limit. The output is ad¬ justed by R1 to properly drive the PA stage, and the carrier null potentiometer is adjusted for minimum vfo output. Usually it will be sufficient, in this service, to set the null pot at its mid¬ point. Carrier suppression is less critical here than in the balanced modulator. Linear Amplifier The linear amplifier (Fig. 8) supplies about 1 milli¬ watt output, sufficient to drive my transmitting con¬ verter to full output. An in¬ put series trap tuned to 14 MHz was included to re¬ duce the level of the unde¬ sired mixer product (proba¬ bly an unnecessary frill but, having the parts, it was easy to include). If greater out¬ put is desired, the collector- base negative feedback Fig. 10. Block diagram of exciter. could be reduced or more stages of amplification in¬ cluded. Vfo The variable frequency oscillator (Fig. 9) is the series-tuned Colpitts or Clapp oscillator driving a push-push doubler to pro¬ vide an 18-MHz carrier for the conversion mixer. The doubler is made with a CA3028 differential ampli¬ fier with its outputs in parallel. Building Ideas This exciter was built in the modular configuration What I had was used to design circuits that would do the job without my buy¬ ing every component as a special part. For example, bias circuits can usually be changed if the voltage divi¬ sion provided remains the same. Tuned circuits are flexible because resonance is controlled by both L and C and both can be changed to meet your needs. Ami¬ don Associates can supply a flyer containing a very ac¬ curate chart for winding in¬ ductors on their various to¬ roid cores if you have a par¬ ticular capacitor you want to use in a resonant circuit. Bypass capacitors can be chosen from many values which will effectively pro¬ vide a short to ground for the signal frequency. A command transmitter ca¬ pacitor was used to pro¬ vide vfo tuning, but any 73 Magazine • January, 1983 95 A Breakthrough for Amateur and Commercial Repeater Users. DIVERSITY RECEPTION -the ability to add a second receiver to your repeater system—can now be a reality for even the small user. The Pegasus VS-2 will allow your repeater to “listen” to two receivers simultaneously and to noiselessly switch between receivers as often as necessary to adjust for fading and nulls. This is particularly useful for repeaters that wish to provide coverage for hand held users or where receiver desense is a problem. You supply the second receiver & RF link and the VS-2 does the rest. Complete instructions and diagrams included with the VS-2. >oo Postpaid Pegasus Electronics, Inc. SB New Dorp Plaza Suite 106 Staten Island. NY 10306 (212)667-9137 AffHated with Comsec Corp ^201 Fig. 77, Suggested conver¬ sion schemes tor amateur- hand exciters . comparable variable ca¬ pacitor would do just as well The transistors used are common, inexpensive, and easily substituted with something you may have on hand. vfo would provide an upper sideband signal on 20 me¬ ters or a lower sideband signal on 40 meters. Many refinements are also possi¬ ble which would make this exciter more versatile, but even without them it is pos¬ sible to have an exciter with a quality single-sideband filter for very little The following parts may not be listed by advertisers, but they usually can supply them: • MCI496-Codbout Elec¬ tronics, jameco Electron¬ ics. • TL442 — Active Compo¬ nent Sales Corp., Box 1035, Framingham MA 01701. • CA3028 — Aldel co. ■ Ideas This crystal filter and single-sideband generator could be used in many other ways (see Fig. 11). Us¬ ing a vfo frequency of 7.3 MHz would give a lower sideband output on 75 meters. Doubling the out¬ put of an auxiliary 5-MHz References 1. J> Pochet F6BQP, 'Crystal Ladder Filters,” Wireless World, July, 1977, p. 62. 2. Pat Hawker G3VA, ' Technical Topics,” Radio Communication, June, 1977, p. 448. 3. Amidon Associates, 12033 Otsego St., N. Hollywood CA 91607. A/EWTS830S for $150? Yes indeed? Just add a Matched Pair of top- quality 2.1 KHz BW (bandwidth) Fox Tango Filters. Here are a few quotes from users: .. Males a naw rig out of my old TS830S1 ..." “...VBTnow works tha way Idraamad it should...” “...Spactacular improvamant in SS8 salactivfty...” Complataly aliminatas my naad for a CW filer...." ”...Simpia installation * axcallant instructions...** The Fox Tango filters are notably superior to both original 2 7KHz BW units but especially the modest ceramic 2nd IF, our substitutes are 8-pole discrete-crystal construction. The comparative FT vs Kenwood results? VBT OFF—RXBW:2.0vs 2.4; Shape Factor: 1.19 vs 1.34; 80dB BW: 2.48 vs 3.41; Ultimate Rejection: 110dB vs 80. VBT SET FOR CWat300Hz BW - SF2.9vs3.33; insertion Loss: 1 dB vs 10dB AND NOW A NEW TS 930S! Tests prove that the same filters improve the '930 even more than our ‘830. Don’t buy CW filters—not even ours. You probably worft need them! INTRODUCTORY PRICE: (Complete Kit)...S150 Includes Matched Pair of Fox Tanao Filters, all needed cables, parts, detailed Instructions. Specify kit desired: FTK-630 or FTK-930. Shipping S3 (Air $5). FL Sales Tax 5% ONE YEAR WARRANTY GO FOX-TANGO - TO BE SURE! Order by Mail or Telephone. AUTHORIZED EUROPEAN AGENTS Scandinavia MICROTEC (Norway) Other INGOIMPEX (West Germany) FOX TANGO CORPORATION Box 15944S. W Palm Beach. FL 33406 Phone (305) 683-9587 ' ^323 VIDEOSCAN IOOO - HIGH RESOLUTION SSTV rea?<v*» sharp picture* with up to 16 times better resolution than earlier units Three scan rates, optional call **gn and much more Easy to use. Amateur, phone line TV, turwd lance, l*t*r»eingu etc ftwt "How To Get Started to SSTV'*.. Kit VS-K $595.00 Wired VS F S795 00 Shipping $6 00 CODE A STAR - ALL MODE CODE READER More Features Per Dollar Than Anything Else! Ideal for novice*. SWLs and seasdhw code¬ practice oscillator and speaker. Copies Morse, Ft TTY and ASCII. Large LEDs, Easy to connect and operate. Automatic speed tracking. Excellent digital/analog filtering. 12VOC Or 120V AC with AC adapter provided. Compact. 25.1 m. Connect computer dike V10201/print#* with optional ASCII aitpws port. Kit CS K $159 95 Wired CS F $219 95 Shipp,nq $5 00 ASCII Port Kit CS IK $59.95 Wired CS IF $79 95 MORSE-A-KEYER — CW Keyboard Kit; MAK K $159.95 Wired MAK F $199 95 Shipping $5.00 Wisconsin residents add 5% Wisconsin State Sales Tax to all derm. Call or write for FREE brochures. Factory Direct - WE RE AS NEAR AS YOUR PHONE! TV Corporation Telephone. (414) 241-8144 *-50 p o Box 513G Thiensville, Wisconsin 53092 DX-Noies have Gained Wide Accept •At DAYTON Heaven!ion *A11 a< SB DtCC PIUS •SEVEN Wide W/C Columns *1.09 Entire DX Callsign • YOU Choose Hodes/Bands PLUS *Buro *3rd Party *Hore : •Enter YOUR Atlas Page * *CQ Zone *IARU Continent •Unique “Rareness" Guide •latitude •Longitude PLUS Info Computed for YOUR QTH *7im« Zone Difference •EXACT fleas Heading •Miles *Ki 1ot»e ter 5 me* *In the Amateur Media 1 •oss the USA ‘With 0* TOO ! 07.-*o!es Invites Comparison ! •Compare Accuracy l •Compare Efficiency f •Compare Useability ! •Compare Convenience ! •Compare Completeness! PUIS PREFIX Cross Reference ! 1200* Current, Commemorative ! Special Event 1 Historic ! Prefixes Indexed ! PIUS COUNTRY Cross Reference ! 500* Possessions, Islands, l Deleted, ETC Names Listed ‘ ■JARt Awards Kit •Highly Acclaimed Worksheets •AdB 10 Call Areas •WA3A 47 Prefectures JCC 647 Cities *JCG 569 Guns Complete with JARL Information •Logical Organization •Efficiency Engineered Alphabetical Cross Reference •Determine the JARl Cede # •Available DULY fro* KH6H0 •1400 Entries Listed PLUS FREE Sonus ••3075 US Counties Listing PLUS FREE Bonus * # 5B WAZ Kit : BUY DX-Notes Oust $12.95PPd * JARL Awards Kit dust S7.95PPd Send Call, Name, Address, Latitude, Longitude, Time Zone AND Check or Honey Order TO: KH6MD Randall Sherman POB 158 Xahului, Haul. HAWAII 96732 96 73 Magazine • January, 1983 King of the Pulse Generators One-shot or a train , TTL or CMOS , f/i/s generator will fit the bill. It's just what your test bench always wanted. Ronald A. Miara WA IRIS 8303 fin fie Id Court #22 Laurel M 0 20703 T his handy pulse gener¬ ator is built around two to output a single pulse by depressing a front-panel push-button switch The outputs are TTL and 5-V-dc CMOS compatible- 10 100 ps, 1 ms, 10 ms, and 100 ms. Variable resis¬ tor R1 is then used to tune the repetition rate between one and ten times the range value selected by SI, Forex- ample, if SI is set to 10 ps and R1 is set to IX (fully commonly available under¬ a-doll ar ICs. Both pulse width and repetition rate are continuously variable over six decade ranges from one microsecond to one second Normal and in¬ verted pulse train outputs are available, and a one- shot feature allows the user To operate the generator, the desired repetition rate range is selected with switch SI. (Repetition rate is the time between the occur¬ rence of each pulse and is equal to the reciprocal of the frequency of the pulse train.) The ranges that may be selected by SI are 1 ps, INTERNAL OSCILLATOR output. ut psn e NORMAL OUTPUT INVERTEC OUTPUT — T2* tOO|»S * F —tops rL Lr _n_ TJ" f/g. 2. Pu/se generator timing diagram. This shows a pulse train which has a 10-ps pulse width and a 100-ps repetition rate. The duty cycle is equal to 10 ps divided by 100 ps times one hundred percent r which equals 10 percent. counterclockwise), a pulse will occur every 10 ps R1 may then be tuned up to ten times this value (10X, fully clockwise), in which case a pulse will be output every 100 ps. Pulse width is similarly set with S2 and R4. S2 selects the same range values as SI, and R4 is used to tune the pulse width from one to ten times the value selected by SI. Pulse widths with duty cycles up to 90% may be set up (Duty cycle is defined as the ratio of time the pulse is on to the time of a complete cycle, times one hundred An ordinary square wave would then have a 50% du¬ ty cycle since it is on half the time of a complete cycle.) To use the pulse genera¬ tor as a one-shot, switch S3 is closed, disabling the out¬ put pulse train. Push-button switch S4 is then depressed and released to output a sin¬ gle pulse from U2. Refer to the schematic (Fig 1) to understand how the pulse generator works Three NAND gates in U1 are configured with capacitors Cl through C6, variable re¬ sistor R1, and resistors R2 and R3 to form a square- wave oscillator. The fre¬ quency of this oscillator de¬ termines the repetition rate of the generator. The re¬ sistors were chosen to pro¬ duce repetition rates in convenient decade ranges. The oscillator drives one- shot generator U2. Capac¬ itors C7 through 02, vari¬ able resistor R4, and resis¬ tors R5 and R6 determine the width of the pulses out¬ put from U2. The values of these resistors and capaci¬ tors were also chosen to pro¬ duce pulse widths in decade ranges. Since the oscillator driving U2 causes pulses to be output at a periodic rate, the output of U2 becomes the output of the pulse generator Construction of this unit is not critical. Short lead lengths and an all-metal en¬ closure should be used to ensure a clean and stable pulse-train output U1 (74COO) should be CMOS, not TTL, to ensure that the oscillator will work. The ac¬ curacy of the pulse width and repetition rate depends on the tolerance of the resis¬ tors and capacitors used and how carefully the front- panel multiplier controls are labeled (from IX to 10X). Since I normally use an os¬ cilloscope to set up my pulse generator, I used sim¬ ple front-panel labeling and rely on the scope for calibra¬ tion of the pulse train Sim¬ ple front-panel labeling also keeps the cabinet size small since less space is required on the front panel. My unit is powered by four pen light batteries which drive a min¬ iature three-terminal -F5-V- dc regulator 1C (LM309H). The small size and low cost of this handy pulse gen¬ erator should make it a nice addition to any ham's workbench.® SATELLITES _/ Late September brought amateur satellite enthusiasts something to cheer about for a change. On the 20th, the University of Surrey amateur scientific satellite (UoSAT) was rescued from oblivion when ground controllers managed to turn its telemetry beacons off for the first time since April. By the time you read this, UoSAT may already be back in full operation. The trouble with UoSAT (also known as UoSAT-OSCAR 9 or, more simply, UO-9) began when both the 2-meter and 70-cm beacons were accidentally commanded on at the same time. The effect was to de¬ sense both receivers aboard the bird, making it impossible for UoSAT to “hear” instructions from the ground. Even the massive 26-dB-gain 2-meter EME array of K1 WHS proved insufficient to break through. After an enormous expenditure of time and effort, the spell was fi¬ nally broken on 70 cm when the UoSAT salvage team obtained the sen/ices of a little-used 150-foot dish antenna at SRI International in California. With a gain at 70 cm of 46 dB and an erp approaching 12 megawatts, the big dish did the trick, though not without practically being rebuilt by the UoSAT gang in the process. Fortunately, UoSAT seems none the worse for the experience. The satellite, which does not carry communications transponders, continues to send a steady stream of scientific data earthward. In addition to telemetry beacons at 145.825 and 435 MHz, look for HF beacons at 7.05, 14.002, 21.002, and 28.510 MHz. An on-board TV camera may be activated as well. Ever since the failure of the European Space Agency (ESA) Ariane rocket during its fifth flight (September 9), the date for the launch of AMSAT’s Phase I MB satellite has been anyone’s guess. The best bet is now sometime in mid-April, assuming no further problems arise. Thanks to AMSAT Satellite Report .—Jeff DeTray WB8BTH, 73 Staff. Amateur Satellite Reference Orbits OSCAR ; 8 RS- •5 RS- •6 R5- ■7 RS- 8 Date UTC EQX UTC EQX UTC EQX UTC EQX UTC EQX Date “ — ~ J3 rma&nr m mzxm scisa ttStKWS **»*• !«*« »=i== Jan 1 0113 97 0041 38 0008 33 0188 46 0041 36 1 2 0118 98 0036 38 0152 61 0059 45 0036 37 2 3 0122 99 0030 38 8136 59 0049 44 0035 38 3 4 8127 101 0025 39 0121 56 0039 43 0032 39 4 5 0131 182 0020 39 0105 54 0030 42 0830 39 5 6 8135 103 0014 39 0050 52 0020 41 0027 40 6 7 8140 104 0009 39 0035 49 0310 40 0024 41 7 8 0801 79 0004 39 0019 47 0081 39 0021 42 B 9 0806 80 0158 69 0004 45 8150 68 0018 43 9 18 8810 32 0153 78 0147 72 0141 67 0016 44 10 n 8814 83 0147 70 0132 78 8131 67 8013 44 11 12 8019 84 0142 78 0116 $7 0121 66 0018 45 12 13 0023 85 0137 70 0101 65 0112 65 0007 46 13 14 0023 86 0131 70 0046 63 0102 64 0004 47 14 15 0032 87 8126 71 0830 60 0053 63 0001 48 15 16 0036 88 0121 71 0015 58 0043 62 0158 79 16 17 0041 90 0115 71 0158 86 0033 61 0156 79 17 18 0045 91 0110 71 0143 83 0024 60 0153 80 18 19 0050 92 0105 71 0127 81 0014 59 0150 81 19 20 0054 93 0059 72 0112 79 0004 59 0147 82 20 21 0059 94 0054 72 0056 76 0154 88 0144 83 21 22 0103 95 0049 72 0041 74 0144 87 0142 84 22 23 0107 96 0043 72 0026 72 0135 86 0139 84 23 24 0112 98 0038 72 0010 69 0125 85 0136 85 24 25 0116 99 0033 72 0154 97 0115 84 0133 86 25 26 8121 100 0027 73 0138 94 0106 83 0130 87 26 21 0125 101 0022 73 8123 92 0056 82 0127 88 27 28 0129 102 0017 73 0107 90 0846 81 0125 88 28 29 8134 103 0811 73 0052 87 0037 81 0122 89 29 30 8138 104 0006 73 0037 85 0027 80 8119 98 30 31 @143 105 0001 74 8021 83 0017 79 0116 91 31 Feb 1 0004 81 0155 104 0086 8 @ 0008 78 8113 92 1 2 8808 82 0149 104 0149 106 8157 107 0111 93 2 3 0013 83 0144 104 8134 106 8148 106 0108 93 3 4 0817 84 0139 104 0118 103 0138 105 0105 94 4 5 0022 8 S 0133 105 0183 101 0128 104 8102 95 5 6 @026 86 0128 105 0048 99 0119 103 8059 96 6 7 8030 88 0123 105 0032 96 0109 102 @056 97 7 e 0035 39 0117 105 0817 94 0059 102 8054 98 S 9 0039 90 0112 105 0001 92 0050 101 0051 98 9 10 0044 91 0107 106 0145 119 0840 100 0048 99 10 11 0048 92 0101 106 0129 117 0030 99 0045 100 11 12 0052 93 0056 106 0114 114 0021 98 0042 101 12 13 0057 94 0051 106 0059 112 0011 97 0040 102 13 14 0101 96 0045 106 0043 110 0002 96 0037 102 14 73 Magazine • January, 1983 101 ( CONTESTS ’ The RaRa Rag NEWSLETTER OF THE MONTH Beauty is not just skin deep. At least, not in the winner of this month's newsletter contest, The RaRa Rag, published by the Rochester Amateur Radio Association The thoroughly professional look of The Rag includes typeset and printed text, with even margins on both sides, headlines, cutoff lines, and clean graphics. It is all printed m booklet format on heavy paper But the beauty doesn t stop there. The Rag's contents go way beyond the usual list of upcoming events, meeting dates, and president s message One extra feature of the newsletter is "Cop s Corner,'* which keeps members posted on local street construction and emergency service For history buffs, there is "The RaRa Rag 20 Years Ago," and to bring the reader up to date, the editors have included news shorts from the W5YI Report and other news services. Other features include news of the club's various special interest groups, a fitting forum for what appears to be an exceptionally active club. Congratulations to Editor Ronald Jakubowski K2RJ and his staff for putting together a club newsletter that reads as good as it looks To enter your club’s newsletter in our contest, send a copy to: Editorial Offices, 73 Peterborough NH 03456 Robert Baker WB2GFE 15 Windsor Dr. Atco NJ 08004 ZERO-DISTRICT QSO PARTY Starts: 2000 GMT January 8 Ends: 0200 GMT January 10 Organized by the Mississippi Valley Ra¬ dio Club Stations outside of zero district will work zero stations only, zeros may work any station. The same station may be worked once on each band and each mode However, mobile stations may be worked each time they change counties EXCHANGE RS(T) and ARRL section. Zero-district stations also must send county. FREQUENCIES: 3560, 7060, 14060, 21060 28060 3900. 7270, 14300 21370, 26570, 3725. 7125. 21125, and 28125. SCORING: Multiply the number of zero-district counties by the number of contacts Zeros score by adding ARRL sections, zero- districf counties, and DXCC countries worked and then multiplying by total contacts. ENTRIES & AWARDS: Certificates will be issued to ali en¬ trants who submit a log and an SASE En¬ dorsements will be given for the high score in each ARRL section, DX country, and Novice/Technician Class Mail logs by February 15th to: W0SI, 3528 W. Colum¬ bia, Davenport IA 52804 Include an SASE for log forms or results. WORLD COMMUNICATION YEAR Starts: 0001 GMT January 15 Ends: 2400 GMT January 15 On November 19, 1961, the United Na Irons General Assembly adopted a resolu¬ tion proclaiming 1983 a World Communi¬ cation Year: Development of Communica¬ tions Infrastructures,” The basic objec fives of the WCY are: (1) to provide the op¬ portunity for all countries to undertake an in-depth review and analysis of their poli¬ cies on communications development, and (2) to stimulate the accelerated devel¬ opment of communications infrastruc¬ tures The Potomac Valley Radio Club is sponsoring this contest in support of the World Communication Year All licensed radio amateurs worldwide are eligible to participate There will be two categories single operator and multi¬ operator, Both categories are mixed mode. Only stations using one transmitter are eligible for an award. The same sta lion may be worked once on each band Telephony (including SSTVi and Tefegra phy (including RTTY) emissions count as separate bands No cross-emission con¬ tacts are allowed The mam objective is to contact as many other amateurs as possi¬ ble. anywhere in the world, using 1.8 MHz to 275 GHz, excluding the 10-. 18-, and 24-MHz bands EXCHANGE Ali stations win send their ITU region and their UU zone For example, the fol¬ lowing stations would send the listed ex¬ changes: DL1AA. 128; W t AAA 208; and JA1AAA, 345 SCORING. QSO points are 4 points per OSO out¬ side your ITU region, 2 points if inside your ITU region but outside your zone, and 1 point If inside your ITU zone, The multi¬ plier is the number of ITU zones worked on each band. For final score, multiply the total QSO points for all bands by the total zones worked for ah bands AWARDS A plague will be awarded to the high- scoring station of each category isingie- and multi-operator) in each of the three ITU regions A certificate will be awarded to the high-scoring entrant of each cate gory in each ITU zone. In addition, a certifi¬ cate will be awarded to one UHF/micro- wave station of each ITU Zone judged to have displayed the most outstanding achievement Members of PVRC may not receive awards. ENTRIES: All entrants are to use a suitable log form and summary sheet of their choice. Logs should include times in GMT, bands, calls, complete exchange, and QSO points for each QSO. Multipliers should be clearly marked In each log Cross¬ check sheets (dupe sheets) are required if more than 200 QSOs are made on any band Summary sheets should be a single page and show number of GSOs QSO points, zone multiplier for each band and the total score. The summary sheet must contain the entrants callsign, region, zone, name, and address, Multi-operator stations must list the name and call (if any) of each operator. Entries for the spe¬ cial UHF/mtcrowave award should be indi¬ cated on the front of the summary sheet with a description of the basts of the UHFl microwave award written on the back of the summary sheet. Entries must be postmarked by Febru ary 28th and mailed to: PVRC, PO Box 337, Crownsville MD 21032. Each entrant agrees to be bound by the provisions of the rules, by the regulations of his licensing authority, and by the deci¬ sions of the Amateur Radio Activity Awards Committee. An entry may be dis¬ qualified if the overall score »a reduced by more man two percent. An entry will be disqualified if more than two percent of duplicates are left in the log A penalty of 8 QSO points will be assessed for each du¬ plicate OSQ or for each miscopied call¬ sign or exchange found by the awards committee HUNTING LIONS IN THE AIR CONTEST Starts: 1200 GMT January IS Ends: 1200 GMT January 16 The contest is sponsored fey Lions Club International and coordinated by Lions Club Rio de Janeiro Arpoador. Brazil. Par ticipation in the contest is open to ali duly licensed radio operators, Lion and non- Lion. There are two modes: phone and CW. Participation in both modes is al¬ lowed but points are counted separately. Ail amateur stations participating must operate within their licensing regulation. Separate categories will exist for single operators and radio clubslspcieties. Mul¬ ti-operators may participate, but each pre¬ fix must be listed on the log Use all bands, 80 through 10 meters. Only one QSO with the same station on each band may be counted Remem ber that phone and CW are Counted separately! EXCHANGE RS(T) and sequential QSO number When a contact is made with any Lion, CALENDAR Janl ARRL Straight Key Night Jan 8 73 40-Meter Worldwide SSB Championship Jan 8-9 ARRL QSO Party—CW Jan 8-10 Zero-District OSO Party Jan 9 73 80-Meter Worldwide SSB Championship Jan 9-10 ARRL QSO Party—Phone Jan 15 World Communication Year Amateur Radio Activity Jan 15-16 73 160-Meter Worldwide SSB Championship Jan 15-16 Hunting Lions in the Air Contest Jan 15-16 QRP CW Contest Jan 15-16 ARRL VHF Sweepstakes Jan 22-23 Texas QSO Party Jan 22-23 North Dakota OSO Party Jan 29-Feb 6 ARRL Novice Roundup Feb 5-6 New Hampshire QSO Party Feb 5-6 South Carolina OSO Party Feb 19-20 YL tSSB OSO Party—Phone Feb 19-20 ARRL International DX Contest—CW Feb 26 RTTY World Championship Contest Mar 5-6 ARRL international OX Contest—Phone Mar 12 13 YL ISSB OSO Party—CW Apr 9-10 CARF Commonwealth Phone Contest Apr 9-10 ARRL QSO Party—CW Apr 16-17 ARRL QSO Party—Phone Jun 11-12 ARRL VHF QSO Party Jun 25-26 ARRL Field Day Jul 9-10 IARU Radiosport Championship VOLUNTEERS NEEDED How would you like to be on the ''inside” of a major amateur-radio contest? Here's your chance! We re looking for volunteers to become members of the 73 Contest Commit¬ tee Anyone with an interest in contesting and a willingness to work hard is wel¬ come. Committee members will help with the following: 1 Contest rules and ethics 2. Forms and correspondence 3 Log checking and scoring 4. Filling out and mailing awards Heading up the contest committee is KE7C Please drop him a note (with SASE) and let him know you can help. Write to Bill Gosnoy KE7C, 73 Contest Committee, 2665 North Busby Road, Oak Harbor WA 98277 We want YOU on the 73 Contest Team! 102 73 Magazine • January, 1983 Leo. or Lioness, the name ol the club con¬ tacted should be clearly identified, SCORING OSOs within the same continent count 1 point while those between different con¬ tinents count 3 points Score 1 extra bo¬ nus point for each QSO with a memoer of a Lions Club, Leo Club, or Lioness Club and 5 points for a QSO with a member of the Lions Club Rio de Janeiro Arpoador. Contacts between Brazilian stations will count only 2 extra points. Contacts be¬ tween members of the Arpoador club will not count any bonus points. AWARDS For single-operator entries the Lions Club International will present trophies for first, second, and third place on both modes. Fourth through tenth places will receive plaques. A trophy will be present¬ ed to the first place radio club/society on both modes., tn addition, each iog sent by participants with a minimum of 5 contacts will receive a special certificate. The con¬ test committee will also select and award the most active Lions Club participating in the contest ENTRIES: Keep a separate log for each mode. Each participant will note in the logs the callsign and information exchanged. Con¬ firmation of contacts will be made by comparing the logs of the participants. Participants should send their logs by air mail not later than 30 days after the con¬ test to: Contest Committee. Hunting Uons in the Air, Lions Club of Rio de Janeiro Arpoador, Rua Souza Lima *149, Apt 402. 22081 Rio de Janeiro, RJ. Brazil MICHIGAN QRP CLUB CW CONTEST Starts: 1500 GMT January 15 Ends: 1500 GMT January 16 This is a CW-only, all bands (160-10- meter} ORP contest sponsored by the Michigan QRP Club. The contest is open to all amateurs and all are eligible for awards. General call will be CQ QRP DE. , " Each station will be competing within their own state, province, or coun¬ try in one of three categories: 1} one Watt or less of output power, 2} five Watts or less of output power, and 3) over five Watts of output power. EXCHANGE: RST, OSO number, and power output SCORING Each contact is worth one QSO point Multiply total QSO points (all bands) by the number of states, provinces, and countries worked per band for total points. If using emergency power (100% natural and 100% battery) then apply a 1.5 bonus multiplier AWARDS Certificates will be awarded to the high¬ est-scoring stations in each state, prov ince, or country. ENTRIES Log information must include full tog data with a separate fog for each band, name,address, equipment used, and pow¬ er output Logs must be received by the contest manager no later than six weeks attertheend of the contest. W/VE stations please send an SASE, all others please send 2 IRCs if contest resuits are desired. Address ail entries to: Contest Manager, Michigan QRP Club. 281 Crescent Drive, Port lane Ml 48875. THE NORTH DAKOTA QSO PARTY 0000 to 0800 and 1600 to 2400 GMT January 22, 0800 to 1600 GMT January 23 Sponsored again by the Red River Ra¬ dio Amateurs of Fargo, North Dakota Work stations once per band and mode. EXCHANGE; RS(T) and state, province, country, or North Dakota county. Novices, please in¬ dicate Novice status FREQUENCIES Phone-1835, 3905, 7280, 14295, 2t380, 20580. CW—1810, 3540, 7035, 14035, 21035, 20035. Novice—3725. 7125, 21125, 28125 SCORING Phone contacts count 10 points. CW 20 points, and RTTY 50 points. North Dakota stations count an additional 100- polnt bonus for working five Novices. North Dakota stations multiply score by total of states, provinces, and countries worked (max 53). ENTRIES & AWARDS Certificates to state, province, and country winners. Plaque to North Dakota winner and highest scorer outside North Dakota. Mail logs by February 28th to: Bill Snyder W0LHS. Box 2704. Fargo ND 50108-2784 include a large SASE for results. TEXAS QSO PARTY Starts: 0000 GMT January 22 Ends: 2400 GMT January 23 Sponsored by the West Texas Amateur Radio Club of Odessa Texas Use all bands and modes Each station may be worked again upon each county change Singie-operator entries only. CW OSOs must be in CW subbands only. EXCHANGE: QSO number (beginning with 001) and state, province, country, or Texas county FREQUENCIES Novice—3710, 7110. 21110, 28110. Phone—3940, 7260. 14280, 21370, 20600. CW—3565, 7065, 14065. 21065, 28065 SCORING All non-Texas stations score points as follows: Phone contact with fixed station in Texas—1 point. CW contact with fixed station in Texas—2 points. Phone contact with mobile station in Texas—5 points CW contact with mobile station in Texas — 7 points Multiply by the number of Texas counties worked 1254 max). Ail Texas stations score 1 point per con¬ tact on phone. 2 points on CW regardless whether fixed or mobile. Multiply by the number of states, countries, and Cana¬ dian provinces worked AWARDS Plaques to top scores US, US Novice, DX, Canada, Texas fixed, Texas mobile, Texas Novice. Certificates to top score in each state, country, and province Certifi¬ cates also to top 10 Texas stations. Spe clal awards as activity dictates, ENTRIES Ail logs must be received by March 15th, Mail entries to: WTARC, PO Box 9944, Odessa TX 79762 0041 RESULTS THE 1ST ANNUAL 40/80 PHONE CONTEST -A TREMENDOUS SUCCESS— “Truly unbelievable, it was fantastic, like catcher fish in a barret.. " Those were the words and phrases echoed by nearly every contestant in 737 s First An¬ nual 40- and 80-Meter Phone Contest. There is little doubt that this event will re¬ main on the contest calendar for many years to come. We are grateful to those who made it all happen! After the dust had finally settled, VE5DX became the World 40-Meter Phone Champion for single-operator stations. Congratulations to you Jim, a superb performance I4YNO and company firmly took the World 40-Meter Champion¬ ship for the multi-operator category Fantastic job, fellas! On 80 Meters. I3MAU is the World Single-Operator Phone Champion, and the group at N9NC tied down the winning score to take the world multi-operator title. Fabulous scores for such a difficult band. Combining both the 40- and 00-meter contest scores, CN8CO became the 1902 Low-Band Champion for single operators while VE2ZP and crew took top honors in the multi-operator category Take a look at the scoring summary, to see an impressive job by two top-notch stations Who made the most contacts, you ask? Among 40-meter single ops, VE5DX made972QSOs, followed by KK9A (856) and W9RE(851)„fn the 40-meter multi-op standings, N9NB was credited with 1090 QSOs, followed by a distant second, KD4TO, with a demanding 972 contact total. On 80 meters, considering band conditions, the competition was just as fierce. N7DF from Utah tallied 700QSOs for the single-operator category, while VE5XK accumulated 672 contacts on the band In the 00-meter multi-operator class. N9NC and crew mustered 793 con¬ tacts with VE2ZP (597) and W4CN (564) trailing. Looking at the combined contest scores for both bands, N7DF turned in 1188 QSOs with 931 QSOs registered by second-place finisher KC40V in the singie- operator category For multi-ops, VE2ZP recorded 1271 QSOs followed by N4BAA of Florida with 1066 contacts. Was the band open? Well on 40-meters the following stations turned in 30 or more DX country multipliers: I4YNO (59), I5MPK (44), YV5ANE (44), W9RE (41), N3AMK (40), VE5DX (39). VE2ZP (30), CN0CO (30), JA2BAY (35), LXUX (35), N4BAA (33), N9NB (3IK and KJ9D (31) As expected, the 80-meter DX totals were somewhat (ess with the following stations scoring 20 or more DX multipliers: I3MAU (58), CN0CO (53). KQ2M (39). DAI RE (34). WB2DHY (30), I5MPK (29), N4BAA (28), KOCS(20), DF9ZP{27), ZF2DX (27), N7DF (24), JAl ELY(22), AK1A(22), and OK1KZ (22). One of the most interesting aspects of tallying any contest Is the opportunity to summarize the equipment used by competing stations. Every year brings new surprises Which antenna dominated on which band? Naturally the wire (economy ver¬ sion) array led the pack. Look at the statistics: 40-Meter Antennas 80-Meter Antennas Dipole/inverted vees 39.0% Delta loop 11.1% Monoband vertical 11.6% %-wavesloper 11.1% Delta loop 9.3% Full-wave vertical 0 3% Trap vertical 9.3% Trap vertical 0.3% 2-element yagi 7.0% Phased verticals 5.5% V* wavesloper 4.6% 3-eiement wtreyagi 5,5% 2-element delta loop 4.6% fnverted-L 2,7% 2-element wire beam. 2-element delta loop 2.7% bobtail curtains, 2-efement quads, 3-element yagis, and phased verticals 2.3% each Of ail the stations that turned in entries, 28% declared that they were running completely “barefoot" while 2% stated that they were running 500 Watts, 15% were running a kilowatt, and a dramatic 55% were radiating two kilos! What were they using as exciters? 39,7% of the contestants claimed to be running Kenwoods, 21.3% were running Yaesu gear, 22.4% were operating Drake equip¬ ment, 6.5% were Collins, while the remaining 10.1 % were divided amongst Ten- Tec, (com. Heathkit. Tempo, and yes, even home-brew equipment. So what does all this add up to? a debut not to be forgotten, an event full of surprises which left a lasting impression on ail who witnessed this two-day extravaganza. This brings us to the second annual event which is just around the corner. Look for the 40- and 00-meter contest announcement in last month's issue of 73. This year the event is being split into two separate parts. The World 40-Meter Phone Championship will be held on January 8, while the World 80-Meter Phone Championship event is scheduled for the following day. January 9. 1903 Each promises to become a record breaker m its own right. For all the details, send your SASE directly to the official contest address, attention Billy Maddox, 468 Century Vista Drive, Arnold MD 21012. So start pruning your antennas. I intend to work each one of you on both bands so mark the dates on your calendar. Get on the band right now and begin telling other amateurs about the contest, especially the DX stations. Pitch in and pass the word! Good luck in the contest. Continued 73 Magazine • January, 1983 103 40/80-METER CONTEST SOAPBOX ‘Giad to take part even if it was just a little bit Really entoyed it f "—NlBMV "Lots o/ fun Am going to try 80 meters next year. **-—KAICDC "Super contest, .1 know HI be back next year!"— WA1ZAM, 44 Too many earners and foreign broadcasts on 40!"—KA2HTH. "My first contest ever. Really enioyed it and am looking forward to next year "— WB2IWJ. "The gang here had a blast, ” —KF2X . "Fine contest but I suggest limiting the action to the general portion of the band." — N3A WS. "Would have liked to have participated more Look tor me again next year W3ICM "You've got another winner !"— K3IXD. "Great contest—fots of great contacts were made on the 40 this weekend "-KF3M "Hope to get a vfo and increase my multiplier total Sure enioyed the contest "-KC3N "Enjoyed the contest and , once and tor ah, recognized the District of Colum¬ bia as a separate multiplier f ” — W3USS "Good propagation at times. Fantastic turnout Should be a classic event"—N4BAA. "Great contest with lots of potential as the years go by. "-N4UH. "Had a very good time and worked some new states, "-N5AFV. "TNX for sponsoring this enjoyable contest Had a great time on40."—N5CPO " Whooee. quite an event f> ’—KC5NQ. "Learned a lot about my station Looking forward to next year WB5YWO. "Better to have the 4(Fmeter test on CW rather than SSB —N6JM "A very good contest Not much heard during the daytime ”— W6YMH "Thanks for staging this contest I enioyed if immensely Hope to be back next year to improve the score, ’—KA7AKQ "Where were the VEs 5 Great stateside turnout!"—N7DF. J *lVfiere were the JAs?"—KB?G "Let’s do if again next year>”—AK7J. "Great contest and HI be back next year r ’—K7PGL. "Fine contest idea, thanks to 73. Lots of activity on the bands. Wish there was more DX on 40,"—N8ATR. “Damn tun despite the tremendous big guns I’ll give it a shot again next year "-KC8GN. "Very successful debut Good time of year too 1 See you next year tor sure r -W8VEN. W/VE 40-METER SINGLE OPERATOR Callsign QTH QSOs QSO Pis. St/Pr. DX Total VE5DX(W) SASK 972 1192 56 39 113240 W9RE* IN 851 1084 56 41 105148 N3AMK* PA 771 1042 55 40 99180 KK9A(-) IL 856 1093 57 25 87440 KA1XN* MA 781 802 56 23 63358 WB8JBM* OH 759 823 56 19 61725 KC40V* TN 600 736 67 14 59616 KC5NQ* TX 663 730 55 18 53290 KC3N{-) PA 674 872 53 3 48832 N8AKYB Ml 441 598 53 21 44252 KF3M PA 675 829 48 5 43937 WAttDK* MN 539 639 51 13 40896 N7DF* UT 488 547 51 11 38290 KA1CDCB MA 516 661 48 4 34372 KC8JHB OH 400 460 52 20 33120 N8ATR OH 477 637 45 6 32487 VE2RV* QU 305 397 55 25 31760 KL7HHXB AK 289 570 40 14 30780 K3MRG PA 380 551 53 29203 K4HAVB GA 434 535 45 9 28890 WD4IBO ga 484 570 47 2 27360 K9MWM{-) CO 468 495 50 5 27225 W1MXJKA1R) MA 370 444 46 15 27084 K5Z0B TX 353 372 52 10 23064 WBIUFLB IA 286 397 46 10 22052 W3BGN PA 259 430 42 8 21500 WA8YTMB WV 423 483 34 7 19703 NF4FB TN 348 357 45 5 17850 K7PGLB MT 284 297 42 13 16335 KA4RKDB AL 278 335 44 4 16080 K3IXDB MD 220 259 45 3 15022 WB2THN* NY 263 266 48 6 14364 NR4S TN 218 349 38 3 14309 WA2HFIZO IL 250 269 45 4 13181 WA0TKJB KS 135 198 35 28 12474 KA9CTM IL 196 240 46 1 11280 AA4FFB VA 161 189 40 19 11151 W8ANM OH 196 259 37 4 10619 N4AR0 TN 213 243 39 3 10026 WB9UZR IL 174 290 32 2 9660 W5PWG TX 154 184 43 9 9568 "I seem to have scored very welt. Lots of good contacts to be had, —KK9A Everyone involved has my congratulations i wish ail contests were this much fun "-KJ9D Surprised at tee number of stations on the 40 meter band Broadcast stations really got fierce! Will try 80-mefers nexf year "—K9FMR. "Bands were in great shape Had a great time . "-KB9TI. "Activity and band conditions were excellent. Korea on 15 was a new one tor me !”— K0CS. "Great contest. Nice to work a confesf teaf doesn’t take up ail weekend. Family-man special!"— WAOIDK. "Excellent contest. Definitely will be back next year "—K0UK. "WB40XZ and I found it rough going on 80 Worth every minute of it though Had a ball." — C6ADV '‘Definitely should become one of the biggies 4 Unbelievable participation for a first time event!”— CN8C0 "Fun contest t*ti tell more Europeans about it "-DL8UI "i know why CW is beautiful now—very hard on phone with 50 Watts. There’s always next year."—G3WKS. "My first touch of 40 and 80 meter contesting and I loved it."—H44SH. "Marvelous contest though conditions weren'f the Pesf for me. Am looking forward to next year."—HI8GB. “Nice contest indeed. We hope to do defter next year"—l4YN0. "Very good contest Not much activity in JA-land on contest "-JA IFFY. "Lots of activity on 40-meters but not many Europeans See you again next year ”— LA5YF "Good propagation but no Europeans m the contest Maybe next year it will get more attention." — LX JJX. "Very good idea to establish this contest Hope more Europeans hear about it! See you next year 0K2BLG "Thanks for the contest, a very good idea Enioyed 80 meters ’—0X3ZM "Dtdn t work a single North American station "— PA3AZM "Nice contest with good propagation Wish W/VEs would listen below 3 800 MHz. Very strong in Europe r ’—SM4CAN "Greaf contest and is sure to grow as it gets more publicity. * — VE1AJJ. “Thoroughly enjoyed the contest. Very well conceived, very well attended—a definite winner!"—VE2ZP "Appreciate the contests 80 was very difficult with 20+ static USA stations forget we can only work 3.5-3,7 on phone. ’’ — VK5BW. "Very little activity in Romania Maybe advertisements will help —Y04BXX KJ7R(-) ID 161 183 40 11 9333 VE1AJJ* NB 143 179 42 10 9308 KR8X OH 262 262 35 9170 AK3J PA 144 208 38 5 8944 W2FTY(-) NY 114 162 36 13 7938 N8TN OH 200 233 32 3 7922 WA4LRO TN 123 133 38 11 6517 K5UCV TX 127 164 35 3 6232 W8DN OH 112 139 41 2 5977 N9AMM-) IN 107 161 37 5957 KB7G(-) WA 120 136 37 6 5848 KD4WYB NC 140 157 33 5181 W3ARK PA 206 206 24 4944 WB5YWOB OK 121 130 35 3 4940 WD8MOV OH 53 111 24 20 4884 K1NCOH CT 106 165 29 4785 W3ETB PA 125 167 25 3 4676 WA3JXW PA 136 136 34 4624 KI7M(-) OR 89 107 30 13 4601 WB90BXH Wl 157 157 29 4553 WA2HCCB NJ 110 156 25 3 4368 N5CPO TX 94 118 37 4366 N5CMF TX 81 97 43 4171 N5AFV OK 102 119 35 4165 KF1B CT 77 98 29 13 4116 N4DEF GA 108 127 29 3 4064 K4FPF VA 82 111 31 4 3885 N3AWS PA 93 123 29 3567 W8VEN WV 96 98 34 1 3430 KJ2N NJ 63 92 20 16 3312 K3ND PA 89 99 32 6 3267 W5GVP TX 80 94 30 4 3196 W3AP PA 73 100 27 4 3100 W6YMH* CA 72 81 28 9 2997 K1VUT MA 94 98 26 4 2940 N®CZO(-) ND 81 95 29 2755 W4KMS VA 87 87 29 2523 KJ9R IL 84 84 30 2520 WB8YEW OH 78 78 32 2496 KC7EH OR 52 68 24 12 2312 K8CV Ml 56 63 29 7 2268 KC8P MI 66 66 32 2112 KC8GN OH 66 67 30 2010 K8JOS OH 64 80 25 2000 104 73 Magazine • January, 1983 WA2IFS NJ 35 59 9 17 1534 NL7D AK 34 67 20 1 1407 KBCC(-) MN 51 52 24 1 1300 KA7AKQ WA 48 49 24 1 1225 K3ZJ(~) DC 70 70 16 1120 N1ADX MA 46 91 10 910 WD80YF OH 53 53 16 848 WD8MRF OH 49 62 15 735 WAWVWW MN 32 32 32 704 W3YA PA 44 44 15 660 W7ABXH NV 26 30 14 4 540 KB9IT IL 39 39 11 429 N6JM CA 19 20 15 1 320 AK7F WA 10 10 6 60 N2DCH NY 9 9 7 56 * District champion H Staterprovincial champion (Wi Contest winner W/VE 40-METER MULTI-OPERATOR Callsign OTH OSOs OSOPts. SUPr. DX Total N9NB|W) IN 1098 1329 54 31 112965 KD4TQ* KY 972 1206 55 24 95432 VE22P* QUE 704 909 57 36 86355 KJ9D* IN 681 927 53 31 77868 N4BAAH FL 645 772 53 33 66392 KF2X* NY 565 774 46 27 58050 N4FKF KY 303 16069 KA2HTHH NY 267 422 28 11816 W3YA* PA 44 44 15 660 * District champion H State/provincial champion {Wj Contest winner DX 40-METER SINGLE OPERATOR Callsign OTH OSOs OSOPts. SUPr. DX Total YVSANE^W) Venezuela 359 732 46 44 65880 CN8CO* Morocco 361 744 44 38 61008 H44SH' Solomon Is, 291 581 45 20 37765 LA5YF* Norway 221 513 37 26 32319 JA28AY* Japan 205 390 38 35 28470 HI4AGE* Dorn Rep. 209 417 45 17 24603 CT4KO* Portugal 169 350 33 20 18550 YV3BQS Venezuela 155 312 32 23 17160 VK5BW* Australia 157 306 21 22 13158 LX1JX* Luxembourg 119 246 1 35 8856 DL8UI* West Germany 72 139 19 16 4865 JA1ELY Japan 68 130 22 15 4810 SM4CAN* Sweden 23 46 15 690 OK1AGN* Czechoslovakia 17 50 1 12 650 I4CSP* Italy 21 38 1 12 494 G3WKS* England 14 44 6 264 Y09CUF/3* Romania 18 23 10 230 G5EBA England 11 22 9 198 JA1FFY Japan 9 17 3 5 136 PA3A2M* Netherlands 9 18 6 108 Y048XX Romania 10 20 5 100 Y03KWJ Romania 3 6 3 18 (W) Contest winner * DX country champion DX 40-METER MULTI-OPERATOR Callsign OTH OSOs OSOPts. SUPr. DX Total I4YNO {W} Italy 672 1400 33 59 128800 I5MPK* Italy 590 1206 44 45 107334 (W) Contest winner * DX country champion W/VE 60-METER SINGLE OPERATOR Callsign OTH OSOs OSOPts. SUPr. DX Total KQ2M(Wi NY 510 666 52 39 60606 N7DF* ITT 700 739 54 24 57642 K6CS* MO 552 635 53 28 51435 WB2DHY* NY 346 545 46 30 42510 VE5XK* SASK 672 681 54 8 42222 K2SWPH NY 492 530 50 15 34450 KB9MW* IL 530 570 52 7 33630 N8ATR* OH 311 326 47 11 32467 NA8T- CA 373 454 51 19 31850 N8AKYH Ml 439 453 50 11 27633 K8UKH CO 407 417 49 7 23352 KC40V TN 331 342 46 10 19152 KC8JH(-) OH 335 342 46 7 18126 WA1ZAM* MA 363 367 45 4 17983 KB3ND* PA 294 305 45 10 16775 KI7MH OR 232 271 53 6 15989 N4ARO(-) TN 254 259 49 4 13727 AKIA(-) NH 168 206 41 22 12978 W6TPHH CA 228 240 41 12 12720 KD4XR(~) AL 244 248 41 3 10912 W4PZVB FL 141 161 46 18 10304 VE1AJJ* NB 149 178 40 17 10146 W3BGNH PA 152 196 30 19 9702 KA1RB MA 202 209 30 7 7733 KC5LK* MS 159 161 45 2 7567 WA1TCAH CT 149 154 40 5 6930 W3AP PA 144 160 38 3 6560 N6ZA CO 112 125 41 11 6500 WA2IFSH NJ 128 133 42 5 6251 KB8WB OH 119 126 42 7 6174 KK8L OH 150 150 36 5400 WB2TK8 NY 126 131 36 4 5240 N8TN OH 153 153 33 5049 W5PWGB TX 114 119 39 3 4996 WAflWWW MN 118 118 38 4484 KF1B CT 94 102 35 8 4386 WD6MRF OH 90 95 37 3 3800 N1SR MA 90 99 33 5 3762 KR8X OH 133 133 28 3724 WB8YEW OH 94 96 37 3552 W8VENB WV 97 97 34 3298 W8ANM OH 88 88 36 3168 KJ2N NJ 87 99 31 6 3069 N1BMV CT 100 100 27 2700 WlGOM(-) OK 71 74 32 3 2590 K3ND PA 71 78 29 5 2516 W4KMS{-) VA 76 76 31 2356 W3ETB PA 82 86 25 1 2336 K3ZJ(~) DC 94 95 22 1 2185 VElOO* QUE 74 79 22 5 2133 WD8MOV OH 55 59 29 2 1829 KB7M{~) WY 55 55 30 1650 WB2IWJ NY 72 72 20 1440 W2FTY NY 47 48 27 1 1344 K1NCD CT 58 58 22 1276 AK7F(-) WA 43 45 26 2 1250 WB90BX(-) Wl 51 51 21 1155 W1LUG MA 52 52 21 1092 K8CV Ml 40 40 27 1080 WD80YF OH 47 47 20 940 KB9IT IL 43 43 19 817 K4FPF VA 41 41 19 779 N0CMC(-) ND 26 26 20 520 W6YMH CA 28 28 17 476 AK7J(-) AZ 19 19 16 304 W3ICM(-) MD 21 22 10 1 242 N2DCH NY 20 20 11 220 W7ABX(-) NV 20 20 10 200 NL7DB AK 11 20 3 1 80 KA7AKQ WA 8 8 3 24 * District (-) Stat^provincial (W) Contest winner W/VE 80-METER MULTI-OPERATOR Callsign OTH OSOs OSOPts. SUPr. DX Total N9NC<W) IN 793 812 54 17 57652 VE2ZP* QUE 567 597 S3 18 42387 N4BAA* FL 421 456 52 28 36480 W4CNB KY 564 581 50 11 35441 KF2X* NY 413 432 48 11 25488 AJ1E* MA 345 369 40 17 21033 N4FKF KY 212 8692 WBfTCF* MO 93 118 37 4366 W3YA* PA 2 2 1 2 * District (-1 State {W} Contest winner DX 80-METER SINGLE OPERATOR Callsign OTH OSOs OSOPts. SUPr. DX Total I3MAU(WJ Italy 507 983 40 58 96334 CN8CO* Morocco 441 882 23 53 67032 C6ADV* Bahamas 296 316 52 16 21468 HI8GBG* Dom Rep 149 294 49 9 17052 OK1MSM* Czechoslovakia 165 320 52 16640 HI8GB Dom Rep 145 284 41 10 14484 73 Magazine • January, 1983 105 DF9ZP* West Germany 121 239 26 27 12667 WB8YEW OH 108 170 53 22 12750 ZF2DX* Grand Cayman 149 178 42 27 12282 K3ND PA 160 177 61 11 12744 OX3ZM * Greenland 117 234 28 18 10810 K1NCD CT 164 223 51 11373 YV3BQS* Venezuela 96 192 35 16 9792 WA0WWW* MN 150 150 70 10500 JA1ELY* Japan 128 216 18 22 8240 WB90BX* Wl 208 208 50 10400 DA1RE West Germany 107 200 34 6800 W4KMS VA 163 163 60 9780 H44SH* Solomon Is. 69 137 19 15 5658 WD8MRF OH 139 177 52 3 9735 8P6KX* Barbados 78 106 25 17 4452 K4FPF VA 123 152 50 4 8208 JH7JGG Japan 89 159 14 9 3657 K8CV Ml 96 103 56 7 6489 OK1KZ Czechoslovakia 52 89 1 22 2047 K3ZJ DC 164 165 38 1 6435 OKI AGN Czechoslovakia 37 73 4 15 1387 W6YMH* CA 100 109 45 9 5886 SM4CAN* Sweden 30 60 11 9 1200 WD80YF OH 100 100 36 3600 OK2BLG Czechoslovakia 26 51 14 7 1071 KB9IT IL 82 82 30 2460 I4CSP* Italy 38 70 1 14 1050 NL7D AK 45 87 23 2 2175 G5EBA* England 32 62 14 868 AK7F WA 53 55 34 2 1980 DL8UI West Germany 20 39 7 6 507 KA7AKQ WA 56 57 27 1 1596 Y04BXX* Romania 21 41 9 369 W7ABX NV 46 50 24 4 1400 PA3AZM* Netherlands 18 36 10 360 N2DCH NY 29 29 18 522 DF3AO West Germany 17 34 6 4 340 * District award JA5AUC Japan 16 28 7 3 280 (W) Contest winner VK5BW* Australia 13 22 1 9 220 JA3HTT Japan 9 16 6 96 Y03KWJ Romania 6 11 4 44 * DX country (W) Contest winner Check log: Y06LV DX 80-METER MULTI-OPERATOR Callsign QTH QSOs QSO Pts. SUPr. DX I5MPK(W) Italy 191 376 30 29 (W) Contest winner W/VE COMBINED 40/80-METER SINGLE OPERATOR W/VE COMBINED 40/80-METER MULTI-OPERATOR Callsign QTH QSOs QSO Pts, SUPr. DX Total VE2ZP(W) QUE 1271 1506 110 56 249996 N4BAA FL 1066 1228 105 61 205076 KF2X NY 978 1206 96 38 161604 W3YA PA 46 46 16 736 (W) Contest winner DX COMBINED 40/80-METER SINGLE OPERATOR Callsign QTH QSOs QSO Pts. StJPr. DX Total Callsign QTH QSOs QSO Pts. SUPr. DX Total N7DF(W) UT 1188 1286 105 33 180040 CN8CCKW) Morocco 802 1626 67 91 256908 KC40V' TN 931 1078 113 24 147686 H44SH Solomon Is. 360 718 64 35 71082 N8AKY* Ml 880 1051 103 32 141885 YV3BQS Venezuela 251 504 67 39 53424 N8ATR OH 788 963 92 17 104967 JA1ELY Japan 196 346 40 37 26642 KC8JH OH 735 802 98 27 100250 VK5BW Australia 170 328 22 31 17384 W3BGN* PA 411 628 72 27 62172 DL8UI West Germany 92 178 26 22 8544 N4ARO TN 467 502 88 7 47690 OK1AGN Czechoslovakia 54 123 5 27 3936 VE1AJJ* NB 297 357 82 27 38913 SM4CAN Sweden 53 106 26 9 3710 KI7M* OR 321 378 83 19 38556 I4CSP Italy 59 108 2 26 3024 W5PWG* TX 268 303 82 12 28482 G5EBA England 43 84 23 1932 W8ANM OH 284 347 73 4 26719 PA3AZM Netherlands 17 54 16 864 N8TN OH 353 386 65 2 25862 Y04BXX Romania 31 61 14 854 KR8X OH 395 395 53 20935 Y03KWJ Romania 9 17 7 119 W3AP PA 217 260 65 7 18720 (W) Contest winner KF1B* CT 171 200 64 21 17000 W2FTY' NY 161 210 63 14 16170 DX COMBINED 40/80-METER WA2IFS NJ 163 192 51 23 14016 MULTI-OPERATOR KJ2N NJ 150 191 51 22 13943 W3ETB PA 207 253 50 4 13662 Callsign QTH QSOs QSO Pts, SUPr. DX Total W8VEN WV 193 195 68 1 13455 I5MPK(W) Italy 781 1582 74 74 234136 D 106 73 Magazine • January, 1983 W9RE AND W8NGO 160-METER WORLD CHAMPIONS “The most activity ever heard on 160 Best contest Ive ever operated", . An absolute winner?" Definitely will try again next year" These welcome com¬ ments were heard again and again in the wake ot 73' s 1982 "top-band" event. "Wrapped up my Worked All States" < /‘Thanks to the contest I worked another new country!" These were some ol the rewards earned lor just a lew hours of con¬ test operation by nearly 1500 participants. If you're a supporter of 160 meters, you can’t help but notice how much the con¬ test has grown since its incept ton some 3 years ago. The br ight tuture ot this world championship event seems assured.. Year a ml* rsroctpantB 1980 569 1981 917 1982 1482 This year, W9RE single-handedly produced 1118 OSOs, 58 slates and provinces, and 8 DX counties to become the 1982 World 160-Meter Phone Champion for single-operator stations Mike managed to beat second-place finisher and 1981 World Champion W8URL by a margin of 136 OSOs and 20,000 points A race as close as this, involving two of the most promment stations on the band, sets the stage tor our 1983 event Just around the corner The upcoming contest will decide the best two out of three Beth W9RE and W8LRL are to be congratulated tor their superb performance in our own "survival of the fittest." Who wifi surpass W9REs 1118 OSOs which now establishes a world record on 160? In the mulli-operalor category, the crew members at W8NGO are the 1982 World Champions. They compiled 877 OSOs, 56 stales and provinces, and 4 DX countries lor a total score of 273.900 contest points The gang at W4CN, last year s World Championship station, finished second with a total ol 238,950 points. It was a very close race for the top slot, with only 73 OSOs and 1 multiplier separating the two stations. Here again, the 1983 contest will decide the best tarn out of three, since last year's champions finished second this time Of all the single-operator entries* the following stations compiled 500 or more OSOs W9RE ill 18), W8LRL #82), WB3GCG 1932) WD8CRY (762). WBOCMM (722). W1CF (697), KJ9D (622). N8ATR (582), N5JB (579). KC8P (561), K9QLL(552), W3BGN (524), and NSCG (502) In the multi operator class, 500 or more OSOs were earned by the following sta¬ tions. W0NGO (877), W4CN (804), AK2E (688), K9ZUH (677), W9ZX (512), and K9YUG (504) W9RE worked the most stales and provinces (58) for the single-operator class, followed by W8LRL and WB3GCG with 57. K9RJ with 56; KC8P WD8CRY KJ9D, N5JB W88CMM and K90LL with 55; W1CF W9DUB. and W©CM with 54, N5CG W4VKK. KB8HW, and W2FJ with 53; K1MNS, W5YZ. KA0HIG. and KA7BTO with 52; and KC40V, K8STF, WA2GZB, N7DF, and K1LPS with 51 W/VE multipliers. For the multi-operator category, W8NGO, K9YUG, and K9ZUH accumulated the most W/VE multipliers, wllh 56 each; AK2E had 54, W4CN had 53, K«UK had 52, and W9ZX had 51 states and provinces. Screening all logsheets. EA5ET worked 17 DX countries, followed by G3XWZA with 15 countries; W8LRL wilh 13; N4IN, OK1AVG, and W1CF with 12; WB3GCG and VE1YX with 11; and ZF2DX with 10 After all the contest entries have been tabulated, it is rewarding to analyze the station equipment and antennas used by the participants The tables below tell the story Equipment Usage Kenwood 38.5% Yaesu 27.0% Drake 20.5% loom 4,9% Ten-Tec 3.3% Collins Z4% Hy-Galn, Astro, Heath, Signal One .85% each Vi-wave sloper 9.3% Trap vertical 9.3% Shunt-fed tower 7.9% Vertical (V». full wave) 7.9% Long wire 5.7% Vi-wave sloper 2.8% Quad, delta loop. 5-efement yagi, windom, zepp .9% each Equipment used in the 1GO-Me ter Phone Contest. Antenna Usage Dlpote/lnverted vee 37.3% Inverted-L 15.3% Receive antennas only: Beverage 10.7% Loop configuration 1.9% Antennas used in the 160-Meter Phone Contest The success ot this very popular contest would not have been possible without the dedication of two superb gentlemen of the "gentleman's band." Our special thanks to Dan WA2GZB and Ed K3IXD who both tackled the responsibilities of scoring all the entries and corresponding with the entrants. These gents have been involved with this world-championship contest ever since its founding some three years ago. Both have burned the midnight oil countless nights when the rest of us were enjoying the openings on the band. The 4ih annual contest is just around the corner, Alter you read these results, pass them on to your Inends on 160. Be sure they're aware ol our world- championship contest, scheduled lor January 15-16, 1983 If you think this year’s scores were record breakers, wait until January 1983! Wilh the relaxation of the FCC rules on this band, we expect to see nearly 2.000 stations participating I'll be there, how about you? WORLD 160-METER PHONE CHAMPIONSHIP MULTI-OPERATOR STATIONS Callsign State QSO St/Pr, DX Points W8NGO (W) Ml 877 56 4 273,900 W4CN* KY 804 53 6 238,950 AK2E* NY 688 54 8 224,750 K9ZUH* IN 677 56 6 213^280 K9YUG IL 504 56 4 152,400 K«UK* CO 467 53 5 137.120 W9ZX IL 512 51 — 130,560 N8AKY* Ml 369 50 3 98,580 KB0TJ CO 324 50 — 81,000 AA1K/3* DE 279 46 7 75,525 KB8AC* OH 244 44 1 56,350 N4DBR KY 219 40 — 43,800 K8UR* KS 189 43 1 41.800 W0CEM KS 143 45 1 31,970 WD8NJR Ml 133 40 1 27.470 KB9SF CO 136 40 — 27,200 DF5ZO/A* Germany 35 — 6 3,135 iWt World Champion for 1962 * Stale.-Provinctal OX Country Champion Disqualified; WB8JBM 160-METER CONTEST SOAPBOX “A very excellent test. Something should be done about improving the conditions, however (hi) "-W1BB. Sugges t you give a multiplier ot zero tor a HkW sta tions With their excess power, that would certainty thm the results considerably”—A A IK "My first try at a contest Hope i help those needing Rhode Island."— W1LOV "Excellent conditions the first night Sure was a fantastic contest and Vm realty looking forward to next year now more than ever ”—K1LPS "Lots of activity, The band was extremely crowded "—K1NBN "A very tine event / Many big signals, and there were more stations on the band than I have ever heard on 160 meters 9 "—K2DWI "Excellent firstmght European opening"—MIN. "Score would have been higher but had 300 kHz interference from an op who lives /us/ down the road. He deliberately QRMs and the FCC has given him warnings about it "—W4PZV "My first 73 contest. Had a great time. Will have a better receiving setup next year"— W4TMR. "The most enjoyable contest Tve ever been in!"— W4TWW "A bunch ot activity on the band. Hardly any DX.”—WB4ZPF "Must say there was much activity and I certainly entoyed it very much — N5CG “Enjoyed the contest Sounded like 20 meters. The strobe light atop my 300 vertical gave my receiver tits throughout the contest "-W5GFR. "Thanks for a fine t60-meter contest ”— AESH. "Nice contest Ended up doing surgery and missed half ot it, unfortunate¬ ly."—K5JZN. "Lots and lots ot QRM!"—W5LFG "Very interesting contest. Sure enjoyed It. "-KC5LK. "Sure had lots ot fun in the contest. Lots of QSOs and lots of QRM,"—K6ANP. "Great contest. Wish I could have worked the entire event."— WD6EFU "Enjoyed it, as I'm sure everybody did. Second night was not as good as the first. Doubled last year's score, though."—W6WBY "Had to work both nights but managed to slip In a tew Nevada multipliers tor the stations on the band,"—W7ABX "Sounds Hke the contest is growing every year Had a great time as did everyone I talked to." — KA7BTQ "Daytime contacts are okay but too bad you couldn 't work a station a second time it you worked him the night before."—N7DF. "Sure enjoyed the contest. Lots of stations heard on the band"—WB7FDQ. "Super contest! I did better than last year and it sure helps toward my 6band WAS award. See you again next year.”—AK7H. "Very enjoyable contest. Amazed at the number ot stations on the band. Alt were very courteous. It was a real gentleman s contest,"—K7SFN. "Great contest. Heard a lot ot activity from my QTH here in Montana Plenty ot QRM, too " — K7VIC “Daytime bonus points should be deleted "-KC8A "Had to/s of fun and looking forward to 1983 The contest is definitely growing each year Thank you, 73!" — N8AKY "S-9 power-line noise throughout the contest!"—W3CV. "Had nothing but antenna problems the 1st night. Blew a borrowed rig to top it off. TH be back next year though "—AK2E. _ * Continued 73 Magazine • January, 1983 107 “A tun. gentlemanly affair Worked maybe f 2 calls on 160 the last 35 years. This weekend I managed over 700 contacts *WD8CR Y Sounded like everyone had a great time "-K8HF “*2 states worked Not bad for a 25 foot helical wound vertical with only 5 radials " — KC8NR “Enjoyed the contest very much l think it is the best one held on 160*“ — KC6P. “Sure enjoyed the contest Lots and tots of stations were on, t see“—AA8S. “Daytime bonus was contusing Had a great time, though. “-K8US. “The first 160-me ter contest ever for me. I invited the Smoke Valley ARC over to help me out. '—W9CEM “Unbelievable activity this year 73 has done if again!**— WBftCMM. “My first effort on 160-meter contesting I was realty impressed with the turnout. Had loads of fun “-KA9HIG “Sony, no US stations heard on the band .. .just Europeans. “—DfSZDfA. “Had a special 160-me ter license and heard only Europeans. “—EA3CCN. “A very popular contest according to the fumouf. Good luck“—KH6IJ. WORLD 160-METER PHONE CHAMPIONSHIP SINGLE-OPERATOR STATIONS Callsign State QSQ SUPr. DX Points W9RE m m 1118 58 8 371,580 W8LJRL* wv 982 57 13 350,700 WB3GCG* MD 932 57 11 322.660 WlCF* MA 697 54 12 236.280 WD8CRY* Ml 762 55 6 234.240 WB8CMM* CO 722 55 8 230,895 KJ9D* IN 622 55 4 184,670 KC8P Ml 561 55 5 169,800 N5JB* TX 579 55 3 169.650 N8AFR* OH 582 50 5 164,640 K9QLL* IL 552 55 3 160.950 mm- KS 484 54 6 147.600 mm IL 471 56 4 142,500 K88BW Ml 491 53 3 138,320 N5CG‘ OK 502 53 1 135,810 W3BGN* PA 524 45 4 135.730 W9DUB* Wl 473 54 3 135.660 K04OV* in 479 51 3 130.140 K1MNS* NH 436 52 3 120.725 K1LPS* VT 440 51 3 119.610 W4TMR* NC 461 48 6 117,720 KA7BTQ* ID 368 52 7 111,805 K0STF* SD 401 51 3 109,080 W4VKK* GA 367 53 4 106.020 W2FJ’ NJ 347 53 6 104.430 N70F* UT 362 51 5 103.880 N41M* FL 318 48 12 101.100 KAQHfG* IA 338 52 3 93,775 W5Y2* NM 333 52 3 92.950 K4AQQ FL 331 49 5 90.720 VE1YX* NS 292 47 11 88,740 N4MM 4 VA 48 4 88.400 K280* NY 285 49 8 84.075 KD4N1 VA 315 49 3 78,645 KG4W VA 347 46 1 77,315 VE2ZP* Quebec 343 42 2 75,900 W4 P2V FL 259 49 7 74.760 K7SFN* NV 293 50 1 74,715 N4ARO TN 289 48 3 74.460 N3G0 MO 283 43 3 73,580 W67ro Q* A2 266 50 3 71,285 K7VC* Ml 263 49 4 70,490 WA2GZB m 253 51 3 69,120 NA4D* KY 251 49 3 66.040 W80BF OH 303 39 3 62.730 NO AN IA 246 50 _ 61.500 WAOOFH* WA, 179 48 7 61,410 K31X0 MD 252 47 1 60.960 W0HW* MN 235 50 1 60,435 AA8S OH 304 36 2 58,140 W5GFR TX 240 41 5 56,350 K3LGC* DE 237 40 2 54,600 KB3MI PA 215 46 3 53,410 AESM* MS 254 40 1 52,480 W3ICM MD 243 39 3 51,650 VP9BO’ Bermuda 251 35 5 51.200 KK&L OH 251 38 2 51.000 WB4TUO TN 192 48 4 50,960 K20WI NY 245 39 2 50.635 KC8A Ml S3 37 1 48.260 K4CNW* SC 215 44 — 47,300 K6ANP' CA 201 42 3 45,900 W3AP PA 235 35 2 44,955 N8TN OH 233 37 1 44,460 WB1CWZ' CT 252 33 2 44.450 KC5LK MS 206 41 1 43.680 VE4WR* Manitoba 176 49 — 43,120 W40WJ FL 167 45 5 43.000 KC8NR WV 190 44 1 42,750 AE3T PA 185 42 2 41,140 K2FL NJ 200 34 3 40.600 weaoFt IA 196 43 _ 40,140 W4TWW SC 179 41 3 40 040 W8DN OH 177 39 2 36,285 KfNBN* ME 175 39 2 35.465 WB7Q2M- OR 191 33 1 32.980 AtftZ IA 154 41 1 32,550 WB42PF VA 154 39 2 31,980 W4YZX NC 165 35 1 30,880 AK7H WA 130 42 4 30,820 WA5NFC* AR 156 34 2 28,620 WA9FTV IL 130 41 1 27,510 KC8JH OH 123 41 2 26,660 K3SXA/MM NY/MM 124 34 6 26,400 K4YFH NC 176 30 — 26,400 KlECK MA 167 24 5 24.505 K8US OH 143 34 — 24,310 K5JZN OK 110 43 — 23,650 NtZA CO 99 43 2 22.725 N7AKU NV 138 3t 1 22,400 WA9RHU IL 118 35 1 21.420 ZF2DX* Grand Cayman 82 37 10 21,150 VE7WJ’ BC 110 33 3 20,160 VE60U* Alt, 127 30 1 19,995 W3CV PA 92 40 1 19270 VE7ERY BC 100 38 _ 19,000 WB9LFD/1 CT 119 29 2 18,755 W4KMS VA 109 31 2 18,315 AA4FF VA 126 27 2 18.270 K40D VA 112 30 1 17.515 W6WBY CA 105 32 1 17,490 K8SVT OH 116 30 — 17,400 WA20RX NY 103 31 1 16.640 VE1BPY* PEI 93 33 2 16.625 VE20G Quebec 93 34 — 15,810 K8AQM Ml 117 27 — 15.795 VE2QO Quebec 101 27 3 15.300 K9CGD IL 89 31 2 14.585 KB8YE OH 85 30 1 13,330 W5LFG TX 98 27 — 13,230 K2MN NY 95 26 1 13,095 Wl BB MA 72 30 3 12,375 WD8LCD Ml 101 22 — 11,110 Wl LUG/4 VA 85 23 1 10.320 W4HVU FL 71 25 2 10260 W1LOV* Rl 94 21 — 10,185 KB0W/6 CA 71 26 — 9.230 WD8MRF OH 73 24 8.760 VE5XU* Sask 60 26 — 7.930 WD8LCN Ml 62 25 — 7,750 KB7M* WY 58 23 3 7.540 G3XWZ/A' England 94 — 15 7.450 K8HF OH 59 23 — 6,785 EA6ET* Balearic Is. 57 1 17 5,130 WD6EFU CA 44 20 — 4,600 OK1AVG* Czech 71 — 12 4.260 W7ABX NV 50 17 — 4,250 KB8UO Ml 62 13 _ 4.030 KB7WN WY 33 20 — 3.400 W1GOM/5 OK 35 18 — 3.150 EA3CCN* Spam 26 — 8 3.120 AK7F WA 40 13 1 2.870 KJ7I AZ 35 15 — 2.625 K8CV Ml 32 16 _ 2,560 KA7HBS WY 28 16 — 2240 KH6IJ* HI 29 15 2,175 KA8MSO Ml 50 7 — 1,750 8P8KZ* Barbados 16 7 6 1.495 VE7FBS BC 23 10 — 1.150 W3ETB PA 14 10 1 825 N8ASB Ml 13 1 — 130 KA8ALO Ml 8 1 — 80 K9GOF Wl 4 2 _ 40 (W) World Champion for 1982 * StatesfProvinciatiDX Country Champion 108 73 Magazine * January, 1983 Listings m this column are provided tree of Charge on a space-available basts The fol¬ lowing information should be included in every announcement sponsor, event, date, time, place, city, state, admission charge (if anyj, features, talk-in frequencies, and the name of whom to contact tor further informa¬ tion., Announcements must be received at 73 Magazine Oy the first of the month, two months poor to the month in which the event takes place Man to Editorial Offices. 73 Mag¬ azine, Pine Street, Peterborough NH 03458. SOUTH BEND IN JAN 2 A ham test swap & shop will be held on Sunday, January 2,1963, at Century Center, downtown on US 33 One Way North be¬ tween the St Joseph Bank building and the river, South Bend IN. Tables are $3.00 each in a carpeted, half-acre room. The Industrial History Museum is in the same building. Four-lane highways lead to the door from all directions. Talk4n on .521.52, 99?' 39. 9303, .78/18, .69409. 145.43, and 145^9. For more information, contact Wayne Werts K9IXU, 1889 Riverside Drive. South Bend IN 46616, or phone (219F233-5307. WEST ALUS Wl JAN 6 The West AiMs Rad*o Amateur Club will hold its tith annual Midwinter Swapfest on Saturday. January 8,1983. beginning at 8 00 am. at the Waukesha County Exposi¬ tion Center Tickets are $2.00 in advance and $3.00 at the door Tables are $2 00 in advance and $3.00 at the door. For ad¬ vance reservations, send an SASE to WARAC. PO Box 1072. Milwaukee Wl 53201 OAK PARK ME JAN 9 The Oak Park Amateur Radio Club will hold its annual Swap n Shop on Sunday, January 9, 1983. from 8:00 am to 3:00 pm. at Oak Park High School, southwest cor¬ ner of Coohdge and Oak Park Boulevard. Oak Park Ml. There will be ample parking and refreshments. Talk-m on 148 52. For prepaid table reservations, write OPARC, 14300 Oak Park Boulevard, Oak Park Mi 48237. RICHMOND VA JAN 16 The Richmond Amateur Telecommuni¬ cations Society will hold Richmond Frost¬ iest '83, the annual winter ham radio and computer show, on Sunday, January 16. 1983, at the state fairgrounds. Richmond VA General admission is S4 00. AH flea- market and commercial exhibit spaces will be indoors in a 30IMXFsquare-toot ex¬ hibit building. SOUTHFIELD Ml JAN 30 The Southfield High School Amateur Radio Club will hold their 18th annual Swap & Shop on January 30. 1983, from 8.00 am to 3:00 pm. at Southfield High School. 24675 Lahser. Southfield Ml Doors will open at 6:00 am for exhibitors. Admission »s $2.50 Reserved tables (payable in advance) are $18 00 for two 8-foot tables and $9.00 for each additional reserved table Tables also will be available at the door There will be food and parking All profits go toward elec¬ tronics scholarships and to support the activities of Southfield High Schools amateur radio club For more information or reservations, write Robert Younker, Southfield High School, 24675 Lahser, Southfield Ml 48034, or phone (313)354-7372 from 8:00 am to 1Q;30 am or (3131-354-8210 from 10:30 am to 3 00 pm Monday through Friday ARLINGTON HEIGHTS IL FEB 6 The Wheaton Community Radio Ama teurs will hold their hamfest on February 6.1983, at Arlington Park Race Track Expo Center, Arlington Heights IL Tickets are $3.00 at the entrance and $2.50 in ad¬ vance. Doors will open at 8:00 am. Flea market tables are free and plenty of floor space will be available There will be a large commercial area (including a com¬ puter section), awards, and clear, paved parking Talk-m on 146 01/ 61 and 146:94. For general information, call W9JTO at (3l2)-23l-9524. For advance tickets, send an SASE to WCRA, PO Box QSL, Wheaton IL 60187 MANSFIELD OH FEB 13 The ARRL-approved Midwinter Ham- fest/Auchon will be held on Sunday, Feb ruary 13, 1983, beginning at 8:00 am, at the Richland County Fairgrounds, Mansfield OH Tickets are $2 00 in advance and $3.00 at me door Tables are $5 00 in ad¬ vance and $6 00 at the door Half tables are available. Talk-m on 146.34/ 94 For ad¬ ditional information or advance tickets, contact Harry Frietehen K8HF. 120 Home- wood Road, Mansfield OH 44906, or phone (4191-529-2801 or (419)524 1441. MARLBOROUGH MA FEB 20 The Algonquin Amateur Radio Club will hold its annual flea market on Sunday, February 20, 1983. at the Marlborough Jr High School, Marlborough MA Admission is $1.00 and children under 12 will be ad¬ mitted free. The doors will open at 9:00 am for dealers and 10:00 am for buyers Re¬ freshments will be available Tables re¬ served before February 12,1983, are $7.00; any remaining tables will be $10.00 at the door. Talk-in on 146.01/ 61 and 146.52 For fable reservations or more information, contact Algonquin ARC. PO Box 258 Marlborough MA 01752. GLASGOW KY FEB 26 The Glasgow Swapfest will be held on Saturday, February 26.1983, beginning at 8:00 am Central time, at the Glasgow Flea Market Building, 2 miles south of Glasgow just off highway 31E. Glasgow KY Admis- ston is $2.00 per person There is no addi¬ tional charge for exhibitors The first table per exhibitor will be free, and extra tables will be available for $3.00 each There will be a large heated building, free parking, free coffee, and a targe flea market. Talk- mi on 146.34/.94 or 147.63/.03. For further information, write Bernie Schwitzgebei WA4JZO, 121 Adairland Court. Glasgow KY 42141 i^aiio TlJorU CENTRAL NEW YORK S MOST COMPLETE HAM DEALER • COM 1C 1 20 WOBOT SOG _ _ ,esu ft rm Featuring Kenwood, Yaesu, loom, Drake, Ten-Tec, Swan, Dentron, Alpha, Robot, MFJ, Tempo. Astron, KLM, Hy Grain, Mosley, Larsen, Cushcraft, Hustler, Mini Products, Bird, Mirage, Vibroplex, Bencher, Info-Tech, Universal Towers, Callbook, ARRL, Astatic, Shore, Collins, AEA. We service everything we sell !_ Write or call for quote. You Won’t Be Disappointed. We are just a few minutes off the NYS Thruway 0*90) Exit 32 Ou* Of state ONEIDA COUNTY AIRPORT TERM INAL BU ILDING Warren - K2IXN OROLA toll f «E€ ORISKANY NEW YORK 13424 Bob - WA2MSH 800 - 448-9338 N v Res Cali i 736-01 84 ✓ 397 Al • WA2MSI NEMAL ELECTRONICS! 5y AV !, COAXIAL CABLE SALE A 77 _ ^ cj /<*' A / 7; ^7 VV! C V POLYETHYLENE DIELECTRIC RG213 noncontaminatmg 95 % sheiid mil spec 36e/ft. RG174/U rml spec 96- - shield lOc/ft RG11U96% shield. 75-ohm nut spec 25c/ft RG8U 96% shield, mil spec $27.95/100 fl or 31c/!t RG6A/U double shield 75-ohm 25</ft RG58AU stranded mil spec I2c/ft. RG58 mil spec 96% shield llc/fl LOW LOSS FOAM DIELECTRIC RG8X 95% shield (black, white or gray) Si 4.95/100 II. RG8U 80% shield RG58U 80% shield. RG58U 95% shield RG59U 100% foil shield. TV type. 17c/lt. 18c/ft. 07c/ft. 10cm $7/100 n ioc/tt. 3lc/ft. RG8U-20 ft., PL 259 ea. end $4.95 RG214U dbl silver shield. 50 ohm $1.35/11. 100 II RG6U with PL-259 on each end $19.95 BELDEN Coax in 100 It rolls RG58U *9201 $11.95 Grounding strap, heavy duty tubular braid 3/16 in. tinned copper lOcrtt 3/6 in, tinned copper 30c/tt. CONNECTORS MADE IN USA Amphenol PI-259 79c PL 259 push on adapter shell 10/S3.89 PL-259&SO-239 10/S5.89 Doubie Mate Connector $1.79 PL-258 Ooubie Female Connector 98c 1 ft patch cord w/RCA type plugs each end 3/S1.00 Reducer UG 175 or! 76 10/S1.99 UG-255 (PL 259 to BNC) $3.50 Elbow (M359). $1.79 F59A (TV type). .10/52.15 UG 21D/U Amphenol Type N Male lor RG8 $3,00 BNC UG88C/U. male $1.25 3/16 mch Mike Ptup for Collins etc $1.25 UG273 BNC to PL-259 S3 00 FREE CATALOG COD add $1.50—FLA. Res add 5% Sales Tax RG8U 97% shield 11 ga (equtv BekJen 8214) Rotor Cable 8-con 2 18 ga, 6 22 ya I9c/ft. Connectors—shipping 10% add’i, 2.50 minimum ^ 41 Cabie shipping $3 00 1st »00 ft $2 00 each add i 100 ft 1327 NE 119th Street, Dept. RLO, No. Miami, FL 33161 Call (305) 893-3924 ✓ See List of Advertisers on page 114 73 Magazine • January, 1983 115 OK, Wayne, I've sal here every month and read how you think that the code require¬ ment is hindering the growth of amateur radio, i think you are missing a problem fac¬ ing amateur radio that is much bigger than a code requirement. The problem that I am referring to is local ordinances that restrict or prohibit amateur towers and antennas I can only imagine the number of hams who have worked hard to upgrade and leei that now is the time to put up that dreamed- of antenna system only to have their local government say it’s Illegal, so take it down. Why upgrade anymore? In fact, why even continue on with ham radio? It is truly disheartening to be told not to practice your hobby to its ultimate limit and enjoyment. Bel ieve me, fighting city hall is no fun {well, maybe a little fun when you win). I speak from experience, tn my city, Cerritos, California, it took about 2 years of fighting city hall to get our ordinance changed. Led by George Goumas N6AWF, we outlasted our city officials by getting to meetings at 7:00 pm and often not being able even to be¬ gin our presentation as to why our ordi¬ nance should be changed until 1:00 or 230 ant Weil, our perseverance paid off with a new ordinance that allowed us to go to 70 feet with a conditional use permit. Wayne, if it had not been for many out-of- town hams who came and helped to fill up the council chambers, we would never have made It, Of the 100-plus hams in our city, only a handful were interested enough to come out for our hearings. It was the back¬ ing of theout-of-towners that saved our bot¬ toms I applied for the first permit under the new ordinance, ft was granted after a two- hour discussion with neighbors who claimed I was causing them continuous interfer¬ ence A well-kept log book blew that argu¬ ment away. I really thought that my permit was to end up on the scrap pile after a 137-signature petition against me was pre¬ sented to the council For a number of rea¬ sons that I won't go Into, it had no effect From these experiences l have come to some conclusions that I would like to share with all amateurs. First of ail, most of you don’t care about what is going on around you until it hits you square m the face. Amateurs need to fight for their property rights as home owners I have a little 50’ * tOO piece of property that I'd like to cail mine, but it is never mine when I have people telling me I can't practice a hobby that’s not noisy or harmful. It’s a lot easier to keep restrictive laws oil the books than it is to change existing laws. Each amateur should make it his (or her} business to keep tabs on what is going on in his city Finally, don't assume that because the guy a mile away has up a tower and antennas that there are no laws against it in your city, ft may be that no one has complained to the city so they just haven’t taken the time to tell the amateur to remove It. Wayne, as much as I dislike fighting with my local government, I'll never stop fight¬ ing. tt looks as if I will be moving in the next year so that f will probably have to go through the permit process again Local governments are slowly taking away our personal freedoms If you don’t believe it, just check to see what kinds of no-nos are on your local government’s books. These ordinances will range from what color you are allowed to pamt your house to what you are allowed to park in your driveway Be¬ lieve me, restrictive antenna ordinances are becoming more of a widespread problem than you will ever know and are certainly more of a problem than a code test. Carol Green KK6V Cerritos CA P S Since writing you this tetter, our city is trying to puli the wool over our eyes again They have decided to take the new ordi¬ nance and put it back into the Planning Commission lor further study So far through all of this, we have received no League backing. If the ARRL won't help us this time then I suspect that 100-plus amateurs in this city will no longer have any reason for belonging to the League because amateurs that cannot operate have no reason for belonging to an organi¬ zation that deals with the operation of amateur radio stations How far have we progressed in ham radio 9 Is it possible that oik technology has passed our intelligence? Can it be that many of our population lean towards hy¬ pocrisy? One of the most common comments one hears on the air is, “Ham radio is so great, it has something for everyone " i suppose they speak of the hobby where if you have the money, you can own monobanders on each band, several transceivers, and ampu tiers. Do we include the other guy? The one who lives by the dipole and rvo amplifier 9 Which hobbyist is more important? Looking back, more than hall of what I now have collected I owe to a list or a net of some kind. Myself, I have never taken a re¬ layed report, which some seem so con* cerned about The percentage of people who operate with the same self dignity set of rules I operate with is probably 98 percent I have sat »n awe at my station listening to what some say is the only way to work a OX station (the pileup). I have heard gentlemen such as FB8WG and A51PN (and the list could go on) try to dig a call or just a letter out of the pileup; being un¬ able to do so because people kept calling so tong, they just go QRT or QSY. Gentlemen, channel efforts towards making ham radio a better hobby. During contests, for example, stations all over the bands run 20-30 kHz wide. These guys don’t care, because it keeps others from moving close. Why not focus support towards allot¬ ting overlapped segments of the General and Advanced band, i.e., 14250-14300 kHz This way, non contesters are not forced out of their weekend of operating. How many lists or nets mess up the whole band for Others throughout the entire weekend 9 I suppose that’s OK, though, because some where, someone up there likes contests. I firmly believe that the majority of the old-timers that are against lists or such have all or nearly all of their countries and have done so during times when the ham population was one-tenth what if is today I would tike to see them start over with a di¬ pole and barefoot l hope any kind of stand against lists andlor nets is only a rumor. Let us consider how much control any organization which 116 73 Magazine • January, 1983 is supposed to help hams should have over how we make a contact I feel the desire for the coveted accom¬ plishment in each of us will stop the taking of the invalid report. Those who are dishon¬ est will find a way to be dishonest In every facet of ham radio, no matter what rules are set Gentlemen, ponder this and let s all try to Improve what we have and not take away that which each of us is entitled to. Philip Pritchett N6ATS Mounds OK You know the cliche: Each of us is eager and ready to take pen in hand and com¬ plain. grumble, bellyache, etc., against or about some vendor or products or services. But to say something nice about someone or something, that is another scenario, and here comes one. I have been a ham for about four years, starting at the tender age of 57. In this rela¬ tively brief period I have sampled the wares and services of many vendors selling to amateur radio people Overall, it has been a pleasant experience, but let me single (or is it double) out two vendors from the many I have experienced. First—Trio Kenwood, makers of fine rigs for two-meter and HF operation along with excellent, if somewhat expensive, audio gear, I have been particularly impressed with service out of their Compton, Califor¬ nia, site They are professional and timely, either by mail or through the reception desk. One gets to speak to a technician right up front, and if the one serving you is not familiar with your particular rig he goes for help In the back room. The rule is courte¬ sy and the proper amount of sympathy. When appropriate, charges are less than the “minimum” posted in the reception area. Service time is often less than posted minimum time. All in ail, rest service after the sale! I am equally happy with the products and service from Communications Specialists, Orange, California, makers of tone genera¬ tors for PL applications. Customer service by telephone has always been polite and ef¬ ficient. You get the feeling that they care about their customers. On several occa¬ sions, they have given no-charge seivice well after the end of the warranty period, sevice required by my clumsiness rather than product failure. Again, a company that unstintlngiy backs up its product. I would like to hear from other hams with similar experiences, I. Oftaky KA6CLE Venice CA For the past several months I have been reading tetters directed to you by pro¬ ponents and opponents of code-free licens mg, I have yet to read one letter that ad¬ dresses the central issue, which i believe is how we as amateurs propose to make our hobby better I struggled with the code and theory as, probably, most do... my callsign attests to that. The pivotal feature Is that persever¬ ance and desire can get most everyone past the hurdles I do not feel that 2&wprn code, 13-wpm code nay, even 5-wpm code, nor Mr. Bash's crib text detract from amateur radio; neither do I feel that those things support ham radio l feel amateur radio s biggest asset lies in the individual hams who comprise our society and the fact that ham radio is a challenging and just plain fun hobby. Each and every one of us, the already- licensed hams, should do our part to fasci nate, encourage, instruct, and support non hams in the acquisition ol an amateur li¬ cense. We should, on an individual basts, be Elmers to any who show an interest. We should, as groups or clubs, promote and participate in spreading the word that ham radio is fun by supporting and teaching classes. Learning aids are available 73, Heathkit 4 , the ARRL Ameco, and others publish many fine learning aids The FCC, while not always as responsive as we would like, is the arbiter of our licensing ex¬ ams and makes those exams available on schedule and without prejudice What may be missing is the incentive for us as individual hams or groups of hams to encourage others. I propose that 73 spear¬ head an effort to encourage hams to teach others about ham radio How? 1) Awards: I propose that 73offer awards to individuals and clubs, similar to operat¬ ing awards, for getting amateurs licensed. 2} Instructor training. Most of us can learn but many require help In the form of syllabi, group instructional aids, and teach mg techniques to enable us to help others Publish these aids 3) Public knowledge: Advertise to make the public aware of amateur radio. The ARRL does this to some extent—more is needed. 4) Hotline: Match Elmers (either individ¬ uals or clubs) with prospective amateurs needing help Might work like an comput er dating service. A national 800 number hotline is one possibility, 5t Service awards: Encourage clubs to promote themselves by offering club awards for participation in activities like SETs, RACES. MARS, etc, These are some of the possibilities There are probably many more ideas which would work better or attack a different front. Not everyone wants to become a radio amateur For one thing it requires some discipline and effort and not every one is willing to devote the necessary energy, I feel that everyone who is willing to make the necessary commitments should be given all the help possible by all ol us amateur radio operators everywhere. Jeff Barstow WD8DLK Rodney Ml 1 am a 15-year-old at Hereford High, and I am writing about the public outcry (what lit¬ tle there is of it) towards Bash Educational Services. In 73 for November, you reported the failure of 89 percent of one of Bash’s classes and restated your opposition to the books and classes. I must admit that I have great respect for anyone who takes a firm stand lor their own opinions. However, I do disagree with you on the “Bash Book" debacle. When you realty think about it. Bash's system was a radical concept, but as with all once-new ideas, an improvement is needed (not a ban). Now think about this: You have to admit that lor anyone intent on passing “Big Brother’s” exam for upgrade it is a Her¬ culean effort to find ail ol the information (much less, carry the ton ol books needed) for passing the bewitching exam; even the ARRL Study Guide is nowhere near enough. Anyone who has no prior knowledge of the theory will quickly find out that the Study Guide is a good book for introducing them to the theory but in no way prepares them for the double- and triple-talk used by the FCC to befuddle our minds. If you get ail of the necessary books to study out of, you wind up studying a Jot of informat ton, 70 percent of which you will probably never use or want to know or is not even on the teat AM of this useless information mainly serves Its purpose by wandering around our minds and mingling with the facts needed. This usually causes a nasty surprise In the form of a failure. My idea for improvement is a simple change. Continue collecting Os and As from tests but not for printing in cheat books i would simply use these and take all of the ham-radio-related books I could get (if I had the sources! and find alt I could in the way of theory and facts to back up all of the answers. Take these arranged facts and write them Into an easy-to-understand form of writing with flavor and a small vocabu¬ lary (you want more young hams; write it so we can understand you). Without using bor¬ ing, dragging wording, present the theory well, and towards the end of the book in¬ troduce readers to the language used by the FCC and get them very familiar with it. Also, a copy of the regs in FCC form with simple English definitions would be desired by many people. I think that anyone bringing out such a book would end the era of the Bash Books. I know that my idea is not new, but I have yet to see it in the print of a large magazine. Thank you for your good magazine and for your time, Glen White NA5Z Hereford TX YOU’RE MY TYPE Your last two issues of 73, namely Oc¬ tober and November, have been more my type of magazine Since I keep my own notebook of the interesting articles I see in the mags, you have kept me busy lately. You see, I look for articles that look inter¬ esting to put on the breadboard and play with and wften iVe played with one long enough and it looks like a good project to finish, so much the better In regard to your continually pressing for more amateurs, I leel that I must put In my two bits worth Of all the 50 or more Nov¬ ices that have passed their exams around here the past two years or so. there are only about two or so on the air. Everyone is in¬ terested in DX—how far can we get out, etc. The biggest problem seems to be money. Very few seem to be interested in building. Frankly, I think we need a good set of text¬ books that will take the prospective ham from beginning to end. I'm all lor your computer networks, but so far your computer articles are way over my head and I cannot afford the price of a computer to figure them out. The day you can show me 73 articles where I can borrow my wife's portable TV set and, with the min¬ imum of cost, put it on the air, that will be the day You'll have to hurry, though: Cm 74 years old. Laurence A. Knutson W9SFL La Crosse Wl SCHOLARSHIPS The officers and directors of the ARRL Foundation announce the recipients of two awards for the 1982-83 academic year The Long island School Scholarship, tor youths attending Long Island colleges or univer¬ sities, has been granted to Paul Michael Silverman KA2DSP, of Levittown NY. He entered State University of New York at Farmingdale in September to pursue courses in electronics technology The $250 ARRL Foundation-administered award was given to this young man tor demonstrated interest and excellence in promoting amateur radio and for aspiring to an electronics carreer The YL ISSB Memorial Scholarship has been awarded, for the second successive year, to Larry Edwin Smith, Jr. WB9UKE. The awarding of $709 to Larry concludes the ARRL Foundation's administration of this scholarship fund for YL ISSB Larry pursues associate and bachelor's degrees in electronics engineering, aspires to a career with NASA communications, holds amateur Extra and 2nd class commercial licenses, has maintained an A academic average, and has been very active in ex¬ tracurricular activities at Vincennes University, ARRL Foundation administered scholar¬ ships are open to all applicants, qualifica¬ tions and specific criteria being reviewed by screening boards consisting of ARRL Foundation officers and directors and panels provided by sponsoring organiza¬ tions Application closing date is May 1, 1983 for the next academic year Andrea T. Parker K1WLX Secretary, ARRL Foundation Newington CT FINDING BIRDS Finally, I have found why the RSn satellites aren't where they were supposed to be: The tracking program was wrong! I’m referring to “Tracker—The Ultimate OSCAR Finder/ p 88, 73 Magazine, January, 1981. The computation tor satel¬ lite longitude is correct only for satellites with inclination greater than 90 degrees The sign of the variable SO needs to be changed for satellites like the recent Rus¬ sian ones with inclination less than 90 de¬ grees t take care of it in my revised Apple version this way 2010 CA * COSONi:SO = - SO‘CA/ (A8S (CA)) + CO* RD + RD *TI/4 There are many ways to accomplish this sign change; this is (he mathematician's way. Actually, this program is not the only place this error is made The RSGB VHF Handbook puts that correction for inclina¬ tion on the Tf/4 term The reference that i found to explain this correction is by Bryan Leipper, “Circulation Orbits with Simple Computing Systems. QST. February, 1979 pp 38-42. Dr. Gerald N. Johnson KtCQ Ames IA Thanks for the tip, Gerald We thought the Russians were iust being obstinate — Eds. NO FAULT, PCBs I just finished reading “ Avoiding the Electrical Nightmare/ 1 on page 64 of the October issue regarding the unusual volt¬ ages encountered by N4UH of Cleveland. North Carolina. I was prompted to write because, while his technical analysis is correct, his terminology js not There is a great deference between a "ground faun and the condibon he describes which is an “open neutral. " A true ground-fault condition is just what the name implies—a fault to ground, or earth. Visualize your electrical panel and the wires in it for a moment. The black wire from the breaker is the neutral or return part of the circuit. An electric light connected between the black and white conductors completes the circuit. The current flowing “out" the black wire is equal m magnitude to the current bowing "in" the white wire If we introduce a fault into the circuit (such as a broken insulation protecting the black wire from shorting to the panelboard box), then current will flow through the light fix¬ ture and back out as before, but also through the black wire to the insulation fault to ground and back to the neutral at the point where the neutral and ground are common This is a ground fault and the cur¬ rent flowing in the ground conductor is not equal to the current flowing in the neutral return Ground-fault circuit interrupters (OF I or GFCI) are devices that sense the current flowing out the black wire and the current flowing in the white wire. If the difference is greater than 5 mA (for the typical residen¬ tial units), then the device interrupts the current. If the fault from the black wire to ground was through your arm, you would be most appreciative The fault described in the article is m en¬ tirety different problem The problem expe¬ rienced by N4UH was an open neutral The return conductor (the white wire) was open, creating a voltage-divider effect between the legs of the power system. The National Electrfcal Code (NFPA-70- 1981) requires that all electrical systems be grounded The grounding should be ac¬ complished at a single location. This loca¬ tion, as required by the code, is at the sup¬ ply side of the service at the main service disconnect This is the only location where the neutral and ground are brought together. Ail of the uninsulated ground wires running around In your Romex are for the purpose of extending this ground point to each and every receptable and light fix¬ ture in your house A ground fault at any location in your home will cause the ground conductor to carry the return current back to the common pomt with the neutral at the service disconnect It should be noted that the type of prob¬ lem encountered is rare and should not cause alarm on the part of those with aluminum service-entrance conductors. Utility practices vary but always account for the problems of aluminum oxidation. Aluminum connections, it properly made, are very reliable and need not be of concern to the homeowner. (This applies to the larger s» 2 es of aluminum and not necessart ly to aluminum branch-circuit wiring, but that would be the subject of an entire arti¬ cle in itself.) As long as I am writing, I also would like to extend a word of caution regarding the article on page 29, "Dissertation Upon Roast Pig," by N6TO The transformers ob¬ tained from the utility most likely were Im¬ mersed »n mineral oil A few transformers are still In circulation, however, which con¬ tain polychlorinated biphenyl (PCB). PCB is a major component in coolant known as “Askarel " This is nasty stuff which is very toxic and must be disposed of in accor¬ dance with EPA regulations. Under no circumstances should you attempt to use a transformer that contained this coolant. The utility should not even consider selling you a transformer which contains PCB. Because the utility may not know which transformers contain PCB, you may dis¬ cover one by mistake in addition to transformers, some high-voltage capac¬ itors used in commercial equipment a few years back also contained PCB insulating material. Be cautious with all surplus and used electrical components containing oil for cooling or insulation. Dave Olsen KL7K Anchorage AK AMERICAN & METRIC 62-PIECE HEAVY DUTY INDUSTRIAL TOOL CHEST $28 Before Midnight Jan. 23 We will send to each reader of this publication who reads and responds to this test before midnight Jan. 23, a 62-piece American and Metric Heavy Du¬ ty industrial tool set and metal storage chest containing all the basic and special tools nec¬ essary to service and repair do¬ mestic and foreign trucks, trac¬ tors, autos, and all heavy Indus¬ trial machinery. Consists of 7 American 3/8 Inch drive sockets (3/8”), (7/16”), (1/2”), (9/16”), (5/8”), (11/16”), (3/4”), 9 American 1/4 inch drive sockets (3/18”), (7/32”), (1/4”), (9/32”), (5/16”), (11/32”), (3/8”), (7/16”), (1/2”), 9 Metric 3/8 inch drive sockets, (9MM), (10MM), (11 MM), (12MM), (13MM), (14MM), (16MM), (17MM), (19MM), 9 Metric 1/4 inch drive sockets, (4.5MM), (5MM), (6MM), (7MM), (8MM), (9MM), (10MM), (11 MM), (12MM). A 3/8 inch fine tooth ratchet with quick release drive combi nation-forward and reversible, a 1/4 inch x 3/8 inch adapter, a 3/8 inch drive exten¬ sion bar 3 inch. A 3/8 inch spark plug socket with oil resistant in¬ sert and speed installation and removal. An 18-plece industrial steel ignition wrench set, com¬ plete set of spark plug gap set¬ ting gauges for any type of spark plug. One ”1/4-drive heavy screwdriver. (One) large set of feeler gauges, industrial “Phillips” heavy duty and “reg¬ ular” screwdriver. All tools are drop forged alloy steel for durable heavy duty repair work, and will be accompanied with a LIFETIME guarantee that It must perform 100% or It will be replaced free. Add $7 handling and crating for each Tool Chest requested, we pay all shipping. Should you wish to return your tools, you may do so for a full refund. Any letter postmarked later than Jan. 23 will be re¬ turned. LIMIT: Six (6) sets per address, no exceptions. Send appropriate sum together with your name and address to: Tool Test Dept. 4M20DW, Viking Ind., 6314 Santa Monica Blvd, Los Angeles, CA 90038, or for fast¬ est service from any part of the country, call collect before mid¬ night 7 days a week (213) 462-1914 (Ask for) TOOL TEST, #120DW, have credit card ready. 73 Magazine • January, 1983 117 W2NSD/1 NEVER SAY DIE editorial by Wayne Green from page 8 Americans to buy more expen¬ sive and technically-inferior bringing world reports to 73 products just because they are could do the job. made here instead of in Asia... We do have a world hobby, so just as there are heavy pres- let's see if we can get it to- sures to force Americans to buy gether more. crummier cars because they are made here. I’d like to see more HAMMING FOR CREDIT? interest in American productiv- Down in Georgia there is a ity. American pride in perfec- proposal to have ham classes tion, and American unions pro¬ count for educational credits. moting something besides the That’s a good move. highest pay possible. .. with the There is a desperate need to result that the products are get amateur radio going again in priced out of the market, our schools and this approach But that’s another problem. . . could generate some interest to some degree. The key to any for the students. It would be a American success in communi- way of, so to say, paying the stu cations and computers in the dents back with credits as well next twenty years lies in our hav- as in fun. mg the technically-qualified Though it is old hat to 73 read people to invent the products, ers to read about the needs manufacture them, sell them, America has for technical peo- operate them, and service them, pie.,.I've been writing about This is going to take an enor- that for several years now...I mous number of engineers, see that the general media are technicians, and scientists, getting more concerned over the vastly beyond anything which problem. Even the normally lib- we even have in prospect to eral writers are getting to worry develop in this country, about the overwhelming loss of Only Japan has laid the technical consumer products to groundwork to develop the high* Japan. technology people who are go- With the increasingly rapid ing to be needed to provide the development of video technolo- whole world with video, comput- gy, microcomputers, data ac- ers, information, and other tech- cess over the phone or via televi- nical services which are going to sion stations, video teleconfer- tie the key to personal happi- encing, satellite services, 100- ness, business success, and ed- channel TV cables, and so on, it ucational achievement in, say, is getting ever more difficult for twenty years, the general public to ignore the While we re busy lowering our coming developments. They've academic standards and seeing even been noticing that almost our proponents of liberal-arts all of the recent developments education winning most of the have been coming from Japan battles in academia, we see Ja- and figured out that this just pan loading their schools with might make it difficult for Amer- enthusiastic technically-in- ica to catch up once we fall seri- dined students. Do you realize ously behind. that there are over 900,000 ama- Articles about this have been teur radio operators in Japan to- appearing with increasing regu- day? They have us outnumbered larity in Newsweek , Time, Bush in active hams by a margin of at ness Week, Fortune, and so on, least three to one... possibly The situation is getting so seri- four to one. . .and Japan has ous that a small handful of our only half of our population! They educators is beginning to get are running rings around us. uneasy. When a problem reach- Amateur radio has never been es that level, you know it has to a very popular hobby in Amer- be serious. ica. Even when we were growing Naturally, there are pressures at our greatest rate, back in the for our government to force 1950s, we were growing at only 118 73 Magazine • January, 1983 about 11% per year, which was teachers to get new hams start- about 22,000 newcomers. Then, ed. The technical competence with the‘incentive licensing 'di- of hams as compared with in- sasterof the 1960s, we fell to ze- dustry has been dropping for ro growth (and worse). Now twenty years, where at one time we’re back into a growth mode, hams were a cut above the aver- but not an impressive one. age engineer or technician. Unless the Japanese technol- 1 can remember the time when ogy program runs out of steam, hams were responsible for vir- their teenagers will be doubling tually every major breakthrough the number of hams in Japan in j n radio communications. Now the next three years, while at our we can merely point out that rate of growth we are looking at | 0ng ago hams pioneered FM, about eight years for a doubling NBFM, SSB, SSTV, BTTY. and of our hams. so on . vVe old. doddering relics There has been some criti- of the past can remember the cism of calls for more engineers pride of those olden days. But with a reminder that only a few the world is ruthless; it wants to years ago massive numbers of know what you've done for it engineers were dumped and lately. Not much, were unable to find work. To a The plan forgiving scholastic degree, that is right. But what is credits for ham classes Is a fine glossed over in that response is move; let s see if we can get that that the engineers and techni- jq ea S p rea( j around. I ll be inter- cians who joined the unem- ested in getting articles for 73 ployed were those who had not on p r0 ven ways of getting teen- kept up with the changes in ag ers interested in amateur technology. There has never ra dio and on successful pro- been any surplus of technically- grams to get amateur radio trained people, growing. Remember that by 1970 it had j n the meanwhile, Td like to dawned on even the most back- see a | G t more articles in 73 on ward of firms that solid state current technologies. Perhaps was here and unavoidable. This we can g e t amateur radio back was when the axe fell. Those en- j n t 0 developing some inventors gineers who were living in the and pioneers of new techniques good old tube days were sud- Running articles on designing denly not needed. This axe was and building kilowatt tube- wielded again when the industry powered linear amplifiers is not discovered ICs and had no fur- jt, . unless someone designs a ther use for engineers who digital automatic-tuning device, could not cope with them. Each There is no shortage of things new generation of electronics is to invent which are well within going to be ruthless in weeding our technical capability. . . if we out the people who do not adapt. let ourselves go and get crack- Today. the need is for young mg on it. For instance, we could engineers and technicians. Our use a system for automatic schools have been almost total- identification of transmitters so ly emptied of these talented that our receivers would indi¬ people, leaving the over-40 rem- cate the call of the station being nants of previous technologies tuned in as we tune. This could to try to teach things they be done via an ASCII signal sent haven't bothered to fully under- on a subcarrier, thus furnishing stand This does not bode well the receiver a reference signal to for our schools or the next use for automatic tuning. Once generation of kids..,the ones we have that development, we we’re depending on to cope with will be ready for receiver-tuning the Japanese incursions. systems which will be automat- Amateur radio can help, at ic, alerting you when chosen least to a degree. By interesting prefixes or calls are tuned in. teenagers in a high-tech hobby. This could be a great stride we may be able to develop the ahead for amateur radio, pio- engineers and technicians we neering a new digital communi- need, both for industry and for cations technology which could our schools as teachers. Of be quickly applied to CB, two- course, the exceedingly slow way, and most other communi- growth of amateur radio over cations services. It could help to the last twenty years has meant bring about some extensive that the average age of ama- changes in amateur radio opera- teurs has been rising steadily, tion, too . perhaps the first with the result that within our real changes in over 50 years, ranks we have few qualified Except for the development of the vfo, our Morse-code commu¬ nications has changed hardly at all In 50 years. And other than the shift to SSB, phone commu¬ nications is almost identical to hamming of 50 years ago, com¬ plete with pileups on DX, jam¬ ming, endless nets, and so on. We’ve had practical RTTY on the ham bands for over thirty years and there still is no notice¬ able dent in traffic handling as a result, Amateur radio, which at one time was the spawning ground for new technologies, has turned into the most rigid and unchangeable remnant of the past. You invent it and we’ll publish it.. . okay? Let’s get amateur ra¬ dio into gear for the first time in years. The last change of any sort was over ten years ago when we went to FM and repeat¬ ers on two meters. Unfortunate¬ ly we contributed little techni¬ cally in this move, merely taking advantage of the already-exist¬ ing technology developed for two-way commercial operating. Now let’s do some pioneering for a change. DIGITAL MANIA With the new freedoms being granted by the FCC, I’d like to see some serious experiment¬ ing on our bands with digital techniques. Ham radio is never going to go anywhere unless we get busy and take advantage of the recent technological advan¬ tages in ICs. For one thing, isn’t it about time that the RTTY crowd stopped puttering around, dodging QRM, and came up with some circuits which will dig out those weak signals and copy them? I tried a recently-advertised computer- ized-RTTY setup and was as¬ tounded to find out how crummy it was... even as compared with the circuits we were building back in 1948. Almost any kind of interference sent it into spasms of incomprehension. Fellows, I have some news for you. You should be designing RTTY gear which uses the el cheapo computers such as the Timex 1000 (Sinclair ZX81), the Atari 400, the VIC-20 and so on. Your circuit should make it duck soup to tune in a signal.. .and copy should be 100%, despite CW or other neighboring RTTY signals. You should copy through QRM, QRN, jamming, fading, with any shift, and so on. Let’s get cracking at this and stop horsing around with junk which falls apart as soon as a vindictive CW-monger gets on channel. There is, as you may not know, apparently an unlim¬ ited supply of CW jammers, all with unlimited time to sit and trash RTTYers. Perhaps we should devise a certificate, with yearly awards. And while one contingent is doing the inventing which should have been done several years ago but which was pre¬ vented by the FCC. bless ’em, others of you should grab your chips and start working serious¬ ly on automatic identification for transmitters. Some early ex¬ periments indicated that a sys¬ tem would work using a frequen¬ cy-shifted subaudible tone, but we need to do a lot more work on this. If someone can come up with a relatively simple system which can be built into every transmitter, we can save the several eons of time every year which are presently wasted with redundant identification. Just think of the saving on pileups alone, where perhaps around five thousand stations are giv¬ ing their calls from fifty to one hundred times per minute, hour after hour. There is a zero in Min¬ nesota with the unofficial record of 117 complete identifications in one minute! A record to be en¬ vied. I understand there is a move to get this amazing chap on "People Are Weird.’’ Once we have a fairly fast au¬ tomatic-identification system, we'll be able to instantly read out the call of any station tuned in on our receiver. We’ll also be able to build in a microproces¬ sor to check the call for wanted calls or prefixes. Those rare ones can come and go pretty fast sometimes, so why miss one just because he is 50 kHz down the band from where you are working? With an automatic tuning system (dual tuning, of course), one receiver tuner will be on your channel for you while the other is scanning the band, checking out the prefixes. And a couple of years later, the whole thing will be in an HT for us. Just ask any of the early two-meter folk about the first FM rigs and compare them with the programmable, scanning- all-channel HTs of today. You know what we haven’t seen yet? Anything! So, while ail you old-timers sit around and fondle your 807s, we’re looking to the youngsters to stop fooling around with girls, 120 73 Magazine • January, 1983 get going with with their pile of ICs, and invent us out of the 1930s morass that amateur ra¬ dio is in today. The technology is here. The parts are here. The need is here. . .and riches are awaiting the entrepreneurs who make it happen. One thing is for sure. ,. if you invent it. I'm anxious to publish your articles in 73 and get the ball rolling. HELP! Every now and then I see a no¬ tice that the League is looking for some hams to add to their staff. Fine, I suppose, though my understanding is that the place is very, very structured. It also isn’t growing much, in case you haven’t read their yearly report. When I say it isn't grow¬ ing much, I mean that the League has been losing mem¬ bers at an increasing rate for the last few years. That would make me nervous. Now. while they’ve been shrinking away, my little empire has been growing steadily. They need people to replace those who have bailed out. I need peo¬ ple to help us grow even more.. . and I don’t think anyone would really characterize this place as rigidly structured. In addition to needing a good all-around ham or two to test ham gear and write reviews, to keep the W2NSD/1 hamshack state-of-the-art in RTTY, slow scan, repeaters, antennas, and so on, we also need someone to keep our microcomputers run¬ ning. We have a hundred or more around here and the darned things keep breaking. I think we could keep a compulsive techni¬ cian exceedingly happy. Our audio department has a serious need for a technician to be on top of all the digital re¬ cording techniques and assure us that our digital and audio cassettes are first-rate. For people who for twisted psychological reasons are not particularly interested in living in the finest area of the whole country (the world?), we do have some part-time jobs available which can be done from any¬ where. These call for a good deal of responsibility, of course. We’re building our national net¬ work of sales people and have several nice areas still open. This would entail getting out to visit computer and electronics stores about three days a week to make sure that they are well stocked with our magazines, books, and computer programs. In Peterborough, we have open positions for people with PR and advertising experience, sales, editing, writing, graphic arts, photography, and so on. In the next year, we expect to add at least 100 people to the staff.. .possibly 200, if we can find them. We’re looking for non-smok¬ ers who are more interested in developing careers than in just landing a job. We’ll be able to keep up our growth only if we keep up our enthusiasm and in¬ novation. Indeed, we’ve been growing briskly for seven years now, and by the end of this month, we expect to be about five times the size of the ARRL. So, if you are not a smoker and you’re looking for a place to put your outstanding talents to work where they can do the most good...and where you will be able to learn more and grow, think in terms of Peterbor¬ ough. Send along a letter detail¬ ing why we can’t go a step fur¬ ther without you...and a resume. COMPUTERIZING With over 40% of the 73 read¬ ers computerized, and with thousands more eyeing the Timex computer . I’d like to make sure there is no misunderstand¬ ing. I want to see you experi¬ menting with amateur radio ap¬ plications of these contraptions and writing up your results for 73. The readers are interested in articles on getting rid of com¬ puter noise.. .in protecting the computers from interference from the rig... in RTTY applica¬ tions... high-speed code... beam aiming.. Jog keeping, automatic QSLing... packet communications. „ .and so on. Unless you write up the re¬ sults of your work, it will be wasted. . .giving only you the benefit. The more you write about what you are doing, the more hams will join you in exper¬ imenting and developing new ideas—and we’ll all benefit. Remember, too, that the market is just starting to open up for add-ons for the low-end computer systems. There are millions to be made by those who come up with practical new ideas. We’ve already seen doz¬ ens of new millionaires as a re¬ sult of the recent microcom¬ puter developments. . .and we haven’t seen anything yet. With hundreds of thousands of Timex computers being sold. Just about any useful accessory for it will be able to generate millions in sales. In order to encourage this de¬ velopment, Microcomputing will be devoting a special section to the low-end computers. We need not only interfaces, pro¬ grams on cassettes, and so forth, but we may also have a need for better ROM character generators and operating sys¬ tems. plug-in ROM programs, and so on. I’ve helped a lot of people get very wealthy in the microcom¬ puter business... and I can help you, if you are seriously interest¬ ed. I write about this in my edi¬ torials in Microcomputing, 80 Micro, and Selling Micros, and 111 be covering this aspect in in- Cider ; too. It's fun to be rich, and the opportunities are almost un¬ ending. As a ham, you have an inside track, if you have the will. HOW’S THE ARRL DOING? Too bad you didn’t get the QST annual report.. . and read it. In amongst the lavish self- praise. . an orgy of it... are the stark financial figures, and they are so dark-cloud that they tend to cut through the baloney. Membership is down. And de¬ spite the massive increase in the subscription price for QST , the income for the League has not even kept up with inflation. Nowhere near it! The financial management in any normal business would call for the immediate replacement of the people responsible. Of the 74 stocks and bonds in which the League has put the money they've made in profits in past years, being a nonprofit cor¬ poration they have to salt away all that money rather than dis¬ tribute it to the stockholders. ., only eight are worth more now than they paid for them. Maybe you were wondering who was in¬ vesting in oil companies, rail¬ roads, and so on. Heh, heh.. . you are. They seem to have concen¬ trated on economizing on mem¬ bership benefits such as awards, cutting that by 76% in 1981. This Is balanced by an in¬ crease in unemployment com¬ pensation which went up by 973%,. .yep, almost ten times, as staffers went through the old revolving door. That’s quite a one-year record. Automobile expenses only 122 73 Magazine • January,! went up 370% in the year. Are they providing limousines for the top echelon these days? We did see healthy cuts in such pork- barrel items as ARRL headquar¬ ters expenses, which were 70% higher in 1978. And the W1 AW ex¬ penses came down, too. They were 51% higher in 1980. It looks as if someone made a trip some¬ where, because while there were no overseas expenses chalked up in 1980, they managed to spend $17,762 in 1981. That’s a very nice trip! Unless you take a serious in¬ terest in League financial mat¬ ters, you have no beef about what they are doing. You are a stockholder of the corporation and should look into how your money is invested. You might even question why the HQ peo¬ ple are salting away millions in stocks and bonds, losing your shirt for you with poor invest¬ ments. when perhaps they should be spending your money on more services. . .or, even better, in encouraging some growth in amateur radio. A million-dollar budget to pro¬ duce some first-rate films about the excitement of amateur ra dio.. .about the benefits of amateur radio to our coun¬ try ... about how to start a high- school ham club...could get amateur radio growing again. We have plenty of friends in tele¬ vision broadcasting to see that the films would get on the air. And a million dollars wouldn't even put a big dent in the bankroll they’ve built up. It might keep them from blowing so much on lousy investments , . .and, after all. isn't that what the money should be used for? Look, I know you hate to have me carping about the League.. . but I’m not giving the League hell right now. I'm giving you , the League member, hell. The chaps at HQ will do whatever they want with your money If you don’t say anything. It’s only by your being a silent partner to the crime that all this money has just plain been thrown away. You haven’t been paying atten¬ tion. You haven’t been insisting on meeting with your directors and finding out from them what the situation at HQ is...and they are not going to level with you unless you push them. They'll put the pressure on for membership benefits.. .and for promotion of the hobby. . but only if you lean on them. The League, under the direc¬ tion of the directors you have elected, has been spending a pittance on membership bene¬ fits and promotion of the growth of the hobby. Get after ’em... let’s see some growth. MAJOR LEAGUE CHANGES AFOOT? Knowing how undependable the rumor mills are, I don't put a lot of stock in repeated reports that Skip Tenney will soon be promoted as a replacement for Vic Clark as president. Tenney, well known as the publisher of Ham Radio magazine, either has sold or seems about to sell what is left of his magazine, so that would make him both available and eligible for the spot. The move makes sense, too, when you consider how close Tenney has worked with the League all these years. At times, it has seemed as if he were al¬ most an untitled League official. Being independently wealthy, Tenney wouldn't be restricted by the lack of remuneration which goes with the position. A lack of expected aggres¬ siveness on the part of the re¬ cently-appointed president seems to have sparked the search for someone to help take hold of the organization and get it into shape. Many of the direc¬ tors feel that it is important to have a businessman with expe¬ rience helping to guide the League into safer financial wa¬ ters ...and perhaps stem the growing loss of QST sub¬ scribers. Others of the directors like Vic and feel that he should have more of a chance to get things turned around...to, so to speak, haul the old boat out of the water and scrape off the bar¬ nacles. I’ve personally always held Vic in the highest regard as a ham and a DXer. The directors should realize that even with a relatively small organization such as they have at HQ, people get set in their ways and it is dif¬ ficult. . .often very difficult. .. to bring about changes, no mat¬ ter how badly they are needed. My unasked-for council would be to give Vic more time and not rush with Tenney. BUILDERS VS, BUYERS? Sometimes I get the impres¬ sion that people will believe just about anything ! First, we had a bunch of old hams, probably irri¬ tated because they had to change from AM to SSB, grous¬ ing that hams weren't building any more. I still hear that chorus when I visit some ham clubs, many of which seem to have been taken over by old old- timers. When I point out that there are more ads for parts in 73 these days percentage-wise than there were in QST forty years ago, they look shifty-eyed and shut up. . .at least until I’m safely out of earshot. The fact is clear that hams are building as much or more than they ever did. It just isn’t the old ones who are doing it. Possibly they’re too busy watching television. The increased coverage of rel¬ atively simple building projects in 73 has sparked a lot more in¬ terest in building and experi¬ menting. Fine. . .for that’s one of the great pleasures of elec¬ tronics and hamming, I put quite a few years in at the workbench myself, with a barn full of old gear I built to show for it. .. and a twisted pelvis from standing on one foot for about twenty years The local chiropractor has given up trying to straighten it.. and I've stopped seriously trying to lift anything heavy I’ve paid my dues in building. There is a gross misunder¬ standing on the part of some of the manufacturers in the in¬ dustry. This is odd, because it really means that they have been reacting emotionally and not giving any serious thought with some research. This has to do with the inter¬ esting concept that hams who build are not very good custom¬ ers for commercial equipment. The facts are the opposite, as even a few moments of contem¬ plation will make clear. The ma¬ jor buyers of new equipment are the exact same people who are also building gadgets. How come? Let’s look at it First, a little lesson in eco¬ nomics. Way, way back, in the early days of amateur radio, hams built their own receivers and transmitters. There were on¬ ly a handful of hams then, so there wasn't enough of a market to warrant commercial equip¬ ment for them. Then, when the first commercial receiver was put on the market, the home construction of receivers virtual¬ ly stopped. Hams quickly real¬ ized that a home-built project would cost more, have a smaller resale value, and not work as well as a commercial receiver. They did just what you and I would do in the circumstances: They bought their receivers. I came along just shortly after these halcyon days, getting started as a shortwave listener along about 1936 and doing my first pirate operating (called bootlegging then) in 1938, There were no practical transmitters for hams as of that time, there being only about 40.000 li¬ censes. These came along after WWII, when our ranks had swelled to about 80,000. But we did have some beautiful receiv¬ ers and the hams ate them up. As a teenager, I was living in Brooklyn and I made it my busi¬ ness to visit as many of the ac¬ tive hams as I could. In those days virtually every licensed ham was active. I visited well over a hundred hams and found just one who had built his own receiver. It really wasn't prac¬ tical from any viewpoint. Once transmitters got prac¬ tical, hams stopped building transmitters. ..with a few ex¬ ceptions. We’ve always had a few stranger-than-normal hams, but not many. I went the same route myself, buying war-sur¬ plus rigs and converting them I did build power amplifiers, but only because they weren’t commercially available. Much of my own building was involved with complex RTTY gear, autocall circuits so that my RTTY could work automati¬ cally, and so on. Those of us building this sort of stuff were getting into digital electron ics.. . back in the late 40s... 35 years ago! But then, as now, we bought our rigs and receivers. Further, then, as now, when we bought our commercial equipment we went for the best and the newest we could get. This was only nat¬ ural since we were deeply in¬ volved with hamming and want¬ ed to get the best out of the hob¬ by. Why would I go to the trouble of spending two weeks design¬ ing and building a piece of Tele¬ type* equipment and then hook it to a crummy receiver? No way! I went for the best and so did the rest of the builders. They’re still doing this. Today hams are building gad¬ gets and enjoying it But you can bet that these active hams are also very particular about the commercial gear they buy. You can also bet that they are lying in wait for anything new that comes along. These chaps are the best of customers for the in¬ dustry because they are the most deeply involved. It is the older hams who al¬ ready have their KWM-2s who sit and rag-chew, who talk endless¬ ly on nets, who are the bane of the industry, not the enthusias¬ tic builders and experimenters. We are fortunate in that we do have a magazine in the ham field devoted to these nice old men, complete with pages and pages of “operating news’* for them to read each month. When you consider what an incredible bargain ham gear is today, I get a bit aggravated when I hear someone griping about the high cost of it. Lordy! When I got started in hamming we had crystal-controlled trans¬ mitters and each crystal cost about $3.50. Not bad—until you translate that into 1983 dollar- ettes, which puts those nice lit¬ tle crystals at about $63 each. The cheapest hunk-of-junk ham receiver on the market, the Hallicrafters Sky Buddy, cost $19.50. Cheap? Well, my friend, if we look at the comparable prices for other things, that comes to about $350 today. The average ham wanted something better, running around $80, or about $1,500 in today’s puny money. No, we’re getting incredible bargains today as a result of the solid-state revolution, iCs, and mass production. Japan, with nearly one million licensed hams, has such a huge market for new ham gear that the pro¬ duction quantities have brought down the cost of manufacture to much less than one half what it would be without them. Each doubling of production normally drops the cost of manufacture about 15% or so. So, though we hams are build¬ ing more than ever before, we also are buying as much as we can get commercially made. . and getting incredible value for our investment. ARE YOU MISSING THE DX? Now. I suppose I should shut my typewriter off and not let you know what is going on. I've been sneaking around twenty meters lately and I want to let you know that you are missing out. The band has been super in recent weeks, and the DX is rolling in at all hours of the day and night. Just in the last couple of days. I’ve had contacts with the following, to give you an idea: ZL2WM, ZL1VY, PY2CYT. PY1BFZ. HR1RBM. 7X2BK. VK6RU, IK7AGT, EZ7BXP, 4Z4JS, EA3CXG, N3RD/VP9, JX1JO, PY0ZZ, HH2MC, TU2HJ, PP6ACP, ZS1DG, ZS6WB, ZS4AF, PR7SSM, S83MMK, TU2LM, ZS6BRD, ZS6BNS, ZS4D, JY3ZH, JY4MB, JY5ZM, YI1BGD, 7X5SI, LX1JAS, Y27FN, Y56FN, SM7DLZ, WB5VIH/DU2. VK6CF, VS6CT, HL9RT, UA0JBN, EA9NG, U9H, UK0SBB. 8Q7AV, 3BD8DB, OD5FB, HZ1AB, 4S7EA, T32AF, F5RV/FC, VU9GI, VU9CK. ZL40Y/A, OH0W. . . and so on. Besides some bragging about working DX, the above list is in¬ dicative of what you can do if you get on the air with a reason¬ ably good rig and antenna. It’s there, with thousands of DX op erators looking for you. While some put up with contest-style operating, whacking out the contacts for GSLs and the good old ARRL Honor Roll listings, most of them will stop this non¬ sense and be most interest¬ ing to talk with if you ask them some questions. Most ol them love to talk... and they love most to talk about the most interesting subject in the whole world: themselves. Think what an impression hamming could make on inno¬ cent teenagers if they could hear us talking with Christmas Island out in the middle of the Pacific Ocean! Or some chap in Baghdad! They’re there, looking for you. Where are you? SATELLITE TV SYSTEMS "COMPARE OUR QUALITY, PRICES AND SERVICE!” WE MANUFACTURE: PARABOLIC DISHES Mt rroRiZA rioN sy st e m s POLAR MOUNTS LNA HOLDERS DEMO TRAILERS ALUMINUM HORNS CUSTOM PARTS WE STOCK WASHBURN (ULLASPIE ALLIANCE KLM DRAKE A TV AVANTEK LOWRANCE CABLE 6t CONNECTORS GARDINER SWITCHES & HARDWARE CALL, WRITE OR ^ FOR OUR LATEST BROCHURE AND PRICES, 1 AUSTIN C LEWIS LEWIS CONSTRUCTION CO K-KjCjC r.o box ioo MO 1-784-2 Wj HUMBOLDT. TN. 18H i a4 IN BUSINESS AT THIS LOCATION SINCE 1964” ^*52 | LIMITED SPECIAL $555.00 HHMEQ 20 MHz DUAL TRACE Oscilloscopes to meet every need mm _ • Si MODEL HM-203 WITH PROBES: x 1 & x 10 •ONE YEAR FULL WARRANTY •SOLID STATE • ASSEMBLED & CALIBRATED NEW RECTANGULAR CRT ( 603 ) 434-5371 DEALER INQUIRIES PfYtTEP ^ 133 rMoo. DERRY, N K 03038 WARNER HILL I LINEAR „ 'tlBOOK ™ A AAA Uf ATT Rtf' 1000 WATT 14 Different Models, 100 pgs $11.95 A.P.Systems Box 263 s m. ^Newport, Rl 02540 (401) 846-5627 See ust ot Advertisers on page 1 14 73 Magazine • January, 1983 123 CIRCUITS _-_ J Do you have a technique , modification , or easy to-duplicate cir¬ cuit that your fellow readers might be interested in? If so, send us a concise description of it (under two pages , double-spaced) and in¬ clude a clear diagram or schematic if needed In exchange for these technical gems, 73 offers you the choice of a book from the Radio Bookshop, to be sent upon publication. Sub mit your idea land book choice) to: Circuits, Editorial Offices, 73 Magazine. Peterborough NH 03458. Submissions not selected for publication will be returned if an SASE is enclosed If'MONE .JACKS U A -x. ii -plug iearj ^ i ^ J| V-■— . j ^ SUS-MM PLUG «MIKE II STAR-SET” HEADSET CONVERSION: This adapter will enable you to use "Star-Set”headsets with an loom IC-2AT(or a similarHT). The IC-2AT has about 1-2 volts present in the mike line to power an exter¬ nal electret condenser mike. This voltage is used to power the “ Star- Set ” as well. To key the PTT, you use the mike mute switch on the belt clip of the ”Star-Set. ” The PTT works by completing the mike cir¬ cuit. If you want to use the set on both the radio and a telephone, simply unplug it, because no changes are made in the headset. Use shielded wire in the adapter to prevent rf feedback . If you don't re¬ ceive anything, reverse the plugs, marking them after you have de¬ termined the proper placement .—Joe Eisenberg WA0WR1, Lincoln NE LIGHT-ACTIVATED RELAY: Fig. 1 shows a circuit which will trip relay K1 when the light-sensitive resis¬ tor R1 is in the darkness. A buzzer can be attached to K1 to indicate that the lights have dimmed. Any small signal diode can be used for D1, which suppresses the high-current inductive kickback, thus pro¬ tecting Q2, Any NPN transistor can be used ford and Q2. R1 is a cadmium-sulphide resistor which has 5 megohms resistance in darkness and 100 Ohms' in bright light. The resistor can be located away from the rest of the circuit. Fig. 2 is a fight-activated relay; the same components are used as in Fig. 1. A power supply circuit is shown in Fig 3. R1 is a one-Watt resistor valued between 200-500 Ohms .—Alan Weinberg KR7D. Tucson AZ CONVERTING THE DRAKE TR-7 TO RECEIVE VLF WITHOUT THE AUX 7: This is a simple modification for the Drake TR-7 which will enable the unit to re ceiveO-to-1.5 MHz. Open the unit and locate U9003. Remove the wire from pm 14 of this 1C. Care¬ fully solder a 6.5-inch insulated hookup wire to pin 14 and con¬ nect the other end of the wire to the unused terminal on the STORE switch. Replace the cover. To receive below 1.5 MHz, you must set the bandswitch to 1.5 , press STORE , press the DOWN switch once, and then re lease the STORE switch, The UP/DOWN switch will now se¬ lect the VLF band in 1 5-MHz segments Repeat the se¬ quence. and the unit will then tune 0-500 kHz. The antenna for the lower bands should be con nected to pin 7 on the accessor¬ ies connector (see pages 3-7 of the manual). This modification does not affect the usual opera¬ tion of the STORE switch .—An* drew H. Kilpatrick K4VKZ, longwood FL RIGID MALE-TO-MALE UHF CONNECTOR: Materials required are two PL-259 connectors, a straight length of no. 10 AWG 3-1/2 inches long . and a straight length of 3/8-inch o.d., 5/16-inch i.d . copper tub¬ ing. 1-1/8 inches long. (You can find the tubing in the plumbing de¬ partment of many hardware stores.) After cutting the tubing . be sure to deburr the inside and outside edges of both ends. Then place PL-259S on either end, connecting the center pins with the no. 10 wire. Solder the assembly together using a large enough iron to avoid cold solder joints —Gary Legef N6TO, Fullerton CA. 124 73 Magazine • January, 1983 REVIEW ELECTRONIC RAINBOW SATELLITE TELEVISION RECEIVER KIT Like a tot of hams who have developed an interest In satellite TV, I have been reading about and watching the market for the last couple of years for a satellite receiver that had all the features i wanted and the right price as well Most of these factory-wired units' price tags still hung up there in the high dollar range, while kits for these receivers were few and did not enjoy the best publicity from articles I had read I felt a kit was the best means to meet my end. Having built quite a variety of electronics kits and semi-kits down through the years, I felt that I could handle a quality kit without too much difficulty. Browsing around the hamtest at India¬ napolis back in July, I spotted a few satel life antennas set up around the area and visited each booth to check out their wares. Most of the equipment was fac¬ tory-assembled, high-priced, turn key stuff, not for me. Then I happened by the booth where Electronic Rainbow was showing its latest offering to the industry The owner Ron Ross and I had met at van ous hamfests and I knew he handled qual ity products. Ron had his satellite receiver hooked up and it had a crisp, clear picture I checked the spec and price sheets he had on hand and was very impressed with the features his satellite kit offered tike built-in rf modulator detent tuning, vari¬ able audio from 5,5 to 7,5 MHz. afc, LNA power supply, remote tuning jacks and baseband jacks for the optional remote tuning control, and stereo decoder along with many other features found only on much higher-priced units I asked Ron it the units were available yet and he said In a couple ot weeks. They were presently getting the assembly man¬ ual ready for the printers. I left with an or¬ der form and spec sheet so I could review the receiver and make up my mind at home. About a week later, l sent my order in for the kit and looked forward to getting started on my very own satellite TV receiv¬ ing system A few weeks went by and l decided to call Ron and check on my order He told me that they were just about ready to ship the units with a photocopied manual because the printer did not have the tinal manu¬ scripts yet. t immediately saw a chance to get my re¬ ceiver quicker and help out Ron with corn- men cs from the consumer point of view, l suggested that if he could sell me a receiver right away, I would be happy to give him some feedback on the assembly of the units from a builder's standpoint Ron ac¬ cepted my offer and 1 picked up my receiver the next day. After sorting through the kit and check¬ ing parts (a few were missing as we both ex¬ pected), I dove into the manual and read It from cover to cover, picking out minor er rors and missing points that would help a builder do a better job of assembly and en¬ suring that the unit would work upon com¬ pletion. I have had a few bad experiences with kits where even experienced builders Photos by David Beightol The completed Electronic Rainbow satellite TV receiver At right is the downconverter unit, which is mounted at the antenna would pull their hair out trying to figure out the sequence of assembly. This is not the case with the Electronic Rainbow satellite receiver kit. I found the manual to be very easy to follow; there was very little chance tor error in the step-by-step assembly of this quality receiver kit. Fortunately, I had a week's vacation coming and I decided to use It to put to¬ gether my kit. t was able to assemble the kit in approximately 15 to 20 hours, making nu¬ merous trips to Electronic Rainbow for changes in the manual and a few parts that were missing or wrong, I completed the receiver and was looking forward to checking it out on Ron's anten¬ na. since I did not have one yet. The final alignment was to be done with an actual picture from the satellite. The receiver kit had all the sections, such as the 70-MHz filter, the remote downconverter, and oscil¬ lator pre-wired and tested, so final align¬ ment was a simple matter of adjusting the picture, sound, and rt modulator under op¬ erating conditions according to the step-by- step instructions in the manual using a VOM to check power-supply voltages. Even though the main board of the re¬ ceiver has all the parts on it, the board is di¬ vided into six sections with each of the sec¬ tions having an A and B part for very easy assembly Ail the parts are in zip-lock bags for each of the sections of the board, mak¬ ing it much easier to find them. I had to wait a week or so tor Ron’s de¬ sign engineer, Paul Turner, to return from vacation, so his ace assembler, Terri Mur¬ phy, and I finished off the tew changes in the manual When the final printing came back from the printer, she could add all the changes to complete and update the fine- quality manual , which was all the individual sections shown in halftones, making place¬ ment of the pads on the silk screened boards a simple matter Finally, when Paul returned, Ron asked me over to his shop and the receiver was hooked up along with my downconverter to the bench monitor: when Paul flipped the monitor onto channel 3, there was the pic¬ ture trom transponder 11 MTV, clear as a bell I was really happy that the unit worked the first time. Paul made his way through the Individual trimmers for each of the 24 channels (transponders), peaking and ad¬ justing the sound for a perfect picture on each He let the unit bum in for about 30 minutes to be sure every thing was okay and then put the cover back on the very attrac¬ tive cabinet. Off I went like a kid with a new toy, proud as could be that my kit was final¬ ly ready to go in conclusion, I am sure that the Elec tronic Rainbow satellite TV receiver kit will be a popular item for those builders who have waited so long for just such a product. I plan to use my receiver with a Wilson MD II B antenna, tocom LNA, Chapperal Super feed, and Seachcraft polarizer > will be glad to answer any questions about any of these items. Please write only and include a self- addressed stamped envelope, The complete satellite TV receiver kit costs $395.00 For further information on the receiver, board kit, or manual, contact Ron Ross or Paul Turner at Electronic Rain bow, Inc . 6254 LaPas Trail, Indianapolis IN 46268, (317y291 7262 Reader Service num¬ ber 477. J. E, Beightol. Jr. WB9ZNU Indianapolis IN ADVANCED COMPUTER CONTROLS’ MODEL RC-850 REPEATER CONTROLLER imagine, it you will, the amateur repeat¬ er that I'm about to describe. It can be con¬ trolled via telephone, over a UHF control link, through the main repeater receiver, and, of course, locally at the repeater site All you need is a touchtone™ encoder and the necessary codes. If you call the repeater on the tele¬ phone, it answers the phone (with a mes¬ sage you’ve chosen) and waits ten sec¬ onds to receive a valid command. After you enter a code, the repeater verities in voice over the telephone the function that has been selected, If does the same if you enter a command through the main receiver, except that the acknowledge¬ ment comes back to you over the air It you want to check your touchtone pad, you only need to enter a test prefix followed by a series of keys. The repeater reads your entry sequence back to you, again in voice. And that’s only the begin¬ ning of what the repeater will do for you. it can evaluate received signals lor frequen¬ cy error, deviation, and percent quieting and give a similar voice response back to the user. Maybe you would like to check conditions at the repeater site from the comfort of your favorite armchair, No problem at all. Just ask the right ques¬ tions with your touchtone pad and the repeater can give you voltage and power output measurements and also the temperature at the site. It will even give you the time of day! This only begins to describe the fea¬ tures of this particular repeater. Whose repeater is it? It could very easily be yours, Just by interlacing your present repeater with the RC-850 repeater controller being manufactured by Advanced Computer Controls of Cupertino, California And please, don’t be put off by the word' inter¬ facing," because in this case you can ac¬ cess most of the features of the controller just by feeding a carrier-operated switch (Of relay) logic signal and audio from your receiver into it and by letting the con¬ troller feed audio into your transmitter along with a push-to-talk logic signal. Plug the controller's modular jack Into a telephone line at your repeat er site, sup¬ ply ft wdh 12 volts dc. adjust one or two audio levels, and you will be able fo pul much of the power of the controller to work tor you right away. Naturally, other connections need to be made between the controller and the re¬ peater station in order for it to provide re¬ ceived signal reports and other voice re¬ sponse telemetry (VRT) information about the repeater ft sell. You can even connect the controller s logic outputs to a synthe¬ sized transceiver and operate a remote base station, complete with frequency selection , through your repeater This makes it simple to ilnk up with another re peater for nets or public-service activities. Software-Based The controller it seif, even without the synthesized voice capability, offers fea¬ tures which to my knowledge are riot available In any other commercially-man¬ ufactured controller or repealer/controller combination. The key to the power of this unit, and the thing that enables ACC to ex¬ pand t h© controller's features on a contin¬ uing basis, is that it is software-based (or, to be technical, firmware-based in the form of several EPROMs), New releases of the operating system software can en¬ hance the capabilities of your machine, in many cases without any additional wiring or work on your part beyond changing out the EPROMs It also makes it possible for the manufacturer to incorporate into the controller some additional feature which may be very important to you. The Blue Knob Repeater Association, which sponsors the highest amateur re¬ peater in Pennsylvania (147.75f.15 MHz), had a special problem which ACC was able to solve through a small amount of 126 73 Magazine • January, 1983 Interior view of the RC-850 additional programming (which then be¬ came available Jo every user of the con¬ troller through an upgraded release of the software). Most of us are familiar with just dialing (or pressing) the number “1” to ac¬ cess the nationwide long-distance tele¬ phone network However there is a fairly rural telephone system operating at our site on Blue Knob Mountain, and It re¬ quires entering "1121" to make a long-dis¬ tance call, Couple this with the fact that most of our members live outstde the lo¬ cal calling area from the exchange at the site and you’ve got a cumbersome number of digits to enter when operating mobile, a number which can rise to 14 digits in order to place a call outside our own area code. What made this even worse was the fact that while the controller has the capability to store up to 90 telephone numbers in its user autodiaier and 10 numbers in its emergency autodiaier (these numbers can then be called )ust by entering an access prefix plus two digits), the storage loca¬ tions are limited to 11-digit numbers at most. This would present no problem for the typical long-distance number, but it would have severely limited the usefulness of the autodiaiers in our system. Ed iriqber WA6AXX. who founded ACC, solved the problem just by program¬ ming the controller to “see” a leading '1*' and substitute an alternate sequence when the number is dialed out (in our case, ‘1121"). This small change, which was relatively easy to handle by modifying software, would have been far more dif¬ ficult. if not impossible in a hardware- based system The controller's autopatch, which is logically separated into three different components (basic autopatch, user auto- dtaler, and emergency autodiaier) Is ex¬ tremely advanced in design Phone num¬ bers are read back to the user for confir¬ mation (in voice with the voice-response option installed, and otherwise in CW) before a call Is placed The controller itself enters the number into the landline system in your choice o! ten pulses per se¬ cond, twenty pulses per second, or stan¬ dard touchtones This greatly increases the reliability of tne autopatch, since tones are not being passed from many dif¬ ferent user’s touchtone pads directly into the telephone system. The user autodiaier codes can be pro¬ grammed by the members themselves, or the user autodiaier can be "locked" so that only control operators can load and change the telephone numbers to be stored The access prefix for the autodiaf- @f can also be changed *f and when necessary. The emergency autodiaier provides for the storage of 10 public-service telephone numbers and associated response mes¬ sages for each agency (such as •Fire'"'). With the voice-response option, the re¬ verse autopatch (which requires entering a code sequence after calling the repeater on the telephone) can actually call a repeater user by callsign Forty callsigns can be stored in the controller's memory for use with these directed reverse autopatch calls (or as part of a demonstra¬ tion message) Separate timers can be set for each type of autopatch call, and the three func¬ tions can be enabled or disabled separately. This can be used as a way of allowing emergency calls to be placed at night, while the other autopatch functions might be turned off A programmable ac¬ tivity timer functions with all autopatch calls to drop the patch if no activity (or constant keying) comes from the repeater user for the designated period of time. It's also possible to place a full duplex autopatch call (for simultaneous receiv¬ ing and transmitting) and a semi-private patch where the repeater-user side of the conversation is not fed through to the transmitter, but instead is replaced with a “cover tone" to alert other users that a call is In progress. H your repeater suffers the misfortune of having someone mali¬ ciously dropping the autopatch on legiti¬ mate users, you can program the control¬ ler to allow each user to define his or her own custom hang up code just before placing a call. Then, only that code or the control operator’s override code will ter¬ minate the call. Long-distance calls can be prohibited on the main autopatch, which then allows the entry of a 7-digit number only, which cannot begin with '1 or “0." There is even an antidiaier," which can be loaded with up to five telephone numbers which may nof be called on the autopatch (such as a local pizza parlor?). One convenience which anyone who has ever used an autopatch will appreci¬ ate is that the controller will give the time and date tor you automatically upon com¬ pletion of a call. This is also very helpful to the repeater owner for the proper logging of autopatch calls. Identification, Please The controller handles repeater identifi¬ cation requirements in a similarly sophis¬ ticated manner. An '‘intelligent" ID algo¬ rithm directs the unit s handling of several different ID messages in accordance with the activity on the machine. For example, if the repeater has been dormant and is then keyed up, an initial ID (typically a voice greeting) is given. As time pro¬ gresses from the initial keying of the re¬ peater and with a OSO in progress, the controller will wait for an opportunity to ID again when a user lets the repeater carrier drop. If this opportunity doesn't occur, then the unit becomes anxious to ID, but will still try to avoid IDIng over the top of a user transmission But. if ten minutes pass without even a break in the OSO, then the controller will do a forced CW ID over the top of the user, but at a fast, un¬ obtrusive level. With the voice-response option, you can use the built-in message editor, either on site or remotely, to program the mes¬ sages you want for IDs and other re sponses The controller has a vocabulary of over 200 letters, numbers, words, and sound effects. You can even have custom words, such as your group’s name or loca¬ tion, merged into your controller’s soft¬ ware. but these words are not cheap at S200 each! Probably the second most remarkable feature of the RC-850 (1 11 save the first one for later) is that all of your repeater's operating parameters. Including timers, courtesy tones (you can select from eight sets that you program yourself), mes¬ sages. autodial numbers, control opera¬ tor and user codes, and even an initial power-up configuration (in case power to the unit is temporarily lost), can be changed remotely Non-Volatile Memory If you’re like me, you're wondering now what happens to all of that information stored in the controller, including the 90 user autodiaier numbers and 10 emergen¬ cy autodiaier numbers, if power to the controller does fail Incredibly, absolutely none of this data is lost, because It has been stored in EEPROMs (Electrically Erasable Programmable Read Only Mem¬ ory) by the controller s own built-in pro¬ grammer/eraser. The controller will awaken’ according to the configuration you've programmed as soon as power re¬ turns. And, by the way, battery backup cir¬ cuitry is included m the unit. Other standard features include several modes of operation based upon a subaud- ible tone input, touchtone upfdown ac¬ cess by users with programmable auto¬ matic timeout, logic outputs for remote control of other devices (complete with re¬ sponse messages to indicate their func¬ tion in your system), provisions for a con¬ trol receiver, a kerchunker filter that can be switched on or off, spare audio inputs, tone signalling, and a host of others liter¬ ally too numerous to mention in this review. One extremely clever feature of the con¬ troller is that it suppresses the squelch tails of user transmissions (which makes listening comfortable for users and con¬ trol operators alike) and also, at your op¬ tion, touchtones. It does this through the use of a 75-ms analog delay line which al¬ lows the controller to cut off audio to the transmitter when the carrier-operated switch signal disappears or when touch- tones are properly decoded by the state- of-the-art Mitel chip set. Without actually hearing it operate, it's hard to believe how effective this circuitry really is Construction A review of a product such as this one wouldn't be complete without some de¬ scription of how it’s constructed I can honestly sum it up with one word: impres¬ sive. Machine-contact 1C sockets, fully sealed, are used throughout the control¬ ler. Signal connectors are gold on gold for long-term reliability. The circuit boards are computer-grade glass epoxy with through-plate holes. They are solder- masked and silk-screened with compo¬ nent designations And. finally, low-cur- rent CMOS circuitry provides highly effi¬ cient operation. Product Support Another Important plus is that the device is fully documented with a comprehensive owner's manual which includes a descrip¬ tion of the unit, how to install it, how to op¬ erate it, service and maintenance informa¬ tion. and schematics and parts placement drawings The manual makes liberal use of figures and tables. It's clearly written, but don't expect to skim through ft once or twice and completely understand the operation of the controller. Careful reading is necessary due to the many advanced features of the unit. From my own experience, however, by far the most impressive support lor the product comes from the designer himself. Ed Ingber WA6AXX is an electronics engi¬ neer, and his background (which Includes a Master's Degree) lies primarily in de¬ signing test equipment, programming mi¬ crocomputers, and working with speech synthesis. I have been able to reach him by telephone (he provides owners with both his factory and home numbers) any time our group has needed information or assistance. I mentioned earlier that I would save the most remarkable feature of the controller for last, which is that it works rust tike the manual says it will (the manual can be pur¬ chased by itself for $30), and it sounds ter¬ rific on the air. The speech synthesis is so good that during the first few days that we had the controller on-line, we actually had people responding to the female “Good Morning" greeting with a complete run¬ down ot their name, location, and other in¬ formation. only to be tremendously sur- 73 Magazine • January, 1983 127 prised to learn that they had been talking to a computer! Few Problems In our controller, problems were hard to find, and t heard essentially the same thing from other owners before we made our decision to purchase one. Our unit was shipped with an interim version of the controller's operating system software designated as 1.4X, and this version drd have a few bugs in it. One example was that grving the controller the code to dis¬ able the auto patch timer disabled the autopatch itself. Another bug caused two of the front-panel display LED indicators to be reversed. In a way, though, these problems actually point out the strengths of a software-based device, because the final release of this version of the soft¬ ware corrected both of these glitches. if you haven't guessed by now that the price tag for one of these controllers Is pret¬ ty hefty, then you might consider price alone to be a drawback. Actually, the RC-850 controller comes In a number of dif¬ ferent configurations, ranging in price from $t 195 for an assembled and tested control circuit board only up to nearly $2800 tor the maximum system, which includes an FCC- registered telephone interface, voice-re¬ sponse telemetry option, and front-panel display option, all contained in a rack mount cabinet ready to install at your re peater site. There are also several versions between these two extremes. For example, you may want to provide your own tele phone interface, which reduces the cost of the unit by $349. Or, while you might want to have synthesized voice IDs and the time- of-day clock, you may not realty need the 16-channel analog measurement and speech readback capability provided by the complete VRT option This would also re¬ duce the cost of the controller And, it s good to know that you can start out small and expand to a maximum system at a later time with very little difficulty, since the con¬ trol board has been designed to be upward compatible. If you want to significantly enhance your repeater s capabilities and at the same time infuse your organization with new enthusiasm and excitement, the RC-850 repeater controller may well be just what you're looking for! For more information, contact Advanced Computer Controls, 10816 Northridge Square, Cupertino CA 95014; (4081-253-8085 Reader Service number 476. Gerald Ft Patton WA3VUP DuncansviUe PA LJM2RK STORM ALERT My wife does not like ham radio. She despises the funny noises my radio makes, and she would really rather rf didn’t ride in the car with us. So, I find my¬ self and my rig relegated (or maybe I should say ' banished") to a remote cor¬ ner of the basement Now, I don't mind fcemg m the base¬ ment, but I’m an Army officer whose spe cialty is tanks. That means, after years of firing tank guns on various ranges in com¬ bat, I'm rather hard of hearing. Conse¬ quently, I can’t hear when someone is catt¬ ing me unless I'm right at the radio, and. while I’m a pretty avid ham (my wife thinks too avid), I do occasionally go upstairs to get a cup of coffee or take care of the effects of an earlier cup. So, f*ve been looking for months for a simple (and af fordable) tone decoder l could put on the two meter rig to alert me to calls I needed to be able to set up a visible signal to alert me when f was copying CW traffic on the HF bands (since I wear headphones to muf¬ fle the sound of the "mill”), and an au¬ dible alarm to call me when I was else¬ where in the house i also needed to mute the audio, since my wife does not have a hearing problem and would have fits on those occasions when the repeater was really busy It didn't take me long to find that a sim¬ ple tone decoder, ever? it you elect to Just buy the parts and home-brew it yourself, isn’t all that cheap, while ready made or kit decoders are downright unreasonable ($50.00 plus is the normal range). I had fi¬ nally decided the only way out was to home-brew one, with the attendant costs involved in making a circuit board and the costs in time to construct it, when I hap pened to stop at a hamfest in Lafayette, Indiana. At one of the booths, a guy (whose name I never did get) was demonstrating something that caused alarms to sound and strobe lights to flash Intrigued. I stopped to watch what turned out to be a demonstration of exactly the thing I'd been looking for. He was demonstrating a tone de¬ coder—he called it the "LJM2RK Storm Alert"—in nine different configurations Each of the nine circuit boards was at¬ tached to a big board and each was wired for a different option. All nine were essen tially the same—only a tew jumper wires were different. The same board. ICs, resis¬ tors, etc., were used in each one. and each was constructed exactly the same, except for the jumpers. When the guy running the show told me they cost only $15.00, I picked up two. I had already proven that parts alone would cost that (not counting the cost of constructing a circuit board and my time to find all the parts). Once I got home, it took me about 45 minutes to build the first one, most of that time spent locating the parts on the board The second one took about 20 minutes. For such a little company, the kit is a real joy to build The written instruc¬ tions, while not elaborate, are more than adequate, and the circuit board is beauti¬ fully silk-screened with both a drawing of the component and its reference number (Rl, C3. etc ) Orientation of every polar ized part is shown on the board and refer enced in the instructions In only one case are the instructions a little remiss. Two of the LEDs have to be mounted with nylon spacers (if you use the company enclosure). The instructions mention that in passing, but when you go down the list of parts to install, as the in¬ structions suggest, the spacers are listed well after the LEDs It would be wise to write in "spacer' next to the LED listing, although it won t damage the operation of the device even if you forget the spacer ft just won't tit as neatly in the enclosure. Once the boards are finished, aligning them is even simpler than building them First, apply an audio source to the decod er. If you use one of the Metheny enclo¬ sure kits, that simply means plugging the thing into the speaker jack. Then attach a power lead and have someone generate a tone. I did mine by hooking my HT into a dummy load and the decoder into my Wil¬ son WE-800. If that is not sufficient at¬ tenuation of the signal, leave the antenna off the receiving unit or attach it to a dum¬ my load. At any rate, that hookup atten uated my !00-mW signal enough to allow me to align the decoder A buddy at the other end of the repeater can do the same for you, if you'd rather. Transmit the tones you want (I used the number 9, since the local RACES net uses that as an alert signal) and adjust a simple pot for tone B fit s well marked on the board) until an LED on the board lights. (They have thoughtfully provided this LED just foralignment.) Then, stilt applying the tone, adjust the pot for tone A until another LED comes on (you'll be able to see this LED even after you put the device in the enclosure) The decoder is now aligned and all you have left to set is the delay. Another little pot allows you to set in a delay so the decoder will not do its thing until the foneis) you choose have been applied for whatever time you want. 1 use one second, but you can go from in¬ stant on to a very long delay. Electronically, the device is equally simple, it uses two 567 tone decoder tCs. one to control each tone and then feeds them to an LM7402N quad 2-input NOR gate. Each 567 is adjusted to one of the re¬ quired tones by varying a single potenti¬ ometer (you could easily change the fre¬ quency range by modifying the value of the capacitor on the circuit, but since the thing already operates on all the touch- tone^W and likely PL* frequencies you will need to do that only if you use really exotic tones}. When the first 567 is trig¬ gered, it lights an LED and signals one of the LM74Q2 gates, which waits for the next 567 to decode the other tone (when using the two-tone option} Once the sec¬ ond tone appears, the gate opens, lights a second LED (labeled “decoding” on the Metheny enclosure), and provides the log¬ ic state that causes the LM7402 to acti¬ vate the delay and, finally the relay H either ton# is removed too soon, the delay resets. Once activated, the relay does whatever you wired it to do, the usual task being to connect the speaker to the audio line. Ail the components, save the circuit board, are generally available at well- stocked Radio Shack stores, so repairs should be especially easy The Metheny enclosure also has a couple of weil- placed mounting holes in it to allow at¬ tachment of the power source and an ex¬ ternal relay, driven by the on-board relay Now. let s see what else this thing will do It has an on-board relay, so the control possibilities are almost unlimited You can have It take two tones (standard touchtones) to open the audio on your transceiver so (he tnmg stays quiet unfit you are called Or you can have the relay sound an alarm or turn something on or off (great possibilities tor a repeater sys tem). Metheny even provides a suggestion for a simple timing circuit that will auto¬ matically reset your decoder after a preset delay. You can also set it up so one tone turns it on and another turns it oft or one tone turns it on and leaves it on Delays can be worked on both ends. If can also be set up to turn on with a subaudible tone and off when the tone is removed. And, by changing a single resistor you can use 12 V-dc, 9 V-dc. or 6-V-dc power sources Alt the required controls mount right on the board and are included in the kit. You can also do a number of other things not mentioned in the Metheny in¬ structions— your tmagmatmn will be your only real limitation With two boards, you can use one dual tone to turn a device on and another to turn it off (retaining all the 128 73 Magazine • January, 1983 The front side of the Metheny enclosure, next to the speaker case The decoder itself Note thai white it does not leave a lot of wasted space on the board, there is sufficient room to work comfortably usual options tor each tone) With one board, you can even use sequential single tones with a delay. In this case, a single pot would establish the delay so that, tn effect, the device will require that you in¬ put both tones within two seconds, or three, or whatever period you program Us mg multiple boards, you could do the same thing, bul with variable delays be¬ tween selected digits to safeguard your autopatch from the guy who breaks your code jhe's not likely to catch on to the vari¬ able delay idea) And it you use the Meth¬ eny enclosure, it is easy to add a battery pack, hang it on your belt, and have an in¬ expensive tone-accessed HT Or you could forego the speaker and package it in an even smaller enclosure. If is really nice to see a little outfit like Metheny offer a really useful and inexpen¬ sive device like this If only we had more such little companies in ham radio. The LJM2KR (I have no idea what those letters mean) is sold tor $15.00 plus ship¬ ping The "Storm Alert” enclosure is avail¬ able for $5.00 plus shipping and includes speaker and patch cable. For more infor¬ mation, contact the Metheny Corporation, 204 Sunrise Dr . Madison IN 4T250. Reader Service number 478. David Boyd K9MX Fort Sheridan II ( RTTr IQOP Marc I Leavey, M.D. WA3AJR 4006 Win lee Road Randallstown MD 21133 Happy New Year! I do hope the winter is going well for all of the readership, with projects underway and the like. One such project we have been dealing with in this column has been the design of a computer based RTTY terminal. This month, another installment: character input and control mechanisms. It should be obvious that m any complex system there is a need for suitable control mechanisms. Now, while we are not talking about Three-Mile Island here, with a com¬ puter-based RTTY terminal there is a need to direct the data flow, fill or empty buffers, change speed, etc. If the terminal being designed operated only on Murray , the job would be relatively easy. The ASCII charac¬ ter set, which most computers use. sup¬ ports many more characters than could ever be sent on Murray ft would be easy, therefore, to use any or all of those codes, such as control codes, special punctua¬ tion, or even lower case, to implement some of these special functions In fact, an earlier terminal I designed did just that However, when designing a terminal which will be able to operate on any of the several modes, including Murray, ASCII, or even Morse, using these extra or control characters becomes difficult, if not impos sible A glance at some of the specialized RTTY terminals on the market reveals the presence of several function switches On the keyboard. These function switches do not send out one ASCII character, but a se¬ quence of characters which can command a task to be carried out. Such a sequence of codes is normally preceded by the ASCII ESCAPE' char acter Normally abbreviated ESC, this character is 27 in decimal, $18 in hex, or 00011011 in binary. As defined in the ASCII standards the ESC character is used to shift into another character set. or code grouping We can use it. as many terminals do, to indicate to the program that the char act erf s) which follows is not to be sent, but to be treated as a special command Once such a protocol is adopted, an es¬ sentially infinite number of command se¬ quences become possible For example. ESC-F might be used to fill a buffer and ESC-S to send it Numbers appended to the command could denote one of a series of buffers, such as ESC-F 7 to fill buffer num¬ ber seven As we have been looking at the design of an "‘Ideal RTTY terminal, such a technique would appear to fill the bill nicely Implementing this scheme Is not as hard as it might sound, Fig 1 is a flowchart of the way a character, once received from the keyboard might be screened for a com¬ mand sequence By use of a flag, input which follows an ESC character can be di¬ verted to initiate the appropriate command sequence I will add here, for the smarlies among you who are worried that you won't be able to send an ESC out over the air even if the distant station requires it because it would be trapped in this sequence, that the command ESC-ESC is normally configured to send the ESC code out Does that make you happy 7 Combining this command input routine with the receive and screen display rou¬ tines presented in previous months begins to suggest just what this terminal will be able to do Additional modules will be presented in the months to come, don't worry i have a panic note here from Roy E Den¬ ney N5D0X of Roswell, New Mexico. Roy bought a “Transallator;' Mod ZUH n at a ham test, and despite being told that it was in fine working order, it isn't Now, I don't know what this beast is, and Roy notes that 130 73 Magazine • January, 1983 the manufacturer, Prossers Industries of Westminister, California, is apparently out of business, i presume it has something to do with RTTY. and so does Roy, and we both address the readers of this column to scrounge around and see if something can t be turned up. If so. send it to me and I will see that Roy gets it. Thanks to Winston Yancey WA4TFB who relates that RTTY Loop is the first thing he looks for in 73 He notes being upset if we miss a month and wonders why that hap¬ pens For those of you not fully acquainted with the schedule a magazine such as 73 must follow, there is a two- to three-month delay between when I write a column and when you read it. Since i try to delay until just before deadline to keep the materia! as topical as possible, it becomes very sen sitive to unscheduled delays, such as de¬ mands from my work fi am a physician in active practice here in the Baltimore area) or family. Hopefully, that's not too often, but it wilt occasionally happen Winston also relates trying to interface his Texas Instruments Tl-99/4 computer for RTTY Apparently little in this vein Is avail¬ able through the users group. I must say that l have noticed Ti-99f4s being widely marketed, from computer stores to dis¬ count outlets to toy stores. I'm Sure some¬ body out there is writing software that would be useful to the RTTYer, if only we can find It. Hopefully we can collect some here and display it for all to see in a future column. Are you listening. Tiers? Greetings to Kevin A. Muench, Pb.D, a RTTY buff working in the Philippines. He is attempting to interface a Flesner TU-170 to a Teletype* Model 33 and is looking lor help. I am afraid that the TU-170 is another piece of equipment I have very little infor¬ mation about, but it is widely used and I am sure someone out there has already accom¬ plished such a mating, tf so, let me know so that 1 can send the details along to Kevin, l am sending Kevin some other material on the 6800 programs detailed here in the past, i am sure that with his 680016809 system, Kevin will be interested in following the cur¬ rent super-terminal' - series as it develops. From one end of the world to another. I have a letter here from John M, Clarke VGlEE, Newfoundland, who is having prob¬ lems of a different sort John has been working on the LNW-6Gcomputer and, after building the boards, apparently has trouble getting the thing to work right He's unable to obtain a good display and thinks that the onboard regulators are running loo warm Well. John, I will offer two words of ad¬ vice. First Of all, regulators usually run warmer than you think they should, but rarely are they hot If they are too warm to touch comfortably, something may well be drawing too much current. Which brings me to my second bit of wisdom. Projects which come on printed circuit boards, especially widely-marketed and complex ones like computers, are usually well designed if they come from reputable manufacturers. In the case of the LNW-80, Fig. 1. ESCAPE code processor flowchart. this is a widely-marketed piece of equip¬ ment which has received good reviews. Prob¬ lems such as you describe, can be traced to anything from an integrated circuit in¬ stalled backwards (that is, 180 degrees out of phase—don't tell me it can’t happen, iVe done it!) to a solder bridge between two printed circuit tracings (ditto!) The critical thing about this is that if something ' hap¬ pened;' the result may be remedied easily by reversing the integrated circuit or clear¬ ing the bridged conductors. But circuit damage could be temporary or permanent. If the former, fine, but if the latter, you are m for a lot of headaches unless you realty know your way around a circuit.. The moral of this story, if there is one, is to check all the work out very carefully for integrated-circuit placement, solder bridges, unsoldered pins, or misplaced plugs before you apply power.. It something ss not working right after power is applied, stop right them* Cut the power to the circuit arid check again. If you find an error and correct it and the unit still does not function or if you are unable to locate any mistakes at all, seek expert guidance. This may be a friend who has a similar device or the exper¬ tise and equipment to troubleshoot com¬ plex digital electronics, if ail else fails, write a clear description of your problem to the manufacturer, including the mode! and serial number of your unit. After ail, changes in printed circuits or designs may make an early production run and a late one two different animals, and in order to help you, the manufacturer needs to know what you have, what the problem is, and any information such as measurements or the like which will aid in diagnosis. Do not just bundle up the unit and ship it back without the manufacturer's consent unless their book teUs you that you can. Doing so will only prompt the string of letters that should have preceded and may have prevented the shipment. While we are up north, regards to another newcomer, Irvin F Haworth VE7CVL from West Vancouver, B.C, Irv has a rather com¬ plete Apple II setup which he wants to try on RTTY, and he wonders how to proceed. Welt, by now I hope Irv has read last month's column with its raft of sources for Apple (and other computer) interfaces You might ask around in your area to get a feel for what others are using, then visit their shack to see how the various units operate. Let me hear from you when you get on the air, OK? My Atari 400 is coming along, for those of you who have asked, although it's not yet "on-line." I will be looking into various inter¬ faces and the like In the coming months and will pass along any tips on what I find I have also been looking into buying eight- inch disk drives and have been having a rather interesting time with a dealer No de¬ tails right now, just a caveat to be sure that what you order by mail is really in stock and shipped. It appears that the back-order is a way of life for some mail-order houses. I will pass along more information if the situa¬ tion warrants it. Stay tuned to this maga¬ zine and don't miss next month's RTTY Loop? John Edwards KI2U 78 56 86th Street Glendale NY 11385 25) What a jammer usually gets on his face 28) Former ARRL president (2 words) Down 1) Not ordinary 2) Popular 1982 ham accessory 3) New ARRL General Manager 4) Above VHF (abbr ) 5) Potential no-code license class 6) Earthquake, fire, etc 7) ARRL listener (abbr.) 11) Standby 14) Peru prefix 16) in the airmobile (abbr.) 18) Man who signed new communications bill 21) Avarice 25) Listening organ 27) Summer contest (abbr.) THE YEAR IN REVIEW-1982 Like most years, 1982 was a year of turmoil. In ham radio and the rest of the worid change was in the wind. Proposed massive FCC rule changes and the advent of micro¬ computers were just two areas that may mark 1982 as the year ham radio embarked on a new era. This month's FUN! takes its annual look at the year just gone. How much can you remember? ELEMENT 1-CROSSWORD PUZZLE (Illustration 1) Across 1) Craft announced last year as a 1983 13) Satellite TV (abbr) expedition site (2 words) 15) Least-crowded DX time 7) CW salutation (abbr.) 17) Prosign 8) Critical sunspot point (abbr.) 19) Half a headset 9) Prompt or poof stick 20) Slang for FCC rule 10) Harvest 22) Interference (abbr.) 11) Pacific prefix 23) Whatever number 12) Problem 24) Your residence ELEMENT 2 - MULTIPLE CHOICE 1) The year 1982 witnessed one of the greatest turnovers in ARRL upper-levs! personnel in quite some time. By now, we all know that Vic Clark is the League's new president and Dave Sumner the new General Manager. What, however, was the fate of Richard Baldwin, the old General Manager? 1) The job of ARRL International Affairs Vice President 2) The job of ARRL Secretary 3) The job of ARRL TVf Task Force Chairman 4) No job 2) What was last year's big news from the Heath Company? 1) Heath's withdrawal from the amateur radio marketplace 2) The mtfoduchon of Heath’s first non-kit amateur transceiver 3) The introduction of Heath's first solar-powered radio 4) None of the above 3) Last year's amendment to the Communications Act of 1934 will permit the FCC to per¬ form which of the following actions: 1) Complete elimination of all code requirements 2) The addition of a new satellite band 3) The delegation of amateur testing to local radio clubs 4) Last year's amendment gave the FCC no new powers Illustration t, Mustration 2. 132 73 Magazine * January, 1983 000000QQOE300 □ 0 m m 0 m\ 0 0E1 EJE10 000 0000 o 0Q 0 n m 0000 0 DQ00 D 0 00D0 00 000 0 IH0S 0CDO HI 0 0 00D HE ED 11 0HH m ES 0 0 0 00BHHH0GIP10PB Illustration lA Illustration 2A. 4| Which of the following countries reached a third-party agreement with the US during 1982: 1) Spain 2) Austria 3) Sweden 4) Australia 5| What did the FCC plan to do to our phone bands m 1982' ; tj Expand them 2) Contract them 3) Eliminate them 4) Leave them alone ELEMENT 3-CRYPTIC PUZZLE By using a standard substitution code, decipher this message YMUOVCEGYMJV GHCK OCO KFH MO M JMZKW SWKUDVJ OMOC LVMW ELEMENT 4-MAZE {Illustration 2) Did 1982 leave you contused 0 Join the dub This maze certainly won't make you any less dizzy. but at least it isn't very difficult CORRECTIONS THE ANSWERS Element t; See Illustration 1A. Element 2: 1— 1 The man's too young for retirement. 2— 2 The SS-9000 computer-cant rots able rig. 3— 3 Soon, perhaps, no more trips to the Federal Building 4— 4 Down Under was the place. 5— 1 Much to the irritation of most foreign hams. Element 3: Coded as follows— ABCDEFGHI J KLMNOPQRST UVWXY2 MUYBVPAXQZ I DJHKSRWOCNEFTLG 'CABLE TV! CAME INTO ITS OWN AS A MAJOR PROBLEM LAST YEAR" Element 4: See Illustration 2A. SCORING Element 1 Twenty-five points lot the completed puzzle. or one-halt point for each question correct answered: Element 2: Five points for each correct cinswer. Element 3: Twenty-five points for the completed puzzle. Element 4: Twenty-five points for the completed puzzle. In the Automatic Beam Aimor." which appeared in ttie Novtinitier issue. there was an error m Ihe schematic on p 23 The Ui odes across Ki K2 and K3 were drawn m the opposite direction from what they should be in the parts list on the same- page. Radio Shack part number 27 1-1715 re fers to a 25k pot Actually, pari 27M715 isa 10k pot, but rl will work equally as well in the circuit Avery Jenkins WB8JLG 73 Staff Our apologies to Steven Katz WB2WIK, author of “Build Yourself A Paralyzed Beam" (December). Readers might better view the photo of the relay box on page 24 by turning the page upside down. Avery Jenkins WB8JLG 73 Staff Several errors crept into the “'Circuits’' feature in recent months. In the September., 1982, issue on p. 92, there were two errors The first occurred in the description of the “Visual Adjust for Gamma Match.“ with the sentence beginning. “Even if you use an swr meter at the transmitter end of the scale..... .." ft should read, "Even, if you use an swr meter at the transmitter end of the cable And in the description ot the "Electronic Phone Bell." "heat-sink tubing" should be heat-shrink tubing. On p 109 of November’s issue, there were two errors in ""Substitute Transformer for Heath Gear." Circuit author Terry Martin points out that the circuit is a voltage trip- ler, not a voltage doubler as stated in the text He also adds that it supplies 980 V, not 450 V. On p. 112 o! the same issue, in “Modifica¬ tion to the- Kenwood TS-52QS lor AFSK. Fig. 3 was incorrectly iabeted. Fig. 3 shows the »*? filters of the 530S. not the 520S as im¬ plied by the text How well did you remember 82? 1-20 points—Skipped the year 21*40 points—Not very well 41-60 points —Bits and pieces 81-80 points—Very well 81-100 + points.Total recall, proceed to '83 FUN! MAILBOX l just got to the June issue of ?3and began your logic puzzles.. Element 3. DXX Couples >s incorrect by your solution as Diane has 206 You say Diane *s Stan's wife, tout mat Frank's wife nas more countries than Stan's wife Therefore Stan s wife cannot have the highest total, if was given that Diane had 206 The correct solution is Stan 198, Wilma 202-Total 400 Frank 194. Diane 206—Total 400 Joe 196. Susan 200-Total 396 Stan has 198 Joe has *96 Bob Gingras W84JMH Cocoa Beach Ft Avery Jenkins WB8JLG Very good, Bob Don 7 you like the way I mess up answers just to keep my readers on their 73 Staff toes 7 — J £ 134 73 Magazine • January, 1983 Chod Harris VP2ML Box 4881 Santa Rosa CA 95402 NEW YEAR’S RESOLUTIONS The new year always provides a good time to review operating practrces and perhaps improve techniques on the air Here is my list o? New Year s OX resolu¬ tions: why don I you come up with your own list and post if next to your ng* 1 1 will not tune up on the air without checking the frequency, instead, I will use a dummy load, mark the controls tor each band, or search lor a clear frequency before tuning up 2. I will listen carefully before I call. No more “Who did I just work?" or calling out of turn when the DX station is working by call areas 3.1 will keep well informed, so that I don’t have to ask "What’s his OSL address?" in the middle of a DX pifeup. 4. l will not be a DX nog ' I won t flaunt my imulti ikitowatts in pileups and then ask the rare DX station to run a few tests with different antennas, etc 5.1 will not be a self-appointed policeman on the DX bands, nor will I talk back to one. The bands are crowded enough without this nonsense. 6.1 wilt keep my transmissions short and listen often, to reduce ORM. 7. I will be courteous at all times to my fellow DXers. no matter what they do 8. i will OSL promptly, with the card care¬ fully filled out 9. I will check out my rig to ensure that my signal is clean and not causing ORM 10. I will try other bands and modes and not sit on 20 SSB, if we alt follow these resolutions, we will have an easier and more pleasant DX expe- rlence in 1983. And we’ll need every advan- tage we can get for the big pileups around Heard Island early this year HEARD UPDATE The race is on to Heard Island. One of the most difficult and expensive DXpedttions continues its relentless drive towards this isolated rock (see this column, September, ?982i, as the members of the VK6 DX Chasers Club nail down many of the details of the trip. At the same time that the VK6 DX Chasers are organizing their trip to Heard, the well-known South Pacific DXer, Jim Smith VK9NS, has chartered his own trans¬ portation to Heard. Jim sports an impres¬ sive record of successful DXpeditions throughout the region and is as knowledge¬ able and experienced as any DXpeditioner Jim aims to arrive at Heard a month before the mountaineering group. So after years with absolutely no activity, it looks like Heard might be the subject of not one but two DXpeditions As of press time, the operators on the VK6 DX Chasers DXpedition are slated to be: Alan Fisher N8CW, Charles Brady N4BQW, and David Shaw VK3DHF. Alan is a mechanical engineer, which is likeiy to be a very useful talent on icy, wind-swept Heard. N4BQW is a physician when not DX- ing. and one hopes his specialty will not be needed on this DXpedition The Australian on the DXpedition team has worked with the Austraiian meteorology department as an electronics technician. Both meteoroL ogy and electronics will certainly be need¬ ed on Heard Island The vessel taking the hams and mountaineers to Heard is as impressive as the list of operators. The Anaconda II is 84’ long, 20’ wide, and sports a 98’ main mast. Anaconda II has Antarctic experience, having just completed the Rio De Janeiro Race through the Roaring Forties’’ and around Cape Horn The yacht comes fully equipped with the latest »n navigational and electronic systems, including radar, satei lite and terrestrial navigation, depth sound¬ er, and access to remote computers. (It’s probably too much to hope that they could keep the radio log in their computer .) The hams and mountaineers will use in¬ flatable surf rescue boats lo get to the rocky shore of Heard. The choice of rigs and antennas for the Antarctic DXpedition presents a difficult problem Sturdy, dependable, easy-to-re- pair radios are the order of the day Another key to dependable operation involves tak¬ ing several of the same radio. Then a malfunctioning radio can be cannibalized for parts if another fails, The antennas and outside gear will take an even worse beat mg than the radios. The combination of freezing rams and high winds can destroy mosl antennas, so spe¬ cially reinforced antennas are required of the day, Finding lubricants that won’t freeze up for the antenna's rotors repre¬ sents another necessity. After the hams collect their equipment they must practice its assembly and repair Each antenna and support system must be put together and taken apart again and again What tools are needed^ Can they be handled with gloves and mittens on? Exact¬ ly what hardware is needed for each opera tion? How many extra nuts and bolts should be taken? What do they do if piece X breaks? The size of the yacht limits the number of spare parts the DXpedition crew can take, so which are the most essential? These are the kinds of decisions which go into a well-planned DXpedition. But even more important than the hard ware ts the "software —the radio skills of the amateur operators There are definite skills necessary for handling pileups. keej> mg the contact rate high, ami giving every one a fair chance at a contact Weather conditions are going to be rough on Heard, and radio conditions might not be much better. Heard is a long, long way from any sizeable collection of amateurs. That means that Heard's signals will be relative¬ ly weak, and European, stateside, and Japanese signals will also be weak at Heard. It will take highly-skilled amateurs to keep the pileups under control. We hope that the Heard Island DXpeditioners will avoid the kind of poor operation shown at the St. Peter and Paul Rocks (PY0) this fall There is simply no ex¬ cuse tor spreading out the callers over 100 kilohertz of the 20-meter phone band. Even the Clipperton island DXpedition used only 75 kHz? There are many ways to spread out the callers without disrupting the entire 20-meter phone band Non-DXers think poorly enough of the DX fraternity without this kind of bad manners. Perhaps it’s time for a standard of DX conduct for DXpedi* tiona Well have more to say about this in a future issue Meanwhile, the question of money con¬ tinues. The mountaineering Heard Island trip may well cost Si50,000 or more Dona¬ tions of equipment, supplies (including warm underwear), and cash have started the ball rolling, Theexpedition istaking film of the entire trip, to recoup some of their costs. An artist on the expedition team in¬ tends to sell paintings of the Heard Island landscape and penguins One major source of expedition funds is the amateur community Both the Northern California DX Foundation (PO Box 2368, Stanford University CA 94305} and the International DX Foundation (PO Box 117, Manahawkin NJ 08050) have pledged $10,000 to the program. And both DX foundations are looking tor new members and contributions to assist their work. The Australians organizing the amateur part of the trip are inviting amateurs and others to become associate members of t he "Antare tic Adventure.’ 4 at $30 (Australian) The VK6 DX Chasers are also selling DXpedition T-shirts at $950 (Australian). Contact them at Box 10, Perth 6005, Western Australia Meanwhile, Jim Smith continues to solic¬ it funds and operators for his assault on Heard. You can send your contributions to Box 103, Norfolk Island, Australia. Your contributions will help with the Heard Island DXpeditions and future trips to other rare spots. Who will get to Heard first? Will there be anyone left to work for the second DXpedf tion? The best way to find out is to turn on your receiver and listen MAILING YOUR QSL CARD If you do work Heard island this winter, either VK0HI or VKfldS. you will want to get a OSL card confirming the contact In the last two months we discussed how to design and fill out your QSL. This month we’ll look at ways lo gel your card to the right place. 1*11 discuss these methods roughly in order from slowest to fastest. The Bureaus By far the easiest way to send your OSL to another amateur in another country is via the QSL bureau system Every civilized country (and some that are not) has an incoming QSL bureau for the benefit of its amateurs. Incoming cards are sorted every so often and distributed to local amateurs Some of the bureaus are excellent. The Japanese and West Germans have espe cially top-notch bureaus. The smaller coun¬ tries have less formal systems; in some cases, they are essentially nonexistent Sending your card to a DX station via the bureau is simply a matter of writing the DX station s call In the upper right comer of the back of the QSL and sending it to the ad dress listed in the IARU information or the Callbook If you have any number of cards going to the same country, the cost is a few cents a card. An even easier system for ARRL mem bers is the League's ongoing DX QSL bureau. A membership label off QST and $1.00 per pound of QSLs (about 150) gets the cards off to the DX bureaus for less money (and probably faster) than any other service. Contact the ARRL for more infor¬ mation. The chief complaint about the bureau method is speed There isn't any. Three to four months is about as fast a turnaround as anyone can expect. A year or two is not unusual With Russian QSLs (through the famous Box 88. Moscow), delays of 3-5 years are common and I have seen 1015-year-old QSLs in packages direct from Box 88. Small wonder that it takes twenty years to get on the honor roll; it can take that long for a bureau card! Commercial QSL Forwarding Services There are other outfits which provide the same service as the League’s outgoing QSL bureau, plus the added benefit of searching out QSL managers and faster QSL methods. These services advertise in most amateur-radio magazines. The price per card runs about $0.10- 20, but service depends on the volume of cards and the expertise of the amateur running the operation W3KTs service used to be the best, before Jesse passed away last year (see this column, September, 1982) It you want to go this route, contact the operator and find out the number of cards per week he handles, how long the cards si! in his hands, how he arranges for return QSLs, and the calls of some hams who have used the service. Then follow up on this information before depending on the QSL forwarding service. The same problem applies to this kind of service as to the League bureau system It can take a long time A well-run forwarding service can get cards to stateside QSL managers and back quite cheaply and rap~ idly But DX QSLs usually go by sea mail and can be months m transit There is an¬ other potential problem with the QSL for warding services Their success depends heavily on the skills of the manager His knowledge of DX and QSLing can make the difference between cards on the wall and wasting your money. Direct QSLs Since DXers are an impatient lot, the pre¬ ferred method involves sending a QSL of an important DX contact directly to the person handling the QSL chores. This person might be the actual DX operator himself or a QSL manager To send the card, you need the correct address Obtaining this accurate address is one of the fine arts of DXing. The first place you look lor this information Is on the air. Listen to the DX station. Where does he say you should send the QSL? The horse’s mouth is by far your best source of QSL information, Next best are second-hand sources, such as DX nets, repeaters and bulletins Pulling information out of the bulletins is a time-consuming task, and errors abound DX nets are a Utile better, but it helps to know who is providing the Information, to help judge its reliability, DX repeaters offer the chance to talk to someone who has al¬ ready received a card back from that DX station. Whatever method was successful once is worth another try. If you don’t want to spend your DXing time reading every bulletin and monitoring every DX net. you might consider subscrib¬ ing to one of the DX QSL lists Look for their ads in the magazines and bulletins W6GO and K6HHD publish a QSL Manager Lis? with more than 5000 calls. This list is up¬ dated monthly and costs $15 00 per year in the US. The address is PO Box 700, Rio Un- da CA 95673 Another possible source of DX address information is the Callbook. Some ama teurs say they are "OK in any Callbook ’ The Callbook also lists QSL bureaus in the various DX countries. The Callbook is available at your local radio store or by mail Addressing the Envelope You have finally located wha? you are sure is the latest word." the ”up-to the- minute” QSL address You could just write the address on the back of your card and mail it. but you would get an answer via the incoming QSL bureau or not at all You probably want to send the card in an envelope, with a seIf-addressed, stamped envelope (SASE) enclosed. Avoid the temptation of putting more than one card In an envelope. Say you worked Eric SMCAGD from several of his Pacific locations this past fall (see this col¬ umn, August, 1982). Please don’t put all the cards for SM3CXS (Eric’s QSL Manager) in¬ to one envelope. Use a separate envelope tor each QSL card. Or if you really can’t af¬ ford to do that, at least send cards for each separate callsign in a separate envelope 138 73 Magazine • January, 1983 Mixing the^calls or cards will only delay the responle Often, different people in different locations handle the cards for different calls, even though the OSL ad¬ dress is the same, as is the case with SM3CXS. If you mix several callsigns, the cards and your return envelope wWI go to one OSL manager, back to SM3CXS, and so on. Anywhere along the line your cards might get lost or separated from the return envelope. Make everyone’s life easier, and speed your return QSL by sending each card in a separate outer envelope. Should you put the callsign of the DX sta¬ tion on the outer envelope^ An excellent question. If the card is going to an address In the States, Western Europe, or Japan, by all means do so The first callsign on the ad¬ dress should be that of the DX station you worked, the second the call of the QSL manager VP2ML via K1RH. This allows the QSL manager to sort the cards quickly On the other hand, I recommend leaving Off the callsign on the envelope if the card is going to an African country. Eastern Eur¬ ope, Turkey, or any other country where am¬ ateur radio is illegal or frowned upon The reason is theft or danger to the DX amateur Callsigns on the outer envelope may indi cate money inside, so many of these enve- lopes never reach their intended destina tions In the case of Turkey, the DX amateur can run afoul of local authorities by receiv¬ ing mail with a callsign on the envelope. The best rule of thumb is, when in doubt, leave It off. And if you ever send personal mall to an active OSL manager, write in large letters, 'Not a QSL’’ on the envelope! Otherwise it may get thrown in with the QSLs to be answered tomorrow When to Mail We are all anxious to get our return QSL card, especially one confirming a rare QSO So many of us rush right out the day we work the DX station and mail off the card. This is fine when the card is going directly to a DX resident in another country. But it is not necessarily the best time to send a QSL card for a DXpedHion contact or to a QSL manager Many DXped it loners handle their own OS Ling. If you can still read them on the ra dto, they can’t be home answering your QSL, Wait a while in fact, most DXpedi tions don't print the QSLs until they get home and know how many they need It will often be a month or more before they even have any cards to fill out. If you really jump fhe gun and send the card out while the DXpeditioner is stilt away from home, you can create some unneeded friction between the DXer and his local post office When l returned from 10 days in the Galapagos, there were 6 bags of QSLs wait ing for me. On one day I received more mail than the rest of the local residents com¬ bined! The post office personnel thought I was running some sort of mail scheme and threatened to charge me a commercial rate and storage fees And somewhere, burled in that lome of mail, were personal letters, Bill Gosney KB7C Micro-80, Inc . 2665 North Busby Road Oak Harbor WA 98277 LABRE AWARD The Worked All American Award has been instituted by LABRE (Liga de Ama- dores Brasiteiros de Radio Emissaot to promote interest in the American area The WAA award will be issued to any li¬ censed amateur station presenting proof of contact with forty-five (45) or more countries in the American area. All applications should be sent to the Awards Manager, LABRE, PO Box 07/ 0004, Brasilia, Distrito Federal, Brasil, CEP 70.000. Confirmations must be accompanied by a list of claimed countries to aid in checking. A Jog verified by the awards manager of the applicant’s country league or association wiH be accepted instead of QSL cards. Logs may also be verified by two amateurs m the appli¬ cant's area. All contacts must be made with li¬ censed amateur stations operating in au thorized amateur bands. Contacts must be made only with licensed and based am¬ ateur stations. Contacts with ships and aircraft cannot be counted. All stations must be contacted from the same call areas where such areas exist, or from the same country tn cases where there are no call areas One exception is allowed to this rule If a station moves trom one call area to another, or from one country to another, all contacts must be made from within a radius of 150 miles from the Initial location Contacts may be made over any period of years since November of 1945 Con¬ tacts may have been made under different call letters in the same call area (or coun¬ try) if the license for all was the same. Any altered or forged confirmations will result in permanent disqualification if ob¬ served by the WAA award advisory com mittee. A minimum readability of 3 (R3) must be recorded for phone and a mini¬ mum signal tone of 5 (S5) must be record ed tor CW All applications must be forwarded with ten IRCs or equivalent for handling and postage and return of OSL cards by regis¬ tered air mall. All certificates will be consecutively numbered and an honor roll showing all those Issued will be kept by the awards manager of LABRE. The following list of countries in the American area (North and South America) is presented as a guide. Deleted countries will not be valid WAA Countries List CE Chile CE Easier island CE Juan Fernandez CE San Felix CM-CO Cuba CX Uruguay FG Guadeloupe FM Martinique F08 French Polynesia F08X Clipperton Island FP St. Pierre & Miquelon Islands FS Saint Martin FY French Guiana HC Equador HC8 Galapagos island HH Haiti HI Dominican Republic HK Colombia HK® Bajo Nuevo HK® Malpelos Island HK® San Andres & Provldencla HP Panama HR Honduras J3 Grenada J6 St Lucia J7 Dominica K-W USA KC4 Navassa KG4 Guantanamo Bay KP7 Alaska KP4 Puerto Rico KP4/D Desecheo Island KS4 Swan Is. (now HR) KS4 Serrana Bank (now uses HK®) KV4 Virgin Islands KZ5 Canal Zone (until March 24, 1978) LU Argentina OX Greenland PJ Neth Antilles PJ Saint Maarten OA Peru PP. P2, PR, PS, PT. PU, PW. PY Brazil PY® Fernando Noronha PY® St. Peter's & St Paul's PY® Trindade $ Martim Vaz Islands PY® Abrofhos Island PZ Surinam TG Guatemala Tl Costa Rica TI9 Cocos Island VE Canada VPl British Honduras VP2A Antigua and Barbuda VP2E Anguilla VP2K St. Kitts VP2M Montserrat VP2S St Vincent VP2V British Virgin (stands VPS Turks & Caicos Islands VP7 Bahama Island (Now C6) VPS Antarctica VP&LU Falkland Island VP&LU Georgia island VP&LU So Orkney Island VP8/LU So. Sandwich Island VP8/LU So. Shetland Island VP9 Bermuda XE Mexico XF4 Revilla Glgedo YN Nicaragua YS El Salvador YV Venezuela YV Aves Island ZFI Cayman Island ZP Paraguay 6Y Jamaica 8P Barbados 8R Guyana 9V Tnmdad & Tobago Islands MARTINIQUE AWARD The FM DX Group of Martinique is offer¬ ing a certificate for QSOs with FM7 and FM® stations. Three hundred points will earn the certificate, with scoring as fol¬ lows: Contacts with an FM DX Group member count 10 points per QSO. FM® contacts count 4 points each, and FM? contacts count 2 points A phone QSO is worth 1 point, RTTY or ASCII count for 2 points, and a CW contact is worth 3 points One point is given for a contact on 10, 15, or20 meters, a contact on 160 or80 me¬ ters is worth 2 points, and a QSO on any other frequency receives 3 points. One point also is added for each 3,000 miles distance from Martinique. A minimum of 7 days is required be tween two QSOs with the same station, and 25 percent of fhe points must have been made in contact with an FM DX Group member Logs and a $5.00 money order should be sent to Gerard Souqui FM7BX, PO 140 73 Magazine • January, 1983 bills, and checks. It took a solid day just to pull my personal mail out of the QSLs* So give the DXer some time to get home, get some cards printed, and catch his breath, before overflowing hts PO Box The same problem can happen when QSL managers get their log information via the mail. The togs might take weeks or months to get to the QSL manager, before he can look up the contact and answer your QSL Some QSL managers get around this by having regular schedules with the DX sta tion. The manager reads the contact in¬ formation, the DX station checks his log. and the QSO is confirmed This system worked so weft tor me at VP2ML that one amateur received fus QSL card less than 48 hours after the contact! Enough about how to gel your QSL card to the right place ft s the next step that s the important one anyway: getting the DX stations s QSL card back* Hang on until next month! Box 152, 97202 Fort de France Cedex. Martinique W. VIRGINIA QSO PARTY The West Virginia QSO Party, spon¬ sored by the West Virginia State Amateur Radio Council, will be f rom 170QZ January 22 unlit 1700Z January 23. Single operator only Exchange signal report, serial num¬ ber, county (WV only), state, or country. WV stations multiply total by sum of WV counties, states, and countries worked. Others multiply QSO totals by WV coun- ties worked. Multiply score by 1,5 if you run 200 Watts or less Suggested frequencies Phone—10 kHz from lower edge of Gener¬ al subbands. CW—35 kHz from low ends; Novice —35 kHz from tow ends. Repealer contacts permissible Mail togs by Febru¬ ary 11 to K88S 950 Gordon Road. Charles¬ ton WV 25303. WISCONSIN SPECIAL EVENT The Eau Claire, Wisconsin, ARC wit! op¬ erate K9EC/9 during the National 70-Meter Ski Jumping and Nordic Combined Cham¬ pionship on January 29 and 30 from 1400Z to 2300Z Frequencies: CW—52 kHz up from bottom edge Phone—3980, 7277, 14282. 21382 and 28620. For an x 11 certificate, send SASE to N9AIX PQ Box 201. Altoona Wf 54720 GROUNDHOG DAY The Punxsutawney (Pennsylvania) Am¬ ateur Radio Club will operate on 14 290 and 7.230 from 9 am to 5 pm, January 30, 1983, in commemoration ol Groundhog Day 1983. We will operate also on 7 230 on February 2, 1983 (Groundhog Day) This special-event station will operate from Gobblers Knob, the home of the Ground hog. Certificate for SASE and QSL card to Art Sweeney K3HWJ, RD tl. Box 371. Punxsutawney PA 15767 GEORGIA'S 250TH BIRTHDAY Savannah area amateurs will have a special-events operation in honor of the State of Georgia s and historical Savan¬ nah’s 250th birthday. Operation will be February 12 and 13, 1500-2000Z on upper 25 kHz, alt General phone, and 21.130 to 21.170 kHz Novice. QSOs on 2 meters 146 52 only For special certificate, send QSL card with QSO number and large SASE to call of contact operator GOLDEN SHEARS AWARD In honor ol the 1983 Golden Shears Sheep Shearing Contest in March, 1983, the members of New Zealand’s Branch 48 in Wairarapa are offering an award for contacts mace that month with their members To he eligible for the award on HF bands, ZL stations must have iG points, VK stations must have 7 points, and DX stations need 5 points. Net contacts count toward the award On VHF, ZL2 stations need 15 points to quality, other ZL stations have to get 7 points, and DX stations must have 3 points. Repeater GSOs count toward the award, but repeater/net contacts do not Scoring is as follows: Golden Shears President 2L2AHU is worth 3 points; dub station ZL20A, a YL operator, farming branch member, or mobile station within Wairarapa are worth 2 points each, and any other member is worth 1 pom! Except tor crossband operation, any band/mode combination is allowed. How¬ ever, only one contact per member is per¬ mitted unless themember is operating the club station or working mobile withm Wairarapa No QSLs are required for the award; send your application with $ 2.00 (N2) or an equivalent international Money Order to Awards Manager, PO Box 880. Masterton, New Zealand. Entries must be received before August 31, 1983. All pro¬ ceeds wilt go toward funding for an oper¬ ating room for emergency situations. ( NEW PRODUCTS APOLLO X10 ANTENNA National Microtech.. Inc., has lust in¬ troduced its new Apollo X10 antenna, which utilizes a 10-toot., eight-segment, compression-molded fiberglass reflector. The reflector provides high slrength-fo- weight ratio and significantly reduces the size of the shipping container, thus pro¬ viding savings in handling and shipping costs, The X10 can be erected easily by two in¬ stallers, The individual reflector segments are Interchangeable and field replaceable. utilizing indexing tabs for position and self- alignment The Apollo X10 delivers 44)! dB gain at 3.95 GHz. Its textured front surface dif f uses sunlight and reduces sola# heating at the focal point, and the high-quality fiberglass material is impervious to salt, pollutants, and contaminants that may be encoun¬ tered in coastal and industrial areas The center-mounted 'button hook" prime feed provides accurate alignment with the focal point without the use of cables and other supporting gear. The LNA is located at the focal point while the rotor is placed at the rear of the dish, permitting rotation of the feed through 360 degrees of polarization by remote control. For more Information, contact National Microtech, Inc., PO Drawer E, Grenada MS 38901 Reader Service number 481 UNITED STATES FREQUENCY ALLOCATION CHART An updated “Varian United States Fre¬ quency Allocation Chart * is now available tree of charge from Varian Associates Electron Device Group. The four-color chart includes radio, television, point-to- point, microwave, satellite communica¬ tions. and millimeter wave frequency alto- cations. This 15" by 21” foidout wail chart features a ledger guide and is both color and line-coded for easy reference Frequency allocations from 3 kHz to 300 GHz are divided into eight one-order of-magnitude divisions. These divisions are color-coded to illustrate frequency uses of government exclusive, non-gov ernment only, and government and non¬ government shared frequencies. Line cod¬ ing is then used for the demarcation of 31 specific frequency categories such as fixed satellite, radio navigation, iand mo¬ bile. broadcasting, and meteorological satellite For further information, contact Vartan Associates, Electron Device Group Mar¬ keting, 301 industrial Way. San Carlos CA 94070 Reader Service number 488 AZDEN INTRODUCES NEW PCS-4000 Japan Piezo Company, Ltd,, and Amateur-Wholesale Electronics have an¬ nounced their new PCS-4000 2-meter FM transceiver Like its predecessors, the PCS-4000 utilizes keyboard frequency control, but many new features have been added, making this a truly unique radio Some of the features are 8 MHz cover¬ age {142 to 149.995 MHz)., extremely small size (2 inches high by 514 inches wide by 6% inches deep), two banks of eight memories which cars be scanned sepa¬ rately or together, capability for up to eight nonstandard repeater splits, and two priority channels. Other feaures in elude a fuff 18-key touchtone^M p a q built in, multicolored display for easy function recognition, discriminator scan centering, repeater reverse button, and freefvacani scan mode selection with auto-resume. For more Information, contact Ama- teur-Whofesale Electronics , Inc.. 8817SW 129 Terrace, Miami FL 33176; (303) 233 3631 Reader Service number 483 SIMPSON’S MODEL 467E LCD DMM Simpson Electric Company has intro¬ duced a new hand-portable LCD digital multimeter.. Model 467E joins the Simpson line of LCD hand-portable DMMs Features include peak hold to capture surge currents and voltages, a continuity mode to provide instant visual audible checks for shorts and opens, and true rms capability for more significant measure¬ ments of non-sinusoidal waveforms over a wide frequency range. The 467E has 26 ranges to provide full acfdc voltage, cur¬ rent. and resistance (including low-power Ohms) measurement capability. Additional features include 0.1% dc V accuracy, high-voltage transient protec¬ tion, a double fusing system, and color coded front-panel graphics, its size is a compact 2” x 5.6" x 4.6” and its weight is 1 v» lbs. For further information, contact Simpson Electric Company. 8S3 Dundee Avenue. El¬ gin li ffli20; (3l2tf97‘22t SO Reader Service number 486. SUBMINIATURE CHANNEL SCANNER Midian Electronics, Inc., has introduced a subminiature channel scanner ft fea¬ tures 6-channei capability on radios em¬ ploying crysia! high switching, 16-channel capability on radios using battery-fine bi¬ nary address, and 8-channel capability on radios using battery or ground switching. The scanner also has a priority channel scan capability as well as a three-second hold timer, manual advance, and an ad¬ justable channel scan length For further information, contact Midi an Electronics. Inc... 5907 E Pima Street. Tuc¬ son AZ 85712, (602F 885-6883. Reader Ser¬ vice number 487 PLUG-IN DTMF DECODER Paiomar Engineers has announced a new single-digit decoder which is avail able for any of the 16 DTMF digits. Replacing the firm's older model T2. the new P200 features improved temperature stability, high input impedance (200,000 Ohms), and a V*-Ampere SPOT output re lay. It operates from 12 volts dc, signa! lev¬ els from - 25 to 5 dBm, and has a re¬ sponse time of 100 ms. The decoder plugs into a standard octal socket. For further information, contact Palo- mar Engineers , 1924F W Mission Road. Escondido CA 92025: (714)-747-3343 Paiomar Engineers’ P200 DTMF decoder National Mtcrofech’s Apollo X10 antenna Simpson’s model 467E DMM 142 73 Magazine • January, 1983 /corn’s IC-290H transceiver. PotyPhaser's new impulse suppressor ICOM'S IC-290H Icom has announced me release of a new 2-meter multimode mobile transceiver,, the IC290H, featuring a powerful 25-Watt output and a highly sunlight-readable green readout in the same compact package as the IC-290A Other features and Styling of the IC-290H am the same as the previous model—the 1G-290A, These include 5 mem¬ ories tor storing your most worked frequen¬ cies, a call channel to make your favorite frequency instantty available. SkHz FM tuning or 1 -kHz! f00-Hz tuning or? SSB. FM/ USBiLS&'CW modes, programmable offsets, a priority channel that monitors 2 frequen¬ cies. and scanning of memories or band. For more information, contact icom America, Inc., 2112 116th Avenue NE, Belle¬ vue WA 98004 ENCON PHOTOVOLTAIC PANELS Encon, Inc... distributors of Sola rex pho¬ tovoltaic products for the Midwest, has in¬ troduced the new Sol a rev SX series of semicrystalline photovoltaic panels, us¬ ing state-of-the-art technology Solarex semicrystalline cells offer unique advantages over earlier technol¬ ogy, including lower cost, increased pack¬ ing efficiency, and higher power output compared with the traditional round sin¬ gle-crystal silicon cells Semicrystallme cells are made by melting iess-than-pure poly crystalline silicon, crystallizing if into feci angular '"bricks,'' and then sawing the bricks into wafers to make rectangular cells. The cost reductions afforded by the new process promise fo bring prices down from $100 per Watt to under $20 per Watt within the next few years Solarex suppplsed the photovoltaic cells for the UoSAT /University of Surrey} OSCAR 9 satellite launched on October 6. 1981. OSCAR 9’s four solar panels each contain 408 high-efficiency 2 cm x 2 cm ceils, Each panel produces 27 Watts when fully illuminated. The Solarex system is designed to produce 18 Watts peak power and 8 Watts average power in orbit to charge the 14-volt nicad battery, Encon, Inc., assembles complete pho¬ tovoltaic power systems for emergency and primary communication applications, as well as residential and commercial packages.. Interested amateurs are invited to contact Encon . Inc. 27584 Schoolcraft. Livonia Ml 48150 Reader Service number 479. ICOM’S IC R70 GENERAL-COVERAGE RECEIVER Icom has just announced its new pro¬ fessional general-coverage receiver, the IC-R70. lt is a full generation newer and fea¬ tures more functions than other (ess so¬ phisticated general-coverage receivers on the market. Features include squelch on sideband, adjustable-width noise blanker, adjustable-speed age, passband tuning as standard, and adjustable notch filter as standard Other convenient features are high-sta¬ bility, synthesized tuning with tuning speeds, an optional AM/FM mode, vari¬ able CW-ftlter widths, dial lock, and two vfo's with data transfer Also, the IC-R70 will operate transceive with the IC-720A, making an ideal combination for the seri¬ ous DXer or CW buff. For more information, contact /com America, Inc., 2112 116th Avenue NE, Bellevue WA 9800* POLYPHASER’S IMPULSE SUPPRESSORS A new series of bulkhead-style impulse suppressors for coaxial lightning protec¬ tion was recently introduced by PolyPhas- er Corporation. This new IS-B50 series can easily replace older air-gap-type arrestors and can be mounted on up to 1/8 thick bulkhead panels These weatherproofed gas tube protectors are designed for re¬ peaters, base stations, and TYROs to 1 GHz. with typical fN) 0 1 dB loss and 11- to-1 vswr Their hefty 20-kA multi-strike and 50-nanosecond turn-on time make protection against most direct strikes possible. They come complete with weather washer and stainless steel hard¬ ware in both N and UHF fittings A tower mounting kit is also available. For further information, contact Poly- Phaser Corporation, 1500 West Wind Boulevard, Kissimmee FL 32741 ; (303} 396-180? Reader Service number 485 DC POWER SUPPLY Many mobile operators would like to be able to operate their mobile equipment at home on ac power mains. Tripp-Ute has just announced a product that meets that desire: a precision regulated dc supply that converts 120 V ac into 13.8 V dc For example, CB radios, automobile tape players, tape recorders, high-power ster¬ eo systems, amateur radio equipment, lin¬ ear amplifiers, and marine- or business- band radios can now be used at home. The new low-cost power supply saves the user money, since it also eliminates the expense of having to buy ac equip¬ ment It features a solid-state Integrated circuit for precise regulation. A built-in filter ensures low-noise operation, and current-limiting electronic ‘foldback" is provided for automatic overcurrent pro¬ tection. Other features include a heavy- duty power transformer for complete line isolation, a maximum ripple voltage of on¬ ly 0.1 volts from zero to full load, an on/off switch and indicator light on the face¬ plate, and a UL-iisted ac cord and plug /type SPT-2). For more information, write Tripp-Lite, 500 N Orleans. Chicago It 60610. Reader Service number 484 W9AV MORSE CODE TRANSLATOR FOR TRS 80 COLOR COMPUTER J C. Sprott W9AV announced some time ago his Morse-code programs for the TRS- 80 Mod I/Mod Hi computers. Now, he has announced the availability of a Morse pro¬ gram in 16K extended color Basic for the TRS-80 color computer It is believed that this program is the only Morse-code pro gram available for sending and receiving Morse code by way of the computer's cas¬ sette port. With 9 programmable memories of 240 characters each and a random-character "practice" mode, the translator program al¬ lows you to send and receive the code by merely plugging the computer cassette plugs directly into the transmitter key jack and the receiver phone lack. Morse code may then be sent at speeds of up to 60 words per minute and received a? speeds of up to 30 words per minute. For more information, write ProfessorJ C. Sprott W9A V, 5002 Sheboygan, H207, Madison Wl 53705. Reader Service num¬ ber 480 SLEP SPECIALS AEA M8A-RO Reader Receive Only,........ . . .$269 00 MSA-RG ReceiveCode Converter...... . . 395.00 MM-2 Morsemattc Ultimate Keyer..135.00 CK-2 Contest Memory Keyer .. .99 00 Isopole 144 2M Antenna,.... ,.35 00 Isopole 220 Antenna....... 35.00 BARKER & WILLIAMSON 370*15 Broad Band Dipole Antenna 3.5-30 MHz, 90 ft., 5 KW PEP. $134 00 370*10 Portable Window Sill Apartment/Mobile Home Whip Antenna covers2,6,10,15,20,40 Meters plus27 MHz........ 39.50 331A Grid Dip Meter Solid State, Range 2 MHz thru 230 MHz, Takes 9V Transistor Battery .....112.00 374 Dummy Load Wattmeter DC to 300 MHz, 1500 Watts input..199,00 375 Coax Switch, 6 Position Rear SO-239.22.50 376 Coax Switch 5 Position Side SO-239.22.50 COLLINS/ROCKWELL 55G-1 VLF Preselector for 51S-1 and KWM-3B0, Limited Supply... . $375.00 312B-5 Station Console/VFO, Limited Supply..... ,550.00 DRAKE TR-7A XCVR $1,439.00 TR-5 XCVR. 695.00 PS-7 P/S25 Amp...... . . . .269,00 PS-75 P/S 15 Am p/25 Amp Surge.... .... ,179.00 RV-75 Synthesized VFO. .269.00 R-7A Receiver 0-30 MHz Digital..... 1.399,00 I COM IC-720A XCVR. .... $1,140.00 1C-730 XCVR. 690.00 10740XCVR. .. .985.00 IC-2AT Hand Held w/TTP 2M.. .235.00 1025A 2M Mobile 2SW.......305.00 IC-45A New Model 440-450 MHz Mobile, 10W, FM...call IC 290H New Model All Mode 2M FM/USB/LSB/CW 25 Watt, Easy-To-Read Green LED Read-Out, Scans.. 489.00 IC-R70 New Model Professional General-Coverage Receiver, Many Beautiful Features. .685 00 MIRAGE B-232M 2/30W Amplifier.. $78.00 B-1082M 10/80W Amplifier/Preamp. 154.00 B-1016 2M 10/160W Ampllller/Preamp.. .239 00 B-3016 2M 30/160W AmpUlier/Preamp. 199,00 D 1010 440 10/100W Amplifier.279.00 RC-1 Remote Control Head, All Models w/18 ft. Cable.24.95 We accept M/C, Visa or Checks. Add shipping FOB Otto, N.C. Save money by ordering today at these Low Discount Prices. Mall or phone Bill Slep 704-524-7519. _ ■ mj SLEP ELECTRONICS COMPANY fgSft I KH1 P.O. BOX 100, HWY. 441, DEPT. 73 Qg gSJ OTTO, NORTH CAROLINA 28763 mm The new Micro-System features a machined 18 parabolic reflector for maximum efficiency, a linear feed-point downconverter with ceramic high perfor¬ mance RF preamplifier transistor, a variable 12 to 18 volt regulated power supply and 50' of 75U coaxial down¬ lead. including a 3' jumper and matching transformer. The Micro-System includes a full 6 month warranty. Micro-System (MS-021) *159’* Micro-System (MS-578) M69* 5 Micro-System (MS-645) *179’* Shipping & Handling USA . . T4 6e AK. HI & PR . l 10 ao Data Samrtcs Campaay 612-636-9469 ✓346 3110 Evelyn Street Roseville, MN • 55113 : _) — HAM HELP 1 am looking for schematics for a SUtroniCS LA 550 bHinear. Arthur Lee Route 1, Box 329 Centreville MD 21617 I need help troubleshooting my Spec* tronics digital readout DD-1C. The display has quit counting, and 1 need a schematic for it. Dr, M, R. Klein WA4GUH 201 East Arbor Ave. PL SL Lucie FL 33452 I am looking for a manual for the Tektronix 524D oscilloscope and a meter movement for a Bird model 43 wattmeter. I will pay any reasonable price and postage Don DeLung WB4LJE 830 Pinecrest Ave. Bedford VA 24523 Can anyone help me eliminate the chirp and drift In my Heath HG-10B vfo? Dave Artman N9CZJ 599 Wheel Estates Greenwood IN 46142 [MULTI-BAND SLIOPERS1 160, 80, and 40 meters Outstanding DX performance of stopers is weti known Now you canon -joy 2 or 3band BIG-SIGNAL reports! Automatic bandswitching * Very low SWR ‘Coax teed * 2kw power * Compact - Ground or tower teed * Hang from any support 25 ft high or higher • Easy to Install • Very low profile - Complete instructions - Immediate shipment-Check ok 3 BAND SLOPER 160, 80. & 4QMeters 60 ft.tong $ 43JS trt ppd 2 BAND SLQPER 80 6 40 Meters 41 It. long $ 3Q.g g_hTppd 3-B A ND NO TRAP DIPOLE. 160, 80.&40M -113lt. long S 66 oo trl.ppd 2-B AND NO TRAP DIPOLE, 80.&40M - 84ft l ong_ $ 49 do trl ppT FOR ADDN L INFO on these and other unique antennas _ send SASE W9INN ANTENNAS BOX 393-S MT PROSPECT IL 60056 | MOBILE POWER \ Mn For Your H.T. \(Uf I-S- y only S21.95ppd S The new MOBILE ENERGIZER will provide [ operating power for your H.T. from any 12 volt source, k and charge it s nicads at the same time! Featuring l a time-proven regulator circuit enclosed in a tough, [ rugged housing that plugs into the cigarette light¬ er jock of your car, it will work with any synthe- 5 sized H.T except Icom, Azden. and Tempo $~15 \ Specify H.T. model when ordering CONTEMPORARY ELECTRONIC PRODUCTS i ___ P.O. BOX 570549 , MIAMI, FL 33157 1B4 L H 1305} 255-7660 ■■■ Introducing the POWER PACKET from VoCom TAn innovative new product that you can combine with your VoCom Power Ampli¬ fier to obtain tne functions of the famous VoCom Power Pocket™ using any hand¬ held radio . AF POWER — 2 to 3 watts of road-noise- overcoming audio to your vehicle speaker or to external Packet Speaker™ (optional). EASY HOOK-UP - Packet Bracket™ at bottom of Power Packet, provides place to clip almost any make or model handheld. Connects to handheld through pin jacks. Hooded light on Power Packet illuminates portable’s front panel. CHARGE POWER — 35 mA charge on re¬ ceive. 400 mA when mic is keyed Unless your handheld draws more than 400 mA, you can talk as long as you wish and the batteries will be at least as charged as when you started. MIC PREAMP — adjustable; tie in your handheld directly without changing its mic input. Also makes Power Packet compati¬ ble with most standard mobile mics. Op¬ tional Packet Mic™ available. Suggested retail $64.95. See your favorite amateur radio dealer: VoCom PRODUCTS CORPORATION 65 E Palatine Rd . Prospect Heights. IL 60070 (312)459-3680 __ Bracket, Packet Mic, Packet Speaker and VoCom are trademarks of VoCom Products Corp 144 73 Magazine • January, 1983 DEALER DIRECTORY Culver City CA Buffalo NY Jun’s Electronics, 3919 Sepulveda Blvd., Culver Citv CA 90230, 390-8003. Trades 463-1886 San Diego. 827-5732 (Reno NV). FontamTCA Complete lines 1COM, DenTron, Ten-Tec, Mirage, Cubic, Lunar, over 4000 electronic prod nets for hobbyist, technician, experimenter. AL«> CB radio, landmobile. Fontana Electronics, 8628 Sierra Ave., Fontana CA 92335, 822-7710, Newcastle DE Factory Authorized Dealer! Yaesu, ICOM, Ten- Tec, KDK, Azden, AEA, Kantronics, Santee. Full Line of Accessories. No Sales Tax in Delaware. One mile off 1-95. Delaware Amateur Supply, 71 Meadow Road, New Castle DE 19720, 328-7728. SanJ^eTJA Bay area's newest Amateur Radio store. New & used Amateur Radio sales & service. We feature Kenwood, ICOM, Azden, Yaesu, Ten-Tec, San¬ tee & many more. Shaver Radio, Inc., 1378 So. Bascom Ave.. San Jose CA 95128, 998-1103. SmyrnaCA For your Kenwood, Yaesu, ICOM, Drake and other amateur needs, come to see us. Britt’s Two- Wav Radio, 2506 N. Atlanta Rd„ Smvrna CA 30080, 432-8006. Preston ID Ross WB7BYZ has the Largest Stock of Amateur Gear in the Inter mountain West and the Best Prices. Call me for all your ham needs. Ross Distributing, 78 So. State, Preston ID 83263, 852-0830. BToornIngton,Tt ROHN TOWERS-Large stock plus alt UNAR- CO ROHN items available for fast drop ship¬ ments. Wholesale prices to all users. Also whole¬ sale distributor for Antenna Specialists, Regency, and Wilson, Hill Radio 2503 G.E. Road Box 1405, Bloomington, IL 61701 663-2141 Terre Haute IN Your ham headquarters located in the heart of the midwest. Hoosier Electronics, Inc,, #8 Meadows Center, P.O. Box 3300, Terre Haute IN 478003, 238-1456. Littleton MA The Reliable Ham Store Serving N.E. Full line of ICOM & Kenwood. Yaesu H*ft, Drake, Daiwa, B&W accessories. Curtis & Trac kevers. Larsen, Hustler, Telex, 1 'Hy-Cain products, Nfirage amps., Astron P.S., Alpha Delta protectors, ARRL & Kantronics instruction aids. Whistler radar detec¬ tors. Full line of coax fittings. TEL-COM Elec¬ tronic Communications 675 Great Rd. (Rt. 119), Littleton MA 01460, 617-486-3400/3040. --ArinAKFMI See us for products like Ten-Tec, R, L. Drake, DenTron and many more. Open Monday through Saturday, 0830 to' 1730. WB8VGR, WB8UXO. WDSOKN and W8RP behind the counter. Pur¬ chase Radio Supply, 327 E. Hoover Ave., Ann Ar¬ bor MI 48104, 668-8696. HudsonTNH New England's Distributor and Authoriz.ed Ser¬ vice Center for all Major Amateur Lines. Tufts Radio Electronics, Inc., 61 Lowell Boad, Hudson NH 03051, 883-5005. Somerset NJ New Jersey's only factory-authorized ICOM and Yaesu distributor. Large inventory' of new and used specials. Most major brands in stock Com¬ plete service and facilities. Radios Unlimited, 1760 Easton Avenue, P.O. Box 347, Somerset NJ 08873, 469-4599. WESTERN NEW YORK Niagara Frontier’s only full stocking Amateur dealer. Also Shortwave, CB, Scanners, Marine. Commercial. Operating display’s featuring Ken¬ wood and others. Towers, Antennas, Sales and Service. DX Communications. 3214 Transit Road, West Seneca NY, 668-8873. Amsterdam NY UPSTATE NEW YORK Kenwood. ICOM, Drake, plus many other lines, Amateur Dealer for over 35 years. Adirondack Ra¬ dio Supply, Inc., 185 West Main Street, Amster¬ dam NY 12010, 842-8350. Syracuse-Rome-Utica NY Featuring: Kenwood, Yaesu, ICOM, Drake, Ten- Tec, Swan. DenTron. Alpha, Robot, MFJ, Tem¬ po, Astron. KLM, Hy-Gain, Mosley. I^irsen, Cusheraft. Hastier, Mini Products. You won’t be disappointed with equipment/service. Radio World, Oneida County Airport-Terminal Build¬ ing, Oriskany NY 13424, 736-0184. Columbus OH The biggest and best Ham Store in the midwest featuring quality Kenwood products with work¬ ing displays. We sell only the best. Authorized Kenwood Service. Universal Amateur Radio Inc., 1280 Aida Dr., Revnoldsburg (Columbus) OH 43068. 866-4267. Bend OR Satellite TV. Known brands. Call today for more information and inquire about our dealer pro gram WESPERCOM, P.O. Box 7226, Bend OR 97708, 389-0996. Philadelphia PA/ Camden NJ Waveguide & Coaxial Microwave Components & Equipment. Laboratory Grade Test Instruments, Power Supplies, Bu\, Sell & Trade all popular makes—HP, GR, FXR, ESI, Sorensen, Singer, etc. Lectronic Research Labs, 1423 Ferry Ave., Camden NJ 08104, 541-4200. Scranton PA ICOM. Bird. Cusheraft, Beckman, Fluke, Lar¬ sen, Hustler, Antenna S|)ecialists, Astron, Avanti, Beklen. W2AU/W2VS, CDE, AEA, Vibroplex, Ham-Key, CES, Amphenol, Sony, Fanon/Couri- er, B&W, Amecxj, Shun:. LaRuc Electronics, 1112 Grandview St., Scranton PA 18509, 343-2124. San Antonio TX Amateur, Commercial 2-way. Selling Antenna Specialists. Avanti. Azden, Bird, Hy-Gain, Stan¬ dard, Vibroplex, Midland, Henry, Cusheraft, Dielectric, Hustler. ICOM, MFJ, Nye, Shun:, Cubic. Tempo, Ten-Tec and others. Appliance & Equipment Co., Inc. 2317 Vance Jackson Road, San Antonio TX 78213. 734-7793. DEALERS Your company name and message can contain up to 25 words for as little as $150 yearly (prepaid), or $15 per month (prepaid quarterly). No men¬ tion of mail-order business or area code permitted. Directory text and payment must reach us 60 days in ad¬ vance of publication. For example , advertising for the March. ’83 issue mmt be in our hands by Jan. 1st. Mail to 73 Magazine , Peterborough NH 03458. ATTN: Nancy Ciampa. DEALER DIRECTORY J. H. Nelson 4 Plymouth Dr. Whiting NJ 08759 EASTERN UNITED STATES TO: GMT: 00 02 04 06 08 to 12 J4 16 18 20 22 ALASKA 14A IBS 7 i m m m m m m m m ARGENTINA 21 14 7B 7B m m ■n pm 03 pm m AUSTRALIA 21 . 14 7B 7B ra IB El Rfl IB ■71 m rh CANAL ZONE 14A m 7 7 m m ■71 EH BH R3 m ra ENGLANO 7 m 7 3A m m ■71 Rfl m ■71 m m HAWAII _21 14 IB 7 m m El 3R 7ft m INDIA 7 7 7B 7B m m ■Q mn Rl EH EH EH JAPAN 21A 7B 7B 7b m m m 13 eh EH El ■71 MEXICO 21 7A y 7 m m m Rl Rl R3 RTI Rfl PHILIPPINES 14A J4B 70 7R El El m 7B EH 7B 7R ■71 PUERTO RICO _n |Jgfr 7 7 m m ■71 ■a Rl RE m ra SOUTH AFRICA _14. m 7 7 El ■71 ri RH Rfl Rl RS U S. S. R. m 7 ._1A E!1 EH ■71 ra ■71 EH _2J El m ■ m ■ EH m IB BB 03 03 CENTRAI . UNITED STATES TC ): ALASKA BBS ■n 7 m El EH EH m m ■71 RH ARGENTINA Rl ■71 ■a El El ■n ■71 m i R1H S3 EH AUSTRALIA R3 ■71 1711 eh El EH EH EH ■71 171 Rl R1H CANAL ZONE _2L 14 7 7 _ i . 7 7 74ft. 21A 21ft 21A ?iaI ENGLANO m m m m EH m ■71 14 El m HAWAII 21A ■71 m m m m m EH 33 S3 R3 INDIA 7B ■71 m EH El EH EH I7R [73 EH El EH JAPAN 30 m m EH m m m EH EH El El MEXICO wn m m m E 7 RH H3 S3 S3 R3 PHILIPPINES m ■Q m EH EH m m m EH EH EH El PUERTO RICO KD m m m m m KD mu EE3 S3 S3 El SOUTH AFRICA d 7 7 m EH EH E9 53 S3 S3 El 173 U.S.S. R. 7 7 7 3A EH EH 7B ,4 BQ SEES EH EH WESTERI' J UNITED STATES TO: ALASKA 2li 14 7 7 3A 3A 7 — 21A m ■71 El eh n m El 14 Rl 33 m 3 AUSTRALIA 303 ei ■Q SEH El m EH EH m in m S3 m m m m m n 171 El 33 33 33 ENGLAND 7B 7 i 3A 3A 3B EH m El 13 S3 7B HAWAII 21A 14A 14 7 7 7 n m E3 33 33 21A m D33 EH 7B EH EH EH EH 1731 Rl S3 S3 3EJ mi EH m m n m m m m 33 MEXICO Rl ei m m m m El m 33 m 33 33 PHILIPPINES 21A 14 14P. 7B 7B 7 7 7 7 7B 7B 33 ra ■n m m ■1 7 m 111 53 33 >1A 33 m m m m m 7B 7B 14 21A 21A 21 m m m m m m 7B JB m im m m 31 m ■71 m _L m El pi m S3 m 33 A - Next higher frequency may also be useful. B - Difficult circuit this period. First letter - night waves. Second = day waves. G-Good, F = Fair, P = Poor. *= Chance of solar flares. #- Chance of aurora. NOTE THAT NIGHT WAVE LETTER NOW COMES FIRST. JANUARY SUN MON TUE WED THU FRI SAT 1 F/G 2 GIG 3 GIG 4 GIG 5 F/G 6 F/F 7 G/G 8 G/G 9 GIG 10 F/F 11 F/F 12 F/G 13 GIG 14 G/G 15 F/G 16 F/F 17 P/F 18 F/F 19 F/G 20 GIG 21 GIG 22 F/G 23 F/F 30 F/G 24 F/G 31 GIG 25 GIG 26 GIG 27 G/G* 28 F/F* 29 P/F 162 73 Magazine • January, 1983 February 1983 $2.49 Vi Issue #269 mJ ■Good bye to [Mobile Noise IPage 88 Untouchable Alarm Page 72 Maximum Repeater Control Page 32 Icom’s Amazing R-70 Page 103 Death to Bugs Page 90 Amateur Radio’s Technical Journal Unleash the TS-900 [\""| A rig like this deserves more room than 2 meters can give Get on HF (including WARC bands) with this transverter W4BF Four-Tone Audio Oscillator: A Potent Troubleshooter Tor anv test ihat requires a tone, this — oscillator does the |ob It can also be computer-controlled W7BBX Superman's Repeater Control System |\“1 This simple system offers tour indepen- 1 dent on/off outputs lust duck into any phone booth to use it K3II Up and Coming: Direct-Broadcast Satellites The only thing not up in the air m this busi¬ ness is the satellites, so this budding technol¬ ogy is not just pie m the sky N8RK Work the Russian Robot Ops The robots aboard Russia s two new satel¬ lites are cantankerous and challenging Here are some tips on how to work them K4TWJ Ham Radio Hits the '82 World's Fair When the gates in Knoxville opened, would WA4KFS be ready' Here's the inside story of the World s Fair station. N4AQI Beef Up Your CB-to-CW Conversion [v 1 A good bto will bring your receiver per- ^^ formance up to par. This one is easy to addon W1BC The Denali Connection Disaster struck these two hams m the back country or Alaska Only a tenuous radio link to civilization could save them Kl 7RD Error Protection for Your Digital Transmissions 11 jj Block coding can make your signal KX)% error-free hoppfully W9JD/2 Drive-Time SWLing a This simple car radio converter will open up a whole new world or driving AC9C Stop That Heist! I'd What would you say about an alarm ^' that's portable, inexpensive, and goes off when a thief iust touches the door¬ knob? We say build it WD5JWY Get the DX Edge! There are ways to stand out in the pileups for Spanish-speaking stations One is to speak their language KB<)SP 10 20 32 38 44 50 56 60 64 70 72 76 A Wayne Green Publication Power-Line Protection: The Weak Link Solid-state equipment may be extremely re¬ liable. but just microseconds of overvoltage can change that N8ADA Higher Voltage, Less Weight , a voltage quadrupler that weighs **— ounces? ^ ou bet - and cheap surplus capacitors make it possible W-CSD Make Room for More Age l\“| Automatic gain control is useful m many applications. With this simple cir¬ cuit, you'll never have to be without it N7APE You Can Troubleshoot Mobile Noise 83 84 86 K5CA tells what to do when a signal is 5-7 and the noise is 5-9 K5CA 88 Electronics vs. Creepy Crawlers f\"l Build this ultrasonic oscillator and drive pests r razv Your pet hamster, loo K7YZZ 90 Slimming and Trimming the R-1000 |\ ] In crowded conditions, the 6 kHz tiller -may not cut the QRM Here's/he way out. 5Z4CL/K5PAW 92 Add a Touch of Class to CB Conversions TyJ Converting a Hy-Gain board to 1u me- L — ter*. I- only halt the story Trv adding a digital readout and scanning capability N2DS 94 Add-on Bto—56 Never Say Die—6 Satellites—96 Social Events—96 Ham Help—96, 107, 108, 124 Circuits—99 New Products—100 Review—102 Fun! —106 Corrections—108 Reader Service—114 RTTY Loop—116 Contests—118 DX —120 Letters —122 Awards—126 Dealer Directory—146 Propagation—146 W2NSD/1 NEVER SAY DIE editorial by Wayne Green SABAH! One of the reasons I got into publishing a ham magazine had to do with a rather serious char¬ acter flaw on my part, one which dictated that whenever I found something really fun to do I was not satisfied until I shared my fun with others. Thus, when I found out what a blast playing with ham RTTY was, I just couldn’t be satisfied until I got others to share my fun and enthusiasm. This got me started publishing a RTTY newsletter and gradually brought me to my present situation with 73 and some other magazines, most* ly for enthusiasts. Well, I'm in a tiny country called Sabah and you really should be here to be sharing my fun with me. The capital city is Kota Kinabalu, which few people have ever heard of. Much to my surprise, I arrived here from Brunei and found a surprisingly large city. The biggest hotel, the Hyatt is 14 floors high; unlike in America, it has a 13th floor. Be¬ ing not far from the equator, it is hot during the middle of the day. That’s a nice time for a nap or to sit around a swimming pool writ¬ ing postcards to those of less ad¬ venturous spirit. Hassan 9M6MA met Sherry and me at the airport and drove us into town to the Hyatt. Later, he picked us up and drove us to his house, which is built on stilts over the water. Hassan expected me to be surprised, but I merely felt at home. When I was a teen¬ ager, my folks had a summer house built on stilts out near Floyd Bennet Airport in Brooklyn. We reached the house by walk¬ ing over about a quarter mile of boardwalk; it was perhaps three feet wide and six feet over the mud flats and a couple of feet above the high tides. Some of the full moon tides would bring water 6 73 Magazine • February, 1963 up to the boardwalk. And I’ll never forget the hurricane of 1938 when the extra high tides and storm washed away most of the boardwalks and some of the houses. We lost a dock and our rowboat, and my family just bare¬ ly made it across the narrow walk as the storm hit. They had to use sticks to keep from being swept off the long walk. I missed out on that drama, being busy at home listening to 20 meters and the un¬ usual propagation which the storm brought. No, Hassan’s house wasn't a bit strange for me. We were joined by Ian 9M6MH. Mohamed 9M6MO, and his broth¬ er Ali, an SWL We had quite an interesting little hamfest. None of them is really a DXer and they would prefer, as would most of the hams in rare spots around the world, to be able to get on the air and talk with people. They want, like every other person to whom English is a second lan¬ guage, to have a chance to im¬ prove their English. They’d like to get to know their fellow hams, yet every time they get on the air they are hounded by hams who ‘need’’ their remote country and have little respect for the inter¬ ests of the DX operator. Many hams get very nasty if deprived of their “right” to a new country. This is the bane of most hams in rare spots and often drives them off the air. As long as we hams continue to support the ARRL Honor Roll, I’m afraid that this is going to be a problem. It isn’t DXCC that’s doing it, just the Honor Roll. Dare we call it a Dis¬ honor Roll and anger the dozens of poor souls who have decided to devote their lives to keeping on top of this blight? What a waste of lives which might otherwise be productive. A year ago, I wrote an editorial QSL OF THE MONTH This month’s winning QSL from Roger Schulte NG6P Is the result ot a family effort. Roger’s XVL, Diane, designed and stitched the original needlepoint for the card. Her work then was reproduced with a clarity that permits you to count the stitches, giving the impres¬ sion of depth to the QSL card. The variety of stitches she used keeps the eye busy, and the border surrounding the design gives the card definition that many other cards lack. To enter 73s QSL of the Month Contest put your QSL card m an envelope with your choice of a book from 73 s Radio Book shop, and send if to 73. Pine Street. Peterborough NH 03458. Attn: QSL ot the Month Entries without an envelope or book choice will not be considered. telling you that I was going to be going to Asia and asking you to come along. Well, you sure goofed this time. You not only missed out on consumer elec¬ tronics shows in Tokyo, Taipei, Seoul, and Hong Kong, but also you missed a great ham conven¬ tion in Bangkok, with about 150 hams coming In from all over the world, plus Interesting visits to weird places such as Sarawak, Brunei, and Sabah. These places are really off the tourist trails, and yet they are each different and fascinating. Sarawak has but one active ham. What a spot for a DXpedition, eh? Well, there was one here recently which knocked off 10,000 contacts and still didn’t cut down the pileups. I think you could DXpedition once a year for a week or so to Sarawak and be kept very busy. One of the main topics of discus¬ sion in Sarawak during my visit was a 25-foot crocodile which has been eating people. They’d flown in a medicine man to try to catch this bugger... somewhere up the Sarawak River. No, I didn’t go for a swim in the river, which went right by our hotel. There not being much of a tourist trade, there are very few stores aimed at tourists. There are hundreds upon hundreds of stores selling things for the local people, plus huge markets, I wandered around one bazaar and saw perhaps fifty stalls sell¬ ing shoes. There were another fif¬ ty selling fruits, an acre or two selling vegetables, and so on. I can’t tell you about all these things; you’re just going to have to break loose and come with me on one of these trips and see everything for yourself. Oh, I’ve been taking slides by the hun¬ dreds, but even that can’t really come close to an actual visit. Kota Kinabalu is so far out in the sticks that neither McDon¬ ald’s nor Kentucky Fried Chicken have found the place! Now, that’s remote! Oh, they do have a McDonald’s-like fast food store which serves hamburgers, fried chicken, sundaes, and even breakfasts. The prices are about the same as in the US. These Asian tours are surpris¬ ingly inexpensive. Commerce Tours has been arranging them for several years and they have them down pat. They take you to the best of hotels. They include most of the breakfasts and a lot of dinners. If you eat only what is provided on the tour, you will put STAFF PUBLiSMEREOrrOH Wayne Green W2NSG>it EXECUTIVE VICE PRESIDENT Sherry Smyths ASSISTANT PUBUSHERfEDlTOR J*«0*TrayW8SSTM MANAGING EDITOR John Burnett ASST MANAGING EDITOR So saw Pntitsric* EDITORIAL ASSISTANTS Nancy Noyd Richard Pheni* Sieve Jewett TECHNICAL EDITOR Avery L Jenkins WB&JtG ASSISTANT TO THE PRESIDENT Matthew Smilh KAttEI ASSOCIATES Robert Baker WB2GFE John Edwards KI2U Bill Gosnay KE7C Sanger Green Chad Harris VP2ML Dr Marc teavey WA3AJR J. H, Netson BtM Pasternak WA6STF Pater Stark K20AW on weight The electronics shows are one of the best opportunities for you to find some little product to import and get your own mail¬ order business going. Or, if you are in the electronics business, this is a way to find an Asian part¬ ner to do some of your manufac¬ turing for you. More and more firms, even smaller ones, have an Asian “plant” which is helping with circuit boards. Just one con¬ nection on a trip like this will pay for the trip several times over. The cost of the tour for the last three years has been around $2,500.. .which includes all air¬ fares, first-class hotels, and a lot of the meals. That's one of the best tour bargains I've seen. After the organized part of the tour, you can add some extra countries on at surprisingly little extra cost. The tour ended with the Hong Kong Electronics LONG-DELAYED ECHOES A former Los Alamos National laboratory scientist has been honored by the Soviet Academy of Sciences for his explanation of long-delayed radio echoes Robert W Freyman received the Commemorative Medal of the Polar Geophysi¬ cal Institute, the first time the institute had honored anyone from outside the So¬ viet Union, according to the Oct 7 tssue of Machine Design Three- to 30-second delayed echoes of radio signals have been observed since 1927. and Freyman conducted a senes of experiments aimed at solving the riddle of these echoes He believes the signals are delayed because they are caught up in ducts of plasma in the solar wind surrounding the Earth The wind blends with the Earth s magnetic field some 45.000 miles above the surface Radio-wave ducts >n the blended plasma often stream toward the sun. Frey- man says, “if radio signals encounter a duct, they are transported into space They bounce back when the duct collapses, thus accounting for the delay *’ The Soviets duplicated and confirmed Freyman s research His work had spe cial significance for the Soviets because they have pursued intensive investiga¬ tions of long-delayed echoes since a 1979 multinational experiment produced the phenomenon over Soviet territory —Thanks to reader Jacques M Percourt F2YS/W2, Millbrook NY. Show, but from there we went on to visit Singapore, Kuching, Bangkok, Bandar Seri Begawan, Kota Kinabalu, and Manila, all for about $500 extra in airfare. There is going to be a big celebration in Brunei in a bit over a year when the country goes independent. The VS5 calls will change to a new prefix Continued on page 108 PRODUCTION MANAGER. PUBLICATIONS ASST PRODUCTION MANAGERS PUBLICATIONS M*efi*e< Murphy ADVERTISING GRAPHICS MANAGERS Scan W. PtteSbncfe panes Sku-c* ttcokn Jan* Pnestcn PROMOTION COORDINATOR Denial Dyer Michael Ford Phil Geraci Dorm# Hartwell K*m Nadeau Dianne K RII son Afme Rocchio Mary Seaver Deborah Stone Theresa Vervilie Jodi Wimberly David Wozmak Karen Wozmak PHOTOGRAPH Y Thomas Vilieneuvc Sandra Dukette Laur*e Jamison Irene Vail Robert M VrReneuve TYPESETTING Sera Bedeo M*rh£ Barker Melody Bedell MsChel* DesSfachevs Jennifer Fay Lynn Names Lmda Locke Nancy WtUwevkHMrmXR DeSKs* Nutting Karen Stewart GENERAL MANAGER CONTROLLER Roger J Murphy ACCOUNTING MANAGER Knud KeMer KV4GGH CIRCULATION MANAGER Patricia Ferrante 603 924-9471 BULK SALES MANAGER Girmie Boudrleau 1|800)-343-0728 ADVERTISING 603-924.7138 Jim Gray WlXU. Mgr Nancy Ciampa, Asst Mgr Ross Kenyon KA1GAV Cornelia Taylor 8 73 Magazine • February, 1983 Fred Studenberg W4BF 1305 E Norfolk Tampa Ft 33604 Unleash the TS-900 A rig like this deserves more room than 2 meters can give. Get on HF (including WARC bands) with this transverter. A fter using my new TS- 900 for a few months, I realized that with the ex¬ ception of its dedicated 2- meter coverage, it had all the features found in the best HF transceivers. It seemed wasteful to keep it caged on 2 meters when all I needed was a transverter for operation on one of the HF bands At about this same time, the three new WARC bands were an¬ nounced and this furthered my desire to put the TS-900 on HF After considerable re¬ search on the subject of synthesizers and conver¬ sion techniques, I managed to design a transverter that is a definite engineering overkill. This box will take any switch-selected 1-MHz band from 0 to 30 MHz and upconvert it for receive to the 144-to-145-MHz range In the transmit mode, the 2-meter transmit signal is translated down to the ex¬ act frequency as on receive. Since I already had a 100- Watt broadband amplifier, I designed the unit for 5 Watts output. This is only 2 S-units below that of the popular 200-Watt PEP input transceivers and is certainly plenty of power for many contacts. If you want more power, I recommend either the 100-Watt-output tran¬ sistor amplifier described in the ARRL Handbook or the unit described in Motorola's Engineering Bulletin EB63 (this is what I used). What Can You Use It For? With this transverter, I can operate anywhere in the HF range, transmit or re¬ ceive, all modes. Unfortu¬ nately, the transmit output drops off below 1 MHz, but I don't need to talk to WCBS anyway. The trans¬ verter works with any multi- mode transceiver in the 10- Watt class and has a built-in attenuator to handle the full transmitter output pow¬ er. There is a bypass relay to permit instantaneous oper¬ ation on either HF or 2 me- vco CiRCUiT SHIELD HF IN /OUT j£ 74 T5 — 76 SUFFER cmcuiT -a © © tOMHi XTAL POWER TRANSFORMER RECTIFIER AND REGULATOR j 2N30S5 (USE HEATSINK) Fig . 7. Suggested layout of the HF transverter for 2-meter multi-modes . 10 73 Magazine • February, 1963 ters without any cable switching This also pro¬ vides an OSCAR mode of operation that automatical¬ ly switches between 2-me¬ ter transmit and 10-meter receive Since my TS-900 has FM capability, I have made ex¬ tensive use of the transvert¬ er on 10-meter FM, The dual-vfo feature makes se¬ lection of any repeater off¬ set possible I have also made many contacts on IO¬ meter AM. Of course, I can operate CW and SSB on any of the 160- through 10-me¬ ter bands and listen to plen¬ ty of activity on commer¬ cial frequencies in between It is also great for MARS and CAP frequencies that are outside the normal overlap coverage of HF transceivers If you are in¬ terested in BCB DX, the 100-Hz readout and super sensitivity are ideal. There is also plenty of interesting VLF activity in the 50-to- 200-kHz region, including the 1750-meter band. Construction The design uses readily- available components. Most are available from 73 advertisers and my old faithful parts store, Radio Shack. The design has been successfully duplicated by 5 other locals and has worked every time. Total cost with new parts should be under $150. I didn't use a PCB layout since 1 was only building one unit, although the lay¬ out could be put on a PCB. If anyone is interested in such a project, l would be happy to give some recom¬ mendations on a layout. My unit was built using the "dead-bug" technique and point-to-point wiring. ICs are mounted upside down on the copper side of a sheet of single-sided PCB, and all interconnections be¬ tween ICs use #30 insulated bus wire. Where possible, components such as disc bypass capacitors are used as tie-points; one lead is soldered directly to the ground plane and the other, free end, supports other common circuit parts. To keep digital noise down, a 1000-pF disc is soldered to the Vcc lead of each 1C. This connection along with direct soldering of the ground lead of each 1C serves to secure the ICs. 1 used a sheet of 8" x 11" PCB that also serves as the top cover for an 8"XII" aluminum chassis. This pro¬ vides excellent shielding and is really not an unat¬ tractive method. Fig. 1 shows a layout of various sections and critical com¬ ponents of the transverter. Fig. 2 provides details on winding the various trans¬ mission line transformers used in the transverter. Theory of Operation Fig. 3 shows the block diagram of the transverter. The key to the versatility of the unit is the synthe¬ sizer. It covers 115 to 144 MHz in 1-MHz steps and drives the bilateral mixer at about + 7 dBm As an ex¬ ample of the conversion scheme, to cover 17 to 18 MHz by tuning from 144 to 145 MHz, the synthesizer outputs a signal at 127 MHz (144 —127 = 17). 1 chose to upconvert in 1-MHz segments and re¬ Transformer Turns Core Material Wire Size T1 T3 T4 T5 T6 17 F-50 F-50 F-50 F-87 F-87 F-125 #28 #28 #28 #26 #26 #24 Transformer Turns Core Material Wire Size T2 4 F-50 #28 Only one winding shown for clarity. Second winding is connected to first as indicated below. Function 1st Winding 2nd Winding Input 1 1 - 20 dB 2 2 Ground 3 4 Output 4 no connection 51Q no connection 3 Fig. 2. Coil-winding specifications. All cores are mix Q1 from Palomar Engineers, Box 455, Escondido CA 92025. All windings are made with two pairs of wire twisted five crests per inch. strict the 2-meter coverage to the 1 44-to-1 45-MHz range for two reasons. It greatly simplifies the syn¬ thesizer design and also eliminates any problems in reading the frequencies on the transceiver dial. You simply ignore the 144 read¬ ing and mentally replace it with the MHz reading on the transverter thumbwheel dials. The other digits are the same. Using the above exam¬ ple, 17.2366 MHz would read 144.2366 on the trans¬ ceiver. A second benefit to tuning the 144-to-145-MHz range is that there are fewer strong repeaters operating there that might feed through the converter. However, this is not a seri¬ ous problem since the de¬ sign has over 80 dB of sup¬ pression of such signals. In the receive mode, in¬ coming signals pass through the transmit relay through a 30-MHz low-pass filter, They are mixed with the signal from the synthe¬ sizer in the balanced mixer. The output of the mixer at 2 meters passes through the T-R relay attenuator circuit and transverter bypass re¬ lay to the 2-meter transceiv¬ er The overall loss through the converter is about 7 dB, so the typical 0.25-^V sen¬ sitivity of a multi-mode will be 0,5 jiV on HF. This makes for a very sensitive HF receiver that can hear anything that the best HF transceiver can hear The scheme used for up- conversion results in an overall receiver that is free from spurious responses without the need for elabo¬ rate multi-pole front-end fil¬ ters. All of the newer-gener- ation commercial and ama¬ teur equipment uses some form of VHF i-f range to eliminate problems with hard-to-suppress mixing products. This design has no spurious responses any¬ where that can't be easily attenuated by the 30-MHz low-pass filter. When the 2-meter trans¬ verter is keyed, the input from its external relay con¬ tacts activates two relays in the transverter The first bilateral MIXER 73 Magazine * February, 1983 11 relay switches the 2-meter input into a 10-Watt load and also allows the mixer to sample a small portion of this signal for mixing with the synthesizer signal. The other relay switches the in¬ put/output of the mixer to the power amplifier chain. The output of the mixer is about -10 dBm PEP. This is amplified to the 5-Watt level by 3 broadband ampli¬ fiers in the power amplifier. Other than the 30-MHz fil¬ ter, no low-pass filters are used for transmit since har¬ monics are at least —30 dBc and I felt that at this power level this was more than enough. OSCAR Mode In this mode, the 2-meter transceiver is automatically bypassed to the 2-meter an¬ tenna whenever the trans¬ ceiver is keyed. The dual- vfo feature of most multi¬ modes makes OSCAR oper¬ ation extremely simple. The only disadvantage is that you cannot monitor your own signals, but I have nev¬ er found this to be a seri¬ ous disadvantage. Options If you don't want or need transmit capability, you can delete the associated relays and power amplifier circuits. The 30-MHz low- pass filter should connect directly from the HF anten¬ na to the mixer. If you de¬ lete the 2-meter transfer re¬ lay and load, make sure you don't ever key the 2-meter transceiver while connect¬ ed, or the mixer will be damaged. With the power amplifier eliminated, you can use a much smaller and cheaper power transformer —see parts list for details. Circuit Operation Fig. 4 shows the schemat¬ ic of the transverter. At first glance, the circuit may look complicated, but it is really quite simple and straight¬ forward. The voltage con- Fig. 4. HF transverter schematic diagram . All resistors 1/4-Watt, 10%, specified in Ohms unless otherwise noted. All capacitors are in pF, disc ceramic50-volt minimum unless noted. Pull-up resistors on BCD inputs are connected to ground or +5 volts, depending on use of positive or negative switch logic. Relay 1 — Radio Shack 275-003; relays 2 and 3-275-214. 12 73 Magazine • February, 1983 iZOVAC ^ IA * l£V Oi>t " «EGUtAT€0 Fig. 5. Regulated + 12-volt supply. Power transformer is Radio Shack 273-1514. Forreceive- only, substitute 273-1515. trolled oscillator (vco) tunes from 114 to 145 MHz with a 1-to-4.8-V-dc control voltage There are two com¬ mon-base isolation ampli¬ fiers—one feeds the vco to the balanced mixer and the other, coupled through a 20-dB coupler, buffers the output to the divider chain Since the desired frequency steps are in 1-MHz incre¬ ments, the 10-MHz crystal- controlled reference is di¬ vided by 10 to produce 1 MHz for one input of the CD4046 frequency/phase detector The other input of the CD4046 comes from the output of the divider chain that produces 1 MHz when the loop is locked The phase detector output is fil¬ tered and frequency-com¬ pensated to deliver a dc control to the vco. As an example of the di¬ vider operation, for a syn¬ thesizer frequency of 115 MHz, which corresponds to a range of 29-30 MHz, the thumbwheels are set to 29. The two MCI 4560 ICs (U1 and U2) are adders that add a constant 66 to the values produced by the thumb¬ wheel input. This sets the first 74LS190 upcounter (U4) to 95. The second 74LS190 (U5) is hard-wired to divide by 8 so the result¬ ing divide ratio is 895 (read left to right). Since this is an upcounter divider, the ac¬ tual divide ratio is 115: (100-89)+ (10- 5) I used up counters instead of downcounters due to the ''backwards" relationship of thumbwheel setting to synthesizer frequency and to simplify design of the adders The 11C90 divider 1C ac¬ tually divides by 11 for a portion of the rf input peri¬ od and by 10 for the remain¬ der. Its operation is con¬ trolled by the 74LS00 and the output of the first 74L190 dividers. The phase detector ac¬ tually operates at 500 kHz, but since both the 1-MHz reference and the variable divider output have identi¬ cal divide-by-2 circuits, the vco is stepped in 1-MHz in¬ crements. I had to operate the CD4046 phase detector at 500 kHz since 1 MHz was too high in frequency for reliable operation with a 5-volt supply. Also notice that the reference frequen¬ cy is divided from a 10-MHz crystal. This was done for stability reasons since any error or drift at 10 MHz is multiplied by a factor of 14. This also gives reduced noise output of the synthe¬ sizer since noise of the ref¬ erence is multiplied by a smaller amount than with a 1-MHz crystal A conven¬ tional regulated + 12-volt supply (Fig. 5) powers the power amplifier and 5-volt regulator for the logic. The circuit is capable of 3 Amps and can be simplified if transmit operation is not needed I would recommend us¬ ing a smaller power trans¬ former, as shown in the parts list, and replacing the 723 regulator and 2N3055 regulator by a simple 3-ter¬ minal + 12-volt regulator. This will be more than ade¬ quate to power the remain¬ ing circuitry. Note that for receive-only operation you don’t really need RLV1, and if you don't mind discon¬ necting cables, you also can eliminate the 2-meter bypass relay, RLV 2, and all associated circuitry The 5-Watt power ampli¬ fier chain is a collection of various circuits that I've used in the past and I don't take any credit for design¬ ing them There is little that can go wrong if normal rf construction practices are followed. Be sure to use short leads on all compo¬ nents, and keep inputs and outputs separated and physically in a straight line Refer to Fig. 2 for details on winding the broadband transformers. Also note that the 2N5590 final transistors will require some form of small heat sink attached to the mounting screw. I used a 3"X 3" square of 060'' aluminum mounted on the underside of the PCB used for the power amplifier chain. Putting It on the Air After all the circuits have been wired and checked out and are working, the best way to tell what kind of a job you did is to put it on the air. The only adjust¬ ment is to adjust the vco coil for about 4.8 V dc when set to (X) MHz (144 MHz actual). If you run into any un- solvable problems, drop me a line with an SASE and I will try to help ■ SATELLITE TELEVISION SYSTEMS WE WILL NOT BE UNDERSOLD!! Complete Systems, Antennas, Receivers, LNA's & Accessories CALL US TODAY! 812 - 238-1456 ' Nation's Largest Total Communications Distributor P.a BOX 3300 • TERRE HAUTE, INDIANA 47803 14 73 Magazine * February, 1983 Four-Tone Audio Oscillator: A Potent Troubleshooter For any test that requires a tone , this oscillator does the job. It can also be computer-controlled. Howard F Baf/e W7BBX 12002 Cheviot Drive Herndon VA 22070 T he versatile four-tone audio sine-wave oscilla¬ tor described here can be used to test originate/an¬ swer modems, to generate RTTY tones, for two-tone testing of SSB transmitters, for aligning tone decoders, for analyzing audio filters and discriminators, and for many other audio appli¬ cations. Its TTL-compatible controls even allow it to operate under software control by virtually any Fig. 1. Oscillator PC board schematic. (©1981, HFB Enterprises] 20 73 Magazine • February, 1983 Fig. 2. Frequency counter PC board schematic . (©1981, HFB Enterprises) computer Also featured is 1 volt rms to a 50-0hm re- an integral, direct-reading, sistive load 4-digit frequency counter with on-board regulated Low-power CMOS digital supply and an on-board au- integrated circuits and dio amplifier. Individual operational amplifiers are signal-output level and au- used to keep current con- dio-volume controls are sumption to a minimum, provided, and the output The four-tone oscillator and signal can supply more than frequency counter each are Fig. 3. Front-panel layout assembled on a 3" X 4" when the frequency count- printed circuit board, er display is on; provisions About 300 mA is required also are included to blank from a 9-15-volt-dc supply the display to reduce cur- Fig. 4. Chassis layout. 73 Magazine • February, 1963 21 tig. 6. Oscillator hoard component layout . rent requirements to about 40 mA when operating from a battery Sine-Wave Oscillators Four continuously-run¬ ning twin-tee oscillators (Q1-Q4) generate the sine- wave audio signals, The fre¬ quency of oscillation of Q1 is determined by C1-C3 and R1-R7; by comparing these values with the Q2-Q4 oscil- 22 73 Magazine • February, 1963 Fig. 5. Oscillator PC board. lators, you can see how changing only resistors R4-R7 alters the center fre¬ quency of oscillation The value of R3 will determine the amount of variation around the center frequen¬ cy permitted by the coarse- and fine-frequency vernier controls, R1 and R2. The output of the twin- tee oscillator is taken from the top of C3 and capaci¬ tively coupled by C4 to buff¬ er/amplifier U2b. Gain of this amplifier is determined by the ratio of RIO divided by R8 The gain of each of the four buffer/amplifiers is slightly different to accom modate the amplitude drop of the twin-tee oscillators as frequency decreases Therefore, with the compo¬ nent values shown, pins 1 and 7 of both U1 and U2 will furnish approximately the same output amplitude The outputs of the four buff¬ er/amplifiers are ted to in¬ dividual CMOS analog switches fU3), When the control pin 5 of U3b is high (logic 1), pins 3 and 4 are et- fectively tied together; however, when pin 5 is taken low (logic 0), pins 3 and 4 are effectively open The resistance between pins 3 and 4 is about 300 Ohms when pin 5 is high, and several hundred megohms when pin 5 is grounded With a logic 1 signal on the control pm, either ana¬ log or digital signals may be passed through the gate; furthermore, because the gate is bidirectional (effec¬ tively only a resistance), either pin 3 or 4 may be used as the input and the other as the output Each of the four sections of U3 is in¬ dividually controlled by S1-S4 If desired, S1-S4 may be replaced with a quad latch which can be driven from a computer parallel output port The four outputs from the solid-state switch, U3, are then resistively mixed by R12, R24, R36, and R48 and capacitively coupled by Cl7 to an audio mixer, U2c. The amplitude of each of the four signal lines is equalized by placing an ap¬ propriate value resistor (R96-R99) in parallel with R1 2, R24, R36, or R48 The gain of mixer U2c is set by the ratio of R50 divided by R49. With the compo¬ nents shown, pin 8 of U2c provides 1.08 volts rms to Uld, an isolation buffer with unity gain Uld drives two output circuits, the au¬ dio amplifier, U4, and the output signal buffer, Ulc. The input to the audio amplifier is fed from a re¬ sistive voltage dixider R36-R57. Neither value is critical; R56 could be re¬ placed by a jumper wire or a lOOk-Ohm resistor, and R57 can be any audio taper Fig. 7(a). Frequency counter PC hoard (top). pot with a value of from 10k Frequency Counter play. Grounding point F will to 100k Ohms R56 is in- jhe audio signal from blank the display to con¬ cluded here only to limit point ) on the oscillator serve power Point G of the the input level to U4 so that board is fed to point D on frequency counter board is it is not accidentally over- the frequency counter connected to the lower driven The output of U4 is board (see Fig. 2). U5c and right-hand decimal point of coupled through C21 di- (J5d form a Schmitt trigger ^be least significant LED rectly to an external whose output is further display to serve as a power- speaker with an impedance conditioned by the CMOS on P ,lot Ij 8 ht of 8 Ohms or greater For transition characteristics of Power for the entire unit convenience, you may U5e and U5b. The output of can be supplied either from want to mount the speaker y 5 b j$ a digital stream of the ac line or an external inside the test-oscillator TTL/CMOS-compatible battery. Polarity protection cabinet pulses with approximately diode DI is included to pre- The output test signal a 50% duty cycle; the pulse vent accidental damage buffer, Ulc, provides final repetition rate (digital "fre- caused by incorrectly con- isolation and can, with the quency") of the stream is necting the battery. The components shown, pro- the same as the analog fre- 4- 5-volt regulator, U16, vide a maximum output of quency of the input to U5c. provides power for both the 0.5 volts rms (no load), 0.43 frequency counter and, volts rms to a 600-Ohm A 1-MHz oscillator is through point E of Fig, 2 to load, or 0 32 volts rms to a formed by U5a and U5f. point X of Fig 1 the oscilla- 50-0hm resistive load If re- This signal is divided by 100 tor board, quired, additional output in each of U6, U7, and U8 to can be gained by reducing yield a 1-Hz gating signal Construction the value of R54 for the frequency counter. The four-tone oscillator In addition to driving The number of pulses in of Fig. 1 is constructed on a Uld, the U2c audio is ca- one second from U5b pin 4 3" X 4" single-sided PC pacitively coupled through is counted by U10 and U11, board, and the frequency Cl 8 to a separate buffer/ decoded by U12-U15, and counter of Fig 2 is on a 3" amplifier, U2d The gam of displayed by LED1 through x 4" double-sided board A this section is purposely LFD4 At the end of the Ten-Tec MW-8 cabinet high both to ensure CMOS 1-second counting interval, (8"W X 4% 'H x 6 D) was transition in the following U9 resets the U10/U11 selected to allow enough stage and to clip the audio counters to zero while re- panel room for the fre- signal peaks to provide taining the previous quency verniers, control some preconditioning prior 1-second interval's count in switches, and frequency to being fed to the frequen- the U12-U15 latches for a counter display bezel The cy counter input continuous, flicker-free dis- front panel is shown in Fig. 24 73 Magazine • February, 1983 3. The frequency counter PC board is mounted above the oscillator PC board on 2" bolts up through the chassis floor The oscillator PC board is installed first and wired to the panel controls. Don’t make the hookup leads so short that you can't lift it off the bolts if required. At this point, you'll have two wires from the oscillator boa rd unconnected, t h e T 5-volt lead (X) and the audio input to the frequen¬ cy counter (f). With a speaker connected to the rear jack, connect the wire from Point X to a 5-volt power supply and check the operation of each audio channel individually and for mixing of two or more channels With an ac volt¬ meter connected to the front-panel terminal posts, check the output level at the center frequency of each of the four audio channels If the mid range voltage differs significant¬ ly, the channels with lower voltage can be raised to that of the highest-voltage channel by installing an ap¬ propriate value resistor at R96-R99. Disconnect; the power supply. Now wire the LED display for the frequency counter; I used a perfboard with 90°-angle 1C sockets and color-coded wires sol¬ dered to the appropriate LED pins. The same color- code wire should be sol¬ dered to the same- numbered pin on each 1C socket Mount the LED display pert board on 3" bolts so that the LED dis¬ play is positioned in the center behind the bezel. Lastly, mount the frequen¬ cy counter PC board on top of the oscillator board and connect to the LED display pert board, transformer, and oscillator board Applications Th e Radio Amateur s Handbook contains an ex¬ cellent section on the test- mini. mini, niiiii. 1111111. Fig. 7(b). f requency counter PC board (bottom). 0 o 01 1N4001 —w— 8 O <3 3 *. C 3 C 3 C 3 X c U5 3 ° 0 a U6 3 C u r U8 3 0 € d -Jr, a 3 C 3 C 3 c CD 3 < q 3 C CD 3 C CD 3 l 1 > q CTt 3 mpr CD 0 a CO p q CD 3 s 1 d O 3 oc'oci 1 cj « 0 a to p a «n 3 Id 9 3 q 3 q b a T 3 Q 3 C _/v_. 0 q P o 0 j 0000000 q U»0 J c 33 im < l U9 45I0B *T 01 45188 [ 45288 b 0 0 0 0 0 0 0 Tjrorrrano 0 013 0 0 0 060 0 0 Jp- 4 C30 Q Q Q 0 Q Q Q 0 qqqqqqqq 00000000 ft ft A ft 001 [ mz l UI3 l Uf4 1 C U*5 1 _L { 45H8 f 4 31 IB f 45118 f 45118 T 2 worms 0000 00000000 0 O"0 0 0 0 0 0 00000000 1 < o 00000000 "fgabcde LSD 00000000 “fgobcde 0.0,0,o o op 60 100135! CD I CO I CD] 00 a:|o:|(r|o:|a:jcc|o: o 000000 o - t g 0 b c 4 e 000000 ’ i 9 0 b c d MSO OE O fig, 8. Frequency counter board component layout ing of SSB transmitters us¬ ing a two-tone test signal to approximate a speech sig¬ nal If you have an oscil¬ loscope or modulation dis¬ play/monitor, the transmit¬ ter-modulation waveform can easily be monitored and the modulation level set to get the maximum PEP (peak envelope power) without distortion or "flat¬ topping" of the audio sig- 26 73 Magazine • February, 1983 nal. The four-tone audio os¬ cillator described here is an excellent piece of gear to use for these tests since from two to four indepen¬ dent sine waves can be mixed to form a composite audio test signal. The four- tone oscillator output may be connected directly to the transmitter microphone input since it has a capaci¬ tive Iy-coupled output. Another excellent appli¬ cation is the testing of acoustically-coupled tele¬ phone modems for use with computers. The four audio channels can be set individ¬ ually to the frequencies of the desired mark-space tone pairs for both the origi¬ nate and answer modes. When connected to the modem inputs, each tone can be enabled separately to fully test the modem without having to reset the oscillator frequencies be¬ tween mark and space. Sim¬ ply set each audio-channel frequency vernier to the de¬ sired frequency and switch back and forth using S1-S4 The same procedure can easily be used to test RTTY demodulators. In this case, only two audio channels would normally be required because of the simplex na¬ ture of RTTY; the same audio-tone pairs are used in both the transmit and re¬ ceive directions. In both the computer modem and RTTY cases, you may want to replace SI and S2 with a single-pole double-throw switch with the center grounded, one side of the SPOT switch going to point E on the oscillator PC board, and the other side of the switch going to point F With this arrangement, tog¬ gling the single switch would then alternate be¬ tween the preset mark and space tones. If you're going to use the four-tone oscillator for aligning audio filters or an¬ alyzing their audio pass- bands, you'll appreciate the relatively constant output amplitude across the verni¬ er range of the oscillator Although there may be some slight variation in am¬ plitude, it can easily be cor¬ rected by R55 if a high- impedance (10k Ohms-per- volt or greater) ac VOM or VTVM is used at the audio- oscillator output terminals between point P and ground on the oscillator PC board. With a separate ac VOM or VTVM, you can monitor the audio-filter output voltage easily as a function of the constant- voltage input as the oscil¬ lator is swept through the audio range You may also want to alter the frequency-deter¬ mining components of one or more of the twin-tee os¬ cillators for your own par¬ ticular application Tone Resistors (Vi W) 28—470 Ohm 1— 820 Ohm 1 —Ik 3— 1.5k 1 —1.8k 1 —2.2k 4— 3.9k 2— 5.6k 1— 6.2k 14—10k 3— 15k 10—22k 2— 39k 3— 56k 9—100k 1 —160k 1 — 10 megohm Pots 4— 500 Ohm iin 4—2.5k iin 1 —25k aud w/Sw Parts List 1— 25k Iin Capacitors 2— 18 pF mica 2—.001 disc 8—.0056 mylar™ 7—.01 disc 4—.022 mylar 6—0.1 disc 1— 4.7 uF ’lytic 1 —10 uF ’lytic 2— 100 uF lytic 1—1000 uF lytic ICs 1 —LM324 1—LM340T5 1 —LM386 1—4049B CMOS 1—4066B CMOS 4— 451 IB CMOS 5— 4518B CMOS 1—4528B CMOS Solid State 1 —1N4001 4—2N2222A 1 — i a TO-5 FWB 4- 7-Seg. LED Miscellaneous 1—Ten-Tec MW-8 cabinet 1 — 1 MHz crystal 1—2Vi” bezel 1—4” 8-Ohm speaker 5— SPST toggle switches 3—RCA phono jacks 1—6.3-V ac, 1-A transformer 1—Ac cord 1 -8-pin 1C socket 3— 14-pin 1C sockets 11 —16-pin 1C sockets 4— 14-pin 90° 1C sockets 10—Knobs Misc. mounting hardware decoders in the subaudible range and a significantly in¬ creased maximum frequen¬ cy for audio-amplifier test¬ ing are only two that come to mind The twin-tee oscil¬ lator design is very versatile in its range as long as both sides of the capacitance and resistance arms remain equal (Cl = C2 and R4 + R5 = R6 + R7). This also ensures minimum distor¬ tion of the sine wave The resistance and capacitance to ground (R1 + R2 + R3 and C3) also will play a part in determining both the center frequency of the os¬ cillator and the range over which it can be tuned. An oscilloscope connected to the oscillator output will be a big help in selecting the right components for mini¬ mum distortion Conclusion This handy piece of equipment is in near-con¬ stant use to test and align other on-going projects. Since the frequency count¬ er reading will be accurate when only one tone is pres¬ ent; tones may be set indi¬ vidually to within 1 Hertz and then mixed to form a composite test signal. One easy-to-include option for additional flexibility is the insertion of an SPDT switch between the oscillator board point J and frequen¬ cy counter board point D. This allows counting the frequency of an external signal and direct display of its last four digits. ■ We accept VISA. MC. COD. CHECK Of M.O FIRST QUALITY COMPONENTS - NOT MAIL ORDER "SECONDS" Min. order S10 OO - add 5% Sh dq and $ 1 00 Ins ARIES ZERO INSERTION “ FORCE SOCKETS- ca m act ua l ed. t rue i ero ■ n serf ion tin plated solder tail pins - capable ot being plugged into dip sachets including wire wrap Stoc* Mo Mo U4 25 50 11055 24 S4 35S390 S340 11Q5* 3# 4 50 4 OS XT5 ftos t 40 5 95 5 35 4 .95 MOSS i4 10.50 *45 8 70 $ 22. 50 S3 95 RESISTOR ASSORTMENT 82506 700 ftt* . 1 *MT, tWW* *550 Stock No 62501 10 ea ot 1CM2 <5 18 22 27 33 394? 55 D«M Stock No 83502 10*4 Ot 58-62 1 OO l 20150-190220270-33<>390 OHM Stock No 82503 to** o« 470560680-820 IK t 2K 1 5K 1 S* 2 2K 2 7 Ohm **«*<■***« Stock No 82504 10** of 3.3K-3.9K 4 7K5 6K-6 8K 8 2K 10K 1 2K 15K t8k OHM Stock No 82505 10** of 22K-27K 33K 39K-47K-56K 68K 82K100K120K OHM Stock No 82506 10 «a ot 1 50K 180K 220K 270K-330K 390K 4 70K 560K 680K 02OK-OHM Stock No 82507 10«* oMM 1 2M 1 5M 1 8M 2 2M-2 7M 3 3M 3 9M-4 7M-5 6M OMM WILD ROVER . 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One side is for 300 centers, Flip fool over for devices on 600 centers Put device in tool find squeeze ONE TOOL DOES 8 Thru 40 PlNS» Stock No 11059 $12. 95 IC EXTRACTOR One-piece, spring sleet con¬ struction. Will extract at) LSI, MSI and SSL devices with 8 to 24 P " m ?£, k 3 N °' $2.1° MODUTEC Mmictamp AC Volt-Ammeter allows singling one conductor out of many without disarrangement ' ..| ^***~*~ r Slock NO AC *«WI»» Pr«r* °° 13730 0-25* *39 50 ACCESSORY LINE SPUTTER allows fast readings Of AC power con¬ sumption of plug in equipment with¬ out separation of leads. _ Stock No 13727 $9. 95 POCKET SIZED BATTERY TESTER , for types of small batteries from W 1 35v to 4,5v djl Q 95 Stock No 13733 * O. IE VOLTI-CATOR automotive diagnostic meter plugs into lighter socket and indicates bat¬ tery condition and charging rates. Stock No. 13736 5.®® AC VOLTAGE TESTER plugs mto any 1 tOv service recept- abfe to check time voltage over 50- 150 VAC A M Stock No 13735 $ | 4. 95 VOM-MULTtTESTER versatile Vait-Ohm-Milliammeter m small package , J-J 3 95 Stock No. 13729 , TOLL 800-526-5960 FREE in NJ (201) 996-4093 See List ot Advertisers on page 114 73 Magazine • February, 1963 27 ★ Technical Forums ★ ARRL and FCC Forums ★ GIANT 2-day Flea Market Saturday and Sunday ★ New Products and Exhibits ★ Grand Banquet ★ Women’s Activities ★ Home-Brew Equipment Forum ★ Special Group Meetings ★ YL Forum ★ Personal Computers Forum ★ CW Proficiency Awards ★ Amateur of Year Award ★ Special Achievement Awards Hara Arena and Exhibition Center — Dayton, Ohio Meet your amateur radio friends from all over the world at the internationally famous Dayton HAMVENTION. Seating will be limited for Grand Banquet and Entertainment on Saturday evening so please make reservations early Banquet speaker is Bill Leonard, W2SKE. former president of CBS News, If you have registered within the last 3 years you will receive a brochure in late February. If not write Box 44, Dayton, OH 45401. Nominations are requested for Radio Amateur of the Year and Special Achievement Awards. Nomination forms are available from Awards Chairman, Box 44, Dayton, OH 45401. For special motel rates and reservations write to Hamvention Housing, 1406 Third National Bldg.. Davton, OH 45402. NO RESERVATIONS WILL BE ACCEPTED BY TELEPHONE. All other inquiries write Box 44, Dayton, OH 45401 or phone (513) 849*1720. Admission: $7 00 in advance, $9.00 at door. (Vhlid for all 3 days) Banquet: $14 in advance. $16 at door. Flea Market Space: $15 in advance. (Valid for both days) Make checks payable to Dayton HAMVENTION, Box 2205, Dayton, OH 45401. Bring your family and enjoy a great weekend in Dayton. Sponsored by the Dayton Amateur Radio Association, Inc, NEW ELECTRONIC KITS RTTY SPEED CONVERTER BAUDOT/ASCH CONVERTER MICRO MSCD RTTY CONVERTER CCRMEJTTS BAUDOT TO ASCII /OR RECEIVE . ASCII TO BAUDOT FOR TRANSMIT INS FEATURES SCLCAL . BUFFERING AND I NTCRFACS . FOR 110 BAUD PTR PCB KIT 21-tBt* *8*.*5 FEATURES CM BOARD TEN MINUTE TIMER BUM TTL. PLUS/M INU3 12 INTERFACE AND UP TO 31 DOTS, DASHES OR SPACES PCS KIT NO 23-172! 4-1/1X4 *24.43 ONE AMR POWER SUPPLY KITS BE LOB 3 KITE 22 EDGE CON I I i' 2X4 TU/LOQP SUPPLY PCS 11-1111 IS? II * ft - 12V * YJ PCS 23 2 I 23 33 3 *8 LOOP SUPPLY PCS 23. 202# *33. »» BELOV 2 K1TB NOT ABOVE FORMAT tft - 12V 8 »•# 2-1/2 X S FOR PLL TU 12 PIN EOCSE CONN.PC8 21-1714 323.45 I OR -5 TO 24V ! SPECIFY POLARITY AND VOLTAGE] PCS 211- 0312 2X8 3/8 *14.43 RTTY DEMODULATORS CM 4# ACTIVE OR OPTIONAL TCRPOIO FILTER, AUTOSTART, ANT! SPACE . SI MOLE SHIFT ; LP> DATED ST 4 ON ONE BOARD | . Tu design • irx active AFSK GENERATOR FOR RTTY ROCK SOLID CRYSTAL CONTROLLED AFSK GENERATOR , VIRTUALLY DRIFT FREE . TVO POPULAR SIZES - SPECIFY B I 2E . PCS KIT NO 23 1 71 7 2 I / 2XS $24 43 PCS KIT NO 21 1710 41/2X4 331.43 NTERFACE KIT TO RS 2 32 2CSTR LOOP TO TT L QUALITY LOW PRICED COMPONENTS A Breakthrough for Amateur and Commercial Repeater Users. DIVERSITY RECEPTION—the ability to add a second receiver to your repeater system—can now be a reality for even the small user. The Pegasus VS-2 will allow your repeater to “listen" to two receivers simultaneously and to noiselessly switch between receivers as often as necessary to adjust for fading and nulls. This is particularly useful for repeaters that wish to provide coverage for hand held users or where receiver desense is a problem. You supply the second receiver & RF link and the VS-2 does the rest. Complete instructions and diagrams included with the VS-2. S 17Q°° ■ Postpaid Pegasus Electronics, Inc 88 New Dorp Plaza Suite 106 HHH Staten Island. NY 10306 (212)667-9137 Affiiated with Comsec Corp 28 73 Magazine • February, 1983 Thomas P Krohn K3tj 55 8 Forest Hill Drive Hazleton PA 1 8201 Superman's Repeater Control System This simple system offers four independent on/off outputs, just duck into any phone booth to use it. I n order to comply with FCC regulations, all re¬ peaters must have incorpo¬ rated within them a means of control If the machine is located in the control oper¬ ator's shack, the control system can be as simple as the switch on the repeater itself. However, the repeat¬ er is usually remotely located well away from the operator's reach, so other means of control must be contrived. Many types of control systems are in use today, from some as simple as a wire pair to exotic UHF links with tones used as the command medium. The dis¬ advantage of this system is, of course, cost A control receiver and antenna is needed at the site and every control operator must have a control transmitter which usually isn't as portable as the HT on your belt However, let's brighten I m m Fig. 1. Wireless-wire remote control system block diagram . 32 73 Magazine • February, 19B3 up the picture a bit. There is a way using resources at hand. The Bell System and friends have provided us with a remarkable commu¬ nications system which is available to anyone (for a nominal fee) almost any¬ where. There have been many control systems developed using the telephone, and here is one that's inexpen¬ sive, easy to build with readily-available parts, and has some very interesting features. For example, this system needs no direct con¬ nection to the phone line, has four independent on/off controlled outputs, uses TTL devices needing only a + 5-volt supply, and con¬ trol can be accomplished from any phone, anywhere, at no cost to the user. Now you must admit, this is pret¬ ty neat. Fig. 1 shows how we go about it Theory of Operation In operation, the circuit monitors the phone line, waiting for an incoming ring. When received, the ring is sensed by inductive coupling to the telephone's internal transformer The ring-detector circuit con¬ verts the rings into a series of logic pulses, one for each ring. These pulses are then counted and stored by a 7490 decade counter The output from the counter is decoded twice, first by a seven-segment decoder which drives a front-panel readout indicating the status of the counter, and again by a BCD-to-decimal decoder which provides an output on an individual line with each successive pulse. Another job for the ring detector is to reset a timer circuit with each ring. This timer (a good ol # 555) will fire every six seconds, pro¬ vided it does not receive a reset pulse from the ring de¬ tector. This prevents the timer from firing during a series of incoming rings. The output lines from the decimal decoder are invert¬ ed and connected to one in¬ put of individual NAND gates. The remaining gate inputs are paralleled and re¬ ceive an inverted positive pulse from the timer. Now we can see that as rings are received, one of the eight used outputs from the 7442, U8, when inverted, will put a high level on its particular output gate. It will remain there until an¬ other ring pulse is received, advancing the counter. Or, if the ring stops, the timer is allowed to time out and upon firing, an output will be generated from one of the output gates which will either set or reset the partic¬ ular output latch. The latch outputs are iso¬ lated from the board out¬ puts by NAND gates con¬ nected as inverters. This prevents any noise picked up by the output wiring from getting back into the latches to cause headaches. Circuit Description Perhaps the most inter¬ esting circuit in the system is the ring detector. It is Numbor of rings 2 3 4 5 6 7 8 9 Commend Function 1 on Function 1 off Function 2 on Function 2 off Function 3 on Function 3 off Function 4 on Function 4 off Table 1 . Operating code . unique because it needs no direct connection to the phone company wiring. The whole show starts with a simple tape-recorder pickup coil available at Radio Shack for a few dol¬ lars It comes with cord, plug, and a handy suction cup for sticking it to the telephone. The coil is connected to the board where it feeds a 741 op amp, U1, wired in a differential configuration (see Fig, 2). This mode re¬ duces the effect of stray rf or noise pickup to a mini¬ mum. The output of the op amp feeds Q1, a PNP tran¬ sistor that converts the out¬ put voltage to a level handy to drive the 7413 Schmitt trigger, U2. R1 and Cl serve as a low-pass filter to smooth out the 20-Hz ring voltage, providing U2 with a slowly dropping voltage during the duration of the ring. Diodes D1 through D3 are 1N914 or equivalent. The Schmitt trigger acts as a NAND gate and pro¬ vides hysteresis of the input signal. Its output is a clean TTL level of either a high ( + 5 volts) during a ring or a low (0 volts) between rings. This point is monitored by LED 5, located on the card front, to visually indicate the incoming rings. A push¬ button test switch, SI, also is mounted on the card and is connected to one of U2's inputs to simulate incoming rings for local control and test purposes The positive pulse from U2 is coupled to the base of Q2 through lim¬ iting resistor R2. The inCOm- ^S v ing ring turns on Q2, effec¬ tively shorting out timing capacitor C2 and resetting the timer. The same pulse from U2 is inverted by U3A and steps the counter, U4. The counter's output, a BCD total of rings received since the last timer firing, is decoded simultaneously by U5 and U8. U5, a seven-seg¬ ment decoder, and its dis¬ play, U6, are not actually Photo A. Top view of board. needed for operation of the board and are there for creature convenience only. It's important to see the status of the counter when testing, and the seven-seg¬ ment LED will indicate when the timer executes the command by displaying the return to zero. U8, on the other hand, is essential to the operation of the system for it converts the counter output to a low level on one of its output lines. In operation, decimal outputs 0 and 1 are not used, leaving lines 2 through 9 to do the work Now that we've covered the ring detector, timer, and decoders, let's take a look at the schematic, Fig. 2, and follow a command through the steering gates and out¬ put latch. Fig . 3. Parts placement. Let's assume the phone starts ringing. The first ring resets the timer and ad¬ vances the counter to BCD 1. U5 and U6 decode and display the 1 count on the LED. The second ring enters and also resets the timer and advances the counter to BCD 2. At this time, the caller hangs up the phone, the ringing stops, and the timer, which is not being reset by the incoming rings, fires after about 6 seconds. Its output, inverted by U3B, puts a positive pulse on one input of each steering gate. Remember, now, that there are two rings racked up in the counter so the LED dis¬ plays 2 and only the deci¬ mal 2 lead (pin 3) from U8 is low. This signal is inverted and applied to U11A, pin 5. The level here is high and sets the gate up to pass the command pulse from the timer. When the timer fires, the high-going pulse is ap¬ plied to the other input of U11 A, pin 4. During the dur¬ ation of the timer pulse, both inputs are high, so the output on pin 6 goes low, setting the RS-configured sections of U11C and D. When set, pin 8 of U11 goes high turning on LED 1, a front-panel indicator of latch 1 status. The comple¬ mentary output from the latch, pin 11, is inverted by U15 and provides an iso¬ lated logic-high output at edge-connector channel 1 output which can be used to activate whatever func¬ tion 1 interface you choose. If the phone is allowed to ring 3 times, decimal 3 out¬ put of U8 (pin 4), after inver¬ sion, will activate gate U11 B. U11 B's output is con¬ nected to the reset side of the function 1 latch thereby turning off function 1 when the timer fires. Note that the timer pulse from U3B continues through U3C and D and is used to reset the counter back to zero. The double in¬ version is necessary to de- 34 73 Magazine • February, 1983 •i2v Fig. 4. Relay-control inter¬ face circuit lay the reset pulse to the counter to ensure that the command is executed before the count is cam celed. Operation of the three additional function latches is identical except for the amount of rings necessary to select the particular command lines. Table 1 shows the operating code. Construction My board was wire- wrapped on a standard 4 1 /?"X6" glass board with edge connector attached. I used a board manufactured by Douglas Electronics, 718 Marina Blvd , San Leandro CA 94577. Made of excel¬ lent quality material, in¬ cluding gold-plated edge connections, it has room for 2016-pin DIPs and a conve¬ nient power bus arrange¬ ment so no Vcc line runs will be over an inch. Desig¬ nated type 11 -DE-6, it's a bit expensive at SI 6.00, but you get what you pay for. Parts placement is not critical. My layout is shown in Fig. 3. As with all TTL projects, be sure to scatter a few 01-fiF disc caps around the power bus to soak up the spikes. Interfacing The TTL levels can be used directly from the con¬ Photo 0. Bottom view of board. troller if your operating system is TTL-compatible. If not, some type of inter¬ face will be required. I use a simple relay con¬ trol circuit. Fig. 4. The re¬ lays and accompanying driver transistors are locat¬ ed on another card placed alongside of the controller in the card cage Some types of miniature reed re¬ lays can be driven directly by TTL levels, and if youTe really a purist and desire to switch the repeater primary power, a solid-state relay driven directly by TTL can be used. Phone Requirements It's obvious that this type of system has some draw¬ backs. It cannot differenti¬ ate between control- operator calls and wrong numbers. We've had no problems in the time this system has been in use, but there are a few things to keep in mind when ordering your phone. Get an unlisted number for obvious reasons and ask for a new number, one that has never been issued. Imagine the frustra¬ tion possible if you get a re¬ issue of a number used by recently defunct “Pietro's Pizza Palace." It's also good practice not to use the same phone line for auto¬ patch and control because the control operator who tries to dump a nuisance patch will get greeted by a frustrating busy signal. Wrap-Up Although the inductive ring detector is new, this system has been in use for about five years with excel¬ lent results. Previously, we used a direct connection to the phone line which also worked well. However, we worried what Ma Bell would say if she knew. When powering the con¬ troller, use a well-regulated supply good for about an Amp to be safe. Another good idea is to float the in¬ put to the regulator on a battery, as momentary power interruptions quickly upset the output latches Hookup and Adjustment Pot R1 must be set to put the input to the Schmitt trigger just above the trig¬ ger level, about 1.5 volts measured at pin 1 of U2. Action of the ring detector can be adjusted by bringing the pickup close to the body of a transformer-type soldering gun while trigger¬ ing it. You may be surprised at how far the pickup can be from the gun and still get reliable action Attach the pickup to the phone case using the suction cup. Exact location can be determined by moving it around the phone while it is ringing and watching the "incoming ring" LED. What to control is left up to your imagination. Some of the control functions we use are: function 1 — repeat¬ er on-off; function 2—auto¬ patch on-off; function 3 — brag-tape disable; and func¬ tion 4 —squelch adjust. So get your wire-wrapper out and get going. When you're done, you will have a versatile and reliable ad¬ dition to your system. Thanks go out to Jim W3BBS for his encourage¬ ment and Joe N3JD for the photography. ■ 73 Magazine • February, 1963 36 Timothy Daniel N8RK 7 Peabody Drive Oxford OH 45056 Up and Coming: Direct-Broadcast Satellites The only thing not up in the air in this business is the satellites , so this budding technology is not just pie in the sky. A sk three? different peo¬ ple about direct-broad¬ cast satellites (DBS) and you are likely to get three dif¬ ferent answers First, there are the entrepreneurs. To them, DBS is the golden op¬ portunity of the 80s, a chance to make big bucks Next, there are the local broadcasters and cable TV operators. They consider television direct from the satellite to be a threat, es¬ pecially since the spacecast- ers will have limited local re¬ sponsibility Finally, there are the engineers The slide- rule and soldering-iron set consider direct broadcast¬ ing to a be a noble challenge requiring powerful transmit¬ ters and low-cost yet sensi¬ tive receivers What does DBS mean to you? That depends But don't go on to the next arti¬ cle in hopes that DBS will go away Why not find out a bit more as 73 enters its second year of satellite TV coverage? Before going too far, it is only proper that we ac¬ knowledge that a form of satellite broadcasting al¬ ready exists. But any sub¬ stantial similarity between the current TVRO craze and DBS ends there Gone is the need for a 10-foot dish in the backyard and a $1000 re¬ ceiver in the living room Central to the concept of 1990s-style DBS is low cost and small size That way, spacecasters hope to attract an audience as broad as the country itself. just about the only as¬ pect of DBS not up in the air are the satellites them¬ selves Even though this is an industry in its infancy and today's plans could very well line tomorrow's waste¬ basket, several things can be said with a good deal of certainty. The direct-broadcast ser¬ vice will use geosynchro¬ nous satellites, meaning that like today's TVRO birds, they'll appear fixed in the sky, All that a US viewer will DBS: IS THERE A DISH IN YOUR FUTURE? Shortly after this article was written the FCC granted ap¬ proval to Satellite Television Corporation’s plan to construct a direct-broadcast satellite-television system. Satellite Television, a subsidiary of Communications Satel¬ lite Corporation, was the first firm to apply for spacecasting rights and is the first firm to get approval. The STC proposal, which calls for four satellites, suggests that three channels of scrambled programming could be activated by 1986. Eight other applications for direct-broadcasting service were scheduled for FCC action by the end of 1982. A Septem¬ ber 24,1982, Wall Street Journal report goes on to say that no DBS hopeful will receive orbital or frequency assignments un¬ til after a hemispheric conference in mid-1983. have to do is point his or her dish to the appropriate point on the southern horizon. No tracking or movement of the antenna will be required once it is locked onto the selected satellite We also know that the DBS signals will be in thell- 12-CHz region, where fre¬ quencies have been allocat¬ ed for such purposes. This will require new technology since relatively little is avail¬ able in the way of low-cost consumer electronics at those frequencies. The choice of the 12-GHz "Ku" band almost makes the pres¬ ent day 4-GHz satellite-TV gear look like it is meant for dc! A third "fact" is that DBS offerings are expected to supplement rather than re¬ place the current system of local broadcasting and ca¬ ble television You might want to wait a while before climbing up on the roof to take down the old VHF-UHF aerial. Pie in the Sky Imagine a business with 20 million customers, each of whom spends $500 for a receiver and shells out an additional $10 per month for the privilege of unscram¬ bling signals. It doesn't take a calculator to figure out that DBS equals big money, probably in the billions of dollars per year And, as you might expect, a lot of people are already looking for a piece of the action. Partici¬ pants in the DBS free-for-all range from big guns like RCA, CBS, and Western Union to a handful of base¬ ment tinkerers bent on building a better mousetrap, receiver style. Someplace in the middle are outfits like Advance, Inc, and Home Broadcast Television, hardly household names—at least not yet Money-making methods vary. Firms like RCA and Western Union, already ex¬ perienced in satellite tech¬ nology, would like to act as US Home EartlvStation Sales 1982 1984 1987 1990 Backyard Terminals Unit Sales (thousands) 25 75 120 5 Installed Base (thousands) 41 161 506 611 Revenues ($ millions) 175 375 360 15 Rooftop Terminals Unit Sales (thousands) — 216 2000 5000 Installed Base (thousands) — 290 3582 15582 Revenue ($ millions) — 650 1420 2270 (Source: International Resource Development, Inc.) Fig. 1. International Resource Development , Inc., shows a growing market for " backyard " TVRO terminals through the mid-l 980s . By the end of the decade f the roof top" terminals will begin to predominate . 38 73 Magazine • February, 1983 ANTENNAS ESTIMATED NUMBER TVHO PRIVATE HOME ANTENNAS Fig . 2. Research by Strategic Incorporated suggests that DBS sales will capture much of the unit total for the Earth-station industry but consist of less than half of the dollar total. carriers, leasing satellite transponders to broadcast¬ ers Other groups, like Unit¬ ed States Satellite Broad¬ casting Co, will need to seek out technical partners to complement their skill in producing programs and sell¬ ing advertising. A third seg¬ ment of DBS hopefuls would like to act in a manner simi¬ lar to cable-TV suppliers. They would purchase most of their programming and generate income from rent on decoder boxes or royal¬ ties paid by local distributors The markets for direct broadcasting are as varied as the potential suppliers. CBS has requested three chan¬ nels One slot would serve as a feed to local CBS stations and individuals unable to receive local broadcasts. The remaining two channels are needed to distribute pro¬ gramming directed at busi¬ nesses like cable TV and movie theaters CBS signals would, in all likelihood, be scrambled to prevent unau¬ thorized reception Other proposals, like the one from National Christian Network, suggest reaching a large audience with costs offset by advertiser support. In this instance, there is little to be gained by scrambling the signal. Crystal Balls Giving a precise estimate of the size of the DBS pie and how it is to be divided is as difficult as it is foolhardy You can get a general idea by turning to expert re¬ searchers. For example, after consulting the woolly worms. International Resource De¬ velopment stated, in a re¬ lease for a $985 market re¬ port, that "over 15 million US homes will have rooftop DBS terminals by the end of the decade " An announce¬ ment publicizing a $1500 re¬ port from Strategic Incor¬ porated is slightly more con¬ servative, predicting (1) that DBS won't get a firm start until 1985-1986, and (2) a 1990 sales figure of 160,000 antennas for DBS. 40 73 Magazine * February, 1983 Fig. 1, from Internation¬ al Resource Development, Inc., shows not only the forecasted growth of DBS, but also the effect that it will have on the TVRO in¬ dustry. Sellers of the back¬ yard terminal can expect a growing market through the mid-1980s but will feel the DBS pinch by 1990 Graph¬ ics from Strategic Incorpo¬ rated (Fig. 2) show that home antennas may constitute a whopping 96 percent of the small Earth stations sold in 1990 yet make up only 45 percent of the dollar vol¬ ume as a result of the much lower per-unit cost of DBS terminals. Whither TVRO? Where does this leave the potential backyard owner and the dozens of firms cur¬ rently in the TVRO market? There have been no signs that distributors currently using the 4-GHz satellites will abandon them in the near future. To do so would place an enormous burden on the cable-TV industry The home TVRO market, which insiders pegged at about 50,000 terminals in 1982, should continue to grow through the mid-1980s. Potential growth stoppers would be federal regula¬ tions restricting or prohibit¬ ing "unauthorized" recep¬ tion or a widespread move towards scrambling signals. So far, few suppliers have considered it worthwhile to invest in encryption to lock out the home segment. With time, the suppliers may overcome their reluctance to "deal direct" with the home viewer and offer some sort of plan for authorized home reception. The entrepreneur who sees the rosy market predic¬ tions and wants to join the home-terminal fray faces a tough road Garage and basement operators are quickly falling by the way- side as firms grow and at¬ tract outside capital The homemade dish on the back of a pickup and the margin¬ al receiver that character¬ ized many early dealers just don't hack it anymore Am¬ bitious selling and truly in¬ novative products will still catapult the small-time op¬ eration upward, but the days of quick profit, if there ever were any, are now over Jobs Dismiss all those dreams of the big bucks? No, not necessarily; just recognize that DBS is not going to be an "afterthought" industry with the hobbyist roots that the present-day TVRO field has. A number of the manu- facturers have already caught on to this and are claiming that their antennas, designed for 4-CHz recep¬ tion, will work just fine at 12 GHz. A few companies are even tinkering with Ku-band circuitry. But no matter what technical standards are finally accepted for DBS and no matter who the pro¬ gram suppliers are, there will be a good market for knowledgeable engineers and technicians After all, someone has to design, in¬ stall, and maintain those twenty million terminals ■ References 1. “Strategic Incorporated/* press release for Small Satellite Earth Stations: US Market Op¬ portunities, 1981-1989; October, 1981. 2. “International Resource De¬ velopment, Inc./* press release for Direct Broadcast Satellite Systems, September, 1982. 3. “Fourteen Seek Direct Broad¬ cast Rights,” Aviation Week & Space Technology , August 10, 1981. 4. “FCC Approves DBS,” Avia¬ tion Week & Space Technology, May 4,1981. Part It of this article, next month, will focus on the technological challenge of DBS. Dave Ingram K4TWI Rte 11 Box 499, #7207 South Birmingham At 352 H) Work the Russian Robot Ops The robots aboard Russia's two new satellites are cantankerous and challenging. Here are some tips on how to work them. T he recent addition of several Russian space¬ craft into the amateur radio satellite program truly has created a flurry of excite¬ ment on the HF and VHF bands In addition to intro¬ ducing many newcomers to amateur satellite activities, these birds are also renew¬ ing widespread interest in mode A communications (2-meter SSB/CW uplink, 10-meter SSB/CW down¬ link). If you would like to relive the sheer fun and enjoyment of your early days in ham radio—those times when every contact held special meaning and gave you a feeling of ac¬ complishment—you've on¬ ly to join the action on our amateur radio satellites. The staggered orbits and comparatively high a It i iudes of RS(Radio Sputniks) spacecraft afford a com¬ munications range and pass-operating time roughly equivalent to the now-clas¬ sic OSCAR 6 and OSCAR 7 satellites: approximately 1700-km altitude and 25 minutes. Numerous inter continental QSOs have been conducted each day via the RS satellites, and you can join this excitement with a minimum of effort. The RS satellites exhibit very high sensitivity, elimi nating the need for sophisti¬ cated antenna systems or high-power uplink signals. As an example, I recently made fine contacts during an RS pass while using low power (10 Watts) and a I ver¬ tical for 2 meters. Mode A communications are the easiest way for HF-laden amateurs to join today's space activities, and the automatic QSOing robots aboard RS5 and RS7 are an absolute blast to contact. RS Satellites and Orbits Two prime attractions of RS5 and RS6 Uplink (MHz) Downlink (MHz) 145.910 29.410 145.920 29.420 145.930 29.430 145.940 29.440 145.949 29.449 Beacon 29.450 the RS satellites are their straightforward hand-to- band frequency relations and their orbital-calculation simplicity As shown in Fig. 1, each satellite receives sig¬ nals within a 50 kHz spec¬ trum of 2 meters and linear¬ ly relays them within a 50-kHz spectrum of 10 meters. Each spacecraft's beacon can be used for determining when that bird is within communications range and for indicating when its trans¬ lator is on/off. The beacon continuously transmits a series of letters and numbers, called information channels. Transmissions containing K00 indicate the transponder is off, K05 to K99 signify that the tran¬ sponder is operational Equipped with his own copy of the previously-mentioned frequency-relation chart for RS7 and RS8 Uplink (MHz) Downlink (MHz) 145.960 29.460 145.970 29.470 145.980 29.480 145.990 29.490 145.999 29.499 Beacon 29.500 Amateur satellite setup at K4TWI includes Icom 202 and 40-Watt amplifier for uplink , /com 730 for downlink. 12-volt power for the 40A/Vatt amplifier is pulled from the Icom 730's PS15 power supply. 55 TV capability included. The program¬ mable Morsematic keyer was used for contacting RS5 and RS7 robots . 5 F radio desk with upper shelf holding 2-meter gear proves a great convenience for satellite operations. 44 73 Magazine • February, 1983 Fig . 1. Frequency-relation chart which can he used for guid¬ ing operations during a satellite pass . An RS6 uplink signal on 745.928 MHz , for example , would he relayed on 29.428 MHz (± Dopplerl Allow ±3 kHz on all RS downlinks for Doppler shifts . Satellite RS5 RS7 Uplink Receive 145.826 MHz 145.835 MHz Downlink Transmit 29.331 MHz (± Doppler) 29.341 MHz (± Doppler) Fig . 3(a )L Frequencies used by the RS robots for contacts with Earth-based amateurs. Frequencies may vary ±3 kHz with Doppler shift Robot: CQ de RS5 QRUon 145.826 MHz AR Amateur RS5 de K4TWJ AR Robot: K4TWJ de RS5 R QSO Nr 740 RST579 OPR Robot: Robot .etc...K Amateur RS5 de K4TWJ R QSO RST579 QTH ALA OPR Amateur Dave...etc...K Robot: K4TWJ de RS5 QSL 73 CQ de RS5 QRU... Robot: etc...AR Fig. 3(b). QSO format used for contacting robot operators aboard RS5 and/or RS7 satellites. Speed must be between W and 20 wpm, and keying must be exact a particular RS satellite, the operator is well on his way to enjoying some exciting space-age communications. The next item of consider¬ ation is an orbital-calcula¬ tion method for accurately plotting a specific satellite's pass. As a matter of conve¬ nience, I suggest rounding out each craft's orbital period from 119 xx minutes to an even 2 hours, and each orbital incrementation from 29.xx to an even 30 degrees. These changes are of minor consequence provided they are used in conjunction with reference-orbit information listed each month in the amateur magazines. An OSCARIocator (with RS curves) is also highly desir¬ able, especially when at¬ tempting to catch early morning north-to-south passes in the United States Assuming a satellite enthusiast is located in the mid-US, his no-problem communications range falls between 70 and 110 degrees. (This information is shown on most world maps.) Assuming a particular day's reference orbit for a select¬ ed bird is listed as 220 de¬ grees at 0630 GMT, simply subtract 2-hour and 30-de¬ gree steps until the craft falls within range: 220 —30 = 190 at 0430 GMT, 190 - 30 = 160 at 0230 GMT, 160 - 30 = 130 at 0030 GMT (almost within range), and 130 — 30 = 100 degrees at 2230 GMT (the previous GMT day): a per¬ fect afternoon pass. Finally, an antenna place¬ ment/operating chart is drawn for the selected pass Since a typical ' high in sky " pass lasts approximately 25 minutes and since a couple of minutes can be expected between equator crossing (EQX) and acquisition of beacon signals (AOS), a typical chart will look like Fig 2 This chart and the frequency-relation chart are then used to automatical¬ ly" direct operator actions during the pass (spotting fre- Time Activity Beam Position 2230 EQX South 2232 AOS South 2234 CW SSW 2236 CW SW 2238 SSB West 2240 SSB West 2242 PASS MIDDLE West 2244 CW/SSB WNW 2246 CW WNW 2248 CW NW 2250 CW NW 2252 LOS NW Fig . 2. A typical antenna placement/operating chart drawn for a planned RS pass , indicating planned activity and antenna movements. Since this information will be used only one time it can be written on a piece of scrap paper The uplink an¬ tenna in this example is tilted approximately 30 degrees to bypass dual rotor needs. quencies, incrementing beam-antenna position, etc.). The operator is then free to enjoy communica¬ tions fun. As RS satellites are quite sensitive, they require only a few Watts ERP (Effective Radiated Power) for suc¬ cessful operations. Please , gang, bear that fact in mind and control your 2-meter power accordingly! Tran¬ sponders on some RS satel¬ lites have been continuously knocked off by amateurs running excessive 2-meter ERP. In order to prevent age clamping and attenuation of others' signals, your satel¬ lite-returned signals should always be slightly weaker than the beacon (approx¬ imately 40-Watts ERP). Working the Robots Two of the Russian satel¬ lites. RS5 and RS7, carry automatic QSOing robots which conduct separate amateur radio activities ap¬ proximately 100 kHz below their spacecraft's tran¬ sponder—see Figs. 3(a) and 3(b) The robot will call CQ, ID (either RS5 or RS7), an¬ nounce its 2-meter CW lis¬ tening frequency, and stand by for calls (bedlam, which I will discuss presently). Assuming an amateur contacts the robot, he re¬ ceives a signal report and QSO number, etc., which can be used for QSLing the unique space-type contact. Following a subsequent reply and exchange of 73s, the robot again calls CQ and begins further QSOs. As this article is being writ¬ ten, heavy pileups and ill-in¬ formed operations on the robot's 2-meter listening frequency are causing jam¬ ming and confusion. Simply stated, all stations must take turns calling and work¬ ing the robot. Transmissions must be held to one station at a time, otherwise Morse transmissions become a se¬ ries of unintelligible dashes or continuous carriers. The robot's receiving bandpass is approximately 5 kHz, yet any (or all) signals load into memory and are relayed on 10 meters with the same pitch Thus you can hear the 2-meter input exactly as the robot hears it. If all stations attempting to contact the robot use FM-re- peater tactics (transmit only when other stations are not transmitting—an easy task since satellite operations are full duplex), confusion is eliminated and all can enjoy contacts Even with those situations dealt with, robot contacts are yet a challenge RS5 may tell you to send faster (QRQ) or send better (QSD). Despairingly, you load the complete QSO format into a programmable keyer of variable speed and plot a wee-hour pass to avoid QRM. That time, RS5's robot only listens (you hear your 10-meter-relayed signals, but where's the robot?), and RS7 follows a few minutes later calling CQ! The Rus¬ sians can truly be proud of their designing and pro¬ gramming of these robots. They're clever, inspiring, challenging, aggravating, and fun. If you manage to wrangle a contact, you're a fairly good operator. Satellite Equipment There's a good chance you already possess the basic equipment for RS- satellite operations, namely an HF rig with full 10-meter coverage and an all-mode 2-meter rig You've only to combine these units at one operating location to join the excitement of amateur space communications Al¬ though the RS satellites usually produce a slightly stronger downlink signal than OSCAR 8, a relatively sensitive receiver is desir¬ able (TS^30, TS-130, IC-730, FT-102. etc ). An outboard receiving preamplifier is also quite beneficial, but 73 Magazine • February, 1983 45 PROGRAMMABLE CTCSS ENCODER • All 37 El A Tones • Quartz Accurate • Less than 1 inch square AVAILABLE FOR IMMEDIATE DELIVERY For more information call TOLL-FREE (800) 828-6884 .2,8 NY: (800) 462-7242 CANADA: (416) 884-3180 FERRiTRONiCS MOBILE DATA SYSTEMS 1319 PINE AVE NIAGARA FALLS NY 14301 (718) 282 7470 TLX 64-6303 not mandatory. Some of the presently-popular 2-meter rigs suitable for RS activities are Yaesu's FT480R, Ken- woods TR-9130 and Icorn's IC-251A Portable units such as Yaesu's FT-290R or Icorn's IC-202 are also grand, al¬ though non QRP enthusiasts may want to add a high-gain antenna or small rf amplifier (operating power can be borrowed from the HF transceiver's 12-volt supply, since very low current is used when that unit is re¬ ceiving) The most popular anten¬ nas for 2 meter satellite operations are twist or crossed yagis which contain an equal number of horizon¬ tal and vertical elements plus a phasing harness for circular polarization. Due to the sensitivity of the RS satellites and the gain of vertical J antennas, however, I've recently experienced quite acceptable results while using KLM's new JV-2 I antenna. That thing really works! Most amateurs mere¬ ly use crossed dipoles or their triband beam for receiving 10-meter satellite signals In fact, the RS birds can easily be worked mobile if desired! Conclusion The RS amateur satellites represent a true era in both space-age communications and Phase 11 (low orbit) oper¬ ations which can be enjoyed by almost every radio am¬ ateur It you're just getting started in amateur satellite activity, I suggest operating RS6 and RS8 The tran¬ sponders aboard these satel¬ lites are somewhat better than RS5 or RS7, and they exhibit less heavy fade Whichever way you go and whatever gear you use, you will find satellite communi¬ cations a refreshing new ex¬ perience in amateur radio. It is indeed tomorrow's fron¬ tier in today's world.® 4511RTTY Interface for TRS-80* Color Computer Owners • Simply plug into Program Pak* slot. • No software to load, it is in ROM. • Split screen features word wrap and continuously displays status. • Selective calling stores Incoming messages on casette tape. • Baudot and ASCII modes. • Standard EIA signals to your T.U • Complete documentation supplied. 4811 RTTY Interface .in $169.98 Z m RlDGF Tested & assembled, 90 day warranty; to pay oYb I tMo shipping Mass, rest f'P) dents add 5% sales tax. * IN vy. *a trademark of Tandy Carp P O Box 772. Acton. MA 01720 (617) 264-4251 R &$P S ACCjff AM*?* Aide" ICO** sr fe* yae sU A** A yan iot S 3 S* sSBgSgpV* ASt*°* V Si# o-ddl" ?s4ff f „ J, M etefS M' rag %bie k-453 you* sWt & Ma fine Co****' in» ca ' ctions 1 ijOt * 1 1 .800 .336 .4796 0 tP F ,.,, »•«° ‘ r asft**, i* UOltfS **,' pM I Orde* H j* l0 a-** l ° COP (C* 5 cubi® 0 suW 46 73 Magazine • February, 1983 Ham Radio Hits the '82 World's Fair When the gates in Knoxville opened , would WA4KFS be ready? Here's the inside story of the World's Fair station. While the health pavilion was being finished , local hams in¬ stalled two towers , tribanders, a 2-meter antenna , and dipoles . 50 73 Magazine • February, 1983 /ohn M C/arfc N4AQI 509 Cimarron Frail Knoxville IN 37919 Photos by WD4MQQ T he theme was energy, and amateur radio gen¬ erated plenty of it —rf and human —during a success¬ ful six-month run at the 1982 World's Fair in Knoxville. SSTV contacts to Europe, the opportunity to send ra¬ diograms to the folks back home, rag-chewing on RTTY, and a lot of conversation about the excitement of ham radio were among the activities fair visitors found at the Tennessee Wireless Association exhibit. Thanks to the tireless work of a group of East Ten¬ nessee hams and the gener¬ osity of US amateur radio dealers and manufacturers, our worldwide, high-tech¬ nology hobby continued in Knoxville the long tradition of ham radio at world's fairs. Officials of the City of Knoxville's health pavilion, where the amateur station was located, estimated as many as half the fair's ap¬ proximately 11 million visi¬ tors could have seen the amateur radio exhibit dur¬ ing the May to October ex¬ position. It was a magnifi¬ cent showcase for amateur radio. Plans for bringing ama¬ teur radio to the '82 fair be¬ gan about a year before the event opened. Many of the original group that met at the Knoxville and Oak Ridge hamfests early in 1981 to talk about the idea of ham radio at the fair went on to assume major responsibility for the effort. The group incorporated itself as the Tennessee Wireless Association, a non¬ profit organization char- Operators from throughout the US and many foreign coun¬ tries stopped by to operate the station. A commemorative certificate and QSLs were available from the Tennessee Wireless Association. tered for the sole purpose of sponsoring an amateur radio exhibit at the fair. Un¬ der TWA president Ed Dunn W4NZW, the group's first order of business was to ap¬ proach fair officials about obtaining a site for the sta¬ tion Virgil Davis KA4RPA, a TWA officer, talked with Knoxville mayor Randy Ty¬ ree and secured a location in the city's health pavilion. Health care under emergen¬ cy conditions was the theme of several exhibits in the pavilion, and the mayor and city officials felt the station would be appropri¬ ate there because of the emergency-corn m u nica- tions aspect of the amateur service The site was superb The health pavilion was a strik¬ ing geodesic dome in the center of the fair site, near the Sunsphere, the fair's theme structure An addi¬ tional benefit was being lo¬ cated in a high-traffic area near the pavilion s entrance With the exhibit space tied down, TWA officers turned their attention to lin¬ ing up equipment which would demonstrate the di¬ versity of amateur radio Ten-Tec, Inc., located in nearby Sevierville, was asked to supply HE rigs for three stations. The com¬ pany agreed, and Tom Sal- vet ti WD4FVU of Ten-Tec accepted the job as equip¬ ment coordinator for TWA Amateur dealers and manufacturers responded generously to Salvetti's calls, and approximately $20,000 worth of state-of- the-art gear was loaned and soon on its way to Knoxville L B Cebik W4RNL, who has written a book on sta¬ tion design, was called on to produce a layout making the most efficient use possi¬ ble of the 105-square-foot space. Three stations, two designated for general oper¬ ating and one for special¬ ized communications, were planned Although equipment needs were largely met by dealers and manufacturers, funds for installation and operation of the station were needed. Eleven area radio clubs and more than 60 individual amateurs re¬ sponded, and Jerry Good- child K4DZR, TWA secre¬ tary/treasurer, reported that approximately $2000 was donated to support the station Jerry also accepted, with the help of station trustee Chip Coker KD4C, the job of scheduling control opera¬ tors for the station. About 40 hams each month worked shifts of three to eight hours as control operators. The George Child N4BCS installed the 2-meter antenna atop one of the two crank-up towers in the shadow of the Sunsphere station was staffed almost all of the 12 hours per day the six-month fair was open. TWA directors talked about asking the FCC for a special callsign for the sta¬ tion, hoping that Knoxville's hosting the first world's fair in the South would persuade the commission to relax reg¬ ulations on special calls. De¬ ciding that prospect was dim, Chip KD4C offered the use of WA4KFS, for which he is trustee. Perfect —the phonetics would be "Knox¬ ville Fair Station A year-long planning ef¬ fort by TWA paid big divi¬ dends when the time came to install the station Con¬ struction at the fair site was on a tight schedule, with several buildings being ready only hours before the May 1st opening While work continued on the health pavilion, TWA erect¬ ed its two 50-foot towers and rotors from Hy-Gain/ Telex and Texas Towers. Aboard were a Hy-Gain TH-3 and a V-2 for 2 meters and a KLM KT34A Dipoles Three complete HF stations with SSTVand RTTY made up the amateur radio exhibit at the Knoxville World $ Fair. In¬ formation on amateur radio for non-hams was available at WA4KFS. 73 Magazine • February, 1963 51 With QSLs in the background , Charlie Price WB4VFP ex¬ plained the many facets of amateur radio to the public. for 40 and 80 meters were cut, and feedlines from Times Wire and Cable Com¬ pany were strung and ready to be hooked to the rigs. The three stations were built around Ten-Tec Omni C transceivers and Hercules solid-state linear amplifiers. Matching tuners, vfo's, keys, and mikes were from Ten- Tec, with MFJ providing memory keyers and clocks. KDK Distributing of Nash¬ ville supplied KDK 2036 transceivers for 2 meters. All the gear was housed in stylish consoles from S-F Amateur Radio Services of California. The latest RTTY equip¬ ment was sent to Knoxville by Hal Communications, and SSTV gear came from Robot Research. Both slow- scan and Teletype® attract¬ ed a lot of attention from non-hams who stopped by the exhibit. RCA and Smith-Victor Sales supplied the SSTV camera, monitor, and tri¬ pod, and Overman Interna¬ tional, which has a manu¬ facturing plant in Knox¬ ville, provided chairs for the station, which was ful¬ ly accessible to handi¬ capped operators. A crowd of 82,000, includ¬ ing President and Mrs. Ron¬ ald Reagan, enjoyed open¬ ing day ceremonies on May 1st. Shortly after the official festivities, WA4KFS went on the air. Pileups were com¬ mon, as hams around the world wanted an '82 World's Fair QSL card or a special certificate for working the station and 10 other Ten¬ nessee hams from May to October. Amateurs coming to Knoxville were provided with World's Fair informa¬ tion via ham radio. A 2-meter information station was built and placed on the air by Robin Rumbolt WA4TEM. By keying the sta¬ tion on simplex and giving their call, hams received in¬ formation on parking, shut¬ tle bus service, and lodging. Area repeaters were moni¬ tored by operators who could give directions and answer questions about East Tennessee and the fair. Many amateurs heard of WA4KFS from the 2-meter information station, but a large number said they knew about the exhibit be¬ fore coming to Knoxville, thanks to the work of public¬ ity director Steve Kercel AA4AK. Some hams spotted the tribanders and followed the coax into the pavilion. All visiting amateurs were asked to sign the guest log at the reception counter and were given the opportunity to operate the station. And operate they did — all modes, all bands. Some kept skeds they'd made in advance, others checked in¬ to nets, some looked for DX. Many added considerable skill to the art of rag- chewing. Control operators an¬ swered thousands of ques¬ tions from non-ham fair visi¬ tors and helped hundreds fill out radiograms, which were moved by Anita Teffeteller NG4J, one of the nation's top traffic handlers. Bro¬ chures about the station with tips on how to become a ham were given to those who stopped by for a chat. Several control operators said they found conversa¬ tions with fair visitors — American as well as for¬ eign-interesting and edu¬ cational. The foreigners came from Australia, South America, New Zealand, South Africa, Europe, and many other parts of the world. If you worked the World's Fair station and want a QSL, send an SASE to Harvey Cross W4PKM. You can get the special certificate for working WA4KFS and 10 other Tennessee stations'by sending $2 and log confir¬ mation to Sarah Hickey N4EFA. TWA, the 1982 World's Fair, and the amateur com¬ munity express their grati¬ tude to the manufacturers and distributors who made the "Knoxville Fair Station" possible. Those firms were: Hal Communications, Hy- Gain/Telex, KDK Distribut¬ ing, KLM Electronics, MFJ, Overman International, RCA, Robot Research, S-F Amateur Radio Services, Smith-Victor Sales Corp., Ten-Tec, Inc., Texas Tow¬ ers, and Times Wire and Ca¬ ble Co. Thousands of people at the fair saw amateur radio at its finest, and East Ten¬ nessee hams who served as control operators and re¬ peater monitors threw in a large dose of southern hos¬ pitality for good measure. Look for some new hams on the airwaves because amateur radio went to the fair. ■ Introducing our Latest Model — NO VAX II SIMPLEX / DUPLEX AUTOPATCH NOW TWO MODELS TO SERVE YOU BETTER YOUR OWN PRIVATE AUTOPATCH N|Vax Monas Connection NOVAX Interfaces your standard 2 meter; 220; 450; etc. Base station and telephone, using a high speed scan switching tech¬ nique so that you can direct dial from your automobile or with your HT from the backyard or poolside — Automatically ... Easy installation transceivers, featuring solid state switching, offer best results ... Available interfaced with an ICOM 22U. FEATURES NOVAX1 NOVAX II • 3 min. Cell duration timer YES YES • Up to 45 tec. activity timer YES YES • Single digit Access Control YES NO • DTMF (Touch Tone)* phone connection YES YES • 4 digit Accees Control NO YES • Toll Restrict NO YES • LED Digits! Display NO YES • Vinyl covered alum, case tire 6" x 6" x 2" 10" x 8" x IX" • Oiractly Interfaces with Repeater NO YES • Rotary Dial System (incf. Last dipt dial) NO YES—"Option"—$4&96 • Ring Back (reverse autopatch) "Option'' YES—$39.96; Kit $29.96 YES—Wired—$39.95 • Price KiC$169.9S/Wred$2t9.96 Wired only $279.96 N.Y.S. Ret. edd appro. Sales Tax SHIPPING ADO $3.60 In U.S.A. | iS 21 To order, send check, money order to: (formarly~R.W.D. Inc.) * Trademark ITT Box 162 - Tudman Rd. Westmoreland, N Y. 13490 or Phone 315-829-2785 52 73 Magazine • February, 1963 Beef Up Your CB-to-CW Conversion A good bio will bring your receiver performance up to par. This one is easy to add on. Penn C lower W1BC 45 9 Lowell Street Andover MA 01810 O ne of the simplest ways to add the bfo function to a converted CB set was described in my arti¬ cle, "CB to CW? —convert¬ ing the Hy-Gain board; in the July, 1982, issue of 73. That technique is to leave the transmitter carrier oscil¬ lator on during receive so that it beats against the re¬ ceived signals It is cheap and easy, but does have the drawback of reducing the receiver dynamic range since the bfo signal travels through the entire i-f path before reaching the detec¬ tor, The rest of that rig turned out so well that the project really deserved a proper bfo to bring the re- Photos by W1GSL ceiver performance up to par The circuit described here did that job nicely and should also be of interest to anyone wanting to add CW or SSB reception ability to a converted AM-type CB set having a 455-kHz i-f. The modified circuit con¬ sists of a straightforward 455-kHz bfo and buffer used together with a simple prod¬ uct detector in lieu of the ex¬ isting diode AM detector Before" and "after" testing at my home QTH and sever¬ al local CB hot spots showed a dramatic improvement. The receiver is still capable of copying a .1 -jiV signal, but the occasional spurious responses are gone. In addi¬ tion, the bfo frequency is ad¬ justable and can be used for variable receiver offset The transmitter carrier oscillator provides a signal for trans¬ mit frequency spotting and the separate bfo circuit has even made it possible to re¬ connect the S-meter. One philosophical drawback is that the bfo is a free-running oscillator that introduces the possibility of drift to an otherwise cr ystal-controlled receiver The circuit compo¬ nents were chosen so that the warm-up drift is only several hundred cycles, that isn't objectionable given the ability of accurately spot¬ ting the transmitter frequen cy The transmitter itself is still fully crystal-controlled and (pardon the pun) rock stable. The Circuit The circuit diagram for the bfo and detector is show n in Fig. 1 2N2222 tran¬ sistors were used in this ver¬ sion. but any NPN i-f transis¬ tor from an old transistor ra¬ dio should work just as well It is a rare transistor these days which won't work at 455 kHz. ♦ e.ev FROM EMITTER OF 0106 Fig. 7. Schematic diagram of bfo and detector circuits. 56 73 Magazine • February, 1983 The oscillator coil is fashioned from part of an old tube-type i-f transform¬ er, At first, a miniature 455-kHz i-f can was used as the tank circuit, but the ther¬ mal stability was terrible Simply placing a fingertip on the side of the shielded coil introduced enough tem¬ perature change to cause a several kHz frequency shift. Assuming the tempera¬ ture coefficient of the ferrite core was at fault, I turned to the older style large i-f can since the inductance there is achieved by using more wire and less ferrite. The top sec¬ tion of the transformer was removed for use as a coil as shown in the sketch of Fig 2 The coil was paralleled with enough capacitance (120 pF in my case) to get a 455-kHz oscillation with the slug al¬ most backed out of the coil That step ensures that any change in the slug permea¬ bility with temperature will have minimum influence on the oscillator frequency In addition, most of the capacitors in the oscillator are polystyrene dielectric types used because of their reputed stability. This step may not really be necessary from a drift standpoint, but it certainly doesn't hurt. The 10-minute warm-up drift of the receiver is only 300 cy¬ cles, and that includes drift due to several crystal oscil¬ lators as well as the bfo The bfo frequency can be shift¬ ed over a 3-kHz range with a variable capacitance diode controlled from a front- panel potentiometer. The oscillator is followed by a buffer stage tuned by one side of the miniature i-f transformer. The transistor collector drives a tap on the coil and the detector drive is taken off at one end This steps up the available drive signal from 8 to 25 volts peak-to-peak. The drive lev¬ el is not critical, but in gen¬ eral the bfo injection should be about 10 times the ex¬ pected signal level. If a number of transformers can The bfo control (labeled RIT) is mounted where the sidetone level pot useil to he . That control (now called MONITOR to save space} is mounted just below and left of the meter. be salvaged from old radios, a suitable one can be select¬ ed with the aid of a simple voltmeter circuit like that suggested in Fig 3. Use an ohmmeter to find which windings have a tap, then put that coil in the circuit and check the output volt¬ age with the meter Don't forget to try swapping the dc feed and output ends of the coil to find which hook¬ up gives the most output level. Any drive above 10 to 15 volts peak-to-peak (3.5 to 5 5 Vrms) will be satisfactory The two-diode product detector works like a pair of SPST switches which make and break the connection between the i-f output and the following audio amplifi¬ ers at a 455-kHz rate. The 33-pF coupling capacitor charges up to the peak value of the bfo sine wave and that makes the final buffer tuning easy-just hang a high impedance dc voltme¬ ter on the junction of the two diodes and tune the buf ¬ fer for maximum The larger this voltage, the more signal the detector can handle without overloading and the less you will have to use the i-f gain control. Since now only off-the-air signals are coming through the i-f stages, a simple enve¬ lope detector is incorporat¬ ed to drive the S-meter With the 5-mA meter and the resistor values shown, the sensitivity seems about right Since there is no age in use, the meter reads in a linear instead of logarithmic fash¬ ion. That limits its useful¬ ness somewhat but didn't seem serious enough a problem to merit the com¬ plication of a meter ampli fication circuit. For those interested in a more accu¬ rate meter action, I would recommend looking into age operation as well Construction It is best to place the bfo circuit close to the detector physically. In my rig, the above-board space in that area was occupied by the active audio filter modifica¬ tion, so the bfo circuit was built on a small board and mounted underneath the chassis The product de¬ tector circuit is easy to fit on the main board and the con¬ nection to the bfo can be made short and direct This helps to prevent the bfo from coupling back into an earlier section of the 455-kHz i-f strip As shown in the photo¬ graph, the bfo frequency ad¬ just pot (labeled RIT) is mounted in the hole former¬ ly occupied by the sidetone level control That control is replaced by a miniature pot and knob mounted at the former location of the trans¬ mit offset switch The cir¬ cuitry for offsetting the transmitter is removed from the 10.695-MHz oscillator, as now the receiver can be offset by means of the bfo control The bfo pot used has a pull-on, push-off switch attached and that is used to turn the 10 695 oscil¬ lator on to permit spotting the transmitter frequency with the receiver There is a frequency in¬ version in the receiver con¬ version process; be sure to wire the bfo pot so that a clockwise rotation lowers the control voltage (and T m T Z> V ESTHER CO!t SALVAGED COMPLETE WITH CENTER TuS£ AND SLUG CORE Fig. 2 . Details of salvaging the coil from an old 455-kHz transformer. 73 Magazine • February, 1983 57 WIUWALL RADIO MODEM l*cipp|G trs-bo ATARI' SEND & RECEIVE CW & RTTY T£RM)NALt is a hardwant un«j software sysssm which eom>®m yowr Personal Com- pvtm into * t’3t» ai the art cammuntaiwni lifflrt.. » TERMiJiAti «s «•* <0 use Pkjg *-t& «** feterwer fwadppx** t*:* *•*:! oro* Morse COT? or »actoW0'hi«> P\<3 «*3 KXJf CVW *»v sac* y«S send Monse cca* Atsae* a Atoacfrene aanrwex* am) se*d SamXK ar ASOi 8TTV aud*} TAfSlii' Trust's #5 »?•«*?*? * to he *.ntnq •:! 14 ? » Pae^gssr Want »«*sKS«r> Vi a»e n&oessar* 53 wjchvw Mtyse code >'i »-jfrr .automate 1 S'* ttagns actve tuta* oernoaytaw arid auto adaptive Morse <ikjOril?srr! top** IN» vwa#*. <*»rt stoppr* one* • Separate RTTY nod CW i**i>Gd«laiors Built m cryslsi r:ori«fCi*KJ AfSK CW and PTT keying (JO m>t loop iritmctmnect. RS 232 IN and Out. Kitvj m*v mmjt an0 «* tone output » Built in parallel prmiw driver sot (ware allows hardcopy ir» all fntxfctt • Hardware etock memUtna accurate time. • <*»«sre*t ¥V*y 'onctwm You 5<aec? rstsiie sxjuenscs ’smvyto w omr** whit *6 (rarer*r» tao and wfwdw *3 mw« on G» tSflA • Word yracong. won} med? didefte, «jnore conwift user oroyammatii* «w'<j of *rm w^ASoce. aoussatite carriage ways* treresrw oew* < fewest rejne cr auto oaapewfr «*e*ftar>t docunr*r.utton tn» mode *rd «mlT‘ mots • TtAMJV&u has tacacwfee* far surpass csmie:.»tm.i wmtnss wsagrm And shoe ■* wo»*& cm a purpose computW'. t'w rtWjOMv ot rOu> «rreesl?r»*n;t iyesur com putBfiffi. sees*} out over many tjrfterent ep {Kurattryn You get more tor your money • Complete with software on cassette and cksMW. asaefnfaasd and tested hardware and tmtemive instruction manual Can o< write i» stierjlrcflitiwis on TERMlNAU few TRS80 Model I or Model lit, Apr* or ATARI 400/000 CGMPU1FRS 5499 • \b (triv error toy back trial period One year pvjtw and tabor limited warranty on lac lory (Mm ! onirtrs To Order (209) 667-2B88 or 634^888 ^44 . ‘ At**r A <1 #*$»***} Trstlefnaty Ape* «r IICS, inc. tRS ®*m» Kesjsawnd r? jmrw* y T.yvjy Aur -S. 4 ft**3».!lr»wl ti«»rrar» ~t AJ3>' inc. ___ S5«jr<»r?;j e 'i Syttj □*« M-X CA aesdwi with it the bto frequency). This will result in clockwise knob rotation moving the re- ceiver up in frequency as you would normally expect. Operation There was a time when the typical amateur receiver had a different calibration scale for each band Now The bfo and buffer circuits are built on a small board mounted below the front right-hand corner of the circuit board. The volume control is visible just to the left of the added boardl The disgraceful saw marks on the lower lip of the main chassis happened when the chassis top was re¬ moved to mount the main board . 58 73 Magazine • February, 1983 just about every receiver has a single 500-kHz tuning range which is switched to cover each band These tun¬ able i-f receivers contain a set of crystal-controlled fre¬ quency converters which move the selected segment of the radio spectrum to the input tuning range of a sin¬ gle-band receiver. In this 10-meter receiver, the bfo tuning provides exactly the same tunable i-f feature on a smaller frequency scale Be¬ cause the i-f passband of this receiver was designed for AM reception, it is about 10 kHz wide and can pass quite a few CW signals. The bfo and product detector can be thought of as the front end of a direct-conver¬ sion receiver which is able to tune across this 10-kHz band segment and pick out the desired signal. In the complete CW transceiver, the transmitter frequency always appears exactly in the middle of the i-f tuning range, so in practice most transceiver tuning is done with the channel switch and delta tuning control while the bfo control is used to provide a RIT (Receiver In¬ cremental Tuning) function. Most contacts are made with both stations on the same frequency; the receiv¬ er is easily set for this condi¬ tion by pulling out the RIT knob (that's how I labeled the bfo control) to turn on the transmitter carrier oscil¬ lator The RIT control is then turned to tune in the trans¬ mitter frequency and pro¬ duce a desired tone in the audio output. The knob is pushed back in to turn off the spot signal; when an in¬ coming signal is tuned via the channel selector and delta tuning controls so as to produce the same beat note, the transmitter will au¬ tomatically be zero beat with that received signal There is one caution to re¬ member when using this procedure. As with all di¬ rect-conversion receivers, the detection process will produce a note on either side of zero beat, so a little care is necessary to ensure that the proper side is cho¬ sen Actually, this is quite easy. If the RIT knob was ro¬ tated clockwise (or counter¬ clockwise) from being zero beat with the spot signal, then the delta tuning control should also be rotated clockwise (or counterclock¬ wise) from being zero beat with the received signal Generally, the bfo will be offset 800 Hz from the trans¬ mitter by peaking the beat note in the audio filter. Then the RIT control is only used as necessary to dodge QRM or follow the other fellow's frequency drift Conclusion This last modification makes a good rig even bet¬ ter. The independent receiv¬ er tuning is appreciated at least as much as the free¬ dom from occasional CB overload The bfo addition also opens the door to one last area of interest: i-f de¬ rived age. Either the S-meter detector or one similar to it could be used to control the gain of the receiver in much the same way as Hy-Gain in¬ tended A possible draw¬ back of this scheme would be age action caused by signals adjacent to the de¬ sired one in the wide i-f pass- band Perhaps some readers will enjoy experimenting along this line. ■ HK»ne OROUW e TO .Qi 20KB/VOLT V0M ON 2&V0C SCALE * - Fig. 3 . Simple rf voltmeter which can he used to measure detector drive level. fulie Collins KL7RD Alaska 99757 The Denali Connection Disaster struck these two hams in the backcountry of Alaska. Only a tenuous radio link to civilization could save them. A lthough I passed my Novice code test and exam in November of 1980, my first contact was not un¬ til April, 1981, five months later. Even when it hap- 60 73 Magazine • February, 1983 pened, I had no real enthu¬ siasm about being on the air I felt a sense of grim despair, perhaps, but no en¬ thusiasm. This may seem peculiar to the many hams who turned on their rigs and dove into the airways the minute they received the anticipated en¬ velope from the FCC. Well, when I got my letter, I glanced at it and stuffed it casually into my pocket before wandering on home from the post office. That little stroll took nearly two hours, for the post office is six miles from my home. I was on foot with a heavy pack, I was breaking trail through the snow, and it was 35 degrees below zero. I have lived in the Alas¬ kan bush all my life, and with no telephone and once-weekly mail, instant communication can be an extremely precious com¬ modity. Hence, the radio li¬ cense is the most feasible and dependable means to find help in an emergency, to relay your whereabouts to your anxious family, or to let the folks know you just shot a moose and the winter's meat is hanging. Unfortunately, the sim¬ ple fact of the matter is that I just wasn't cut out to be a ham. I didn't have much trouble picking up the code but copying frustrat¬ ed me and the bookwork Photos by Miki Collins WL7AOM Our home in central Alaska is located on a remote lake north of Denali. The big tog cabin is studded with various radio antennas which my father has set up. 73 Magazine • February, 1963 61 Miki Collins WL7AOM gives the dogs a break while she ties down the load in the sled. Bouncing over bare tundra like this was only part of the pile of troubles we had on this ill- fated trip through Denali National Park. really got me I didn't have friends or instructors, I just taught myself from books When you start out hating math, despising physics, and abhorring electrical principles, you aren't doing so hot. Once I began to under¬ stand it a little better it was a lot more interesting, but even so I just wasn't cut out for it even though both my parents and my brother have ham licenses. I didn't become a ham because I wanted to. I did it because I had to. I was attending college when I got my license and had no use for it at that time. It sat in my pocket, its privileges not exercised Until, that is, that fateful day in early April when my sister Miki and I ran out of Generally speaking, around here running out of time is synonymous with running out of dog food On this particular occasion, we were embarked on a 10-day dogsled trip through Denali National Park. (Denali is the Alaskan name for Mt McKinley.) With something like 150 miles to go with our 8-husky team, it was natu¬ rally quite a disappoint¬ ment to break one of our only pair of skis the first day out, for this would consider¬ ably diminish our speed Undaunted, I set up our tiny 80-meter rig, stringing the long antenna through the scrubby spruce border¬ ing the Teklanika River with the intention of letting our folks know that our pro¬ gress might be delayed My first contact! Or was it? We had a good team , but after a few days they began to grow run-down. We rested them often , especially while climbing over passes. Stony Hill is in the background. All the suspense and ex¬ hilaration of getting on the air crashed down when the tuning knob broke off in my hand and, as it was nearly dark, I could not hope to fix it that night. By morning, my already dampened en¬ thusiasm for the wide world of radio had plummeted and I resolved to leave the nasty set in the bottom of a tattered burlap bag. On the third day out, we used the broken ski to jury- rig a broken sled runner The fourth day, our eight sled dogs got wind of a grizzly bear fresh out of hibernation and led us on a tumultuous chase for two miles along the glare ice of a creek before we pulled them under control. Six more days of increas¬ ingly difficult travel saw us less than 100 miles out Blizzards, deep soft snow, and open creeks slowed our progress as much as the broken sled runner. By the tenth day, we were quite out of dog food The sled was shot, broken from crashing down 30-foot snow¬ banks, sliding down steep gullies, and crossing rocky glacial outwash plains. The snowshoes were shot, mak¬ ing trailbreaking nearly im¬ possible, and the dogs were shot —tired, run-down, hungry, and discouraged We were shot. The trip was shot Miki and I pulled off the broad creek we had been on and set up camp in a grove of spruce. My sister built a fire. I dug out the radio The 80m call for help . I swear I didn't believe I could make it work I am by no means an electrical ge¬ nius. Aside from this, my sis¬ ter and I had been totally alone for 10 days. We didn't even know President Rea¬ gan had been shot and seri¬ ously wounded nearly a week bed ore. We had spoken to no one but each other When you are alone in the woods or on the tundra for any length of time — even as little as ten days — and when you are surround¬ ed not by humanity but by natural wonders, when the dominant theme in your life is the magnificently tower¬ ing Mount Denali, then you begin to suspect that you are the only human being in existence. You are nothing but a bit of human dust floating through the broad expanse of natural won¬ ders—you are alone, de- 62 73 Magazine • February, 1963 pendent on yourself, your ingenuity, and your strength to keep you alive. There is no one else —no one else at all. Civilization and the magic of radio just don't exist. That's why I didn't place one jot of faith in my ability to communicate with the outside world Inwardly, I cursed the great and power¬ ful FCC for giving me the privileges of using a medi urn I felt I knew nothing about. I was, in my humble estimation, unqualified, in¬ competent, and inade¬ quate But I had no choice. If 1 didn't make contact, we could well have another 50 miles to go with hungry dogs, breaking trail at one mile an hour or less through snow that was knee- to hip- deep. So 1 tried. For one horri¬ ble instant it occurred to me that I might have forgot¬ ten my callsign, but no, I The 20,320-foot Mount Denali rises about 17,000 feet up from a fairly flat base on the north side where we were traveling . This mountain has the peculiar ability to reflect radio signals so that any two points that can see a particular face of the mountain can communicate by 2 meters; a knife- edge effect allows communication across the top of the mountain. was WL7AOL, and my father, whom I was calling, was KL7IS. For another hor¬ rible moment, the battery seemed dead, but no, after warming it by the fire, it sparked to life. The line from the radio to the antenna was just a cou¬ ple of feet long, so I stood up in the dogsled holding the radio near the antenna, lamming the tiny plug into my ear, I began awkwardly poking the tiny button-key. I had to use my thumb since the fingers of one hand were occupied with the ear¬ plug which kept slipping out, and those of my other hand were supporting the radio KL7IS, KL71H oops KL7IS uh Dt Good heavens! What was W? Oh yes! WL7AOL. I pushed the switch to re¬ ceive, my thumb icily cold. I planned to listen a minute or two before call¬ ing again, and again, and again, for five or ten minutes before giving up until nightfall when I was more likely to raise some¬ one But hardly had I turned over the switch when to my astonishment there was a prompt reply! Glory be! It was a faint signal but steady, sneaking softly from the ear¬ plug into my ear The radio was slipping from my fingers and the ear¬ plug from my ear, but I was so stunned I could only choke and sputter When I had recovered from my shock, I shoved the radio hastily to Miki, snatched up a map —the only available piece of paper —and with trembling fingers scribbled madly on the back Daddy was sending slowly, but the best I could do was take down the dits and dahs as such and translate later Then, shoving the map to Miki and snatching back the radio, I painfully sent out my message, not only to Daddy but to hams all over the great outside who might be monitoring The following day we were picked up by bush plane and flown home with our dogs And that is the story of my first contact. It epitomized the very reason I went for my license —so that I could communicate in times of need It will never be a hobby with me; I will never enjoy DXing, bunny hunts, or other ham sports, but ham radio will serve a purpose for me just as it does for many hams in less isolated areas the purpose of com¬ munication ■ lerome T, Diiak W9}D/2 275 Tareyton Drive Ithaca NY 14850 Error Protection for Your Digital Transmissions Block coding can make your signal 100% error-free. . . hopefully. I n a previous article ("Computers and HF," 73, January, 1981), I discussed the direction I thought ama¬ teurs should go in develop¬ ing inter-computer data communications tech¬ niques on the amateur bands. (By "data" here I mean 8-bit ASCII characters which may be making up formal messages, a digital TV image, computer graph¬ ics, or anything else.) In my opinion, the best course is to pursue frequency shift keying schemes since diver¬ sity reception of the mark and space frequencies may be used to gain interference immunity. Since small com¬ puters are to be used at each end of the communi¬ cations link, error-detecting or error-correcting codes should be used to allow er¬ ror-free reception of the ba¬ sic data even over a com¬ munications channel which produces transmission er¬ rors. Central to the success of these schemes will be block coding of the basic data and the ability of the receiving computer to re¬ quest retransmission of data blocks that were gar¬ bled. In this article I will dis¬ cuss in some detail one im¬ plementation of an auto¬ matic repeat request (ARQ) inter-computer link using error-detecting block cod¬ ing. This discussion is in- 64 73 Magazine • February, 1963 tended to form a basis for conducting experiments with this technique (with special FCC approval) Background We are trying to design a system that will allow error- free transmission of data over a radio channel de¬ graded by noise, fading, and interference from other stations. The most impor¬ tant characteristic of this channel is that we can ex¬ pect it to produce transmis¬ sion errors. We must there¬ fore design our system to recognize when errors have been encountered and to somehow correct them. We will assume that our chan¬ nel is at least good enough to allow error-free recep¬ tion occasionally. The com¬ puters will then keep trying to transfer their data and re- transmit that data de¬ stroyed during periods of interference on the chan¬ nel. Though we will be able to get our data transferred without errors even on a very degraded channel, many retransmissions may be required. This means that the worse the channel is, the longer it will require to transfer (without errors) a given size file. Error-Detection Coding The first thing we must be able to do is transmit our data in such a way that the receiving computer can positively determine when it has received it correctly and when it has not. We do this by error-detection cod¬ ing There are a number of schemes for doing this, and I will not attempt to explain all of them. Each scheme has its own advantages and disadvantages, but in my opinion, the best scheme for our purposes is the "checksum" method With this method, the sending computer breaks down the data into blocks with a certain number of characters in each block. Then it numerically adds all the characters together (thinking of them merely as 8-bit binary numbers). This 8-bit sum, called a "check¬ sum," is then transmitted at the end of the data block When the block is received by the receiving computer, it adds together all the char¬ acters in the block as it re¬ ceived them and compares this sum to the checksum that it received over the link. If the two sums match, the receiving computer can be fairly sure that it re¬ ceived all the characters with no errors in the block, but it cannot tell which characters have been gar¬ bled. Automatic Repeat Request Once we have the capa¬ bility to determine when we have received good data blocks and when we have received garbled data blocks, the next step is to get the sending computer to retransmit the garbled ones. This is done by a sys¬ tem called automatic re¬ peat request (ARQ) The sending computer will normally send a num¬ ber of data blocks in one transmission. At the end of its transmission, the send¬ ing computer waits for re¬ sponse from the receiving computer which will indi¬ cate if it needs any of the blocks retransmitted due to errors. The sending comput¬ er will then begin a new transmission and include at the beginning a repeat of blocks requested by the re¬ ceiving end These repeated blocks will be followed by new data This process con¬ tinues until all data has been transferred During the reception of the data blocks, the receiv¬ ing computer keeps track of the blocks that are re¬ ceived error-free. At the end of the transmission, it sends a short message back to the sending computer acknowl¬ edging the blocks that it re¬ ceived correctly (an ACK message). The sending com¬ puter then assumes that all other blocks were not re¬ ceived correctly and re¬ peats these in its next trans¬ mission. If for some reason the ACK message back to the sending computer is gar¬ bled, the sending computer will simply assume that all blocks in the previous trans¬ mission were garbled and will repeat them all. This is safer than allowing the pos¬ sibility that some garbled data blocks might not be re¬ peated when required. If blocks that have already been correctly received are again encountered by the receiving computer, they simply will be ignored. The important thing is that we receive every data block correctly at least once. This process obviously requires some "intelli¬ gence" in the terminal equipment at both ends of our communications link This will take the form of a computer and suitable pro¬ gram to accomplish the re¬ quired arithmetic, buffer storage, and record keep¬ ing. These tasks will not be difficult to do with a small computer, but they are much beyond the capabili¬ ty of an ordinary TTY ma¬ chine. (This is why straight TTY machines are referred to, with no disrespect in¬ tended, as "dumb" termi¬ nals.) Block Length We need to be careful about the chosen length of our data blocks. If, for ex¬ ample, our channel on a given day is producing er¬ rors about twice per minute on the average and we have chosen a block length that requires 3 minutes to trans¬ mit one data block, it is ob¬ vious that we may never be able to receive even one block error-free. The send¬ ing computer will be forced to continually repeat the first data block of the file, and the file may never be completely transferred. (Our communications sys¬ tem, in this instance, would have broken down.) On the other hand, if we chose data blocks to be so short 66 73 Magazine • February, 1963 that they only required 100 milliseconds to transmit, we would be able to trans¬ fer many data blocks error- free over our example chan¬ nel. If we make the blocks too long, we find that we seldom receive error-free blocks and we spend too much time retransmitting If we make the blocks too short, our overall rate of data transfer ("throughput") is reduced under good channel conditions be¬ cause we are spending too much of our time transmit¬ ting checksums instead of data characters. If we could reliably predict what our channel would be like all the time, it would be possi¬ ble to find a block length that was the most efficient all the time But on some days you may have a tele- phone-quality channel, and on other days the interfer¬ ence may be severe. For this reason, I am rec¬ ommending that the block length be variable and un¬ der the control of the send¬ ing computer (and/or opera¬ tor). This will allow the block length to be opti¬ mized from one transmis¬ sion to the next, if desired, simply by experiment. One would normally want to be¬ gin with a fairly short block length (perhaps 16), and then increase it if few re¬ transmissions are neces¬ sary If, at another time, the retransmission rate gets too high, the block length could simply be shortened on the next transmission Signal Format There are a few other de¬ tails we must consider in or¬ der to make our scheme workable. We require three types of data structures: (1) a block of text characters, (2) an acknowledgment block, and (3) a block of characters to signal the end of transmission. Fig, 1 shows how a text block would be construct¬ ed. It may be preceded by any number of ASCII SYN characters as fillers. The STX (ASCII Start of Text) character flags the start of the block. Following STX are a variable number of 8-bit data bytes The num¬ ber of bytes may vary be¬ tween individual blocks in a given transmission, but it may not exceed 256 The end of data in a block is sig¬ nalled by the ETX (ASCII End of Text) character. Im¬ mediately following the ETX is the 8-bit checksum and then the 8-bit block label. The checksum is formed by numerically adding to¬ gether each data byte and discarding any register overflow Each data block of a transmission must be uniquely identifiable, so we add the block label. The sending computer will se¬ quentially assign 8-bit la¬ bels to each data block it sends. These will allow the receiving computer to iden¬ tify the blocks it has re¬ ceived correctly, and also allow it to properly se¬ quence the data blocks af¬ ter they have all been re¬ ceived correctly. Fig. 2 shows how an ac¬ knowledgment block would be constructed. It also may be preceded by any number of SYN charac¬ ters. An ACK (ASCII Ac¬ knowledge) character flags the start of an acknowledg¬ ment block. The contents of the block are the block labels of the text blocks re¬ ceived correctly during the previous transmission. We will allow a variable num¬ ber of labels, up to 256, in one ACK block The end of the block is flagged by an ETX character. No error¬ checking will be done on the ACK blocks, so no checksum or block label is transmitted. Fig. 3 shows how an end of transmission would be in¬ dicated. The ASCII ETB (End of Transmission Block) character will be used to in¬ dicate to the receiving com¬ puter that it may begin transmitting To ensure that at least one ETB is received even with interference, it will be sent 5 times. After recognizing the ETB char¬ acter, the receiving com¬ puter will wait until the loss of receive signal is detected and then begin transmitting We want to allow the use of many different types of computers to process this code. Since different com¬ puters will require different amounts of time to perform the arithmetic and book¬ keeping operations neces¬ sary to process data blocks, we cannot know for sure how much time must be al¬ lowed between blocks. To make sure we don't make it impossible for some com¬ puters to keep up, a vari- —: .y«y / / —- UP TO 256 ! BLOCK CHARACTERS I LABEL j m bits} CHECKSUM <8 SSTSI Fig . 1. Text block. - ~/ 5YW f ~ -■LABELS- yETXy ^-- y^SYNy ^- UP TO 256 BLOCK LABELS Fig. 2. ACK block. CARRIER Off Fig . 3. Transfer of link control. able number of SYN charac¬ ters will be transmitted be¬ tween data blocks. Depend¬ ing upon the speed of the receiving computer, any number between 1 and 10 SYN characters might be re¬ quired to allow adequate processing time at the re¬ ceiver. The number of SYN characters transmitted be¬ tween blocks can be varied to suit the sending or receiv¬ ing operators. A certain minimum number of char¬ acters will be necessary to allow the receiving comput¬ er enough processing time, but any number of addi¬ tional SYN characters will not disrupt the scheme, since the receiving comput¬ er will simply wait until it encounters an STX charac¬ ter to start processing the next data block. The only effect of sending more SYN characters than actually needed will be to reduce data throughput below the optimum for that combina¬ tion of computers Another reason to allow varying the number of SYN characters is that we want to be able to use this scheme over a variety of ac¬ tual data rates. Since the computer processing time will remain fixed while the character transmission time may change considerably, it will be advantageous to use fewer synchronizing characters at the lower data rates and more at the higher data rates to allow the same processing time at the receiving computer. This system does not lend itself well to informal conversation at low typing speeds and would primarily be of use after initially es¬ tablishing contact with an¬ other station and mutually deciding that a large block of data (perhaps 100 formal messages) is to be trans¬ ferred. At this point, both stations would switch to the block-encoded mode to transfer the data Once in the block-encod¬ ed mode, we would begin a transmission with a leader of SYN characters perhaps 5 seconds long The remain¬ der of the transmission would consist of ACK or text blocks. We will require that the text blocks be transmitted sequentially, but we will allow the ACK blocks to appear anywhere during the transmission Since we will not be using error-detection on the ACK blocks, it will be a good idea to send the ACK blocks more than once to make sure they are received cor¬ rectly. Between blocks any number of SYN characters may be transmitted The last block of the transmis¬ sion will be followed by several SYN characters and then the five ETB charac¬ ters to signal the end of transmission. Diversity How can diversity opera¬ tion help us in this scheme? If a receiving interface is available where the mark and space frequencies can be detected independently, the receiving computer can treat the two frequencies as separate signals, and we get fwo chances for each data block to be received cor¬ rectly. If either the mark or space channel produces an error-free block, the receiv¬ ing computer can ACK that block This can greatly re¬ duce the number of retrans¬ missions under moderately degraded conditions and greatly increase through¬ put. Summary I have described one of several possible methods to achieve error-free transmis¬ sion of digital data over a very imperfect radio chan¬ nel by using error-detecting coding, ARQ, and comput¬ ers at each end of the radio link I hope these ideas will help to get some experi¬ menting underway in this direction ■ Introducing The SRT-3000 A High Performance RTTY Communications Send Receive Terminal • Built-in demodulator & AFSK modula¬ tor for 170,425,850 Hz shifts, high and low tone pairs • 60,66,75,100,132 WPM Baudot, 110,300 Baud ASCII, 5-99 WPM Morse • 1000 character text buffer with BREAK feature • Ten 80 character mes¬ sage memories with battery backup • Selectable display formats, 24 lines x 72 characters (2 pages), 24 lines x 36 characters (4 pages), 16 lines x 36 characters (6 pages) • Split screen operation • On screen status line displays a tuning bar, mode, speed, shift, tone pair, normal/reverse, USOS, WRU, SELCAL, buffer mode and buffer count • Cassette Interface for long “Brag Tapes” or unattended message storage • Baudot and ASCII printer outputs • Built-in audio monitor • Built-in 110 VAC power supply • Other features—PTT control, WRU, SELCAL, sync Idle, CW ID, USOS, autostart, full or half duplex, scope outputs, weight control, intercharacter spacing, reverse video, RS-232, word wrap around • Compact size only 13.3 x 10.3 x 4 inches • Made in USA. SRT-3000 List Price $ 995.00 INTRODUCTORY PRICE $ 795.00* Send For Free Information 787 BRIAR LANE, BELOIT, WISCONSIN 58511 introductory prices good thru Feb, 28, 1983. Optional 9" video monitor shown $149.00 . (608) 362-0410 68 73 Magazine * February, 1983 Bob Morrison AC9C 6517 Wakopa Court Fort Wayne IN 46815 Drive-Time SWLing This simple car radio converter will open up a whole new world of driving. T ired of rock music on your car radio? Then lis¬ ten to the BBC, Voice of America, Radio Canada, and other shortwave broad¬ cast stations. Only a 2-tran- sistor converter is required. The circuit converts the 16-, 19-, 25-, or 31-meter bands to AM standard- broadcast frequencies. Sim¬ ply insert the converter be¬ tween your car antenna and antenna input Maybe you prefer your shortwave listening in¬ doors. Then you will need a low-cost surplus car radio (Olson Electronics, 260 S. Forge St., Akron OH 44327) and a 12-volt power supply (Radio Shack). The car radio is well shielded and will not pick up AM standard- broadcast interference. The converter schematic is shown in Fig. 1. The sim¬ ple Pierce oscillator circuit uses a 2N5397 JFET to re¬ strict oscillator output noise. No tuned circuits, other than the crystal itself. are used in the oscillator. The 3N204 MOSFET mixer provides low noise, good dynamic range, and moder¬ ate gain. Mixer gain must be high enough for antenna noise to mask the car radio internal noise. On the other hand, mixer gain must be low enough so that over¬ loading of the car radio by strong signals is not a prob¬ lem. Thus, the higher-gain 3N211 is not recommended here. Temperature tests show the converter performance to be virtually constant over the range —40° C to 85° C. Oscillator frequency drift, for a 16.3-MHz AT- type crystal, is less than ±1.5 kHz over this temper¬ ature range. Crystal* frequencies are selected so that one crystal *AT-element, fundamental mode, parallel-resonance, 32-pF load capacitance. Jan Crystals, PO Box 06017, Ft. Myers FL 33906. Cost is approximately $5.00. SW Band Xtal can be used for two short¬ wave bands. Signals from these two bands do not overlap. The mixer input circuit selects one of the two bands. Table 1 lists the values of LI, L2, and the crystal frequency for each band. The values of LI should work well with CM wind¬ shield antennas. Regardless of the antenna type, LI should be selected for max¬ imum signal strength at center band. LI and Cl, in addition to matching the antenna to the mixer, act as a low-pass filter at TV and FM broadcast frequencies. This filtering function is very important since unat¬ tenuated signals from pow¬ erful VHF stations can pro¬ duce undesirable mixer products at the converter output. A 19-meter version of the converter is mounted under the dashboard of my Chev¬ rolet. Standard broadcast Freq. LI L2 I2-J5VDC Fig. 1. Schematic for the converter for shortwave listening . 70 73 Magazine • February, 1963 16m 16.3 1.5 1.8 19m 16.3 1.8 2.2 25m 11.0 2.7 3.9 31m 11.0 3.9 5.6 Frequency in MHz. Inductance in microhenries. Table 1. Number One On 2 Meters! The best selling and per¬ forming 2 meter FM rig in the USA, gives you more for your money. 25 watts, Touchtone® mike, 10 memories with built-in memory retention, scanning priority channel, sub-audible tone module built-in_ and much, much more! Call or write for brochure. ORDER NOW DIRECT CALL TOLL FREE 800 - 251-4141 This number for ORDERS ONLY! ORDER DIRECT or at your dealer! DISTRIBUTED BY: at* - 1 1 KB 11 1 1 Q n oi 1 O O O \ Q Q e — 1 1 INCLUDES Tone Pad Microphone and all accessories. Shipping: $5.00 Eastern U.S.A. $7.50 Western U.S.A. FM2030 Central & South American orders: PHONE: (305) 592-7016 $ 30 ? - Bank Cards SSI KDK DISTRIBUTING CO., INC. 782 S. GALLATIN RD. (MADISON SQUARE SHOPPING CTR.) MADISON, TN 37115 Mail Order - COO - Bank Cards Jg Company reserves the right to change specifications and prices without notice. 15 — PHONE (615) 665*7949 -TLX56-8652 feedthrough causes no sig¬ nificant interference with shortwave signals More specifically, a 1-kW station at 11 MHz is not detect¬ able beyond a half mile from the station antenna. For negligible feedthrough, the converter must be con¬ tained in an aluminum box Also, a shielded cable (Ra¬ dio Shack) must connect the converter to the car ra¬ dio To avoid generator/al¬ ternator whine, the convert¬ er box must be securely fas¬ tened and grounded to the metal frame of the dash¬ board with sheet-metal screws. To control ignition noise, resistor-type spark plugs must be used in the car engine. The converter circuit is constructed on top of an unetched, copperclad PC board No etching or cut¬ ting of the board is re¬ quired Circuit grounds are soldered directly to the board A few VS-Watt, 4 7-megohm resistors, with one end of each soldered to the PC board, are used as standoffs. The crystal sock¬ et is epoxy-glued to the board Inductors must be at least one inductor diameter from the PC board All in¬ ductors must be separated by at least two inductor di¬ ameters Naturally, all cir¬ cuit leads are kept short All resistors in the sche¬ matic are VS -Watt carbon with values in Ohms All in¬ ductors are molded rf chokes, unshielded type, with VS-inch-length bodies and values in microhenries. Integer values of capaci¬ tance are in pF, and the cor¬ responding capacitors are ceramic or dipped mica Decimal values of capaci¬ tance are in jiF, and the cor¬ responding capacitors are ceramic. One final note Experi¬ ence indicates that, after in¬ stalling the converter, one should tune the car radio while keeping one s eyes on the road.B ALL NEW H.F. 10/160 METER SOLID STATE P.L.L. TRANSCEIVER USB-LSB 4 Memories 3 Way Auto-Scan Includes New Bands 3-Step Tuning Speed IF Tune ± 1 KHZ Built-in Dual VFO CW-W CW-N 200 W. PEPU60M-12M) 100 W. PEP(IOM) Built-in Power Supply AC-120 VAC DC-13.8 V -Ground External ALC 13.5 VDC Relay JUST SLIGHTLY AHEAD 1275 N. GROVE ST. ANAHEIM, CA 92806 TO ORDER OR DLR INFO. CALL (714) 630-4541 NOTE Price. Specifications sublet lo change without notice and obligation See List oi Advertisers on page 114 73 Magazine • February, 1983 71 Stop That Heist! What would you say about an alarm that's portable , inexpensive, and goes off when a thief just touches the doorknob? We say build it. Dennis Pharr WD5IWY to the input circuit. When 3521 5£ 45th Street the doorknob is touched, Oklahoma City OK 73135 the alarm will sound. T his article will describe a low-cost alarm circuit that is activated by a simple touch of the hand. Its opera¬ tion depends upon a source of 60-Hz signals that is pres¬ ent in virtually all homes wired with standard 110 V ac. The sensitivity of the alarm is adjustable and easi¬ ly varied to suit the par¬ ticular 60-Hz environment. The alarm requires no in¬ stallation; it is simply hung on the doorknob by a hook formed from heavy-gauge copper which is connected Circuit Operation Operation of this circuit is fairly simple. Referring to Fig. 1, when the doorknob is touched, a 60-Hz signal is applied to the gate of FET Q1. This signal is then ampli¬ fied a small amount and ap¬ plied to the trigger terminal (pin 2) of U2, which acts as a one-shot. The output of U2 then goes high, causing the output of the Set/Clear flip- flop, which consists of U3A and U3B, to go high also. The high on the output of the Set/Clear flip-flop en¬ ables audio oscillator U4 which acts as the alarm. The alarm will continue to sound until it is reset by depressing push-button S2. Also built into the circuit is a delay feature which will allow the alarm to be used while you're away from your house or apartment. The de¬ lay portion of the circuit, made up of Q2, U1, and U3C, allows you to activate the alarm and go out the door while still handling the doorknob. Operation of the delay circuit is also quite simple. When power is initially ap¬ HE Fig. 7. Schematic diagram of touch alarm. 72 73 Magazine • February, 1963 plied to the circuit, a trigger pulse is generated by Q2 which causes the output of U1 to go high. The high on the output of U1 is inverted to a low by U3C and applied to pin four of U2. This low on pin four of U2 disables the alarm for approximately thirty seconds, with the components specified. This should be plenty of time to exit the door. If you don't wish to include the delay feature, simply leave out Q2, U1, and U3C and con¬ nect pin four of U2 directly to Vcc. Quiescent current drain of the circuit is about fifteen milliamperes with the nine- volt battery specified; there¬ fore, two nine-volt batteries in parallel or six penlight cells in series should be used for powering the alarm. Construction The circuit can be built most easily using perfboard- type construction. Sockets should be used for all the ICs, should replacement be¬ come necessary. A plastic case similar to those sold by Radio Shack can be used for housing the unit, and a piece of #14 gauge, or heavier, bare copper wire may be used for the touch element. The wire should be bent into a hook shape for hanging on the doorknob. R1, the sensi¬ tivity adjustment resistor, should be a panel-mount- type potentiometer instead of a trimpot mounted on the perf board, as this will great¬ ly ease adjustment when the alarm is to be used. Test and Adjustment The alarm may be tested for proper operation with¬ out hanging it on a door¬ knob. To do so, first adjust sensitivity control R1 for minimum resistance and then apply power. It you have included the delay cir¬ cuit, you will have to wait approximately thirty or forty seconds before the alarm will arm itself Now, while touching the pickup ele¬ ment. adjust R1 towards maximum resistance At some point while adjusting R1, the alarm will trigger and go off. To reset the alarm, momentarily depress S2. I must mention here that depressing $2 will only reset the alarm; it will not activate the delay. To reactivate the delay, power must be momentarily interrupted by opening and closing SI. Also, after the sensitivity has been increased, the alarm will sound when power is ap¬ plied. To prevent this, hold down the reset button while applying power R1 will have to be readjusted when the alarm is hung on the doorknob, as this changes the sensitivity of the input circuit. Summary This alarm would prob¬ ably be most useful to those living in apartments and could easily be thrown into a suitcase for use in motel or hotel rooms when away on trips. But, wherever used, it will provide a sense of security otherwise un¬ known. if you have any questions or comments concerning the operation of the alarm, an SASE to me will bring a prompt reply.® HAL’S SHOPPER’S GUIDE HAL 2304 MHz DOWN CONVERTERS (FREQ RANGE 2000(2500 MHz; 2304 MODEL »1 KIT BASIC UNIT W/PREAMP LESS HOUSING & FITTINGS St 9.95 2304 MODEL #2 KIT (with preamp) S29.95 2304 MODEL #3 KIT (with High Gain preamp) S39.95 MODELS 2 & 3 WITH COAX FITTINGS IN & OUT AND WITH WEATHER-PROOFED DIE CAST HOUSINGS BASIC POWER SUPPLY . 119.95 POWER SUPPLY KIT FOR ABOVE WITH CASE S24 J5 A NTENNAS A OTHER ACC ESSORIES AVAILABLE SEND FOR MORE INFO 2100-2500 MHZ •HMR-li COMPLETE UNIT COMPLETE SYSTEM AS SHOWN NOT A KIT INCLUDES A PC BOARD, POWER SUPPLY. CABLES 5 CONNECTORS-PRE ASSEMBLED AND TESTED 24dB GAIN OR GREATER 1 UNIT.SI 49.95 2 UN ITS . .SI 39.95 aa. 3 OR MORE UNITS Sl29.95aa. •HAM MICROWAVE RECEIVER PRE-SCALER KITS HAL300PRE (Pr«K>niled G 10 board and ait components) S14J5 HAL 300 A/PRE {Same as above but w.th preamp? S24.95 HAL 000 PRE (PrinJntted G-1Q board and ail components) 129.95 HAL S00 A/PRE (same as above but with preamp) S39JS PRE-AMPLIFIER HAL-PA’19 WIDE BAND PRE AMPLIFIER. 2-200 MHz BANDWIDTH (- 3dB POINTS). 19dB GAIN FULLY ASSEMBLED AND TESTED S8.95 HAL-PA-1.4 WIDE BAND PRE-AMPLIFIER, 10 MHz TO 14 GHz l2dB GAIN FULLY ASSEMBLED S1Z95 HAL-PA-2.1 GHz 2STAGE PRE-AMPLIFIER, DESIGNED FOR 2304 OOWN CONVERTER. MADE TO PIGGIE BACK ON THE 2304 BOARD. OFFERS 20 dB GAIN ALSO HAS AN IM¬ AGE REJECTION FILTER. SHIPPING INFORMATION ORDERS OVER S2S WILL BE SHIPPED POST PAID EXCEPT ON ITEMS WHERE ADDITIONAL CHARGES ARE REQUESTED ON ORDERS LESS THAN 125. PLEASE INCLUDE ADDITIONAL S2 60FQR HANDLING AND MAILING CHARGES SEND 20c STAMP FOR FREE FLYER . t* H al-T ronix inc P.O. BOX 1101 [M SOUTHGATE, MICH. 48195 C PHONE (313) 285*1782 ^31 ® MEgc! HAL HAROLD C NOWLAND W9ZXH m Pro ■ Mi « fi a ■— iiia a— SOON TO BE LB-VHF-UHF SOON TO BE TYPE ACCEPTED CALL OR WRITE FOR OUR COMPLETE CATALOGUE. Phone: 215-436-6051 TELEX: 499-0741 MELCO ^See Ust of Advertisers on page 114 73 Magazine • Februaiy, 1983 73 Ron Hornberger KB9SP Rte . I Box 258 Cairo \L 62914 Get the DX Edge There are ways to stand out in the pileups for Spanish-speaking stations. One is to speak their language. D o your present operat¬ ing activities make your heart beat faster and your nerves tingle from ex¬ citement? If not, you could be in a bit of a rut. Novices seldom have this problem, but many other hams later find that they need to try other avenues of their hobby Operating an exotic mode like slow-scan television is one approach; another is chasing certifi¬ cates My choice is talking with hams of the Spanish¬ speaking countries. Why try the Spanish lan¬ guage? For openers, the Spanish-speaking people are among the most gra¬ cious people in the world and are very patient with beginners speaking their language. They bend over backwards to overlook er¬ rors and always enthusiasti¬ cally encourage beginners. A knowledge of Spanish gives you an edge in work¬ ing Mexico, Central Amer¬ ica, South America, the 76 73 Magazine • February, 1963 West Indies, Spain, the Ca¬ nary Islands, the Balearic Is¬ lands, and the North Afri¬ can cities of Ceuta and Mel i I la. (These are Spanish enclaves on the coast of Morocco.) And that consti¬ tutes a lot of DX! Spanish is a good begin¬ ner's language It often is pronounced nearly as it is spelled For example, the F sound is always spelled with an F It does not have spelling nightmares as does English, in which an F sound can be represented by gh(in enough) or by ph (in phone) Another advantage is that when the other operator hears you attempting to use his language, he often will try his hand at speaking English It's a bit like fish¬ ing—you throw out your lure in the form of spoken Spanish and reel in your catch in the form of a con tact in English Most hams begin their hobby as Novices working other Novices, and this is a good way to begin using Spanish The Novices from Spain are licensed to use voice communication from 29,000 kHz to 29,100 kHz. Their callsigns begin with EC instead of EA. During the fall, spring, and winter months, they can often be worked from about 1200 LHC until 2000 UTC in the mid western United States Spanish Novices exhibit that universal trait of Nov¬ ices everywhere—enthu' siasm A contact w ith them is not the usual one of "You are 5X9 in Madrid, QSL via the bureau and QRZed/* They usually will answer with an excited tone in their voices, often with a rapidly spoken "OK, OK, OK!" For many this may be their first DX contact, and they will QSL direct Their QSLs are often beautiful postcards of their QTH, with the technical information stamped on the back 1 al¬ ways look forward to checking my mail for a new postcard with interesting stamps. They may also send a red ribbon with a yellow center stripe, which repre¬ sents the Spanish flag. After working a stateside Novice station, you always enjoy working that same station again when he has upgraded. You will get an even bigger kick doing this with Spanish Novices. One day I called CQ in Spanish on 15 meters and was an¬ swered by an EA whom I had worked several months earlier when he was a Novice EC. He remembered me, desc ribed my QSL card, and noted what a great pleasure it was to have another contact You don't get that from a DX pileup! If you have ever wanted to be a DX station but you live in Chicago or Los Angeles or Detroit or oper¬ ate low power with some¬ thing less than a gain an¬ tenna, take heart; the Spanish Novices consider Reader Service for facing page you to be good DX I know, because one day after re¬ turning home from work I found 10 meters to be open into Spain I answered a CQ in Spanish, and at the end of the contact I had a new ex¬ perience: Several Spanish stations shouted my call- sign! It was a bit nerve- wracking at first, but I got used to being a hotly sought-after DX station In one hour I worked about a dozen stations, exchanging complete QSL information, and could have worked more, but the band went dead. If you enjoyed the chal¬ lenge of working all SO states in the US, why not try your luck at working all 50 provinces in Spain? When you have all 50 confirmed, you can apply to the U R.E , Box 220, Madrid, Spain, for a certificate. If you are hav¬ ing a hard time working the EA9s from the North African Spanish enclaves of Melilla and Ceuta, you might try the EC9s in the Novice bands There also are quite a few EC6s from the Balearic Islands and EC8s from the Canary Is¬ lands They might even con¬ sider you to be DX, espe¬ cially if you know Spanish. Incidentally, if you are a person with a bit of imagi¬ nation, get an atlas and a guide book or travel book about Spain and look up the cities in Spain that you work It's like an inexpen¬ sive vacation I use the guidebook by Baedeker which lists the main cities in alphabetical order with col¬ or pictures, a short descrip¬ tion, history, and a list of fiestas and events. It's a bit expensive at about $11 00 Rand-McNally has a good pocket-size one for about $4.00. Both are available at most bookstores. Also on the 10-meter band from 28,900 kHz to 29,000 kHz are the Novices and Intermediates from Argentina, and they are allowed to use voice com¬ munication here They can 78 73 Magazine * February, 1963 be worked almost anytime that 10 meters is open, and their operating hours are close to ours, since their local time is 3 hours behind UTC, The calls of Argentine Novices begin with LU, as do the calls of higher-li¬ censed Argentine stations. You can start working these Spanish-speaking sta¬ tions with just a few basic words and phrases First, most consonants are pro¬ nounced similar to ours. The vowels are pronounced clearly and distinctly Pro¬ nounce A like the English ah, E like our ay in say, I like the i in machine, O like our oh, and U like oo in cool You already know the Q signals and have only to pronounce them as letters of the Spanish alphabet QSB is pronounced coo- aysay-bay ; QSL is coo- aysay-ay/ay; QTH is coo-fay- ahchay ; QRM is c oo-airray- aymay, QRA (which means "my name is ") is coo- airray-ah Know the numerals 0 to 9 and a few useful phrases (see box) A typical contact might go thus: Esta es W1AW , this is W1 AW; gracias , thanks; su reporte es cinco nueve, your report is 59; QRA Hiram , name is Hiram; hay QRM, there is QRM; QTH Newington , estado de Connecticut , location is Newington, state of Connecticut; habla despacio , speak slowly; cambio, over. This article touches on only the essentials, and its main purpose is to promote interest in working Spanish¬ speaking stations Several aids have appeared recent¬ ly which are shortcuts to a proficiency in using Spanish on the ham bands The Radio Amateur's Conversa¬ tion Guide by OH1 BR and OH2BAD lists, in eight lan¬ guages, 147 sentences relat¬ ing to ham talk, and this is available from Transelec- tro-America, 2301 Canehill Avenue, Long Beach CA 90815. It has a dictionary listing ham-related words. also in eight languages. For example, if you need to find the Spanish phrase for "fre¬ quency shift keying/' just look it up in this dictionary. The book has quite a few spelling mistakes, at least in the Spanish section, and is a bit expensive, but it has some interesting cartoons and the dictionary is unique Tapes in each lan¬ guage are available for $6.00 each, and buying the Spanish one certainly would be a wise invest¬ ment. Another tape, "Hola CQ" is available with 15 pages of text from the ARRL for $7 00 The basic goal is not to learn a lot of grammar and a large general vocabulary When you are on the air, you likely will not be asking a Spanish repairman the cost of a new carburetor for your car, but you would be informing a Spanish-speak¬ ing operator that his modu¬ lation is good or bad Learn a little grammar and a small specialized vocabulary and have a good time I did study Spanish about 15 years ago for two years and had some success with the written language, but the spoken language would drive me to find the nearest interpreter for anything more complex than "Buen¬ os Dias," I have been using Spanish over the air for over a year now, and with the help of the conversation guide, I can make it through a contact even if I don’t understand everything. Much like learning the code, practicing Spanish makes perfect. The FCC says one of the reasons that the Amateur Radio Service exists is "the continuation and extension of the amateur’s unique ability to-enhance interna¬ tional goodwill" I think I know what these words mean. One day after eight hours of hassles and harass- ments at work, I came home and turned on the rig I made contact with a Novice from Argentina. We made the usual exchanges of name, QTH, and reports. Then I heard some words that I had not heard at work that day which translated into: "Magnificent, I con¬ gratulate you for your very good Spanish!" —the first kind words I had heard all day! And I knew that my goodwill had certainly been enhanced that day. I hope that your goodwill also will be enhanced as a result of talking with Spanish-speaking countries; besides, it's a lot of fun! Siete tresfM Spanish Words and Phrases Spanish Pronounced English cero— say-roh zero uno— oo-noh one dos¬ dose two ses— trace three quatro— kwah-troh four cinco— sink-ho five seis— say-iss six siete— see-ay-tay seven ocho— oh-cho eight nueve— noo-way-vay nine hay eye or 1 there is gracias grah-see-ahss thanks habla despacio ah-blah des-pah-see-oh speak slowly codigo postal koh-dee-goh poh-stal zip code apartado postal ah-par-tah-doh poh-stal PO Box cambio kam-bee-oh over direccion dee-rek-see-own address su reporte es soo ray-port ay ess your report is mi mee my R. R. McKay NSADA 317 Ernst Avenue Dayton OH 45405 Power-Line Protection: The Weak Link Solid-state equipment may be extremely reliable > but just microseconds of overvoltage can change that. M ost amateurs take pre¬ cautions to prevent damage to their homes and equipment from lightning strikes or near strikes on their antennas or towers. Few of them, however, are as well protected from the other common source of problems — power-line surges. These surges fre¬ quently result from strikes on power lines and can cause transients of thou¬ sands of volts in ordinary 110/220 household systems in the vicinity of the strike. Pulling the plug on ham equipment during electrical storms has been one way of solving the problem. How¬ ever, many hams participate in weather nets during se¬ vere storms, so pulling the plug on the rig is not the an¬ swer. Also, pulling the plug on everything in the house is a difficult way to live. It's much better to put one of the new transient voltage suppressors on your line, re¬ lax, and know you are safe from anything except a di¬ rect hit. Most amateurs who grew up in the vacuum-tube era have paid little attention to transients as most electrical and electro-mechanical de¬ vices with tubes can with¬ stand large instantaneous overloads with little appar¬ ent damage. The advent of the solid- state age has brought with it a new set of problems. Solid-state equipment is ex¬ tremely vulnerable to tran¬ sients. Voltage surges above rated values, even though only microseconds in duration, will destroy this circuitry. Many baffling failures of solid-state equip¬ ment, when thoroughly in¬ vestigated, have been found to be due to transients which no one knew existed. Fortunately, the technol¬ ogy that brought us these solid-state wonders has also brought us protective de¬ vices to compensate for their weakness. The de¬ vices, called transient or surge protectors, are basi¬ cally metal-oxide varistors. Recent improvements in composition and fabrica¬ tion have allowed the de¬ velopment of a whole fami¬ ly of devices for overvolt¬ age protection. Surge protectors de¬ signed for home electrical systems are now available at most electrical supply houses. The units are in¬ tended for use in service-en¬ trance boxes and fit into standard knockout holes. They will provide protec¬ tion for household circuits against surges capable of damaging common electri¬ cal equipment. The protection unit is connected across the line as shown in Fig. 1. Connec¬ tion is simple; anyone with a basic understanding of electricity can connect it. Open the main breakers when installing the unit. The protector remains in a non-conducting state under normal conditions. Volt¬ ages exceeding 175 V cause the unit to conduct, divert¬ ing the transients to ground. The action is somewhat similar to that of the com¬ mon zener diode. The unit returns to a non-conclucting state when the voltage re¬ turns to a level below its critical breakdown value. Not only ham equip¬ ment, but also most of the new things we buy for our homes, from clocks to ranges, now include solid- state devices. So a sup¬ pressor on your incoming line could save more than just your ham gear. Manufacturers recom¬ mend placing a protection unit as far ahead of your household wiring as possi¬ ble for maximum protec¬ tion. However, your local power company may have ideas on placement. Mine would not allow placing the protector ahead of the main breakers. You can argue with them, but camp lanterns are tiring and they won't run our refrigerator or my ham rig. So, do what they say. Connected this way, a severe surge could wipe out the main breakers but the individual circuits are still protected. It's a small investment in peace of mind.B Reference General Electric, Transient Volt¬ age Suppression Manual, 2nd Edition. 73 Magazine • February, 1963 83 Bob Baird W7CSD 3740 Summers Lane Klamath Falls OR 97601 Higher Voltage, Less Weight A voltage quadrupler that weighs ounces? You bet—and cheap surplus capacitors make it possible. V oltage doubler, tripler, and quadrupler cir¬ cuits were in the books way back in the days of vacuum- tube rectifiers. But with the vacuum tube, we had prob¬ lems of separate insulated filament supplies and/or limited insulation between an indirectly-heated cath¬ ode and its filament. Solid- state diodes took care of this problem very neatly, but the day of the high-ca¬ pacity capacitor for a rea¬ sonable price had not yet arrived. So, the admonition always was, "This is a good circuit for a very limited load The voltage vs. load characteristic is terrible!"' Well, all of the above shortcomings have been pretty well overcome Six- hundred-uF, 360-working- volt photoflash capacitors have appeared on the mar¬ ket recently at various bar¬ gain prices. I was able to buy 10 for $7.50. Now we have all of the necessary ammunition Let's see what we can do STANDARD VOLTAGE MULTIPLIER MOOIEIED VOLTAGE MULTIPLIER t>) Fig. 1 - 84 73 Magazine • February, 1983 with it. First of all. in the in¬ terests of safety, we need a circuit where the ground side of the ac line is also the negative terminal to our power supply, if there is to be no transformer. This rules out the full-wave doubler and any quadru¬ pler that might be derived from it. The full-wave doubler has been a favorite for converting a 700-volt TV transformer to 1500 volts dc. With a transformer, you can earth ground at any point you want, but with just the ac line, one side already is grounded. A floating ground in elec¬ tronic gear is a very dubious thing. It's possible to tie all negative returns together, insulated from a grounded chassis, and then go to the chassis through a by-pass capacitor. There have been some commercial electron¬ ic devices that have done this, generally with a plastic cabinet surrounding the unit Let's not do thisf Fig 1 (a) shows the stan¬ dard-voltage multiplier cir¬ cuit At the risk of duplicat¬ ing most handbooks, the first negative half cycle on the hot side charges Cl to peak voltage (in the case of 120-volt line, E=120X V r l = 170 volts) On positive half cycle, the line is +170 in series with Cl, which makes 2E, thus charging C2 to 2E The next half-cycle ground side is + E with re¬ spect to the hot side This is in series with C2 and the third diode, thus charging C3 to 3E The next half¬ cycle hot side is + E with respect to ground and in series with C3 to make 4E, and C4 is charged to 4E, etc This can go on indefinitely as long as no current is drawn from the supply, but if the capacitors are large enough, you can get close to the no-load value with considerable load. Now, it will be noted that we need capacitors with in¬ creasing voltage values. For a quadrupler, for instance, we need a capacitor capa¬ ble of withstanding about 170X4 = 680 volts This will take two of the aforemen¬ tioned 360-volt caps in se¬ ries. So, let's use C2 a sec¬ ond time instead. )ust re¬ turn from C4 to the plus side of C2 instead of to ground. Also, return C3 to the plus side of Cl instead of to the hot side of the line With these modifications we get Fig 1 (b), and no ca¬ pacitor has more than 2E across it 2E = 340 volts, and the working voltage of the caps is 360, so we are safe Our voltage regulation may not be quite so good with this modification, but it is still better than many peo¬ ple would have guessed. Fig. 2 shows the charac- VOLTAGE V* LOAO LINE VOLTS 0)7 RMS Fig. 2. AT LAST! This service will be available nationally. Lab tested & time proven modifications professionally installed in your amateur Handy-Talkie 2M, 220, 440, MH2 transceiver. HAVE ALL PL TONES AVAILABLE AT YOUR FINGER TIPS (Xitboard the dip switch! Have it neatly iniayed into the back cover of yourHarxty-Talkie making ail 32 PL Tones Selectable at a moment’s notice §23 Got your own PL? Send it to us with youf Hancty-Taik»e unit and we do the professional installation for you. 355 We wifi install a new PL and miay the dp switch into the back cover of your Handy-Talk* ready to operate. Send us your Handy Tafloe unit and a check o f money order plus S3.50 for shipping and hand¬ ling payable to AAW PRODUCTIONS, INC. For TEMPO units the dip switch is iniayed into the Pustvto-Talk bar The TEMPO 8-15 will have the dip switch iniayed into the back cover. 345 We will install a NEW BATTERY BEATER in your TEMPO S-1,3-2, S-4, 3-5 READY to operate Your New Battery Beater will use the same jack as the charger with no new holes and regulation circuits built wm unit, Comes with Cigar Lighter Adapter with internal tuse CONTACT AAW PRODUCTIONS FOR SPE¬ CIAL MODIFICATIONS YOU MAY WANT TO HAVE DONE. WE SPECIALIZE IN THE TEMPO HANDY-TALKIES. ALL WORK GUARANTEED FOR 30 DAYS. SENO YOUR HANDY-TALKIE AND A CHECK OR MONEY ^^/FEomtcjjpNS - Wm W California 90405 (213) 829-9310 teristics of voltage vs load for a doubler, a quadrupler, times six, and times eight The quadrupler seems most interesting. This voltage would be enough for a sizable linear and, with speech peaks to half an Amp, might not go much below 600 volts. The times eight supply would deliver about a quarter of an Amp at 1000 volts. This might fit someone's needs This is a power supply weighed in ounces? Now let's look at a few practical aspects How do you get this thing fired up? I used 1000-piv, 2.5-Amp di¬ odes because I had them. Then I brought the voltage up slowly with a variac to run the tests. Once you are up to line voltage you are in business, but don't throw it on the line point blank or the surge current of the ca¬ pacitors will wipe out your diodes. On a second power sup¬ ply, a quadrupler, I put 250 ^ See Ust of Advertisers on page 114 Ohms in series to charge up the capacitors and then shorted it out with a switch before putting any signal in¬ to the linear amplifier I used for a load. But you must remember to open that switch before you turn on the power the next time! A 30-second thermal time delay could be installed to take care of this. A second must is that you must carefully polarize your power plug If you have three-pronged plugs in your wall, determine which pin is hot and which is cold An NE51 can be made into a tester very easily. Solder a short piece of hookup wire to the center contact. Hold the brass base in your fin¬ gers and insert the wire into one pin of the wall plug. If the neon lights, that is the hot side. (Of course, a light bulb wired between one pin and the earth ground will tell you the same thing.) The same procedure goes for two-pin plugs, but you must mark them and al¬ ways plug in in the proper way. If you are going to plug the supply in in several places, you need to check each plug. Journeymen electricians have been known to get the hot and cold wires reversed even in modern three-pin plugs The advantages of the transformerless power sup¬ ply are obvious. In addition to the savings in bulk and weight, you can mount the whole thing on a piece of perfboard and put it inside the unit you wish to use it with —600 volts for some¬ thing like $5. If you live in ZL-land or some country that has two- wire service with 240 volts to ground, a voltage qua¬ drupler has possibilities for something pretty big ■ Doubler Original Data Quadrupler mA Volts mA Volts 0 330 0 663 140 323 75 643 280 316 160 623 375 313 185 616 550 308 220 611 270 602 350 585 410 573 480 561 x6 X8 mA Volts mA Volts 0 987 0 1300 70 950 104 1170 250 834 90 1190 300 807 250 976 Table 1. 73 Magazine * February, 1983 88 Ed C. Miller N7APE 306 W. Court St. Weiser ID 83672 Make Room for More Age Automatic gain control is useful in many applications. With this simple circuit , you'll never have to be without it. W hat with avc, ale, age, etc., we have some form of automatic control over the gain or output of a lot of circuits. Still, there is a place where there's room for some more automatic gain control. That's in a speaker amplifier. There are many times when we use a small speaker amplifier to up the level of an output de- signed for headphones, where the amplifier is used to monitor two or more cir¬ cuits, or where the amplifier is used with some special equipment that has large output variations. In these cases, manual gain can have a drawback or two—forget¬ ting we've cranked the vol¬ ume down or up, missing something, or shocking our eardrums. Here's a circuit for a small speaker amplifier with auto¬ matic gain control that is both simple and flexible It's simple because it uses one 1C, one FET, a couple of di¬ odes, and a few standard re¬ sistors and capacitors, with no complicated setup ad¬ justments. It's flexible be¬ cause it allows for a wide range of release times set only by a resistor and/or capacitor. There are two primary methods to automatically control the output level of an amplifier stage One is to vary the gain of the ampli¬ fier (remember the 6L7 tube); the other is to operate the amplifier at normal gain and introduce a variable loss pad at its input or out¬ put. The latter is the sim¬ plest when many of the parts may be coming from the junk box. In the unit shown, the loss pad is at the input to the amplifier where the signal level is small. This reduces the distortion intro¬ duced by the variable im¬ pedance leg of the pad —in this case, an FET. Distor¬ tion is further reduced by applying a proportional sig¬ nal through the FET to the inverting input of the amplifier. Layout is not too impor¬ tant. It should be remem¬ bered that the LM-380 is a high-gain 1C and the input wires should be as short as possible and not be run in close proximity to the out¬ put circuitry. Most P-chan- nel JFETs will work in this design-some better than others. My first grab in the junk box got a T-1812, so it was used for the perfor¬ mance measurements. Sim¬ ilar performance was ob¬ tained with several other types that were tried. JFETs with pinch-offs that are con¬ siderably removed from those of the T-1812 might re¬ quire another value for the zener diode. Note that diode D1 is ger¬ manium and D2 is silicon. Germanium is used at D1 because it requires less volt¬ age to conduct, increasing the first step voltage of the voltage doubler signal recti¬ fier. This same characteristic would be desirable for D2, the voltage doubler's sec¬ ond stage, but even more we need a diode with high re¬ verse resistance. In order to get a release time of about 4 seconds, we need a large RC combination. To keep the attack time short, C should be less than 3 uF, which means an R value of about 2 megohms. The reverse resis¬ tance of D2 should be some 5 to 10 times this value. Almost any silicon signal diode such as the 1N914 or 1N4148 will meet this criterion. Figs. 3, 4, and 5 show the Fig. 1. This photo shows the simplicity of the speaker amplifier to be used in a modular receiver. 86 73 Magazine * February, 1983 SO*? frequency response, com¬ pression characteristics, and distortion at various levels of compression. These were all measured at 125 mW Fig. 2. Schematic. output, which seemed to drive a 6-inch-high efficien¬ cy speaker at the volume I wanted in my shack. The potentiometer sets the output level at which compression starts. When its arm is at the ground end, the compression circuit is, in ef¬ fect, disabled Although no input control is shown, one could be inserted by replac¬ ing R1 with a 50k pot to per¬ mit monitoring a variety of levels greater than the com¬ INPUT♦ - SDBM pression range of the ampli¬ fier If the output is too much with the FET you're using, a resistor in series with the speaker is the sim¬ plest way to bring it into line. It will affect the fidelity a little, but not enough to bother in communications service The resistor value can best be determined ex¬ perimentally and probably will be between 47 and 100 Ohms. A variable speaker pad also would work well. There are many reasons why it pays to build this compression circuit into almost any audio amplifier that uses an LM-380 For one, it takes nothing away from its normal opera¬ tion—when the arm of the pot is at the ground end, you have a standard amplifier The small amount of time, money, and space that it takes to add this circuit gives big rewards in keeping the output at a consistent, comfortable level. Try it. You'll like it.B 400 IK FREQUENCY- HERTZ !0K 2 OK OUTPUT IN db BELOW 200mW Fig. 3. Frequency response vs, input Fig. 4. Compression characteristics. -20 INPUT OBM Fig. 5. Distortion . PCS-2800 10-METER MICROCOMPUTER FM TRANSCEIVER ► Just 6-3/4" x 2-3/8" x 9-3/4" ► Microcomputer con¬ trolled ► Detachable head * 6 channels of memory with scan * Full band scan * 10 watts output - also 1 watt low power » Dynamic microphone, internal speaker, mobile mounting bracket, and hard¬ ware included SPECIAL $ 229 °° 28-29.995 MHz, 10 kHz steps with -100 kHz offset AMATEUR-WHOLESALE ELECTRONICS 8817 S.W. 129th Terrace, Miami, FL 33176 Phone 305-233-3631 Toll Free 800-327-3102 CREDIT CARD HOLDERS MAY USE OUR TOLL FREE ORDERING NUMBER •See List of Aoventsers on page ? f4 73 Magazine • February, 1963 87 Donald C. Wiseman K5CA 4816 33rd Street Dickinson TX 77539 You Can Troubleshoot Mobile Noise K5CA tells what to do when a signal is 5-7 and the noise is 5-9. O ver the years ham ra¬ dio interests, along with methods and equip¬ ment, have continued to evolve Early in ham radio history the desire to convert heavy fixed-station receiv¬ ing and transmitting gear to use in vehicles appeared, resulting in the first “mobile" operations. This modification process was difficult enough consider¬ ing weight, size, and power requirements, but along with these came a whole new realm of problems. Fixed-station operation has always had problems with the noise and interfer¬ ing signal environments Great as these problems have been, at least they are generally consistent and geographically contained. Mobile operation, however, not only is affected by all these noise problems, but also adds the new dimen¬ sions of vehicle-generated noise and noise from chang¬ ing locations. Although to¬ day we have developed much more reliable, more -LIGHTS ► ACCESSORIES sr BATTERY sophisticated, and easier- to-integrate equipment for mobile use, the old noise problem continues Unfortunately, rf noise comes from many sources and when in motion, practi¬ cally all of these come into play at one time or another. To be honest, there's little that can be done about many of the noises encoun¬ tered — high-noise power lines, ignition radiation from other vehicles, spurious sig¬ nals from other transmitters, etc. In some of these cases, a good-quality noise blanker provides help. In others, pa¬ tience and operating skill are the only solution By the way, although the mobile high-frequency systems (SSB. CVV. etc.) have classi¬ cally been the ones to be the most bothered by noise, the "noise-free" VHF/FM sys¬ tems so popular today also have their share of noise problems This article at¬ tempts to provide a sum¬ mary of noise conditions that any of our radio equip¬ ment is subjected to in mo¬ bile use and to provide a re¬ lated approach to minimize the noise effects. There is a class of noise which is very disturbing in mobile operation and for which there is some reason- Fig. 1 . Electrical power system. Fig. 2, Ignition system . 88 73 Magazine • February, 1983 able solution. This class of noise is that generated within the vehicle where the station is installed. Right off the top, even using the best equipment and techniques, some noise may persist. However, to wage a solid battle against the aggrava¬ tion of vehicle noise, the ap¬ proach outlined here may be of real value. This ap¬ proach is not new; many publications have presented such information in the past, and several were consulted in putting this article together. The secret to lowering rf vehicular noise levels is: • Identify the noise and the noise source. • Eliminate the noise at the source if at all possible. • Minimize noise-conduct¬ ing and/or radiating paths. When working on noise problems, you may find sev¬ eral distinct noises present. Work on these starting with the loudest/strongest first, then proceed downward through the list by next strongest one at a time. The following approach may help to identify the source of each noise. Perform a vehicle-in¬ motion test. Run the vehicle in an area large enough to maneuver, but away from fixed noise sources (build¬ ings, power lines, etc.). Run the auto at moderate speeds; while moving, place the transmission in neutral and turn the ignition switch to accessory. If the noise goes away as you coast, it's most likely coming from the ignition system. (Be careful with this test, especially if you have power steering.) If the noise is a varying-pitch whine and stops with the ig¬ nition off, it's probably com¬ ing from the alternator. If the noise has a clicking or popping sound without any particular frequency and it disappears with the engine at idle or off, it's probably produced by the voltage regulator. A hash that has some variation with engine speed but doesn't come from the charging regulator indicates you have a Ford (Ford uses an electrome¬ chanical instrument regula¬ tor which is a notorious noise source). In normal driving situa¬ tions, the following noises and related sources may be noticed. While in motion, a sharp popping noise which doesn't seem to vary with engine speed probably comes from "tire static." (This may come and go as the road surface changes.) A rushing noise with an as¬ sociated popping indicates a general auto high-static condition. This generally occurs when close by a thunderstorm. A jiggly, scraping noise indicates the production of body static caused by metal elements of the vehicle not electrical¬ ly connected and rubbing together. In order to put some sys¬ tematic approach into play to help identify and combat these noises. Table 1 was prepared. In addition, to outline the typical auto electrical system, Figs. 1 and 2 were developed. These schematics indicate the par- ticular components and hookups which may require attention. Good luck in identifying and eliminating or reducing your particular vehicle noise problem. Keep in mind that although noise is an aggra¬ vation for us in mobile oper¬ ation and the fixes may take some time and effort, the re¬ sult is well worth it. Happy motoring! ■ Noise Sound Popping changing to hash as engine speed increases Possible Source Ignition Steps Use new resistor spark plugs. Check all ignition cable for loose or poorly- crimped connections (solder where possible). Install resistors in distributor/coil lines and spark-plug lines. Use resistance ignition wires if available. As a last resort, install shielded ignition sys¬ tem (kits available, listed in QST). Whine which changes pitch with engine speed Alternator Use a 0.1-uF coaxial capacitor in series with the alternator armature (A) lead. For “hard” cases, place a parallel tuned trap (with heavy wire) in series with the A lead. Tune to the operating frequency. Irregular clicking Regulator 0.1-uF coaxial capacitor in series with battery (B) and armature (A) leads. A series .002-uF mica capacitor and a 4-Ohm carbon resistor from the field (F) terminal to ground. Irregular clicking Vehicle wiring 0.1 coaxial capacitor in series with battery lead to ammeter; .5-uF coax capacitor in lead to gas gauge; .5-uF coax capacitor in lead to oil signal switch; .5-uF capacitor across head¬ light and taillight leads and other accessory lines. Popping noise which changes with road ma¬ terial Wheel static Install front wheel hub static discharge springs (from auto parts houses). Same Tire static Inject anti-static powder in tires. Popping, scratching noise following jolts as the auto moves Body static Tighten all screws and bolts. Bond major auto elements to each other with heavy braid and lugs (engine, firewall, frame, fenders, hood, exhaust pipe, etc.). Hashy Fords Instrument Replace with 5-volt electronic module regulator regulator. Table 1. Mobile noise reduction. 73 Magazine * February, 1963 80 Louis /. Hutton K7YZZ 12235 $. E. 6 2nd Street Bellevue WA 98006 Electronics vs. Creepy Crawlers Build this ultrasonic oscillator and drive pests crazy. Your pet hamster , too. O ne thing you will find out when you become interested in electronics or have ham radio as a hobby is that eventually your curi¬ osity will expand to investi¬ gating all sorts of electronic devices. This includes ac¬ cessories for the ham shack, microwave downconvert- ers, radar speed detectors, cable TV gadgets, and other interesting items. This arti¬ cle describes a gadget which has recently ap¬ peared on the electronics scene and really caught my attention as something I needed very badly in my ham shack. Now, I don t know about your ham shack, but mine is firmly delegated to a room in the basement of my house The only problem is that since it is at ground lev¬ el, all sorts of unwanted creepy crawlers invade my shack and take up resi¬ dence in my ham gear. For many years, pet supply and garden stores have sold all sorts of products to rid a home of those pesky bugs and such. Well, now the Photos by Betty Hutton Front view of unit . 90 73 Magazine • Febru ary, 1963 electronics industry has taken on the challenge and thinks this is the answer on how to run those bugs out of my ham shack Circuit Description and Construction Notes Low-intensity ultrasonic sound waves have been used to repel insects and small rodents. Square waves and pulsed waves have been tested and square waves are reported to be most effec¬ tive in the 3045-kHz fre¬ quency band The ultrasonic sound waves are intended to damage the insects nervous systems. The goal is to drive those creepy crawlers right out of the house The ultra¬ sonic sound waves are shift¬ ed in frequency 60 times per second to cover all of the communication frequencies of the most common pests (how about that—legal jamming!). The ultrasonic sound emitted by the unit is above the hearing range of people, dogs, cats, and birds. It is re¬ ported as not affecting plants, TVs, and radios, but will bother gerhils, ham- Component layout for the ultrasonic hug<haser. Fig. 1. Ultrasonic bug-chaser schematic . sters, and other pet rodents. Several commercial mod* els of bug-chasers have re¬ cently appeared on the mar¬ ket (see box). The schematic diagram shown is typical of such units and is designed to generate a swept square wave from 30 to 45 kHz. The LM555 1C is wired as an ul¬ trasonic oscillator driving a piezoelectric speaker of the hi-fi super-tweeter type. The output of the oscillator is swept by a 60-Hz signal from the ac input of the bridge rectifier, The LED acts as a pilot light to let you know the power is on, as the only noise you will hear when this unit is running is a slight buzzing noise coming from the speaker. An oscilloscope is neces¬ sary to observe the square- wave signal on pin 3 of the LM555 oscillator My unit is built in a cabinet 3-1/2" x 7-1/8" x 5-11/16" (Radio Shack #270-269) The speaker is a 3.5-inch Piezo Super Horn (Radio Shack #40-1381). The oscillator and power supply were built on two small perfboards and bolted on metal standoffs to the chassis floor. No effort was made to design a PC board or to miniaturize the design. The front, bottom, and rear of the cabinet were covered with simulated wood-grain shelf paper to improve the appearance of the unit Operation I set my unit in one corner of my ham shack facing out into the room so that the ul¬ trasonic sound waves would fill the room by bouncing off the walls, floor, and ceil¬ ing, Things like curtains, rugs, and upholstered furni¬ ture will absorb the sound waves. You should expect it to take several weeks before the full effect of the irri¬ tating ultrasonic sound waves will get to the bugs. I have had several visitors in the shack and they soon note the slight buzzing noise coming from that strange- looking box on the shelf When told what it is, they unanimously say they want to build one for their own ham shack. Try it; the on¬ ly thing you will have to lose is those pesky creepy crawlers. ■ COMMERCIAL BUG-CHASERS “Pest Free,” Joe Weiss Co., Rancho Palos Verdes CA 90274. •‘Scram,’* American Acoustics Labs, 629 West Cermak Road, Chicago IL 60616. MOBILE POWER 3 For Your H.T. only $2125p p d| The new MOBILE ENERGIZER will provide J operating power for your H.T. from any 12 volt sourceJ \ and charge it's nicads at the same time! Featuring] la time-proven regulator circuit enclosed in a tough,4 j rugged housing that plugs into the cigarette light-| ) er jack of your car, it will work with any synthe¬ sized H.T. except Icom, Azden. and Tempo S“15. I Specify H.T. model when ordering. CONTEMPORARY ELECTRONIC PRODUCTsj P.O. BOX 570549 MIAMI, FL 33157 ^ H {305) 255-7660 rntm 2 GHz Mcrewnw Receiving Systems The new Micro-System features a machined 18” parabolic reflector for maximum efficiency, a linear feed-point downconverter with ceramic high perfor¬ mance RF preamplifier transistor, a variable 12 to 18 volt regulated power supply and 50’ of 75(1 coaxial down¬ lead. including a 3’ jumper and matching transformer. The Micro-System includes a full 6 month warranty. Micro-System (MS-021) .*159” Micro-System (MS-578) .*169” Micro-System (MS-645) .*179” Shipping & Handling: USA .. .*4” AK, HI & PR , . .‘10 00 Data 8arvlce Company 612-636-9469 ^346 3no Evelyn Street Roseville, MN • 55113 ORBIT is the Official journal for the Radio Amateur Satellite Corporation (AMSAT), P.O. BOX 27, Washington, DC 20047. Please write for application. For a FREE SAMPLE COPY please send $1 to cover First Class Postage and handling to: Orbit, 221 Long Swamp Road, Wolcott, CT 06716. See ust ot Aaverttsers on page f u 73 Magazine * February, 1983 91 Slimming and Trimming the R-1000 In crowded conditions, the 6-kHz filter may not cut the QRM. Here's the way out. Milton Ertelt 5Z4CUK5PAW States causes many to try PO Box 305U shortwave listening to re- Nairobi, Kenya ceive news features from home. Our family's habit is to listen to broadcasts of the iving overseas and not Voice of America and the being able to have at Armed Forces Radio and your disposal the type of Television Service (AFRTS) news and entertainment in addition to broadcasts available in the United from other countries for Fig. 2. After modification. 92 73 Magazine • February, 1983 news and information about AM situations, and it is to current events in the States, this end that circuit changes Being in East Africa and were made, tuning the shortwave bands, The plan is to utilize the one quickly notices that 2.7-kHz SSB ceramic filter Africa is the focal point for for both the SSB and AM- hundreds of powerful short- narrow modes, while the wave broadcasts which re- 12-kHz filter normally used suit in crowded band condi- for the AM-wide mode is re- tions and interference be- placed by the 6-kHz AM-nar- tween rival programming row filter. The 12-kHz filter Sometimes it is almost im- will be left on the receiver possible to separate from circuit board, but will not be pileups weaker signals like used. These changes can be AFRTS not normally made by the addition of one beamed to East Africa. silicon diode (1N914 type) With this background, I and one wire and the remov- purchased the Kenwood al of two existing wires. R-1000 communications re- These changes can be ac- ceiver for shortwave listen- complished in less time than ing The R-1000 is an ad- it takes to explain No holes vanced general-coverage re- are drilled, so the R-1000 can ceiver providing continuous be returned to its original coverage from 200 kHz to configuration at any time 300 MHz It features a PLL Here, then, is a step- synthesizer and a digital by-step record of these display for both frequency h readout and the built-in g clock and timer It also in- 1. First, remove both the top eludes an rf attenuator, a and bottom covers from the noise blanker, and capabil- receiver The speaker leads ities for receiving LSB/CW, can be easily slipped off the USB, and AM. For AM, speaker terminals, either ceramic filters for 2. Remove 2 wires, white/ 6-kHz or 12-kHz bandwidth brown and white, from ter- are selectable for AM-nar- minal #1 of the AMW mode row or AM-wide reception switch, and tie these leads Crowded band conditions off, taping the ends to pre- here in East Africa preclude vent shorts Terminal num- the use of the 12-kHz filter; bering (on the Mode switch) the 6-kHz filter is sufficient- is derived from the R-1000 ly wide for good fidelity for Service Manual and is not shortwave music programs, clearly marked on the However, a narrower band- switches themselves. How- width is required for many ever, terminal #1 on the Fig. 3. Receiver unit PC board (top view). AMW mode switch is the one to which the wire pairs white/brown and white are terminated 3 Remove the white/red wire from terminal #2 of the AMN mode switch and sol¬ der to terminal #1 of the AMW mode switch Again, identify terminal #2 as the one to which the white/red is terminated 4 Add a wire from terminal #2 of the AMN mode switch now vacant as a result of step 3 above, and dress it near the vfo case, running it through the slot formed be¬ tween the vfo case and the receiver circuit board to the top side of the chassis. Con¬ nect this new wire to resistor R80 The connection should be made on the lead of R80 nearest to connector #3 (see Fig 3T There should be enough room between the surface of the circuit board and the insulated portion of R80 to make the solder con¬ nection 5. On the bottom side of the receiver, locate, within a bundle of wires running from the Mode switch near the Band (megahertz) switch, the orange wire run¬ ning between terminal #4 of the USB mode switch (this is the only orange wire on the USB Mode switch). Then find terminal #8 of connec¬ tor #4 on the top of the chassis Pull the orange wire away from the wire bundle at a point near the Band (megahertz) switch and cut the wire at a point just behind the Band (mega¬ hertz) switch. Strip about !4 " of insulation from both ends of this wire and solder a 1N914 or equivalent diode between the two ends of the orange wire The cathode should be closest to the USB Mode switch and the anode facing terminal #8 of con¬ nector #4 (see Fig 2) 6 Replace the leads on the terminal of the speaker and install the top and bot¬ tom covers of the receiver. Pressing the AMW posi¬ tion on the Mode switch now selects the 6-kHz band¬ width filter for AM-wide re¬ ception Pressing the AMN position selects the 2.7-kHz bandwidth filter for AM-nar¬ row reception, while the SSB position remains as before The end result is a receiv¬ er with bandwidth suffi¬ ciently wide for good fideli¬ ty during listening periods when interference is light During periods of high inter¬ ference or in crowded band conditions, the bandwidth of the new AM-narrow mode is extremely sharp, pro¬ viding an increased ability to separate closely bunched signals. The SSB operation of the receiver is unaffected by these changes. There are other ways to accomplish the same modi¬ fication. One could pur¬ chase from Kenwood an ad¬ ditional SSB ceramic filter and substitute it for the cur¬ rently installed AM-narrow filter But this would be more expensive, and, I be¬ lieve, more work These changes improve the opera¬ tion of an already fine piece of radio equipment Ji DIGITAL DISPLAY 30 DAY FREE TRIAL YAESU HEATH DRAKE COLLINS KENWOOD HEW YAESU DIGITAL DISPLAYS CONVERTED FOS THE ABOVE. 5/8 INCH RE!) |J[! DIGITS KAO DOWN TO lOHj. REAR PANEL lOHz DIGIT OFF SMlKJf. FROM A COLD START - MXIftJK lGGHz DRIFT IN 2N HOURS. 1 5/3- HIGH, u 1 /?* WIDE t G 1/2* DEEP. STEEL CASE IS BUCK. i.a*Hs3 FRONT V- Afctu IS aauSHED ALUKIMUM. UNITS *03 MOD. UZBEKS UNIX-* l I MSEC WITHOUT A Hr INSTALLATION 9Y FLUSHING INTO existing jacks at* rut raoios. NODEii wJth an • asterisk hav» a powm and off switch. all postage paio, it v#a jac*. n useo top a vfo, sec. as so* * flus/jac* ado 15.OC ■ SUL. 3D , t W To? ? ivy** | epir s s sts talla t s i FRS7 ***** 1 i»rc IUS.C ‘ , S2r.-"-5”3 0-1U —all 4 nwe. —- Il'O.CO » 5 S f •/$ «» FT325P t 3!6 - *35.00 .. •. tmim CMC* 3* «.€•.. K DA'? H»fY BAC*. yol **» *«? FL'iTLU. S ?!E *UT> sec. & *£»i*L A® - *5* i ** t*W* T f 3*. mm jf .basic is act .rsTt-. will *a**, mg *a •**«►*»* 30 M KITS & MORE w'im'ip waml wHtiss.—TOP aaAim cckhide *aoic* pram- m.~ wstm». troy* *»3io umc *<*s itom. aa wif • read* nmtsun am® isu. »osj will m 5€ue*«tB. i«C!A» »Ai| A«5 msii. 0* J4.ACK 0« #*©** UAT«J*. *30,00 A5SD AVAHABlL FINALLY!» A CAR UNDO* LEDGE CUP CD BRACK** TO HOLS YOU* HAJi&HitO 3AOIO. TOo’l LOVE IT. 40 HOSE fyXJUNfc QU The dash 03 SEAT. JIWU A*D ADJUST ABLE FOB YOUR CM. SPECIFY MMGMEL& W«l A«3 HDDEL. 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BOX 1050 KODIAK, ALASKA 00015 (007) 400*5110 ORDERING INFORMATION: Check. M O or C.O.D. S «c cepted Airmail shipping coats within U S included in price 1 allow l week for delivery i Foreign orders include $5 00 for shipment by air READ/..VHEM YOU ARE OVER 150,000 TYPES OF MRO ITEMS ON THE SHELF NOW FOR IMMEDIATE OVER THE COUNTER SALES. Besides the world’s largest selection of semiconductors, we also stock hard-to* find RF connectors, caps, chip caps, trim caps, trim pots, chokes, tantalums, feed-thru’s, fuses, precision caps & resistors, indicator lamps, etc. For the common items, anywhere will do . . . for the darn near impossible, CALL USU SEMICONDUCTOR SUPERMART 1042 E. GARVEY AVENUE WEST COVINA, CALIFORNIA 91790 (213) 967*4611 • (213)967*3846 ^ See Ltsl of Advertisers on page lt4 73 Magazine • Febtuaiy, 1963 93 Dave Schmarder N2DS 11 Beaver Avenue Bea ver Da ms N V / 4S12 Add a Touch of Class to CB Conversions Converting a Hy-Gain board to 10 meters is only half the story. Try adding a digital readout and scanning capability. . . H ave you been bitten by the ten-meter FM bug? Do those Hy-Gain CB boards look interesting? Here is your chance to do a little bit of building and have a lot of fun. Since the actual rf conversion of the Hy-Gain boards has been Fig. 1. Ail transistors — 2N3904. All unmarked resistors are Ik Ohms . All + are 5 volts. All diodes- 1N4148. 94 73 Magazine • February, 1963 well described in past 73 Magazines , ? I will only deal with this digital-scanning frequency selector. This circuit will give you direct frequency readout Example: 60 = 29.60 MHz, and so on. There are 40 channels available at 10-kHz increments with a repeater offset for 20 of these channels. A squelch- operated scanner allows you to search the band without lifting a finger. The crystal in the radio which is 11.8066 MHz has to be changed to 12.69166 MHz. This crystal can be obtained from Jan Crystals in Ft. Myers, Florida. Pins 8 and 9 of the PLL-02 have to be tied to plus 5 volts (pre¬ load to binary 192), Pin 10 must be separated from pin 9. This is the conversion that differs from the origi¬ nal in the reference. It is im¬ portant to get a CB board with a 16-pin PLL chip. The ones with 18 pins require changing the chip to a PLL-02 and rewiring The best way I found to build this is shown in Fig 2. I use perfboard with the holes spaced at .1 inches The parts are not critical, but an LS series IC can be used to reduce current drain. Five volts must be provided and a 7805 IC can be mounted on the TA7205P heat sink on the radio. Refer to Fig 1 for the fol lowing circuit details, ICI is a BCD-to-binary converter. The PLL-02 1C in the radio requires a binary code to se¬ lect the frequency we want. But to make it easier for us to select the frequency, it is converted from BCD. IC2 and IC3 are up/down count¬ ers that provide the se¬ quence counting and the memory for the selected frequency. The counters are driven from IC4, IC5, and IC6, which are gated astable multivibrators, IC7a is used as a Schmitt trigger which is driven from the squelch output. A dc signal must be fed to this so that a high level (greater than one volt) will raise up the base of Q120 in the radio, thus squelching the radio. IC8 and IC9 are BCD decoder/ drivers for the LED read¬ outs. The pinout of the readouts depends on what type of common anode dis¬ plays they are. IC10 is a bi¬ nary adder. This circuit "adds" 3 to any number found at the output of IC2 (Oto 4). This will let the LED display read the operating frequency, not just a chan¬ nel number. For example, when the outputs of IC2 and IC3 are all zero, the fre¬ quency of the radio is 29.30 MHz. But without IC10, the readout would read "00". But with the "3" added, the readout reads "30". Sla and Sib is a momen¬ tary SPDT center-off toggle switch. When the switch is closed in either direction, it turns off the transistor asso¬ ciated with it and this al¬ lows the up or down multi¬ vibrators to operate. S2, the scan switch, when closed prevents the squelch cir¬ cuits from starting the IC6 multivibrator, which is used to run the scanning section. The repeat switch, S3, when open does nothing to the ra¬ dio. But when closed, it will add 100 kHz to the operat¬ ing frequency on receive only. When the PTT is pushed, the radio will trans¬ mit on the displayed fre¬ quency. The anode of D106 in the radio provides about 7 volts in receive only, which makes this offset possible. A special note: This offset circuit works on¬ ly between 29.30-29.39 and 29.50-29.59 MHz. But the repeater inputs are be¬ tween 29.51 and 29.59 MHz. Another feature of this circuit is that when the ra¬ dio is turned on, the fre¬ quency will be 29.60 MHz, which is the international simplex calling frequency. This is done by slowly bring¬ ing up pin 11 on IC2 and IC3 during power-up. In closing, I would say that the use of this circuit really adds polish to these converted CB boards. I would like to thank Charlie DeVoe WA2IUJ for build¬ ing one of these, to show it could be repeated, and for his opinion of its operation. 3 5 in FRONT MOUNTING HOLES Fig. 2. I welcome any comments, and I will reply to any ques¬ tions when an SASE is enclosed. ■ Reference 1. Howard Knickerbocker K1DCS, Andrew Weise N1XN, and Robert Stieiau W1WRO, “CB to 10 FM—best conversion yet?”, 73 Magazine , January, 1980, p. 117- AMATEURS SHORTWAVE k SCANNERS* Full Service Shop • Spectrum Analysis • Antennas New and Used Equipment •CW-SSB-FM, Etc. •Towers FCC Study Guides *Code Tapes •Books •Accessories SPECTRONICS H0URS ^S©W 5 MON.TUES, WEO 9:30-6:00 PM THURS, FRI. 9:30-8:00 PM SAT. 9:30-3:00 PM Specialists in Amateur Radio, S*. Short-Wave Listening And Contemporary Electronic Gear. SPECTRONICS 1009 GARFIELD ST OAK PARK, It 60304 Hi PORT APE ATER© $179.00 assembled unit TT\ *4Channel PROM CW I Dcr •VOX or COR operation •250 volt switching capability •An Instant Repeater led MIOOA S! INSTANT REPEATER ANY BAND ANY MODE % fl PORTAPEATER* $99.00 assembled ^ board •Works with any type radios •Complete Timer Functions • Built In Test Functions •20 Page Technical Manual Repeater (Fully tested, programmed, assembled) ^302 W-S ENGINEERING P.O. BOX 58, PINE HILL, N.J. 08021 (201-852-0269) \ GILFER'S "BEST SELLER" SHORTWAVE BOOKS 11 jjptiiii New 5th Edition CONFIDENTIAL FREQUENCY LIST Identifies 9,000 non-broadcast shortwave stations (utility, coast, military, FAX, etc.) from 4-28 MHz, Includes ' Updater*' $10.95 ppd USA, $13 UPS, US$16 elsewhere. Up¬ dater separately $2.50. 1983 Edition WORLD RADIO TV HANDBOOK ■‘Bible^of the SWL—comprehensive list of all shortwave broadcasters with all details— plus new receiver reviews. $17.50 ppd USA, $19 UPS; US$25 elsewhere. Totally New 2nd Edition GUIDE TO RTTY FREQUENCIES Details on 5,500 radioteletype stations (in¬ cluding Press skeds) plus reverse list by callsign. How to read USSR Cyrillic. $9,95 ppd USA, $12 UPS; US$14 elsewhere. SPECIAL 1.CFL+Updater + RTTY: $21, UPS. nPFPBCi 2. CFL+Updater fWRTVH; $27. UPS 3. RTTY+WRTVH; $26, UPS. SAVE 4 . ALL 3 BOOKS $36, UPS. NOTE: All SPECIAL OFFER books shipped UPS (Ex¬ cept Canada, AK & HI). First Class Mail add $1.00. per book. Non-UPS orders shipped USPS Book Mail. • Receivers • Accessories • Books • GILFER SHORTWAVE Dept732, Box 239, Park Ridge, NJ 07656 USA Phone 201/391-7887 ^See List of Advertisers on page 114 73 Magazine • February, 1963 95 SATELLITES _ / AMATEUR SATELLITE NEWS CQ CO Earthside de STS-9 Wei!, maybe not, but there is a good chance that amateur radio will be among the as¬ tronauts' leisure-time activities aboard STS-9, the ninth flight of NASA's Space Shuttle. Dr. Owen Garrlot W5LFL, one of four STS-9 crew members, will operate a small 2-meter FM rig, if all goes according to plan. Actually, though the proposal has plenty of support from the amateur community, NASA has yet to grant its final approval. W5LFL himself is said to be pushing for the ham activity, and there is plenty of backing from the ARRL, AMSAT, and a number of promi¬ nent individual amateurs. Yet to be decided is the format of the space-borne amateur festivities. A free-for-all op¬ eration would likely result in the greatest pileup of ail time, complete with frayed nerves and rising tempers. A much more organized method will no doubt evolve—perhaps even a series of one-way transmissions from W5LFL to the thousands of us listening on the ground. iskra—Again! Cosmonauts aboard Russia’s Salyut 7 space station have once again launched an ama¬ teur satellite. Iskra 3, like its predecessor Iskra 2. was literally tossed out the back door by the cosmonauts, who pushed it through an air lock normally used to jettison refuse. The sat¬ ellite was launched last November 18 and features a telemetry beacon on 29.583 MHz. If the example of Iskra 2 is the norm, Iskra 3 may be short-lived, iskra 2 survived only eight weeks in orbit following Its May 17,1982, launch before plunging back into the at¬ mosphere. And what of the never-mentioned Iskra 1? If the Soviets know, they aren't telling. Orbital Calendars Once again this year, Project OSCAR, Inc., has produced an orbital calendar for ama¬ teur satellite users. The 1983 version contains the time and longitude of every north¬ bound equatorial crossing for each of the amateur satellites carrying a communications transponder: OSCAR 8, RS5, RS6, RS7, and RS8. It’s a real time-saver. Thecalendar is available in the USA, Canada, and Mexico for a $10 donation ($12 else¬ where). Send a mailing label, along with your check or money order, to: Project OSCAR, Inc., PO Box 1136, Los Aitos CA 94022. Thanks to Amateur Satellite Report and the W5Yi Report for portions of this month’s news.—Jeff DeTray WB8BTH, 73 Staff. Amateur Satellite Reference Orbits OSCAR , 8 RS- ■5 RS- •6 RS- •7 RS- ■8 Date UTC EQX UTC EQX UTC EQX UTC EQX UTC EQX Date = »» = = === = IBSE = = = = = :««! = =»»« l«» = ==»»»=»= === = = = = = = > 1 0002 80 0154 103 0006 80 0008 78 0113 92 1 2 0007 81 0149 104 0149 107 0157 107 0110 93 2 3 0011 82 0144 104 0134 105 0147 106 0107 93 3 4 0016 83 0138 104 0118 103 0138 105 0104 94 4 5 0020 84 0133 104 0103 100 0128 104 0101 95 5 6 0024 85 0128 104 0046 98 0119 104 0059 96 6 7 0029 86 0122 105 0032 96 0109 103 0056 97 7 8 0033 88 0117 105 0017 93 0059 102 0053 97 8 9 0038 89 0112 105 0001 91 0050 101 0050 98 9 10 0042 90 0106 105 0145 119 0040 100 0047 99 10 11 0046 91 0101 105 0129 116 0030 99 0044 100 11 12 0051 92 0056 105 0114 114 0021 98 0042 101 12 13 0055 93 0050 106 0059 112 0011 97 0039 102 13 14 0059 94 0045 106 0043 109 0001 96 0036 102 14 15 0104 96 0039 106 0028 107 0151 125 0033 103 15 16 0108 97 0034 106 0012 105 0141 125 0030 104 16 17 0113 98 0029 106 0156 132 0132 124 0028 105 17 18 0117 99 0023 107 0140 130 0122 123 0025 106 18 19 0121 100 0018 107 0125 127 0112 122 0022 106 19 20 0126 101 0013 107 0110 125 0103 121 0019 107 20 21 0130 102 0007 107 0054 123 0053 120 0016 108 21 22 0135 103 0002 107 0039 120 0043 119 0013 109 22 23 0139 105 0156 137 0023 118 0034 118 0011 110 23 24 0000 80 0151 138 0006 116 0024 117 0008 111 24 25 0005 81 0145 138 0151 143 0014 117 0005 111 25 26 0009 82 0140 138 0136 141 0005 116 0002 112 26 27 0013 83 0135 138 0120 139 0154 145 0159 143 27 28 0018 84 0129 138 0105 136 0145 144 0156 144 28 : 1 0022 86 0124 139 0050 134 0135 143 0153 145 1 2 0027 87 0119 139 0034 132 0125 142 0151 146 2 3 0031 88 0113 139 0019 129 0116 141 0148 146 3 4 0035 89 0108 139 0004 127 0106 140 0145 147 4 5 0040 90 0103 139 0147 155 0056 139 0142 148 5 6 0044 91 0057 140 0131 152 0047 138 0139 149 6 7 0046 92 0052 140 0116 150 0037 138 0136 150 7 8 00 53 93 0047 140 0101 148 0027 137 0134 150 8 9 0057 95 0041 140 0045 145 0018 136 0131 151 9 10 0102 96 0036 140 0030 143 0008 135 0128 152 10 11 0106 97 0031 140 0014 141 0158 164 0125 153 11 12 0110 98 0025 141 0158 168 0148 163 0122 154 12 13 0115 99 0020 141 0142 166 0138 162 0119 154 13 14 0119 100 0015 141 0127 163 0129 161 0117 155 14 15 0124 101 0009 141 0112 161 0119 160 0114 156 15 16 0128 103 0004 141 0056 159 0109 159 0111 157 16 17 0132 104 0158 172 0041 156 0100 159 0108 158 17 SOCIAL EVENTS Listings in this column are provided free of charge on a space-available basis. The fol¬ lowing information should be included in every announcement: sponsor, event, date, time, place, city, state , admission charge (if any j, features, talk-in frequencies, and the name of whom to contact for further informa¬ tion. Announcements must be received at 73 Magazine by the first of the month, two months prior to the month in which the event takes place. Mall to Editorial Offices, 73 Mag¬ azine, Pine Street, Peterborough NH 03458. ARLINGTON HEIGHTS IL FEB 6 The Wheaton Community Radio Ama¬ teurs will hold their hamfest on February 6,1983, at Arlington Park Race Track Expo Center, Arlington Heights IL. Tickets are $3.00 at the entrance and $2.50 in ad¬ vance. Doors will open at 8:00 am. Flea market tables are free and plenty of floor space will be available. There will be a large commercial area (including a com¬ puter section), awards, and clear, paved parking. Talk-in on 146.01/.61 and 146.94. For general information, call W9JTO at (312J-231-9524, For advance tickets, send an SASE to WCRA, PO Box OSL, Wheaton IL 60187. MANSFIELD OH FEB 13 The ARRL-approved Midwinter Ham- fest/Auction will be held on Sunday, Feb¬ ruary 13,1983, beginning at 8:00 am, at the 96 73 Magazine • February, 1963 Richland County Fairgrounds, Mansfield OH. Tickets are $2.00 in advance and $3.00 at the door. Tables are $5.00 in ad¬ vance and $6.00 at the door. Half tables are available. Talk-in on 146.34/.94. For ad¬ ditional information or advance tickets, contact Harry Frietchen K8HF, 120 Home- wood Road, Mansfield OH 44906, or phone (419J-529-2801 or (419)-524-1441. MARLBOROUGH MA FEB 20 The Algonquin Amateur Radio Club will hold its annual flea market on Sunday. February 20, 1983, at the Marlborough Jr. High School, Marlborough MA. Admission is $1.00 and children under 12 will be ad¬ mitted free. The doors will open at 9:00 am for dealers and 10:00 am for buyers Re¬ freshments will be available. Tables re¬ served before February 12,1983, are $7.00; any remaining tables will be $10.00 at the door. Taik-in on 146.01/.61 and 146.52. For table reservations or more information, contact Algonquin ARC, PO Box 258, Marlborough MA 01752. MELVILLE LI NY FEB 20 The Long Island Mobile Amateur Radio Club Indoor Hamfest will be held on Feb¬ ruary 20,1983, from 9:00 am to 5:00 pm, at the Electricians Hall, 41 Plnelawn Road, Melville LI NY, located just north of Exit 49 of the Long Island Expressway (495). Gen¬ eral admission is $3.00 and sellers’ tables (4’ x 6’ with oval corners) are $10.00 in ad¬ vance. Food and refreshments, lots of parking, and coat and equipment check¬ ing will be available. For reserved tables, contact Hank Wener WB2ALM, 53 Sher- rard Street, East Hills NY 11577, or phone <516)-484-4322 between 10:00 pm and mid¬ night. For additional information, phone Sid Woiln K2LJH In the evening at (516)-379-2861. ELKIN NC FEB 20 The sixth annual Elkin Winter Hamfest will be held on Sunday, February 20,1983, at the Elkin National Guard Armory, lo¬ cated two miles off Interstate 77 at Exit #85 In Elkin NC. Doors will open at 0800 to the public, and breakfast and lunch will be served at the hamfest by the Foothills ARC of Wllkesboro NC and the Brlarpatch ARC of Galax VA. Talk-in on 144.77/145.37, 146.22/.82, and 147.69/.09. For ticket In¬ quiries, table reservations, or other infor¬ mation, contact either George Reeves WD4BMG, Routes, Box 412, North Wilkes- boro NC 28659, (919)-670-2803, or Tommy Lineberry WD4BTF, 308 Poplar Street, Galax VA 24333, (703)-236-8424. LANCASTER PA FEB 20 The 1983 Lancaster Hamfest will be held on Sunday, February 20, 1983, from 0800 to 1600, at the Guernsey Sales Pavil¬ ion, US Route 30 East, Lancaster PA. Gen¬ eral admission is $3.00 for all hams and dealer personnel. Table fees are $10,00 In the main display area and $6.00 in the an¬ nex area. There will be tailgating if weath¬ er permits. Dealer setup Is at 0600 by res¬ ervation. Talk-in on 146.01/.61, 147.615/ .015, and 146.52. For reservations, send checks made payable to SERCOM, Inc., to Hamfest Committee, RD#1, Box 56V, Blue Ball PA 17519. ROBBINSDALE MN FEB 26 The Robbinsdale Amateur Radio Club (K0LTC) will hold its Midwinter Madness Amateur and Computer Fest on February 26, 1983, beginning at 8:30 am, at Sacred Heart Church School Auditorium, 4087 West Broadway, Robbinsdale MN. Gener¬ al admission is $2.00 in advance and $3.00 at the door. Contact Bob Reid N0BHC, 19725 Jackie Lane, Rogers MN 55374, for commercial exhibit space (tables are $15.00 each). Flea-market space is avail¬ able from Barry Blazevic WB0FBN, 5437 Virginia Avenue N., New Hope MN 55428. Doors will open for setups at 7:00 am. Ac¬ tivities will include seminars on antennas, towers, and computer interfacing, as well as a slide presentation on the voyage of the Viking ship Hjemkomst. Lunch will be available in the building. GLASGOW KY FEB 26 The Glasgow Swapfest will be held on Saturday, February 26, 1983, beginning at 8:00 am Central time, at the Glasgow Flea Market Building, 2 miles south of Glasgow just off highway 3lE, Glasgow KY. Admis¬ sion is $2.00 per person. There is no addi¬ tional charge for exhibitors. The first table per exhibitor will be free, and extra tables will be available for $3.00 each. There will be a large heated building, free parking, free coffee, and a large flea market. Talk- in on 146.34/94 or 147.63/03. For further information, write Bernie Schwitzgebel WA4JZO, 121 Adairland Court, Glasgow KY 42141. JENSEN BEACH FL FEB 28 The Martin County Amateur Radio As¬ sociation will hold Its annual free hamfest on Saturday, February 26,1983, from 8:00 am to 4:00 pm, at Langford Park, Route 707, Jensen Beach FL There will be free table or tailgate space and free admis¬ sion. Food will be available or bring your own picnic. There is an area for cooking and playing, so bring the family. Talk-in on 146.46/147.06 (Stuart repeater). For more Information, write MCARA, PO Box 1901, Stuart FL 33495. LAPORTE IN FEB 27 The LaPorte Amateur Radio Club Winter Hamfest will be held on Sunday, February 27,1983, at the LaPorte Civic Auditorium, LaPorte IN. The donation is $2.50 at the door and tables are $1.00 each. Dealers will receive help unloading starting at about 6:00 am. For more information or reservations, send an SASE to PO Box 30, LaPorte IN 46350. LIVONIA Ml FEB 27 The Livonia Amateur Radio Club will hold its 13th annual LARC Swap ’n Shop on Sunday, February 27, 1983, from 8:00 am to 4:00 pm, at Churchill High School in Livonia Ml. Reserved table space (12-foot minimum) is available. Talk-in on 144.75/145.35 and .52. For further informa¬ tion, send an SASE (4" x 9") to Nell Coffin WA8GWL. c/o The Livonia Amateur Radio Club, PO Box 2111, Livonia Mi 48151. VIENNA VA FEB 27 The 10th annual ARRL-approved winter season hamfest, WlNTERFEST™ ’83, celebrating the 20th anniversary of the Vienna Wireless Society, will be held on Sunday, February 27, 1983, beginning at 8:00 am, at the Community Center, 120 Cherry Street, Vienna VA. Tickets are $4.00 and safes tables are $5.00 and $10.00. Parking is free. Features will in¬ clude a CW contest, commercial displays, an indoor flea market, and outdoor Frost¬ bite tailgating. Excellent food service will be available. Talk-in on 146.31/.91 and 146.52. For additional information, send an SASE to WlNTERFEST ’83, PO Box 418, Vienna VA 22180, or call Jeff Wilkes W4NFA at (703)-281-4249 or on the Virginia Sideband Net. MORRIS PLAINS NJ MAR 4 The Split Rock Amateur Radio Associa¬ tion will hold its sixth annual electronics auction on Friday, March 4, 1983, at VFW Post #3401, State Route 53, Morris Plains NJ. The Morris Plains VFW hall is located a short distance from US 202 and NJ 10 and is easily reached via 1-80, 1-287, and US 46. Admission is $1.00. Doors will open at 7:00 pm for unloading and inspecting equipment and the auction will com¬ mence at 8:00 pm sharp. Items to be sold must be working equipment and loose parts must be bagged in the largest quan¬ tity possible. A commission of 10% will be taken on the first $50.00 of each sale. Commissions are payable in cash only. Refreshments will be available. Talk-in on 146.385/146.985 (WR2ADB) and 146.52. For more information, please write to SARA, PO Box 3, Whippany NJ 07981. OLD BRIDGE NJ MAR 6 The Old Bridge Radio Assocation will hold its third annual auction on March 6, 1983, at the K of C Hall, Pine Street (just off Route 18), Old Bridge NJ. Doors will open for registration and inspection at 9:00 am and the sale will begin at 10:00 am. Admission Is $2.50. On successful sales, there will be a club commission of 10% on the first $100 and 5% on the re¬ mainder. Food and drink will be available. Talk-In on .72/. 12, .34/.94, and .52. For more Information, contact Fred Goldberg WA2BJZ, 29 Clearview Road, East Bruns¬ wick NJ 08816, or phone (201)-257-8753. SOUTH ST. LOUIS MO MAR 11 The Jefferson Barracks Amateur Radio Club will hold its annual auction and ham¬ fest on March 11,1983, at the Carondelet Sunday Morning Athletic Club in South St. Louis MO. FORT WALTON BEACH FL MAR 12-13 The Playground Amateur Radio Club will hold Its 13th annual North Florida Swapfest on Saturday, March 12, 19&3, from 8:00 am to 4:00 pm, and on Sunday, March 13,1983, from 8:00 am to 3:00 pm, at the Okaloosa County Fairgrounds, Fort Walton Beach FL. MARTINSVILLE IN MAR 13 The Morgan County Amateur Radio Club will sponsor the Martinsville Ham¬ fest on March 13,1983, beginning at 8:00 am, at the Morgan County 4-H Building and Fairgrounds. Admission Is $3.00 In advance and $4.00 at the door; children 11 and under will be admitted free. Flea-mar¬ ket space with a table is $5.00 and flea- market space without a table is $3.00. Pre¬ mium tables are $20.00. Tables will be available on a first-come basis and the best spaces will be assigned first. Vendor setups will start at 5:00 am and parking will be free. Talk-in on 147.66/.06. For tick¬ ets, table reservations, and information, send an SASE to Aileen Scales KA9MBK, 3142 Market Place, Bloomington IN 47401. ERIE PA MAR 19 The Radio Association of Erie PA will hold The RAE Eyeball QSO Party on Satur¬ day, March 19, 1983, at the Perry Highway Hall, 8/10 of a mile south of 1-90 on the west side of Route 19. Admission Is $2.00 per person. Tables (8-foot) are $3.00 each and are by reservation only. Food will be available. There will be FCC testing for ap¬ plicants that mail Form 610 to the Buffalo office by February 22nd. Talk-in on .01/.61 and .22/.82. MARSHALL Ml MAR IS The Southern Michigan ARS and the Calhoun County Repeater Association will hold the 21 st annual Michigan Cross¬ roads Hamfest on March 19, 1983, begin¬ ning at 8:00 am, at the Marshall High School, Marshall Ml. Tickets are $2.00 at the door and $1.50 in advance. Table space is $.50 a foot. Doors will be open at 7:00 am for exhibitors and there will be plenty of carry-in help and free parking. Food service will be available in the cafe¬ teria. For tables or tickets, contact SMARS, PO Box 934, Battle Creek Ml 49016, or phone Chuck Williams at (6l6)-964-3l97. MIDLAND TX MAR 19-20 The Midland Amateur Radio Club will hold its annual St. Patrick’s Swapfest on March 19-20, 1983, from 8:00 am to 6:00 pm on Saturday and from 8:00 am to 3:00 pm on Sunday, at the Midland County Ex¬ hibit BuMding, east of Midland on High¬ way 80 on the north side. Pre-registration is $5.00 (at the door, $6.00). Tables are $4.00 each. Refreshments will be avail¬ able. Talk-in on .16/.76 and .01/.61. For fur¬ ther information and reservations, please contact Midland Amateur Radio Club, PO Box 4401, Midland TX 79704. JEFFERSON Wl MAR 20 The Tri-County Amateur Radio Club will hold Its annual hamfest on March 20,1983, from 8:00 am to 3:00 pm at the Jefferson County Fairgrounds, Jeffersorf Wl. Tickets are $2.50 in advance and $3.00 at the door. Tables are$2.50 In advance and $3.50 at the door. Parking is free and there will be plenty of food available. Talk-in on 146.52, 146.22/.82, and 144.89/145.49. For more In¬ formation, advance tickets, and tables, send an SASE to Horace Hllker K9LJM, PO Box 204, 261 E. High Street, Milton Wl 53563. TRENTON NJ MAR 20 The Delaware Valley Radio Association will hold its 11th annual flea market on Sunday, March 20, 1983, from 8:00 am to 4:00 pm, at the New Jersey National Guard 112th Field Artillery Armory, Eg- gerts Crossing Road, Lawrence Town¬ ship. Registration is $2.50 in advance and $3.00 at the door. There will be an indoor and outdoor flea-market area and refresh¬ ments, including breakfast at 7:00 am. Sellers must bring their own tables. Talk- in on 146.52 and 146.07/.67. For further in¬ formation, send an SASE to DVRA, PO Box 7024, West Trenton NJ 08628. CIRCLEVILLE OH MAR 20 TheTeays Amateur Radio Club will hold its sixth annual King of the Pumpkin Ham¬ fest on Sunday, March 20, 1983, from 8:00 am to 4:00 pm, at the Pickaway County Fairgrounds Coliseum. Tickets are $2.00 in advance and $3.00 at the door. Tables (8-foot) are $4.00 in advance and $5.00 at the door. Doors will be open for setups on Saturday at 4:00 pm and overnight securi¬ ty will be provided. A large parking area and food will be available. Talk-in on 147.78/.18 and .52/.52. For additional infor¬ mation, please send an SASE to Dan Grant W8UCF, 22150 Hulse Road, Circle- ville OH 43113, or phone (6l4)-474-6305. STERLING IL MAR 20 The Sterling/Rock Falls Amateur Radio Society will hold Its 23rd annual hamfest on March 20, 1983, beginning at 7:30 am, at the Sterling High School Field House, 1608 4th Avenue, Sterling IL. Tickets are $2.00 in advance and $2.50 at the door. Commercial tables and flea-market tables requiring electricity are $5.00; all others are $3.00. A concession stand, free park¬ ing, and overnight space for self-con¬ tained campers will be available. There will be commercial distributors, dealers, and a large flea market. Talk-in on 146.25/.85(W9MEP). For advanced tickets, tables, and Information, contact Sue Pe¬ ters, 511 8th Avenue, Sterling IL 61081, or call (815)-625-9262. BLACKSBURG VA MAR 21-24 The Virginia Polytechnic Institute and State University will hold a Personal Mi¬ crocomputer Interfacing and Scientific In¬ strumentation Automation Workshop on March 21-24, 1983, on the Virginia Tech campus in Blacksburg VA. The workshop, directed by Drs. Paul Field, Chris Titus, Jon Titus, and Mr. David Larsen, is hands- on, with the participant designing and testing concepts with actual hardware. The charge is $595.00. For more informa¬ tion, write Dr. Linda Leffel, C.E.C., Virginia Tech, Blacksburg VA 24061, or call (703)-961-4848. JOHNSTOWN PA MAR 27 The Conemaugh Valley Amateur Radio Club will hold its sixth annual hamfest on Sunday, March 27, 1983, from 8:00 am to 4:00 pm, at the East Taylor Fire Hall, which Is located on Route 271, 5 miles south of Route 22 (4 miles north of Johnstown). There will be plenty of food and refresh¬ ments available. Talk-in on 146.34/.94. GRAYSLAKE IL MAR 27 The Llbertyvilie and Mundelein Ama¬ teur Radio Society will hold LAMARS- FEST 1983 on Sunday, March 27,1983, be¬ ginning at 8:00 am, at the Lake County Fairgrounds, Routes 45 and 120, Grays- iake IL. Tickets are $2.00 in advance or $3.00 at the door. Tables (9-foot) are $5.00 each. Reservations are encouraged be¬ cause choice locations will be assigned first. Commercial setups will begin at 6:30 am and other setups will begin at 7:00 am. There will be free parking, and breakfast and lunch will be available. Taik-in on 147.63/.03 and 146.94. For tickets, table reservations, or exhibitor information, send an SASE to LAMARS, PO Box 751, Llbertyvilie IL 60048. BALTIMORE MD MAR 27 The Baltimore Amateur RadioClub, Inc. (BARC), will hold the 1983 Greater Balti¬ more Hamboree and Computerfest on '- HOME BREW ' THE SOUTHERN CROSS ** ONE OF THE MOST EFFECTIVE. SIMPLE, STRONO AND INEXPENSIVE, TWO ELEMENT MULTI - BAND QUADRICUBE ANTENNA EXTRAORDINARY OX PERFORMANCE IDEAL FOR 20-IS AND tO METER SANDS, THE TOTALLY PLASTIC MATERIAL 8 STRUCTURE OF TRIANGULAR SHAPE THAT MATCHES PERFECTLY THE ELECTRONIC REQUIREMENTS , LENDS TO j straightforward design that reduces losses, simplifies adjustments S STRENGTHENS CONSIDERABLY THE ANTENNA. MATERIALS REQUIRED ARE OBTAINABLE IN ALMOST ANY LOCALITY. COMPLETE DESCRIPTION, DRA¬ WINGS AND ALL NECESSARY INFORMATION TO BUILD IT, IN ENGLISH OR SPANISH, AIR MAILEO TO ANY COUNTRY $20 U.S. CHECK CASHABLE IN U, S A. TO A . L ASCURAIN PINO N° 59 | ^ M E X. P. F 01030 MEXICO ^214 J See List of Advertisers on page 114 73 Magazine • Februaiy, 1963 97 March 27, 1983, beginning at 8;00 am, at the Maryland State Fairgrounds Exhibi¬ tion Complex (located east of 1-83 exit 17, three miles north of t-695, north of Balti¬ more), Timonium MD. Admission is $3.00; children under 12 will be admitted free. Overnight accommodations are available in the immediate area. Amateur-radio, per¬ sonal-computer, and small-business-com¬ puter dealers will be present. There will be an indoor flea market, a large hard-sur¬ faced outdoor tailgate area, food service, free parking, and guest speakers through¬ out the day. For additional information and table reservations, contact GBH&C, PO Box 95, Timonium MD 21093-0095, or phone (301 )-561-1282. For a recorded an¬ nouncement, dial (301)-HAM-TAIK. MADISON Wl APR 10 The Madison Area Repeater Associa¬ tion, Inc. (MARA), will hold its eleventh an¬ nual Madison Swapfest on Sunday, April TO. 1983, at the Dane County Exposition Center Forum Building, Madison Wl. Doors will open at 8:00 am for commercial exhibitors and flea-market sellers, and at 9:00 am for the general public. Admission is $2.50 per person in advance and $3.00 at the door. Children twelve and under will be admitted free. Flea-market tables are $4.00 each in advance and $5.00 at the door. Features will include commercial exhibitors, a flea market, an all-you-can- eat pancake breakfast, and a barbecue lunch. Plenty of parking space and nearby hotel accommodations are available. Talk-in on 146.16/,76 (WR9ABT). For reser¬ vations (early ones are advised) or more information, write to MARA, PO Box 3403, Madison Wl 53704. SOUTH SIOUX CITY NE APR 15-17 The 39 Hundred Club will hold the 1983 Midwest ARRL Convention on Friday, Sat¬ urday, and Sunday, April 15-17, 1983, at the Marina Inn, South Sioux City NE, di¬ rectly across the river from Sioux City. On Saturday, features will include a QCWA breakfast, a 3900 Club luncheon, an all¬ day ladies’ program, and an evening ban¬ quet with entertainment There will be seminars, displays, commercial exhibits, and a 66-table flea market, all indoors in the same building. Tables (8 ft. x30 in.) are $5.00 for the 3 days, $4.00 for Friday night and Saturday. For table reserva¬ tions, contact Al Smith W0PEX, 3529 Douglas Street, Sioux City IA 51104. Ex¬ hibitors should contact Jim Boise KA0GZY, 22 LaSalle Street, Sioux City IA 51104. Setup time is Friday afternoon. April 15th. Convention fees are $6.00 for the 3 days; advance banquet reservations are $10.00 (at the door, $12.00). For ad¬ vance banquet tickets and motel reserva¬ tions, write to Jerry Smith W0DUN, Akron IA 51001. For general information, contact Dick Pitner W0FZO, General Chairman, 2931 Pierce Street, Sioux City IA 51104. We are happy to provide Ham Help list - ings free, On a space-available basis. We are not happy when we have to take time from other duties to decipher cryptic notes scrawled illegibly on dogeared post cards and odd-sized scraps of paper. Please type or print your request (neatly!), double spaced, on an 8Vi’'x11" sheet of paper and use upper- and lowercase let¬ ters where appropriate. Also, please make a “1” look like a “V hot an *7," which could be an “el” or an “eye,” and so on. Hard as it may be to believe, we are not fa¬ miliar with everyplace of equipment man¬ ufactured on Earth for the last 50 years! Thanks for your cooperaf ion. I am looking for manuals and schematics for the Gonset G50 6-meter transceiver and the Conco 611 VHF transceiver, model 861-0611-001. I will pay a reasonable price for the original manuals or photocopies. Gary Kohtala DA2XF USAFS-A, Box 1415 APO NY 09458 I would like to find the schematics or technical manual for the VHF Engineering TVX-10 transmitter. I also need the address of VHF Engineering’s new parent company. I will pay all copying costs and postage costs. Lee Robinson WA3HJC 317 Peninsula Dr. #53 Erie PA 16505 I would like a copy of the schematic for the Wang 629 double cassette deck, which is part of the Wang 500/600 programmable calculator. Dave Overton 1709 W. 30 Austin TX 78703 I need help in Identifying some of the components in the Sabtronics #8610B-A 600-MHz, 9-digit counter. I would like to identify 2 chips: one is In the preamp of the prescaler, marked SAB 1009 (also marked J7940) and the other is in the frequency di¬ vider and is marked SP 8680B (also marked 96 73 Magazine • February, 1983 PS 5 A2). Any information on these ICs would be greatly appreciated. Patrick Chivington 1476 Grace Ave. Lakewood OH 44107 I would like to locate a copy of the in¬ struction manuals for the Beckman models 607 and 609 heterodyne con¬ verters. These plug-ins extended the fre¬ quency range of the Beckman 6100 series counter. Lyle Pellock W9MWP 2423 Holt St. Vienna VA 22180 I am forming a nationwide network of motorcycling amateur radio operators. Anyone Interested should please check in on 3967 kHz at 0300Z on Thursdays. Send an SASE for more details. Gary McDuffie AG9N Route 1 Box 90-A Bayard NE 69334 I am having difficulties running phone patches with Radio Shack model ET-100T and ET-100 telephones. Rf is causing in¬ terference in the telephones. Can anyone give me ideas on how I can clear up the problem? Everett C. Bollin WA3DVO 8000 Ray Leonard CL Palmer Park MD 20785 I need a wrench that can remove the spanner nut from the microphone jack of the Kenwood TR-9000. I would also like to increase the scan delay to 10 seconds. Any help would be appreciated. Curtis R. Olsen WA9NZQ Box 115 Regent ND 58650 I have a synthesized 2-10-MHz AM-CW transceiver made by Delco. Their designa¬ tion is Delco 1600. Does anyone know the military designation, or have a manual schematic for the unit? Gary Cain 1428 Marigold Way South Bend IN 46617 Wanted; two 60-kHz coil assemblies, part number M42005-1, for the Hammar- lund HQ-170.They are marked asTIO.TII, and T28 on the schematic. John Seety WB3EPG 7080 Moore Avenue Pensacola FL 32511 (904)-456-8096 Has anybody worked out a computer pro¬ gram for converting helical scan transmis¬ sions such as weatherfax to information that could be printed on a dot-matrix printer? Larry J. Clark do USCG Marine Safety Office Galveston TX 77550 I need information on X- and K-band traf¬ fic-control radar units. I would like to build X- and K-band oscillators with an output of about 10W and any schematics or other in¬ formation would be greatly appreciated. A1C Mark LaSalle Box 2241 APO NY 09130 I am looking for the schematic and manu¬ al for the Eico model 249 VTVM. I will pay for any copying costs. Len TenEycke VE31NK 132 Silverhiil Dr. Islington, Ontario M9B 3W7 Canada I am looking for proven modifications or ideas for improving the Ten-Tec Omni D- or C-series units. In exchange, I will provide modification data from my files. Mickey McDaniel W6FGE 940 Temple St. San Diego CA 92106 Wanted: bandswitch or individual wafers for the Hallicrafters SX-110 receiver. Sugges¬ tions welcome; whole radios considered. Nick Adams WA4YKV 3009 NE 14th St Gainesville FL 32601 I need the manual and voltage specifica¬ tions for the Heath HG-10 vfo for 2-80 meters, as well as the manuals for the HP500B frequency meter, the Ameco R5 re¬ ceiver, the Heath FM adapter and the Heath SSB adapter. Finally, does anyone need an “as is” TEK oscilloscope? Kevin Neat Route A Box 221A Fllppin AR 72634 DAYTON OH APR 23 The Washington University Amateur Radio Club will hold a reunion dinner on Saturday, April 23, 1983, at the Dayton Hamfest. All past members of the club are invited. For more information, contact Washington University ARC W0QEV, Box 1128, St. Louis MO 63130. PARAMUS NJ MAY 1 The Bergen ARA will hold a Ham Swap ’n’ Sell on May 1, 1983, from 8:00 am to 4:00 pm, at Bergen Community College, 400 Paramus Road, Paramus NJ. Admis¬ sion for sellers is $3.00; buyers will be ad¬ mitted free. There will be thousands of spaces but tailgating only. Sellers must bring their own tables. Talk-in on .79/.19 and .52. For more information, contact Jim Greer KK2U, 444 Berkshire Road, Ridgewood NJ 07450, or phone (201)445-2855. I am looking for the schematic to an RME pre-war receiver. David R. Nadeau S. 1200 Kelly Ave. Coeur D’Alene ID 83814 I need assistance in locating the man¬ uals and schematics for the SBE model 34 SSB transceiver and the EMC model 213 tube tester, I will reimburse any expenses. Jim See be r 708 Avenue I Matamoras PA 18336 1 am looking for information on software for using the VIC-20 on RTTY and CW. In ad¬ dition, I would like to know if there is a VIC-20 net or if anyone would be Interested in starting one. Just send your suggested time and frequency to me. Dave Land KD5FX 2512 Bonnie Ponca City OK 74601 I am interested in receiving the Space- Shuttle communications on 296.8 MHz with a JIL SX-200 AM-FM programmable scan¬ ner. Anyone knowing whefe I can purchase a converter system, please contact me. Larry Powell 111 Traiiview Dr. Terrell TX 75106 I want to locate the schematic for a Western Electric #2565 HK 3-73 telephone with five incoming lines. I am reassembling the phone with a Western Electric 35AF3A 3-73 pad and a Western Electric 425 ter¬ minal block. The telephone will dial out, but it does not ring properly and the feedback monitoring system is dead. H. Lee Hancock, Jr, W4NXC 301 Forest Hills Blvd. Naples FL 33942 I need the manuals, either originals or copies, for the Hallicrafters model SX-146 receiver and the companion model HT-46 transmitter. I will gladly pay the costs. James Hogarth 421 Gruber Rd. Harieysvllie PA 19438 I am looking for the operation and maintenance manual for a Tektronics type L high-gain, fast-rise-time plug-in for a mode! 545 oscilloscope. I will copy the manual and return it. Bruce Rahn WB9ANQ 410 Coronado Trail Enon OH 45323 TO PIN 2 XVRT JACK CIRCUITS TO SSB TERMINAL ON IF BOARO BROWN LEAD FROM - IF BOARD Do you have a technique, modification, or easy-to-duphcate cir¬ cuit that your fellow readers might be interested in? If so, send us a concise description of it funder two pages ; double-spaced} and in¬ clude a clear diagram or schematic if needed In exchange for these technical gems, 73 offers you the choice of a book from the Radio Bookshop, to be sent upon publication. Sub¬ mit your idea (and book choice) to: Circuits, Editorial Offices, 73 Magazine, Peterborough NH 03458. Submissions not selected for publication will be returned if an SASE is enclosed. J! <$>• / ' LED NICAD CHARGER WITH CURRENT AND VOLTAGE LIMITING: Lamp LI will glow brightly and the LED will be out when the battery is tow and being charged, but the LED will be bright and the light bulb dim when the battery is almost ready . LI should be a light bulb rated for the current you want (usually the battery capacity divided by 10). Diode D1 should be at least 1 A, and II is a 1-W zener diode with a voltage determined by the full-charge battery voltage minus 1.5 V. After the battery is fully charged, the circuit will float it at about battery capacity divided by 100 mA.—Dave Land KD5FX, Pon¬ ca City OK. FAST AND RELIABLE PHOTODETECTOR: Using only 3 compo¬ nents, this circuit yields very reliable operation. Gates have been chained together for rapid action and wired in parallel for increased output current. Analog output can be obtained from either the col¬ lector of the phototransistor or the output of the first gate. A pot can be substituted for the resistor to adjust the circuit's sensitivity.— Terry Fletcher WA0ITP, Ottumwa IA. SIMPLE SWITCHABLE CW SELECTIVITY FOR THE KENWOOD TS-520S: Open the case of the transciever and remove all the knobs and dial face plate. Unsolder the five wires from the RIT control. Remove the RIT control. Mount a 0-5000-0hm potentiometer with a push-pull switch in the hole where you removed the RIT control. Solder a six-inch length of hookup wire to each of the switch ter¬ minals on the new control. Connect the five wires to the new control (these are yellow , blue, orange, orange, and orange). Ground one of the switch wires to chassis. Connect the other switch wire to the relay's coil terminal. Connect the other relay terminal to the transverter output jack to obtain the 14 V dc for the relay. Discon¬ nect the brown SSB i-f lead and attach it to the switching contact on the relay. Connect the normally-open relay to the CW terminal on the i-f board. Connect the normally-closed relay contact to the SSB ter¬ minal on the i-f board. Reassemble the rig. Calibrate the CW selec¬ tivity to a zero-beat obtained on WWV .—Harry A. Ober WB6CGZ, Canyon Country CA. EL EF T Cl 220*»F 15V CRI IN 4444 OR EQUIVALENT Dl SUBMINIATURE LED (RADIO SMACK 276-042) RI IM PC POTENTIOMETER • VARY SIZE FOR OTmER TIME RANGES SIMPLE MICROPHONE TIMER: To avoid accidentally timing out a repeater, install this 555-based timer circuit in your microphone. R1 can be either fixed or variable. A one-megohm resistor and a 100-uF capacitor provide a one-minute, forty-second cycle. The second cir¬ cuit shown will provide a higher key line output. The subminiature LED will be visible when mounted into a hole drilled into the micro¬ phone. To save space, the circuit can be built directly on the pins of the 555. The circuit will light the LED when the transmitter is keyed, and the LED will go out and the transmitter unkey when the timing cycle is completed .—John S. Wilcox KA4DZY, Millington TN. CRYSTAL OSCILLATOR RE¬ PLACEMENT FOR THE COL¬ LINS R390A: This circuit, when used in conjunction with a div¬ ider and phase detector which are not shown, will replace the first and second crystal oscilla¬ tors in the R390A. The varicap diode is a nonlinear device, so oscillation amplitude should be kept as low as possible. The os¬ cillator is a common-base cir¬ cuit providing maximum output impedance, and the 300-pF cou¬ pling capacitor feeds a clean waveshape to the emitter. Aik trim pot is used to set the de¬ sired amplitude .—Eiichi Takar- ada, Rockford IL. 73 Magazine • February, 1983 98 HAND-HELD COUNTER-TIMER Global Specialties Corporation an¬ nounces the new Model 5000 Counter- Timer. it is the first portable, hand-held instrument of its kind. The 5000 combines all of the Important features and perfor¬ mance capabilities of a bench-top unit with the convenience of a fully portable, battery- operated instrument. The 5000 measures 7.6" x 3.75" X 1.7" and weighs in at 14 02. (without batteries). As for performance, the 5000 is designed to measure frequency, period, and pulse width with extreme accuracy and excep¬ tional reliability tt features full signal conditioning including: attenuator (x 1, x t0, x 100), slope selection (+• or - edge for pulse-width measurement) ac or dc coupling, and variable trigger level, A high-contrast 43-inch LCD display of¬ fers 8-dsgit precision loi last and accurate readings LCD annunciators indicate over¬ flow, gate-open, and low-battery condi¬ tions, With a simple flick of a switch, the display-storage mode will maintain the last reading in the display Indefinitely. The 5000 features a unique automatic master reset logic This time-saving reset function instantly clears the display and ini¬ tiates a new measurement cycle eliminat¬ ing erroneous partial measurement, A self-diagnostic function performs anal ysis of infernal logic and provides instant assurance of accurate operation.. The 5000 Counter-Timer Pas 3 modes of operation: frequency, period, and pulse width Signal input is via BMC connector —input impedance is 1 megohm # 25 pF for all modes. In the frequency mode, the 5000 can handle inputs from 0.1 Hz to 50 MHz, Gate times of 01 , 0 . 1 , 1 . 0 , or 10 sec¬ onds can be selected. Frequency will be displayed in kilohertz on the easy-to-read LCD screen. The 5000 will measure any periods from 25 ns to 10 seconds and deliver a single cy¬ cle measurement or an average of 10. 100, or 1000 cycles. Time will be displayed in Pulse-width measurement from 25 ns to 10 seconds can be made Either the high or low portion of the input signal can be selected. The 5000 Counter-Timer from Global Specialties Ali of the controls on the 5000 Counter- Timer are convenient slide switches and are front panel mounted. These include: Trigger Level, Gate Time/Cycles Averaged, Mode, Power (OnlTest/Off), Display (Nor¬ mal/Hold), Polarity (+ to ~ or ~ to + edge selection in pulse-width mode), Coupling, and Attenuation. The 5000 is powered by 6 AA nicad or al¬ kaline batteries or an optional ac adapt¬ er/charger Optional accessories for the 5000 include a 120-V-ac adapter/charger (MMAC-2), a 220-V-ac eharger/adapter (MMAC-3), an automobile cigarette lighter adapter, a 24 * BNC input cable terminated with color-coded quick hooks, an antenna, and a rugged carrying case For additional information, contact Global Specie dies Corporation, W Fulton Terrace, Mew Haven CT 06509 1942; I800h2436077 MOSCOW MUFFLER™ WOODPECKER NOISE BLANKER The AEA model WB-1 Moscow Muffler Woodpecker Blanker represents the latest of many AEA breakthroughs, This blanker is the first to offer effective blanking of the Russian Woodpecker signal with no modifi¬ cations to the receiver required. The WB-t Is designed to be connected in the antenna teedhne between the antenna and the receiver. The WB-1 effectively blanks the interfering pulses before they have been stretched out by receiver tuned circuits, thereby causing the least amount of distortion possible Because the WB-1 is a synchronous blanker, it simply does not overload from strong adjacent channel signals. The over ioad condition is a significant problem with all i-f blankers, making the Moscow Muffler the most effective Woodpecker blanker under most band conditions. In addition to the superior blanking fea¬ tures, the WB-1 offers an effective low- noise broadbanded 6-dB rf preamp with -t- 13-d8m intercept point. The preamplifier may be switched in or out whether or not the WB-1 is in the blanking mode The WB-1 Moscow Muffler Blanker is available in a transceiver version (model WB IQ which features a earner-operated relay (COR) for automatic transfer from re¬ ceive to transmit A COR AOJ control is pro¬ vided for adjusting the relay dropout delay in switching from transmit to receive The Model 340 ThinCoder™ from CES. The WB-1 features a pulse blanking width control for reducing the blanking width to the minimum width necessary' to achieve maximum blanking. The minimum blanking width will assure the minimum signal distortion that must result from plac¬ ing holes tn the received signal. Blanking of both 10- and 16-Hz Wood¬ pecker modes is achieved with the WB-1 At the time this brochure is being written, most Woodpecker transmissions are made with a 10-Hz pulse repetition rate. The WB-1 is simple to operate and the most effective blanker of Russian Wood pecker signals that we have been able to test, including the most popular biankers built into modern transceivers. The WB-1 will typically display 45 to 50 dB of Woodpecker signal attenuation with no overload from strong adjacent channel signals The WB-1 comes with a 90-day limited warranty and is backed by the same AEA customer service that has earned AEA a prominent position in the amateur radio market For more information, contact Ad¬ vanced Electronic Applications, Inc, PO Box C-2160, Lynnwood WA 98036 , (206y 775-7373. Reader Service number 476. THINCODER™ The Thin-Coder, the smallest manual tone dialer made, is now being introduced by CES. CES president Ron Hankins states '"The Model 340 Thm-Coder is truly a pocket- sized encoder. You don't need bulky cases or pouches to carry it with you." The Model 340 measures 2-1(2 * by 3-143 * by only 3/4* deep and effectively dials the user Into private networks, computer ac¬ cess, or dimension systems. Its rugged white case features a brown faceplate and white digit blocks. A convenient normal/ high switch allows flexible volume control, Up to 10,000 long-distance calls are possi¬ ble with the Thin-Coder’s long life 9-volt battery. CES encoders utilize single-con¬ tact tactile keyboards for extra reliability. Communications Electronics Special¬ ties is a leader in the design and manufac¬ ture of quality encoder, microphone, inter¬ connect, and other specialized equipment lor communications markets worldwide For complete information on the Thm-Cod er Model 340 Encoder and other CES prod ucts, contact Ron Hankins, CES Inc., PO Box 507, Winter Park Ft 32790, (3Q5h 645-0474 Reader Service number 484 SIMPSON 470 CALCULATOR-STYLE DMM Simpson Electric Company has Intro¬ duced a brand-new calculator-style DMM, the 470.. a high performance DMM with Woodpecker noise blanker features that are usually found only on more expensive units. 2$ ranges are provid¬ ed, including 1000 volts dt, 750 volts ac, and 10 Amps aoidc, All voltage and resis¬ tance ranges are protected against tran¬ sients up to 6 kV at 100 microseconds. Convenient recessed human-engineered thumbwheel knobs control ranges and func¬ tions. An audible tone on the 2000-Ohm range provides fast checks tor shorts and continuity. A diode test provides quick, good- bad checks of semiconductor junctions. The easy-to-read, high-contrast, 3 1 /*- digit. 7-segment LCD display also features a low-battery indicator—battery life is about a year s average use The instrument is manufactured by Simp¬ son in the USA and carries Simpson's 1-year warranty The high-impact. sealed case is 1S* x 3.4 * x 7,1 A two-way fold-out stand provides for convenient bench-fop use or tor hanging in an upright posh von The 470 weighs less than 1 lb. The 470 is supplied complete with UL- recognized, color-coded test leads with screw-on alligator clips, 9-V battery, and in¬ struction manual Optional accessories in¬ clude Simpson's Amp-Clamp ac current adapter, as welt as temperature, rf, and high- voltage probes, and the recently announced test-lead systems "The 470 and other calculator-style instru¬ ments will join the growing family of Simp¬ son UL-listed DM Ms," announced Simpson's sales director, Mel Buehnng "They will be available from leading elect ncal/eiectronics distributors worldwide," For further information, contact Simpson , Katy Industries, tn c, Bactricai Equipment and Products Group., 853' Dundee Avenue,, Elgin it 60120: (31210872200 Reader Service number 483. The Simpson 47Q calculator-style 0MM. 100 73 Magazine • February, 1963 Micro craft's Videoscan 1000 high-resoiution SSTV converter Non linear Systems' PE-5 frequency counter NEW FREQUENCY COUNTERS Non-Unear Systems, fnc, recently an¬ nounced two new digital-panel frequency counters capable of counting up to 10 MHz Designated the PF-4 and PF-5 respectively, the new counters are packaged m minia¬ ture cases measuring only I5n6 x 2V» x 3’>y inches and provide four selectable tirnebases: 001.0.1,1, and 10 seconds. The decimal point may be externally selected and the display may be blanked, dimmed, or tested externally. The PF-4 is a four-digit display, while the PF-5 is a five-digit display. Internal signal- conditioning circuitry permits input signals having stow rise and fall times to be accom¬ modated without difficulty, and both ac coupled or decoupled inputs are accepted. Input impedance is 75 kiiohms and input signal amplitude may be + 3 to +30 volts peak-to-peak The instruments may be field- modified to accept up to 700 volts peak-fo- peak The units operate from an external 5-volt dc supply. For additional information, contact Non- Unear Systems, Inc., PO Box N, Del MarCA 92014. Reader Service number 485 SOLAR PHOTOVOLTAIC BATTERY CHARGER The Phaeton It photovoltaic battery charger manufactured by International Solar Products Corporation of Durham, North Carolina, is being called "the most revolutionary development in rechargeable technology since the rechargeable bat¬ tery” The unit produces 4.8 volts of direct- current power at 240 miiliamps in peak sunlight. Four AA ceils, two C cells, and two D cells can he charged with the unit Bat¬ teries are fully recharged in 14 to 16 hours of sunshine. Phaeton II measures 6' x 7" and weighs less than two pounds tt is constructed with spage-age materials—annodized gold or silver frame, heavy-duty aluminum battery cradles, and the same silicone covenng used to protect the solar cells on orbiting communication satellites. The unit con¬ tains no plastic parts. According to the manufacturer, the average consumer could spend as much as $100 per year on throwaway batteries to power the portable radios, tape recorders, toys, games, flashlights, cameras, and other electronic appliances found in many homes today. For additional information, contact International Solar Products Corporation, 1105 W. Chapel Hill St., Durham NC 27701, (919h489-6224. Reader Service number 478. HIGH*RES0LUT10N SSTV CONVERTER Microcraft Corporation has announced the new Videoscan-1000, a high-resolution SSTV converter. Although the converter is compatible with amateur standard and first-generation SSTV equipment, the Videoscan-1000 also has two high-resolu- The Phaeton // photovoltaic battery charger manufactured by International Solar Prod¬ ucts Corporation lion modes producing 256 line pictures with 256 pixels per line The converter's pixels are quantized to 64 levels ot gray, and it features a built-in gray-scale pattern to use in setting controls as well as three scan rates for optimum versatility. With the Videoscan-1000 s split-screen mode, lour SSTV pictures may be viewed at one time, and the boill-m memory can hold one frame of video from the camera or other sources Your callsign may also be pro¬ grammed into memory The converter takes care of all switching between the transmitter, microphone, and tape recorder The only additional equip¬ ment necessary for operation is a camera and a monitor For additional information, contact Mi- crocraft Corporation, PO Box 5 13, Thiens- ville Wl 53092; (414^2413144 Reader Ser vice number 481 SELFRESET POWER-LINE INTERRUPTER Electronic Specialists expands its Ac Power-Line Interrupter series to include au¬ tomatic reset models. Should ac fine volt¬ age be disrupted or exceed preset safety limits, the Power Interrupter disconnects ac power from controlled apparatus. A 4-minute time delay, followed by automatic self-reset, helps avoid wide voltage fluctua¬ tions associated with power-line malfunc¬ tions, An optional line voltage monitor is available. Intended for Installations operating unattended for long periods, the Self-reset Power Interrupter provides safety and protection tor equipment and personnel. Connecting to the ac line with a standard 3-prong plug, the Self-reset Power Inter¬ rupter can accommodate a 15-Amp resis¬ tive toad or a 10-Amp inductive load For further information, contact Elec¬ tronic Specialists „ tnc .. 171 South Main Street, PO Box 389, Natick MA 01760; (617> 655-1532 . Reader Service number 477 RTTY SOFTWARE John Yurek K3PGP has Introduced a line of TRS-80 programs for use in the ham shack, CW runs on 4K Level I or Level tl and turns the stock machine into a CW key¬ board and receive terminal The hardware interface for the program consists of a transformer and a transistor, both available from local Radio Shack stores. The pro¬ gram features a FIFO butter and 8 regular buffers. CW creates a split-screen display, allow¬ ing you to fill the buffer with a return mes¬ sage before you transmit. Speeds are ad¬ justable from the keyboard, and text editing is provided for error correction. RY turns a TRS-80 stock machine into a 5-levei (Baudot) teletype machine This pro¬ gram also includes a FIFO buffer and a split-screen display. It will operate at all legal amateur speeds, and T/R switching Is controlled automatically. Both programs use the audio output of the cassette port to key the transmitter, without using the cassette relay. For$1, which is refundable with your first order, a catalog may be ordered trom John Yurek K3PGP, RD #6, Box 413, Irwin PA 15642. Reader Service number 482. WIDEBAND ANTENNA PREAMPLIFIER Grove Enterprises, prominent manufac¬ turer ot accessories tor scanner and short- Self-reset Power Line Interrupter from Electronic Specialists, Inc 73 Magazine * February, 1963 101 Microwave Filter Company's 3923-T TVRO filter. fefSS'" I 11 "'"'""" The PRE-1 Signal Amp preamplifier tram Grove Enterprises . wave reception, has just announced its PRE-1 Signal Amp masthead preamplifier Designed to provide high-gam, low-noise amplification for received VHP and UHF signals, the PRE-1 boasts a mid-band gain of at least 15 dB with a noise figure of only 1,8 dB. The Signal Amp consists of a lightweight antenna-mounted preamplifier module and an indoor control unit Switch-selectable high and low gam allows the user to cus¬ tomize his signal-enhancing needs Guaranteed to outperform competitive Indoor preamplifiers, the PRE-1 Signal Amp comes with ail necessary hardware, con¬ nectors, and instructions- For additional information, contact Grove Enterpnses , 140 Dog Branch Road, Brasstown NC 28902 . i?04h83T2216 TUNABLE TVRO FILTER Microwave Filter Company's new 3923-T bandpass fitter tunes to any of the 24 TVRO transponders by means of three cali¬ brated dials. When tuned to a particular transponder, the 3-dB bandwidth is 40 MHz with less than 1.5 dB loss. Selectivity is3GdB at ± 76 MHz.The new filter features type-N connec¬ tors and passes dc power. Delivery can be made m ten days from date of order, and the 3923-T fitter comes with specification sheet and tuning instructions. For more information contact Emily Bostick , Microwave Filter Company, lnc. t 6743 Kinne Sfreef, East Syracuse NY 13057 Reader Service number 479. FACSIMILE WEATHER-CHART RECORDER BY ALDEN ELECTRONICS Remember the old adage, ‘Everyone talks about the weather, but nobody does anything about it"? Well, that's not quite true-™if it ever was—and Alden Electron¬ ics of Westborough, Massachusetts, is surely proof that somebody really does do something about the weather They have Introduced a facsimile weather-chart-re¬ corder kit for the home hobbyist and ham. Specifically, Alden Electronics is one of the world’s largest manufacturers of radio- facsimile receiving and recording equip¬ ment . . equipment that prints charts of significant weather information from around the globe, gathered by weather sta¬ tions and rebroadcast in coded form for use by ships, aircraft, scientific expeditions, military and oceanographic groups, and many other stations. The world depends upon radiofacsimiie weather charts and satellite photographs for up-to-date information about storms, icebergs, significant changes in weather patterns, and other vital data needed by virtually everyone who lives, works, and travels in an interdependent world. Mer¬ chant mariners, naval officers, fishermen, and small boatmen make critical deci¬ sions based on local weather and ocean conditions. Air force officers, pitots, com¬ mercial airlines, airport operators, and Others make critical decisions based on weather and atmospheric conditions. Modern radiofacsimiie and satellite tech¬ nology is now abie to bring timely and ac¬ curate weather information to these users on a worldwide basis. Correct interpreta¬ tion of the information inevitably leads to increased safety, improved efficiency, and even competitive advantage. It has been said that a picture is worth a thousand words, and so M seems to be with weather information whose presen- 102 73 Magazine * February, 1983 tation in chart or picture form is so much more meaningful to the end user than in¬ formation represented merely by strings ot coded symbols, numbers, and letters The location of major weather systems, storm fronts, areas of violent oceanic or atmospheric activity, and similar informa¬ tion can be seen and understood quickly on a weather map or from a satellite pho¬ tograph. Therefore, if your own personal situation or livelihood depends on or is as sociated in any way with weather-related phenomena, you are certainly a candidate for Aldan's goods and services The Alden weather-chart recorder prints weather charts and satellite pic¬ tures from radiofacsimiie signals trans¬ mitted by a network of government-owned and -operated stations located around the globe The recorder requires an external re¬ ceiver, It features solid-state circuitry and a simple electromechanical design to en¬ sure long, trouble-free operation. The Alden weather-chart recorder uses eiectrically-sensitive paper packaged In handy, disposable cassettes, the 11 *-wtde paper requires no threading and replacement involves the mere insertion of another cassette. The printing process is quiet and free from smoke, odors, and fumes. No venting is required, and the asm- pact size and light weight permit a variety of desktop or wall-mounting arrangements Background and Amateur Applications Many hams have theirown home weath¬ er stations which record or display tem¬ perature, pressure, and wind velocity,, , and weather is usually a part of the con¬ versation between two hams. It's good fun to tell the other station just how bad {or how good) your weather is, compared with that in his own area. Historically, how¬ ever, facsimile has been used for the transmission of other information- maps, schematic diagrams, drawings, photographs, and other images. Radio amateurs have often built their own fax transmitting and receiving equip¬ ment, and many have converted surplus military or commercial units to this purpose. There are several systems of encoding and decoding fax information for its broadcast and reception, all of which work satisfactorily None need be dis¬ cussed here, because the information is available in a variety of references on the subject, Some hams have received the radtofac simile weather information direct from the satellites that broadcast it, while others prefer to use the information rebroadcast on the HF bands by weatherfax stations. in one sense, fax is like RTTY, amateur television, or similar modes of communi¬ cation...it is enjoyed by small, select groups of hams who prefer the challenge and fun of doing something slightly differ ent. For a long period of time, hams built their own TUs for RTTY reception and con¬ verted old Model 15s or Model 19s to ama¬ teur use. Then, with the revolution in solid- state electronics and computers, home made apparatus gave way to commercial fy-avai table units of advanced design and infinitely increased capability. ft appears that radiofacsimiie is now on that threshold of development at which commefcially-avaiiabie units have made home-buii? or converted surplus units a thing of the past A!den r s Weather-Chart Recorder Our staff received two units for test, . one ready-to-go. and the other a kit. Each was accompanied by an amply illustrated and detailed manual which told how to connect the unit to the receiver, and how to tune and adjust It for best reception and printing. The kit unit had, in addition, a construction manual which included pictorial as well as schematic diagrams, plus detailed step by-step instructions for the mechanical and electrical assembly The Kit The kit arrived packed m a large box di¬ vided into twelve or so internal compart¬ ments, each partitioned from its neighbor by corrugated paper bamers. Each com¬ partment was numbered and contained a correspondingly-numbered plastic enve lope of parts wrapped in protective packing material. The manual calls out the contents WEATHER-CHART-RECORDER KIT MODEL 9321 SPECIFICATIONS Recording rate: 120 spm (scans per minute). Index ot cooperation: IOC 576 CCIR. 169 lines per Inch Control signals: Automatic start, stop, frame; manual start and frame, Start: Signal shifting between 1500 Hz and 2300 Hz at a 300-Hz rate for 5 seconds. Frame: A 1500-Hz signal interrupted by a short burst of 2300 Hz each scan line. Duration—20 to 30 seconds immediately following start signal. Stop: Signal shifting between 1500 Hz and 2300 Hz at a 450 Hz rate for 5 seconds. Circuitry: Solid state Input impedance: 600 Ohms balanced. input frequencies: FSK-1500 Hz black. 2300 Hz white Scanning electrode: Stylus belt. Recording paper Alfax electro-sensitive paper in throw-away cassettes with bttiiMn printing electrode. Each cassette contains 35 feet of li-ineh w»de paper Input voltage: 115 V ac * 10%, 50/60 Hz. Maximum power Standby mode; 10 Watts; operating mode; 30 Watts. Net weight; 10.1 pounds Dimensions: 3-5/8 * H, 17-1/16 * W, 10-1/2" D. Alden* s weather-chart recorder. of each compartment and invites the kit builder to identify, check off, and repack each component ready for use. Everything you will need, including sol¬ der, is included. Most of the more difficult assemblies have been prefabricated and subassembled so that you won’t have any trouble with difficult or critical compo¬ nents. You assemble the mechanical parts first, according to a logical step-by- step procedure. Then, you solder the pre- cut wires to length and solder them to the subassemblies. Finally, you interconnect the wires, harnessing them as you go. All critical construction, board-stuffing, testing, and adjusting has been done for you, meaning that your task will be pleas¬ ant, simple, and straightforward. Two of us started construction on Fri¬ day evening, each helping the other with the work of selecting and positioning parts, fastening them in place, connect¬ ing them, and checking them off in the manual. The work goes fast, and there is nothing to be done that could not be han¬ dled by even a beginner. Saturday evening saw all but final as¬ sembly and checkout... which took place on Sunday morning. We logged 24 man¬ hours {12 hours total time) on assembly and test. Preliminary checkout and test before hookup to radio receiver is done with a mul¬ timeter and consists of measuring some re¬ sistances, voltages, and continuity. Again, each step of the way is detailed in such a way that the procedure is fail-safe. There is no such thing as a smoke test. Operation Alden thoughtfully included a world¬ wide marine radiofacsimile schedule in which you will find a list of stations around the world which broadcast the ra¬ diofacsimile signals. We tuned our all¬ band, general-coverage Icom R70 receiver to the Halifax, Nova Scotia, and Norfolk, Virginia, stations whose signals came roaring in on their assigned frequencies. Also included is a Facsimile Products Guide, which is an aid for interpreting HF radiofacsfmile charts transmitted from the US Naval Eastern Oceanography Center in Norfolk VA. The guide is reproduced with permission of the US Naval Eastern Oceanography Center, whose personnel originally prepared it. You will find information covering broad¬ cast frequencies and schedules. Each chart is illustrated and described In detail, covering atmosphere analysis, at¬ mosphere prognoses, oceanographic analysis, and oceanographic prognoses. The charts are typical of what is transmit¬ ted worldwide. Using this information, you can tune in to the exact information you want or need, and immediately start receiving pictures and charts. There are only two connections for you to make with the finished weather-chart recorder. One is to plug it into the house mains—115 V ac. The next is to connect the terminals on the back of the recorder to the audio output of your receiver and to ground, respectively. Although the in¬ structions called for 600-Ohm output, we were able to receive perfectly satisfactory charts using the 3.2-Ohm receiver output. Later, we built a little Impedance step-up device that transformed the R70’s output to approximately 500 Ohms for a better match to the unit, although this was not considered necessary. After connection, and before turning the unit on, you make sure that the paper cassette is properly installed and the cov¬ er of the unit (which has a safety interlock) is snapped into place over the paper cassette. As you tune in the USB audio-frequen¬ cy-shift signals on your receiver, you will notice two little LEDs on the top of the re¬ corder blinking red and green. The green LED represents the white image, and the red LED represents the black image on the paper. We found that the receiver’s RIT (in¬ cremental tuning) control helped adjust to the exact frequencies needed after the main tuning dial was locked on to the fre¬ quency. Proper adjustment is thoroughly covered in the manual. The next step Is to depress the start switch, which begins the drum rotation and the stylus scanning. If the broadcast is already in progress, you will need to press the frame button to center the map on the paper. The weather-chart recorder is set to receive broadcasts at 120 lines (scans) per minute, which is the standard for most stations you will tune. After a few minutes, you’ll see the paper coming out of the recorder with a map or picture on it. Then, it’s just a matter of waiting until the map or chart is complete before you tear the paper(or cut it) to sep¬ arate the completed picture. A very nice feature of the recorder is its auto-start and auto-stop function, which allows you to leave the unit in operational condition, but silent, until a broadcast of live material begins. The broadcast itself will issue start and framing pulses which will activate your recorder and properly frame the picture. After a transmission, a stop pulse will be transmitted, stopping the machine and placing it in the standby mode, ready for another chart. It was fun to see the satellite picture taken over the North Atlantic just a few hours before, showing the cloud cover (what else?) over the New England area. Much of the United States is covered, as well as most of the North Atlantic ocean. You can see the Caribbean islands, some of Central America, and parts of Green¬ land and Iceland. The weather charts containing pres¬ sure isobars, temperature and wind-veloc¬ ity data, and much more require some study to understand. You’ll be fascinated at all the things you can discover with your recorder. For example, if you have a directional antenna, you can tune in the weather facsimile broadcast stations in England, France, Russia, Germany, the Pacific, Australia, Japan, etc., etc. These will give you charts and maps, as well as possible satellite pictures from their own parts of the world. You could even tell that DX station what his own weather is like, if you wanted to! One of the better books available from Alden is A Mariner’s Guide to Radiofacsimi¬ le Weather Charts which, in its 127 pages of text, charts, and photographs authored by Dr. Joseph Bishop, presents the best under¬ standing of the earth’s atmospheric and oceanic processes I have ever read. It is simple, lucid, and interesting. Even for someone who has no formal education in weather interpretation or analysis, the book is easily read and understood. By all means, be sure to order this book. I must say that Alden has opened my eyes to an unexpected and pleasant facet of radio that I had never before experi¬ enced, in spite of my 32 years of hamming. Radiofacsimile reception is fun, it’s fasci¬ nating, and—believe it or not—it kept me off the ham bands for two weeks while I explored the intricacies of the world’s weather.. .through the weather-chart recorder. You should avail yourself of the small (approximately 17"x 10”x A") and light¬ weight (about 10 pounds) Alden weather- chart recorder ($995) and experience a new thrill in radio. It’s guaranteed to be fun and educational. For further information, contact Alden Electronics, Washington Street, West- borough MA 01581. Reader Service num¬ ber 488. Jim Gray WlXU 73 Staff Gene Smarte WB6TOV Hancock NH THE ICOM R70 The Icom R70 is a general-coverage communications receiver covering a fre¬ quency range of lOOkHzto 30 MHz. Newly introduced to the market, it made me anx¬ ious to review it and share my impres¬ sions. As with most hams, I could not resist the urge to unpack the radio and begin us¬ ing it immediately without, of course, reading the instruction manual. It Is be¬ cause of this ease of use that I have such good things to say about it. The IC-R70 has a front panel that is both uncluttered and functional. All controls are clearly marked, and after studying it for a few minutes I became aware of the radio’s versatility. Bringing It to life was extremely easy, with just two connections, power ca¬ ble and antenna. The 117/235-V-ac input is standard, with optional 13.8 V dc available. It is also internally modifiable to 100/200/ 220 V ac. The built-in speaker eliminated hunting around the shack for the phones or that bullet-riddled speaker that usually turns up. The receiver is a quad conversion unit with its first i*f at 70.4515 MHz. The sec¬ ond i-f is at 9.0115 MHz. Without an antenna, I tuned across about all of its range, observing the birdies. The few I found at expected places were, however, far below the level of signals present with the antenna connected. Ail of the initial testing took place on the ham bands using my triband beam. Twenty meters provided the kind of sig¬ nals I was looking for, especially at the lower portion of the phone band. The R70 features a Pass-Band-Tuning (PBT) sys¬ tem allowing you to narrow the width of frequencies passing through the crystal filter. The passband can be moved up to 500 Hz from the upper or lower side In SS8 mode (2.7 kHz in the AM mode). With the control in the OFF position, the passband is 2.3 kHz wide in SSB mode and 6 kHz in the AM mode. Using this control, I was able to hear stations that could not be re¬ ceived by using the notch control alone. No information was published as to the shift and depth of the notch filter, but it seems as effective as any other I’ve used. While the PBT system took some get¬ ting used to. the frequency and mode se¬ lection did not. The radio has three select¬ able-tuning rates, 1 kHz, 100 Hz, and 10 Hz. These controls are located to the right of the tuning knob and, with a little prac¬ tice, I could quickly zero in on the desired frequency. The one thing that did get a lit¬ tle confusing was the fact that the fre¬ quency does not roll over. Increasing from, say, 7.999.9 kHz returned you to 7.000.0 and not on to 8.000.0 kHz. This, however, turned out to be a time-saver when tuning from high to low ends of a band or vice versa. A LOCK push-button also is provided to disable the tuning knob, preventing accidental changes in frequency. To the left of the tuning knob are three controls marked BAND UP, DOWN, and HAM/GENERAL These are used to incre¬ ment or decrement the most significant digit of the frequency display when in the general-coverage mode When in the ham coverage mode* these controls step you through 160m, 60m, 40m, etc „ skipping all of the frequencies in between. It does stop at the new 10% 18*, and 15-MH2 bands, also. Other front-panel controls include CW (wide and narrow—500 Hz), SSB, RTTY, AM, and FM (with the optional module). There is a separate FUNCTION push-but¬ ton designed to select the sideband oppo¬ site the one you are in and select the nar¬ row CW filter. The receiver automatically chooses upper or lower sideband depend¬ ing on whether the frequency is above or below 9 MH 2 . A SQUELCH control also is provided, obviously getting used more for the FM mode than any other It did work very well in SSB mode, however, but only on strong stations. Its action was depen¬ dent on the age timing, and in the slow setting took quite a while to open (or close). I cannot see any real need for it ex¬ cept in the FM mode. The frequency-display panel includes a 7d»git readout with 100-H2 resolution; it displays which mode and vfo is in use. There are two vfo‘s that can be loaded with the current frequency information and catted independently of each other. An RIT control is provided to shift the re¬ ceived frequency ±800 Hz from the dis¬ played frequency. No indication is given on the display except for a status LED showing that the control is in use A use¬ ful feature is the fact that the RIT control is automatically disabled once the main tuning knob is moved It can be re enabled anytime by depressing the push-button. This assures you that you are receiving the displayed frequency A built-in preamplifier and attenuator is switch-seiectabfe from the front panel. Claimed attenuation is 20 dB, with no men¬ tion of the amount of preamplificatton. Judging from the S-meter indication, it seems to be in the order of 6 dB. An age se¬ lector permits a timing of fast or slow, or OFF. This I found more than adequate for all types of communications using the fixed rates. A switchable noise bianker proved very effective in both the available narrow or wide settings. It also seemed very effective with wood pecker-type noise. No decrease in signal levels was perceived with the noise blanker switched in. The built-in speaker provided good- quality reproduction of all types of sig¬ nals, In the AM mode. SW broadcast sta¬ tions were very enjoyable to listen to without the high-pitched sound that one might expect from such a small speaker In any event, an external speaker jack is provided should you wish to use it, as well as a recorder output jack. The latter outputs an audio level independent of the volume-control setting. Although advertised as a general-cover¬ age communications receiver, rear-panel connectors are provided to allow easy use of the unit with a transmitter or transceiv¬ er. The IC-R70 has a mute input allowing it to be quieted during transmit. Transmit¬ ted signals can be heard in the receiver, however, by using its monitor function. The volume of the monitored signal can be adjusted with the front-panel control. The rear-pane? accessory socket can also be used to control VHF and UHF con¬ verters The switching arrangement is covered in sufficient detail in the manual Also available on the accessory socket is an output from the receiver's detector stage. This output ts at a fixed level re¬ gardless of the volume or gam settings, ft is intended to be used to drive a RTTY ter¬ minal unit. Other rear-panel connectors include a scope output from the first i-f 104 73 Magazine • February, 1983 (70.4515 MH2). This would be useful for us¬ ing a panoramic-type display. Rear-panel antenna connectors are of both the PL-259 type and spring-clip type The former is intended for approximately 180 meters and up, while the single-wire in¬ put is intended for the AM broadcast band below. The coaxial connector is designed for a 50-Ohm-impedance antenna system, and no specifications are given for the long-wire connector. No provisions are made for antenna matching, leaving it en¬ tirety up to the user to determine optimum performance. My final comments deal with the In¬ struction manual and schematics. As one who likes to maintain his own equipment, I found the documentation included total¬ ly lacking in content. The manual is an ex¬ cellent operating instruction manual, but very little information »s given on circuit description, troubleshooting, and general maintenance The schematics are of the type showing detail of individual circuits, but interconnections are vague In summary, l would consider this re¬ ceiver an excellent value. Its performance would make it suitable for the beginning ham. as a standby receiver for the shack, or to fill the void between hamming and casual listening. Its usefulness for Field Day or emergency communications can¬ not be overlooked. Also, I don’t think the new or seasoned SWL could find fault with its performance—again making it a worthwhile addition to the shack. My wife, on the other hand, did not like the radio; that was after I told her that I would like to have one. For further information, contact /com America, tnc , 2112 116th Ave. NB. Belle¬ vue WA 98004:1206H54 8158 Walt Lewandowskl WA2VSN SpoffonJ NH CK-2 MEMORY KEYER Keys and keyers. like tools, are inter faces between a worker and his work. The right tools make the job easier—even pleasant. Sometimes, when the work is pleasant and the craftsman is in a proper frame of mind and the tools are of superb quality, the tools become an extension of the craftsman—seeming to have no inde¬ pendent existence—and the finished product becomes a work of art In case you wonder what all this has to do with a product review, let s go back to the beginning and talk about keys and keyers Each CW operator prefers a certain type of key, and within that type exists an al¬ most infinite variety of examples Dozens of varieties of hand keys are in daily use, and the same holds true for semiautomat¬ ic mechanical keyers, electronic keyers, iambic keyers, and memory keyers. Each has its own group of devoted adher¬ ents—operators who swear by a particu¬ lar kind or make and wouldn't have any other, Memory keyers recently have come into greater use and acceptance than ever be¬ fore, particularly by contest operators, for very good reasons. Electronic memory keyers not only have the capability of forming nearly perfect Morse characters into ideally spaced and -weighted’ let¬ ters, words, and sentences, but they also have the ability to store words and sen¬ tences for later transmission, merely by pushing a button or touching a keypad In typical contest work, the same message or exchange is sent over and over again, meaning that repeated retransmission of such a message from memory is both practical and necessary if high contest scores are to be obtained. Non-contesters also have found that a CO message is practical, and even the simplest memory keyers now in use permit limited storage of simple messages In the field of electronic keyers, Morse trainers, CW-generating devices, and character-encoding and -decoding de¬ vices, Advanced Electronic Applications of Lynnwood, Washington, has carved a niche for itself and has gained a reputa¬ tion for quality and reliability. AEA elec tronic memory keyers set the pace for others to follow with their Morsematlc—a do-everything memory keyer and top-of- the-line product which, in the hands of ex¬ perienced operators, is equally capable of sending exquisite CW or teaching new operators to do the same. Following on the heels of the Morsematlc came the CK-1, a contest keyer with ail of the features of the more expensive keyer (ex¬ cept for the "beacon’' feature and training capability) at a significantly lower price. The Morsematic and CK-1 offered se lectable characteristics of "weight” (i.e., dot-dash length ratio) and spacing, speed control, and message stofage, all avail¬ able by means of a keypad located on the top of the unit within easy reach and sight of the operator. Beyond that, there were pitch and volume controls which allowed the operator to adjust the keyer sidetone to exactly suit his or her preference. Final¬ ly, AEA packaged all of these features into a neat, lightweight, and versatile box that conveniently fits on the disk or table at the operating position and unobtrusively gives the operator station command from tune-up to rapid fire exchanges. Now, the CK-2 Mike Lamb N7ML and the folks at AEA have just released their newest electronic memory keyer, the CK-2, which incorpo¬ rates the CK-1 features and adds a few more to make CW even more pleasant and simple. CK 2 stands for Contest Keyer. second model, but it also has a name Contester Recently, I was fortunate to be asked to review the Contester for 73. Fortunate, be cause I am a CW afficionado and because I had heard so much about the CK-1 and Morsematlc but had used the Morsematlc only a few times and the CK-1 not at all, Let’s take a look, together, at the CK-2, pretending that we are seeing it for the first time. The sturdy 10* x 10'x 4’ cardboard car¬ ton is your first clue to the careful and rug ged packaging Inside, you find the CK-2 neatly sealed in a plastic bag and nestled down into its shock-protective wadding Alongside, you'll see another plastic bag containing the following items: a battery eliminator-type power supply (optional) that plugs into the wall and furnishes 12 volts dc at .35 Amps, a three-circuit, PL 68-type plug attached to a length of two-conductor shielded wire, a separate dc power plug and cable for attaching the CK-2 to a separate dc source, and a 2-circuit PL 68 plug con¬ nected by a shielded cable to an RCA- type phono plug. AEA has thought of nearly everything, because the 3-circuit plug connects your keyer paddle to the CK-2 and the 2-circuit PL-68/RCA phono combination connects the CK-2 to your rig. Not much else to do. Now for the piece de resistance, the CK-2 itself. The housing is a matte-black- finished metal box with rounded corners, measuring approximately 2* high by 5* deep by 7* wide A twelve-button keypad occupies the right-hand top surface of the CK-2, and two knobs—a switch and an LED—occupy the left-hand top surface. The first knob is the on-off/sidetone-vol¬ ume control, and the second is the delay max/min control. The switch activates the memory-repeat function, and the LED Is a full memory indicator. The rear panel con¬ tains the power jack, the paddle jack, and the key * and key — jacks which allow your CK-2 to key a high-current tube-type rig that uses cathode keying, or a low-cur- rent, solid-state keying circuit My particular keyer has serial number 364, and was inspected by “Robin'*—a nice touch in this day of faceless manu¬ facturers and nameless inspectors. You have the feeling that AEA cares about you and wants you to know who they are in case you need their help. Bravo! A confi¬ dence-builder that costs very little but means a lot. We can’t forget the instruction manual that accompanies the keyer. It’s there, all right, and tells you how to operate the CK-2 in each of its various modes and pa¬ rameters. Now let’s plug the CK-2 in and turn it on to see how it plays. Memory Functions The CK-2 memory storage accommo¬ dates up to 500 characters in either a sin¬ gle group or in up to ten different groups, selectable by the keypad. Two basic types of memory storage are available: real time or auto memory. Real¬ time memory means that everything you send, including pauses between charac¬ ters and words, is loaded and counted in the 500-character group. Auto memory means that whenever you pause between characters or words, the CK-2 begins counting to itself, and when you have ac¬ cumulated the equivalent of a word’s worth of spaces. It shuts down—thereby saving you lots of space For the speed de¬ mons this may not be necessary, but for us slow thinkers it’s a real boon. Counting begins again when you send the next character By switching on the "memory load" function and then keying **9„ you select the auto load function If real-time loading is your preference, a mere *9 will get you there. Memory location is keypad-selectable, too. By selecting any digit between 0 and 9. you can put each message into that particular storage space ready for later recall. The # symbol terminates memory load¬ ing. Already-loaded messages can be de¬ leted from memory when desired merely by pressing #N, where N is the number of the memory location In storage. If you for¬ get where you put it (as I have done), that's your problem you’ll just have to keep trying until yc ■'Sind it. In the playbe rode, your message keeps going out over the air (at the select¬ able deiay-between-messages of your choice) until you hear an answer Just a single tap on your paddle will halt the message and allow you to pick up the break. If, or when, you wish to resume the message, all you have to do is request it from your friendly Contester. Oh, yes, before I forget. You can edit messages as you load them without hav¬ ing to start all over again—a real time- saver! The Contester’s memory includes a long-term ‘‘keep-alive’ circuit, battery- powered from an alternate power source.. a 9-volt transistor battery, for example (not supplied) This feature al¬ lows you to keep intact those previously- stored messages while you travel to the contest site or to your Field Day location. Take some time to get acquainted with your CK-2 before you try out the message- storage functions There s a lot to learn, and it’s best to relax with the regular func¬ tions before beginning any new ones. I might add that the automatic message-re- peat function will be available to you when you need It, and the delay between repeats can be adjusted from about 2 sec- ondsto3minutes. . .affording you almost infinite variations between casual rag chewing and high-speed contesting. Operating Your CK-2 When you turn on the CK-2, it beeps once at about 500 Hz, the sidetone bari¬ tone note. If you prefer tenor, you can get that, too. Here—let’s try it: press *1 and hold the 1. Notice the tone climbing the scale, the pitch getting higher and higher? Okay, when you reach the note you like, just lift your finger off 1 and there you are. Simple, huh? (Lower the tone with **1.) Now, how about speed? Well, there are two speeds already preset into the CK-2. Here—try keying something—at about 20 wpm, right? That's memory A for speed. Now, touch *9 and try keying. About 30 wpm. That’s memory B. Let’s say you want to change both memory A and mem¬ ory B for speed—no problem. **8NN lets you put the desired speed In memory A; the NN is the speed in wpm that you want. Example: **815 will give you 15 wpm. Okay, let’s set that in memory A. In memo¬ ry B, let's put in 25 wpm. Hit **925 and there you are! Now, by hitting ‘8 you get 15, and *9 gives you 25. (If you turn off the keyer, and then come back on, memories A and B will have reverted to their original 20 and 30 wpm respectively.) Here’s another neat trick. Suppose you don’t know the speed you want (in terms of a particular number of words per min¬ ute) but wish to listen until it sounds about right. Okay, simple: press *6 and hold the six while keying your paddle on the dot or dash side. When the length is what you want, remove the pressure from the 6. Let’s say you want to decrease speed smoothly: press *7 and hold the 7 until the speed is down where you like it. Release the 7, and presto, right on! Speeds from 1 to 99 wpm are available, in t-wpm increments. Here’s another f’rinstance: Suppose you want to keep a serial-number record of the messages sent out by your CK-2. No problem; just press *0 and set the mes¬ sage number into memory. Incrementing from that number forward will then take place automatically each time the mes¬ sage plays back from memory. If you want to reset to 01, press **0. To set the serial number to any desired value between 0 and 9,999, you just press *0NNNN (where the Ns represent the number). Other Features The CK-2 allows you to tailor its parame¬ ters to your own liking. For example, if you prefer fully-automatic dot-and-dash com¬ pletion for iambic keying, you can have it. If you prefer a bug version, you can have just automatically-completing dots and manu¬ al-dash formation. If you don’t like iambic keying but just want to have an ordinary electronic keyer, that's possible, too. For tuning the rig. you can select a tune mode which will key the carrier until you have completed your adjustments; a tap on your paddle will instantly shut it off. The CK-2 has rf protection against false keying, too. This might have been some¬ what of a problem with solid-state devices operated in strong rf environments, but AEA has solved the problem for you. Your friends at AEA provide full-service backup for your purchase and are always willing to help with questions or problems should they arise; since they are your friends, they want satisfied, enthusiastic customers. You’ll find the instruction manual com¬ plete, not only for using the CK-2 but also for troubleshooting and repairing it should that need ever arise. Schematic and pictorial diagrams plus a parts list are provided in the manual. Summary These are by no means all of the tricks that the CK-2 can teach you, but you'll learn them all if you get one for yourself I'm still learning some of them myself! What didn't I like about the CK-2? Weil, very little, to be honest. It did tend to show me where my shortcomings lie, and it forced me to get out of my comfortable rut and learn something new and different. As Churchill was supposed to have said: "I love to learn, but I hate to be taught " In my case, the CK-2 was a good teacher— and I didn’t hate it at all. In fact, learning was pleasant, fast, and fun. If you need a lifetime keyer that allows you to grow in proficiency while matching your requirements exactly—the CK-2 will stick with you all the way. On the other hand, if you’re just a Sunday afternoon rag chewer, the Contester can be a trusted and patient friend. The choice is yours.. . and the CK-2 can do it all. The CK-2 is priced at $139.95 and a dc adapter is available for $14,95. For further information, contact Advanced Electronic Applications , PO Box 02160, Lynnwood WA 98036; (206^775-7373. Reader Service number 486. Jim Gray WlXU 73 Staff THE PALOMAR ENGINEERS PT-407 ANTENNA TUNER The true test of a race car is on the long track in Indianapolis, and the strength of a dune buggy is discovered in the heat of the Baja desert. So, to test the Palomar Engineers PT-407 antenna tuner, I put it on the first floor of a brick apartment building, with a random-wire antenna and no earth ground. And it performed flawlessly. In an apartment, all of the possible problems of operating a station become a reality. Antenna space is extremely limit¬ ed, TV! problems are multiplied by the closeness of neighbors, and the lack of an earth ground exacerbates the other prob¬ lems. With these difficulties in mind, the PT-407 was hooked up between a Ken¬ wood TS-520 and about 75 feet of wire. My first surprise came during the tune- up After having had visions of going through two sets of finals before I finally found an acceptable swr, I was pleased to settle in at 1.4 to 1 on 15 meters with two or three bursts of knob-fiddling. Tune-up on the other bands was just as easy, and I found that I could always get a match of 1.5 to 1 at the highest. However, on most of the frequencies tried, a lower swr could be found in just a few seconds. Tune up procedure for the T-network of the PT 407 is standard Two controls—An¬ tenna and Transmitter—adjust variable capacitors, and the 12-position Induc¬ tance switch selects connections on an air-wound coil. In addition, the tuner has a balun for open-wire feeds and a coaxial switch to use in conjunction with a dum¬ my load or an antenna that needs no matching device. Its total capacity is for four antennas. Tune-up is done at low power to avoid damaging the finals while they are load¬ ing onto a mismatch. The first control to be adjusted is the inductance; you set that at the lowest swr. The antenna and transmitter capacitances are interactive, making the second part of the tune-up the most trying. The tuner will handle up to 300 Watts, which is enough to use with almost any rig running barefoot, and it takes up only 8" by 8" by 4Vi ". Construction inside the unit is solid; knowing from sad experience that a single poor connection is anathema to good output. I checked the unit over care¬ fully during the first trial and could find no flaws. With the case on, the tuner is unobtru¬ sive yet handsome. The three-sided top is finished in a biack crinkle, with a brushed aluminum front and back. The connec¬ tions in back are made via three SO*239s and three porcelain insulators for a bal¬ anced feedline and the single-wire antenna. To my surprise, the tuner proved to be quite broadbanded. Going from phone to CW on 40 meters required tittle peaking, and readjustment within band segments was not needed. Assured that my finals were safe from the dangers of high swr, my attention turned next to the tuner’s TVI-reduction capabilities. For this admittedly unscien¬ tific test, I used an old-model television with absolutely no shielding; my fellow apartment dwellers also (unwittingly) par¬ ticipated in this test. In my situation, TVI suppression is not good enough; the num- The Palomar Engineers PT 407. 73 Magazine * February, 1963 106 ber and density of television sets in my area necessitates a completely clean signal. With the television on and next to the transceiver, there was minimum TVI. At voice peaks, the familiar lines we all know and fear broke the picture, but otherwise no interference was present. In the living room, a bare 15 feet away, there was no in¬ terference. And so far, I have not received any complaints from irate neighbors. As with any component in a system, one unit's performance is limited by the other parts of the system—so other con¬ figurations could produce better or worse results. But the final question when using a matching device is if the tuner isabsorb- ing most of the output to create an accept¬ able load. A few short minutes later, my question was answered in a QSO with KA7BEX in Louisiana and a second With KEOS in Colorado, both of whom gave me a good signal report. Admittedly, most hams would not con¬ sider this great DX. But from the depths of an apartment building in Boston, Colora¬ do is just short of a miracle. For further information, contact Palo- mar Engineers, Box 455, Escondido CA 92025: (714^747-3343. Avery L. Jenkins WB8JLG 73 Staff AMATEUR RADIO CALL DIRECTORY Since 1920, there has been only one di¬ rectory of amateur radio operators. The Radio Amateur Callbook has been the sole source of names and addresses of hams worldwide—until recently. Now, in addition to the Callbook, there is the Amateur Radio Call Directory, pub¬ lished by Buckmaster Publishing in Ridge¬ field, Connecticut. Though similar to the Callbook, the ARCD has a slightly different format and comes in three books, each in¬ dexed differently—by call, by name, and by area. Like the Callbook , the AftCD's callsign index ($12.95) is divided into three columns per page. However, where the Callbook has separate sub-columns for the state and the zip code, the ARCD only separates the state and zip by commas. This makes the ARCD more difficult to read or copy from. In addition, the ARCD does not have some of the operating aids which are in¬ cluded with the Callbook, such as a prefix list, QSL bureaus, Q signals, and time charts. And although the ARCD is the same width and height as the Callbook, it is somewhat thicker. When using the ARCD, I found that I missed having that additional information at my fingertips. The ARCD' s geographical and name in¬ dexes are about half the length of the call- sign index, but they are priced substantially higher than the callsign index. However, both of these indexes are good ideas, and I am surprised that nobody published these books earlier. The geographical Index ($25) is divided first by state, and then by city in alphabeti¬ cal order. The city is followed by the street address and the callsign, enabling the reader to cross-reference to the call directo¬ ry and get the full name and address. Although this process is rather cumber¬ some, it does save space and reduce the amount of redundant information. Each page is topped by the state abbrevi¬ ation and the listing is divided into six col¬ umns per page. Fortunately, divisions be¬ tween columns have been clearly marked. This index will not find much daily use in the average shack, but it would be quite useful If a club were putting together a prospective member mailing list or estimating the density of hams in a given area. The ARCD name index ($25) is an alpha¬ betical listing, by last name, of all hams in the US. The index includes the full name, middle initial, callsign, and state, again en¬ abling the user to cross-reference to the callsign directory for more information. Nor will this index quickly become dog¬ eared, although I am sure enterprising hams will find uses for it. My first response was that hams more frequently know each other by first name than they do by last. However, this is a useful source of informa¬ tion for clubs or nets. Together, these three volumes comprise an extensive source of information, and al¬ though their comparison with the Callbook is necessary and inevitable, the Callbook and the ARCD are useful for different pur¬ poses. Because of the operating aids in the Call- book, as well as its format, I find it handier in the shack than the ARCD. However, when you need an index for uses other than filling out a QSL card, the various indexes of the ARCD prove to be a valuable adjunct to the Callbook. Together, the Callbook and the ARCD would provide a highly versatile source of information For further information, contact Buck- master Publishing, 70 Florida Hill Rd.. Ridgefield CT 06877. Reader Service number 487. Avery L Jenkins WB8JLG 73 Staff FUN! J John Edwards KI2U 78-56 86th Street Glendale NY 11385 HOW HAMS VIEW THEMSELVES Well, it's that time of year again. What time of year? Why it's time for the annual FUN! Poll, amateur radio's only free-form opinion survey where every ham gets his or her chance to speak out on the issues of the day. A ham tradition for three years. If the past is any indication, this year's poll should manage to stir up a substantial amount of heat. And considering February's reputation for bitter cold breezes, a little heat just may be what we could all use right now. I can hardly wait until I see my mailman strug¬ gle up the icy walk to my house with a bag loaded with reader response forms. As you may have already guessed, there’s a definite sadistic streak in KI2U, This year, as in previous FUN! Polls, we’re keeping some old questions in order to keep track on developing trends in our hobby, and adding some new ones to keep up with the times. Sharpen those pencils. ELEMENT 1-BACKGROUND 1) Sex: A) Mate B) Female 2) Age: A) 15 or below B) 16-21 C) 22-39 D) 40-59 E) 60 or above 3) License class: A) Novice B) Technician C) General D) Advanced E) Extra 4) Number of years licensed: A) 1 year or less B) 1-5 years C) 6-10 years D) 11-20 years E) 21 years and up 5) Do you have a new (post-March 78) call? A) Yes B) No 6) How many hours a week do you devote to amateur radio? A) 0-1 hour 106 73 Magazine • February, 1983 B) 2-5 hours C) 6-10 hours D) 11-20 hours E) 21 hours or more 7) Which HF band do you use most? A) 80-75 meters B) 40 meters C) 20 meters D) 15 and/or 10 meters E) Don’t operate HF 8) Which VHF-UHF band do you use most? A) 6 meters B) 2 meters C) 220 MHz D) 420 MHz and/or up E) Don’t operate VHF-UHF 9) Which mode do you use most? A) SSB B) CW C) FM D) RTTY E) Other 10) How much money have you spent on amateur radio within the past year? (In¬ clude QSL expenses, magazine subscrip¬ tions, club dues, and other incidental ex¬ penses.) A) 0-$250 B) $251-$500 C) $501-$1,000 D) $1,001-$2,500 E) $2,501 and up ELEMENT 2-SOCIAL CHARACTERISTICS 11) Has amateur radio influenced your career choice? A) Greatly B) Somewhat C) Not at all 12) Do you answer QSLs that include a self- addressed, stamped envelope? A) Yes B) No 13) Politically, how would you define yourself? A) Conservative B) Middle-of-the-road C) Liberal 14) Do you think amateur radio will exist 20 years from now? A) Yes B) No 15) How old were you when you first became a ham? A) 15 or below B) 16-21 C) 22-39 D) 40-59 E) 60 or above 16) Were you a CBer before you became a ham? A) Yes B) No 17) Do you own a home computer? A) Yes B) No 18) Do you think hams, compared with com¬ puter hobbyists, are: A) More technically inclined in their hobby B) Less technically inclined in their hobby C) Both are about equally skilled in their hobby 19) Do you think that home computing is siphoning people (including youngsters) away from amateur radio? A) Yes B) No 20) Did you ever use a “cheat book" (not counting the ARRL License Manual) to upgrade your license? A) Yes B) No 21) If someone offered you ten million dollars, tax free, on the condition you give up amateur radio forever, would you? A) Yes B) No 22) Do you belong to a local ham radio club? A) Yes B) No 23) Have you ever attended a ham flea market? A) Yes B) No 24) Do you think the new ARRL leadership is better than the previous administration? A) Yes B) No ELEMENT 3—OPERATING HABITS 25) Should Novices have phone privileges? A) Yes B) No 26) Do you think US phone bands should be expanded at the expense of foreign-station- only bands? A) Yes B) No 27) Have you ever used a personal com¬ puter in connection with your amateur radio activities? A) Yes B) No 28) Is it time to completely deregulate amateur radio by having the FCC turn over ail responsibility for ham operation to the amateur community? A) Yes B) No 29) Where do you think the future of ham radio lies? A) On the HF bands B) On the VHF-UHF bands 30) Should we get rid of, or reduce in size, the CW subbands? A) Yes B) No 31) Do you think religiously-oriented nets have a place in ham radio? A) Yes B) No 32) Do you think politically-oriented nets have a place in ham radio? RESPONSE FORM Instructions: Read each question and mark your response by circling the appropriate tetter next to the number of the question. Element 1: 7) ABCDE 12) A B 19) AB Element 3: 31) A B 38) A B 45) ABCDE 1) AB 8) ABCDE 13) ABC 20) A B 25) AB 32) A B 39) ABCDE 46) ABCDE 2) ABCDE 9) ABCDE 14) A B 21) A B 26) A B 33) ABCDE 40) A B 47) ABCDE 3) ABCDE 10) ABCDE 15) ABCDE 22) A B 27) A B 34) ABCDE 41) A B 48) ABCDE 4) ABCDE 16) A B 23) A B 28) AB 35) A B 42) A B 49) A B 5) AB Element 2: 17) A B 24) A B 29) A B 36) A B 43) A B 50) A B 6} ABCDE 11) ABC 18) ABC 30) A B 37) A B 44) A B Comments: Please mail Response Form to: John Edwards KI2U, 78-56 86th Street, Glendale NY 11385. A| Yes 8) No 33) tf white tuning across a band, you heard a net of gay hams in progress, would you: A) Jam it S) Ignore it C) Complain to the FCC or some other organization 0) Listen E) Join it 34) It. while tuning across a band, you heard a net called 'The American Communist Radio Society" in progress, would you: A) Jam it 8} Ignore it C) Complain to the FCC or some other organization D) Listen E) Join it 35) If required, could you solidly copy CW at the speed at which you were licensed? A) Yes B) No 36) If required, could you pass the FCC theory test for your license class without consulting a “cheat book"? A) Yes B) No 37) Have you ever purposely operated in an amateur subband you weren’t licensed to use? A) Yes B) No 38) Do you think the FCC affects amateur radio in a positive manner? A) Yes B) No 39) Do you ever speak to foreign, non-En¬ glish-speaking hams in their own lan¬ guage? A) Always B) Sometimes C) I attempt it D) Rarely E) Never 40) Do you feel yourself competent to replace the finals In a tube-type rig? A) Yes B) No 41) Do you feel yourself competent to re¬ place the finals in a transistor-type rig? A) Yes B) No 42) Have you ever built an electronic project from a kit? A) Yes B) No 43) Have you ever home-brewed an elec¬ tronic project from a book or magazine’ A) Yes B) No 44) Have you ever designed your own elec¬ tronic project? A) Yes B) No 45) What do you think of contesting? A) Great B) Good C) Okay D) Don’t like it E) Despise It 46) What do you think of DXing? A) Great B) Good C) Okay D) Don’t like it E) Despise it 47) What do you think of repeaters? A) Great B) Good C) Okay D) Don’t like them E) Despise them 48) What do you think of traffic handling? A) Great B) Good C) Okay D) Don’t like it E) Despise it 49) Do you plan to use Phase III OSCAR within a year of its launch? A) Yes B) No 50) Do you plan to use the new 10.1-MHz band within one year of Its opening? A) Yes B) No I have a Swan 350 and would like to know if anyone has added an RIT to this transceiver. I’ll be happy to pay for any copying or postage fees. James Herriges WB9RSK 542 E Van Beck Ave. Milwaukee Wl 53207 I would like to find the manual (or copy) for the Alda ICS. I am willing to pay a reasonable price. Larry K. Pittman WD9EME 18919 E Rd., 410N Hops IN 47246 i need the manual, schematic or any in¬ formation on a rack mounted modem marked as both Penphomcs DSU-4QG and as WOnex Type Autotone model 302 * am also looking tor work m electronics in up¬ state New York 1 have a BSEE. FCC Gen eral-ciass license, and I am very good with computers, especially assembly language Michael Moroney WA2VXY 18 Seville Drive Clifton Perk NY 12065 Wanted: AA, AB, AC. and AD coils for a National HRO-60 receiver Fred P. Robbins Jr. W5LNE Star Route Box 166 Bay City TX 77414 I am looking for the Hallicrafters Super Skyrider model SX-28A, Ihe UHF model S- 37, and the Panoramic Receiver, model S- 35. I will pay all costs. Peter Dal Corobbo 18650 S. Marshfield Homewood IL 80430 I need the manuals (or copies of them) for the Yaesu FT-7B and the Azden PCS 2000 Larry Fields, Engine Dept. US NS Silas Bent T-AGS26 FPO San Francisco CA 96661 I need a manual for a Model 75 Aero- vox resistance-capacitance bridge. Can you help? A. D. Buckley WB1AQV 14 Knapp Drive Prospect CT 08712 Wanted: manual for the Tektronix 564 mainframe. I would prefer to buy it, but I am willing to copy a manual and return it Hugh Watson 59 Orchard St Elmwood Perk NJ 07407 NICAD MEMORY ERASE - WHAT?? • Complete automatic operation • Erases - Charges - Checks • Rapid charges in 35 min, (typically) • Automatically repairs shorted cells • No dangerous heat build up • Front panel selects up to 3 different packs • Unlimited battery combinations with program modules (user programable) • LEO status indicators • Supplied with universal EZ hook wire leads Specify Voltage of Battery PaeMsI with order. $79.95 plus $3.00 Shipping (PA Residents add 6% sales tax) Coming Soon — Multiple pack memory erase charger for municiple commercial applications- write for information or send requirements. The GMS 401 is a complete automatic NICAD condi¬ tioner and rapid charger. Never before has this been offered anywhere at any price and it's so good it's be¬ ing patented NICAD memory characteristics must be dealt with otherwise your battery pack is not delivering all it could. The GMS 401 will automatically erase and rapid charge any type NICAD pack from 1 to 10cells automatically. CONTROL PRODUCTS UNLIMITED, INC. P.O. Box 10, Downingtown, PA 19335 215 383-6395 ^ 190 See List of Advertisers on page f*4 73 Magazine * February, 1983 107 W2HSD/1 NEVER SAY DIE editorial b>y Wayne Green from page 8 at that time, so this might be a good opportunity to mount a major DXpedition. The hams in Brunei are enthusiastic about this—anything to get DXers off their backs. I’ve talked with hams in Sabah about this, too, and perhaps the independence of Brunei might be a good ex¬ cuse to mount an all-Borneo DX¬ pedition. I’ll bet we could get coverage on television for something like that. We might send a team to 9M8, 9M6, and YB7 as well as Brunei and put these countries on the air for a week solid. Anyone game for this? I think we could arrange for a very reasonable charter air flight, group accommodations at a reduced rate, and so on. I have been assured that licenses can be arranged if we start far enough ahead. I’d suggest this as a project for DX clubs, with each choosing one country for their group to activate. Then we could all get together in Singa¬ pore at the end for one hell of an Asian hamfest. By the way, I’ve found that there is considerable enthusi¬ asm from all of the DX amateurs in our starting a foreign operating news section for 73. All of them are interested in keeping up with rule changes in other countries, reciprocal li¬ censing news, DXpeditions, and anything else unusual happen¬ ing around the world. This is a world hobby today, but none of the ham magazines has really treated it as such. We are all in¬ terested in knowing about coun¬ tries which will be becoming in¬ dependent, in the formation of new countries such as Qua Qua, in new certificates and con¬ tests, and so on. We want to know about major hamfests and conventions around the world. We’d like to know about any out¬ standing cases where amateur radio provided emergency com¬ munications. With a couple new magazines in the works for 1983,1 may have to skip the next Asian tour myself, but this is no reason for you to pass up this fantastic trip. Hit the major cities and their electronics shows, then ad lib some unusual spots on your way back home. You’ll find the local hams outstanding in their hospi¬ tality. And, if you start well ahead of time, you may be able to get your own license and do some DXing from the rare end. By 1984, I think we’ll be putting together the Borneo Super DXpedition if enough of you like the idea. As I told the chaps when we were go¬ ing to Navassa, no matter what else you ever do in life, this is one experience you will never, never forget. The experience is priceless. One little hint for those with the guts to make the decision to come to Sabah: You will enjoy it. I guarantee you will enjoy It. But be sure, if you stop at the Hyatt, not to take an inside room. The entertainment in the central atrium is loud and continues un¬ til midnight, filling the room with 90-dB sound. Take an outside room. HAM HELP A I need schematics or service manuals for the Heath DX-150 transmitter and the Heath 10-10 oscilloscope. I will copy and return them. William Bohnenberger 18 E. 199 St. Bronx NY 10468 Wanted: a lower sideband crystal, 251.650 kHz. for the Collins KWS-1 transmitter. Please advise me of the condi¬ tion and the delivered price. Edward Dobblelaere 4184 Long Lake Road SE Port Orchard WA 98366 Can anyone send me a copy of the schematics and manual for the Realistic DX-120 communications receiver? I will pay for copying. John P. Centers 514 Pine St. Wapakoneta OH 45895 Anyone who can provide historical infor¬ mation on the defunct American Legion net, which operated in California from 1924 to 1952, please contact me. J. Phil Scherck WA7AGY 8987 Curbaril Ave. Atascadero CA 93422 I am looking for the manual, schematic, or parts tist for the Measurements Corpora¬ tion model 62 VTVM. I wilt gladly pay copy¬ ing and mailing costs. Vernon Jones WB1BVH 32 Cat Mousam Rd. Kennebunk ME 04043 I would like to get in touch with other users of the R390A/URR, 1 need a source 106 73 Magazine • February, 1983 for manuals, schematics, and modifica¬ tions. Bob Lombardi WB4EHS 2046B Renee Place Melbourne FL 32935 1 am looking for a manual for a Knight KG-685 color pattern generator and a tube chart for a B & K model 650 tube tester. I will pay for shipping both ways so I can photocopy. Larry Schuldt 545 Willow Rd. Marengo IL 60152 I am trying to find schematics tor the Heath HO-10 monitor scope and the Ameco model CN 6-meter nuvistor converter, I will reimburse all expenses. Howard Robb 340 S. 5th St. Bird Island MN 55310 I would like to add 10-meter capability to my DenTron GLA 1QO0B linear amplifier. Please write me; i wiil defray costs. George Gauggei 3660 Puuku Mauka Dr. Honolulu HI 96818 I need a schematic and a manual for the Eico model 320 signal generator. I am will¬ ing to buy it or pay copying costs. Edwin Adams KB3DH RD4 Box 241A Blooms burg PA 17815 We need the manuals or schematics for a Fermont Engine Generator Plant 10-kW diesel generator, model J-141-1, bearing serial number J-141-0018. The generator is marked as a General Electric #LC74?0B16 type 6J. model number 5SJ4254P22Y12. The battery recharging circuitry, marked Fermont #6064-0001, has been damaged. We will gladly make arrangements to ob¬ tain information on this generator. Wayne Richardson Lebanon Junction Area Coordinator Bullitt County Division of Disaster and Emergency Services Main St. Lebanon Junction KY 40150 I am looking for information on the Western Electric Indicator BC 1152-A. par¬ ticularly the schematic and data on the 3HP7 CRT. I will pay costs for copying and postage. Torgny Kartsson SM7CFQ Sandormsvagen 7 S-260 41 Nyhamnsiage Sweden t am looking for pen pals in the US. I am 18 years old and an engineering student. Isaac Maxwell Kyereboah PO Box 078 Takoradl, Ghana West Africa I am looking for modifications tor the Heath SB-101 transceiver. I am particular¬ ly interested in improving IO meter recep- In Fig. 1 of “The Automatic Beam Aim¬ er/' on page 23 of November’s issue, the power-supply diode was drawn back¬ wards. The cathode should be connected to the transformer secondary. Avery Jenkins WB8JLG 73 Staff The parts values were omitted from the tion, adding an RIT and improving the se¬ lectivity. I will answer all replies and refund expenses. Paul Newman G4INP 3 Red House Lane Lelston, Suffolk IP16 4JZ United Kingdom I need 3 tubes, type 12JB6, for my Drake TR-3. I cannot find these tubes in Brazil. Waiter Pereira Da Costa PY4ZO PO Box 207 Araguari, Minas Geraid 38440 Brazil I desperately need parts to repair my Hallicrafters FPM-300 transceiver. I will pay for a complete non-working unit or the audio amplifier module, a U401 balanced mixer assembly MX-1, part number 150-018555-001. Robert Sondack VE2ASL 260 Rue Beiierive St-Luc, Quebec Canada J0J 2A0 I need the manual for the Hammariund HQ-1 BOA receiver. I will pay for copying costs and send a note of thanks. Bob Napoli K2LGO Box 158 Riverhead NY 11901 “Headlight Reminder" which appeared in the November “Circuits" feature on page 109. Q can be any common PNP transistor, but a 2N 3638 or a 2N 2907 works well; Dl and D2 are 1N4002 diodes; R1 is a 5.6k, Vi- or Vj-W resistor; R2 is a 4.7k, Vi- or Vi-W resistor. Avery L. Jenkins WB8JLG 73 Staff CORRECTIONS ( RTTY LOOP Marc /. Leavey, M.D . WA3AJR 4006 Winlee Road RandaUstown MD 21133 There’s a great old song written by James V, Monaco and Joe McCarthy catted “You Made Me Love You.” It's that kind of feeling that I get In February, what with Valentine s Day and alt, aiong with the tet¬ ters from you, the readers, whom t truly adore Let’s see what you alt have to relate this month Starting with the foreign desk" (sounds like ’World News Tonight'*), 1 have a note here from a colleague in Central America. David Reuben Harris, M.D., a physician in Costa Rica, is a TRS-80 user who Is trying to obtain software for his Model I that will en¬ able him to both copy RTTY and fully inter¬ face his computer on the air. Now, I have always been a fan of software solutions to "hard” problems, but not this time. A perusal through the published literature realty fails to demonstrate much in the “strictly software" vein, On the other hand, I have received a packet of material that just might answer some of Dr. Harris's needs. Kantronics, lo¬ cated in Lawrence, Kansas, produces a ver¬ satile RTTY interface, which we touched upon in December With some more infor¬ mation in hand, let s see what they say It can do. Their box, called “The Interface," is the hardware link that turns a computer and amateur transceiver into a highly sophisti¬ cated RTTY system. It allows transmission on Murray, ACSIt, or Morse with essentially the same operating convenience The unit itself is contained in a small box that attaches to extemai devices through a series of jacks on the back panel Inputs and outputs are provided which accept audio and digital inputs between speaker audio, computer, and accessory keyboard or key. Front-panei indicators include aton¬ ing LED and bar-graph LED, used to center incoming signals within the demodulator’s passband. There is even a loop driver avail¬ able to switch an external 60-mA loop so that an antique Model 15 can be used as a printer for such a modem system. No hardware of this complexity is any good without equally able software and, recognizing this, Kantronics has made available a group of programs known gen¬ etically as “Hamsoft" that interface The In¬ terface to the Apple II, Vic-20, TRS-80C, and Atari 400/800 computers. Additionally, it Is entirely possible to write custom software to use The Interface with other computers. An interesting possibility is raised by the note that the Hamsoft programs, which allow for Morse code in the 5-99-wpm range, 60-, 67-, 75-, and 100 wpm Murray, 110- and 300-baud ASCII, spirt-screen display, trans¬ mit buffer, Morse ID during RTTY, printer output, and more, will operate with other terminal units. That means that you might, and I emphasize might, be able to use the Hamsoft program between your computer and terminal unit if ail else is compatible. Kantronics makes no promises that you can, but it might be interesting to try. A further indication of the care that went into this product is a full section in the manual of The interface which details mod¬ ifications needed to operate with certain transceivers which present problems. Whether the modifications need be made to The Interface or the transceiver, it is spelled out in enough detail that accomplishing the change should be no real problem. Kantronics has put together a nice pack¬ age here, and I will be interested to hear from those of you who have used The Inter¬ face and Hamsoft in its various configura¬ tions. I am sure that Phil Anderson WUXI, rMULTI-BAND SLOPERS1 160, 80, and 40 meters Outstanding DX performance of stopers is well known Now you can en¬ joy 2or 3band BlG*SiGNAL reports* Automatic bandswitching* Very low SWR *Coax teed • 2kw power • Compact - Ground or tower teed * Hang from any support 25 It. high or higher * Easy to install - very low profile • Complete instructions • Immediate shipment-Check ok 3 BAND SLOPEB 160, 80, & 40 Meters 60 «L long $ 43 22 Irt ppdl 2 BAND SLOPER 80 & 40 Meters 41 ft. long S 30 20 trt.ppdj 3-BAND NO TRAP DIPOLE. 180, 80,4 40M * 113ft. long enaarara11 2-BAND NO TRAP DIPOLE, 80,4 40M * 84ft. long FOR ADDN'L INFO on these and other unique antennas send SASEI 1 W9INN ANTENNAS 1 I BOX 393-S MT. PROSPECT, IL 60056 | SATELLITE TV SYSTEMS ‘COMPARE OUR QUALITY, PRICES AND SERVICE!** WE MANUFACTURE: PARABOLIC DISHES MOTORIZATION SYSTEMS POLAR MOUNTS LNA HOLDERS DEMO TRAILERS ALUMINUM HORNS CUSTOM PARTS WE STOCK: WASHBURN GILLASPIE ALLIANCE KLM DRAKE ATV AVANTEK LOWRANCE CABLE &. CONNECTORS GARDINER SWITCHES & HARDWARE CALL, WRITE OR ✓ FOR OUR LATEST BROCHURE AND PRICES. 1 AUSTIN C LEWIS LEWIS CONSTRUCTION CO K4GGC P O. BOX 100 901.784*2191 HUMBOLDT. TN 1 *TN BUSINESS AT THIS LOCATION SINCE 1964” | president of Kantronics, and the other folks out there will be happy to answer your ques¬ tions. Write them at 1202 E 23rd Street. Lawrence KS 66044, and be sure to men¬ tion 73’S RTTY Loop, Speaking of Phil Anderson, he passes along a question which several others have also posed, Kirk Baxter WB8AXX, in Mis¬ sion, Kansas, and John Ryan, in Alcove, Quebec, both also are interested in several of the encoded RTTY signals heard on com¬ mercial frequencies. Kirk relates a series of such codes, including bit inversion, bit transposition, TOR codes, SITOR codes, ARQ, FEC, and SEL-FEC codes. These sig¬ nals are uncopyable on a standard system and can represent a real challenge to the hard-core RTTYer. The first few codes asked about are sim¬ ple techniques, designed merely to ensure some degree of privacy It is fairly easy to envision manipulating a standard Murray character to, say, invert one or more bits from mark to space, or vice versa. Thus, the letter "FT would change from 01010 to 00110, if bits two and three were inverted, and would print as an "I" on an unmodified machine. Similarly, one can consistently transpose two or more bits in each charac¬ ter, again rendering it unprintable without the key for deciphering These codes are not difficult to decode with a computer program which recognizes the cipher and undoes what the sender did. Of course, If the encoding station is really nasty, the characters can have bits both in¬ verted and transposed, but that is another convolution. The Murray code, as we all know, is a five-level code. While ASCII is the most common code using more than five bits, it is apparently quite rare on radio circuits. A complex series of codes is used on many commercial circuits which has error-detec¬ tion abilities. Known as the Moore code, or CCITT No. 3, If is a seven-bit code sent syn¬ chronously. as opposed to the asynchro¬ nous Murray code Thirty-five characters are each com¬ posed of three marks and four spaces, in various combinations. If a character is re ceived which does not have the correct number of marks and spaces, the receiving station can send a code to repeat the last transmission. This is called the “Automatic Repetition on Request” and yields the mnemonic "ARQ” when referring to this code Another code system which allows for er¬ ror correction is the “Telex Over Radio.” or TOR system Some trademarks tor systems using TOR include SITOR and SPECTOR, The TOR codes resemble the Moore system in their formulation, but are each four marks and three spaces; thus, the charac¬ ters themselves are completely different The FEC noted above is a Forward Error Correction in which each character is sent multiple times to receivers unable to re¬ quest a correction. The receiver is set up to select any of the repetitions which meet the correct mark/space ratio and discard the rest. Although this is an overview, I hope this explains the more unusual codes heard on the air. If there is sufficient interest, we may be able to devote more time rn the future to schemes to decode some of these code types. Let me know with your cards and let¬ ters; I look forward to them I will close this month with a request from another reader out west. Bob Sanett W6TWR, in Van Nuys, California, is trying to hook up a Siemens T-1000 RTTY unit. He describes this as a daisy wheel printer for TTY* Sounds interesting, but he needs any information he can get Anyone with any¬ thing of note should drop me a line and send Bob a copy at PO Box 7323, Van Nuys CA 91409. I'm sure he will appreciate It, Will try to outline some more on the ter¬ minal next month, and of course something from you, the readers. This is our column, yours and mine, and between old Model 15s and new computers, that's quite a range, here, in RTTY Loop LIMITED SPECIAL $5551)0 HRMEQ 20 MHz DUAL TRACE Oscilloscopes to meet every need MODEL HM-203 WITH PROBES: x I & x 10 •ONE YEAR FULL WARRANTY •SOLID STATE • ASSEMBLED & CALIBRATED NEW RECTANGULAR CRT ( 603 ) 434-5371 DEALER INQUIRIES IWVTTED ^ 133 RTD-5 DERRY. N H 03038 WARNER HILL i€' COMPARE the HAZER™ with foldover + telescoping towers • Antenna systems mount on Hazer-Hazer follows parallel to outside of tower - Raise to tower top or lower completely to ground level • Safety lock system on Hater operates white raeung-towermg & in normal position. Never can faH • Weight transferred directly to tower Winch cable used only for raising & lowering, • Will support most antenna arrays up to 20 sq ft • High quality materials & workmanship • Safety - speed - convenience - smooth travel • Ease to install and use • For Rohn 20 & 25 tower — Other towers on request Complete with winch, 100 ft, of cable, hardware and instructions. HAZER II Heavy alum $279 95 * $17 00 UPS HAZER ill Standard alum $199 95 * $13 00 UPS HAZER IV Heavy gal steel $249 95 * $28 00 UPS Specify mast diameter when ordering MARTIN ENGINEERING P O. ROM 253 BOONVILLE, MO 65233 *^134 816-882-2734 A 116 73 Magazine • February, 1983 [ CONTESTS Robert Baker WB2GFE 15 Windsor Dr. A too NJ 08004 ARIZONA QSO PARTY Starts: 1800 GMT February 5 Ends: 0600 GMT February 6 Sponsored by the Southern Arizona DX Association Single-operator and club en¬ tries, ail bands and modes but no repeater contacts allowed- Each station may be worked only once per band, EXCHANGE: RS(T) and state, province, DXCC country, or Arizona county. Novices and Techni¬ cians also sign /N or IT, respectively, FREQUENCIES: Phone-3895, 7230, 14280, 21365, and 28560 CW— 60 kHz up from lower band edge Novice—25 kHz up from lower band edge SCORING Count 1 point per phone QSO, 2 points for each CW or other mode QSO. and 4 points per QSO with Novice or Technician in the Novice bands. Arizona stations multiply QSO points by number of states, provinces, and DXCC countries Others multiply QSO points by number of Arizona counties (13 maximum; The club station, W7NQ, also counts as 1 multiplier for non Arizona stations. Anyone working all Arizona counties and W7NQ may double the multiplier AWARDS: Certificates tor the highest-scoring sta¬ tion in Arizona, non-Arizona, and Novice/ Technician. In addition, certificates for highest score in any Arizona county, state, province, or DXCC country in which there are at least five entries. Other certificates for Arizona and non- Arizona clubs whose members' scores combine for the highest score Club emry must consist of at least five individual en¬ tries to be eligible Club residency deter¬ mined by mailing address ENTRiES Individual entries should show each sta¬ tion worked, exchange, and time and fre¬ quency of each QSO include a summary sheet of your scoring and dupe sheets for bands with more than 50 QSOs Entry may designate one club with which you are par¬ ticipating. Deadline for individual entries is March 5th. Club entries should be submitted by a club officer with a summary of callsigns and claimed scores. To be counted toward the club total, the individual entries must also designate the club. Deadline for club summaries is April 5th. Include a large SASE for results. Entries should be addressed to: Southern Arizona DX Association, c/o Philip M. Stickney N7BUP, 1890 West Paseo Cuenca. Tucson AZ 85704 SOUTH CAROLINA QSO PARTY Starts: 1800 GMT February 5 Ends: 2359 GMT February 6 The QSO party is agam sponsored by the Colleton County Contestors The same sta¬ tion may be worked on each band and mode, simplex only South Carolina mobile stations that change counties are con¬ sidered new stations Novice and Techni¬ cian stations please sign /N or ft. EXCHANGE: RS(T) and state, province, country, or South Carolina county. SCORING: Phone contacts are worth 2 QSO points, CW contacts are worth 3 points. The multi¬ plier for South Carolina stations is the number of states, provinces, and DX coun¬ tries worked. Others multiply QSO points by the number of South Carolina counties worked (46 maximum). FREQUENCIES: Phone—3895, 7230, 14280, 21365, and 28560 CW—3560, 7060, 14060. 21060, and 28060 Novice—3725, 7125. 21125. and 28125 AWARDS: Certificate to top-scoring station in each South Carolina county, state, province, and DX country. Novices and Technicians com¬ pete only with other Novices and Techni c«ans ENTRIES: Include a summary sheet with your entry showing scoring and other information. In* dicate each new multiplier in your tog as it Is worked. Novices and Technicians in¬ dicate class on your entry. Include a large SASE for results. Mailing deadline is March 5th, Send to: Colleton County Contestors, c/o Elliott Farrell, Jr. KE4VP, Rt. 3 Box 658, Walterboro SC 29488. NEW HAMPSHIRE QSO PARTY 1900 GMT February 5 to 0700 GMT February 6 1400 GMT February 6 to 0200 GMT February 7 Sponsored by the Concord Brass- pounders, Inc. fWlOC). to promote the Worked New Hampshire Award Stations may be worked once per band, per mode New Hampshire stations may work each other. EXCHANGE: Send RSCn and country ARRL section, or New Hampshire county as appropriate FREQUENCIES Phone-1820, 3935, 3975, 7235, 14280, 21380. and 38575. CW—1810, 3555, 7055, 14055, 21055, and 28130. Novice—3730, 7130, 21130, and 28130. VHF—50.155 and 145.015 FM simplex, no repeaters. SCORING: New Hampshire stations score 1 point per QSO multiplied by the number of ARRL sections plus countries plus New Hamp¬ shire counties. Others score 5 points per New Hampshire QSO times the number of New Hampshire counties worked. RESULTS 1982 A5 MAGAZINE NORTH AMERICAN FSTV-UHF CONTEST t W6VCF 9989 2 WA8RUT 5685 3 WD8MRV 3560 4 WB6ROP 3403 5 KBCXL 3015 6 WB9MCF 1955 7 W2RPO 1907 8 WB0ZJP 1905 9 WA9NJR 1895 10 VE3FYY 1621 11 W6RVP 1620 12 W2WHK 1496 13 WA8SAR 1494 14 K8HVA 1445 15 KACBVT 1225 ENTRIES: Send your entry no later than March 12th to the Concord Brasspounders, Inc., c/o Norman W. Littlefield, RFD 1 Buck St., Box 323, Suncook NH 03275. Include a large SASE for results and/or award. VERMONT QSO PARTY 2100 GMT February S to 0700 GMT February 6 1100 GMT to 2400 GMT February 6 Sponsored by the Vermont Amateur Radio Club (W1BD). Each station may be contacted once on each band and mode. Repeater contacts and multiple contacts with the same station on the same band and mode are invalid. EXCHANGE: QSO number and state, province, coun¬ try, or Vermont county. FREQUENCIES: Phone-3930. 3960, 7230, 7260, 14280, 14320, 21360, 28570, 50.110, and 144.2. CW—3530, 3730. 7030, 7130, 14080. 21060. 21160, 28070, and 144 1. SCORING Vermont stations score one point per contact with any station Multiply QSO points by number of states plus Canadian provinces plus countries (exclude US/ Canada). Others score one point per Ver¬ mont contact and multiply by the number of Vermont counties (14 maximum). AWARDS- For non-Vermont stations, certificate to highest-scoring station in each state, prov¬ ince, and country and to highest-scoring Novice/Technician, Certificates will be given each Vermont station submitting a log. W/VT Award given to stations working 13 of Vermont's 14 counties ENTRIES: Send SASE for official log and score sheets. Send logs/facsimiles, name, class of license, and address not later than March 1st to; D. Nevin KK1U, W, Hill, North- field VT 05663. Include an SASE for a copy of the results. QCWA QSO PARTY—CW Starts: 0001 GMT February 12 Ends: 2000 GMT February 13 This is the 26th annual QCWA QSO Par¬ ty, with separate weekends tor CW and phone. You can work the same station more than once providing It is on another band Only the bands listed under frequen¬ cies will count in this QSO party EXCHANGE: QSO number, operator’s first name* QCWA chapter identification (official number or name), and state or country. Members not affiliated with a chapter should use "AL" FREQUENCIES: Any authorized amateur frequency in the bands that are listed below ts permissable. The following suggested frequencies have been selected to minimize interference to others, but please feet tree to wander up or down from these If you so desire. Bands: 3530-3560, 7030-7060, 14030-14060, 21040-21070, and 28040-29070, The above are selected as a starting place When plleups occur, don’t be afraid to go to either side of these frequencies. SCORING: Each contact made with another QCWA CALENDAR Feb 5-6 South Caroline OSO Party Feb 5-6 Arizona QSO Party Fab 5-6 Vermont QSO Party Feb 5-7 New Hampshire OSO Party Fab 12-13 QCWA OSO Party-CW Feb 15-16 America Radio Club international OX Contest Fab 16 20 AS Magaima UHF-ATV (FSTV) OSO Party Fab 19-20 YL ISSB QSO Party-Phone Feb 19-20 ARRL international OX Contest—CW Feb 26 RTTY World Championship Contest Mar 5 6 ARRL international DX Contest—Phone Mar 12-13 YL ISSB QSO Party-CW Mar 12-13 QCWA OSO Party-SSB Mar 12-14 Idaho QSO Party Mar 12-14 Virginia QSO Party Apr 9-10 CARF Commonwealth Phone Contest Apr 9-tO ARRL QSO Party-CW Apr 16*17 ARRL QSO Party—Phone Jun 11*12 ARRL VHF QSO Party Jun 25-26 ARRL Field Day Jul 9-10 IARU Radiosport Championship Jul 15-17 AS Magazine SSTV DX Contest Aug 6-7 ARRL UHF Contest Aug 19-21 A5 Magazine UHF FSTV OX Contest Sep 10-11 ARRL VHF QSO Party 118 73 Magazine • February, 1963 PARKING ™ TICKET PLANO AMATEUR RADIO KLUB NEWSLETTER OF THE MONTH Although most people do not like to get parking tickets, the hams in Plano, Texas, get one every month—and they enjoy it. The Parking Ticket is the newsletter ot the Piano Amateur Radio Klub, and it en¬ compasses a rare combination of humor, information, and good looks. The good looks came from recent experimentation with the newsletter, varying the type and layout in response to reader feedback The result is a very clean news¬ letter: the columns are well laid out and rarely can a typographical error be found. Inside features include a two-month calendar of events—not just a list, but a full- hedged calendar with enough room to write notes. Regular features include “Traf¬ fic Talk.' an educational column on traffic handling, and The Novice Comer.’ a tongue-m-cheek tribute to beginning hams December's issue featured a review of some books titled The BMP That Ate Worldwide Communications, and Prachcai Tree Pruning With Mobile Antennae However, editor Rick Goodin N5CBI admits that he does have his limitations. “i had grand delusions; he said m a recent editorial, of writing a coherent, cogent, and otherwise brilliant column, but that was quite a few hours ago when my body still felt awake and my cerebrum had not yet lapsed inlo autopilot. ~ Take a nap, Ride you deserve it for a job weil done 73 encourages clubs to send in their club newsletters. Just address them to 73. Pine Street , Peterborough NH 03458 Let us know what is going on in your area member will count as a single point This year’s contest has three multipliers: chapters, states, and countries For each band, every new chapter is a multiplier of one, every new state (USA) is a multiplier of one, and every new country |ARRL DXCC list) is a multiplier of two At the end of the party add up your total contacts for ail bands and multiply it by the sum of all your multipliers for ail bands This will give you your total and final score ENTRIES: Please keep separate logs for each band. Logs should include the following Informa¬ tion: time (GMT), call, QSO numbers, name, chapter number or name, stale or country It is the responsibility of each contestant to provide a legible log {no carbon copies) and to list all claimed contacts. The total con¬ tacts and multipliers for each page should be recorded at the bottom of each page. The total contacts tor the party should be recorded on the first page of the log. Log sheets will not be returned, Make sure you have correct postage when you mail your logs. Send logs no later than March 31st to: Spaceport Center #66, Donald McClenon N4IN, 3075 Florida Avenue, Melbourne FL 32901 Separate logs and scores must be submitted for the CW and phone parties. AMERICA RADIO CLUB INTERNATIONAL DX CONTEST Starts: 0400 GMT February 15 Ends: 2400 GMT February 16 Any amateur station making two con¬ tacts with America Radio Ciub DX member operators during the two-day contest will be eligible to apply for the Special Silver OSL Award. Stations making three con¬ tacts will be eligible tor the Special Gold Silver OSL Award Contacts must be durmg the two-day period listed above Suggested frequencies include ail authorised frequen¬ cies in the 10-, 15-, 20- and 40 meter phone and CW bands Exchange RS(T) and QTH 3WL stations aiso may apply for this award on a heard basis. For special award, send OSL and $2.00 in US funds or 3 iRCs to: America Radio Ciub QSO Contest, PO Box 3576, Hialeah FL 33013 YL ISSB QSO PARTY—PHONE Starts: 0001 GMT February 19 Ends: 2359 GMT February 20 Two six-hour rest periods are required Operating categories include: single operator DX/WK partners, and YL/OM teams All bands will be used and the same station may be contacted on different bands for contact points but not as country multipliers. VHF and UHF may be used but all contacts must be direct and not through repeaters Nets are not allowed! EXCHANGE Name, RS. SSBer number, country, W/K state or VE province, and DX/WK partner's call. If no partner, leave blank. If nonmem¬ ber, send NO NUMBER.” FREQUENCIES: On HF, use the USA General class band portions. On 20 meters, be aware of the nets on 14313 and 14336. Stay away from 14332; leave it open for DX members trying to make contacts. Check 80 and 40 meters on the hour. SCORING: Score 3 points for each member con¬ tacted on your own continent, 6 points if dif¬ ferent continent. Nonmembers’ contacts count one point. Only member station con¬ tacts count for multipliers. Multipliers are each state, country, and VE province. Also, each team contacted but only once for each team. When DX/WK partners contact each other it counts as a double multiplier. If your total dc input power is 250 Watts or less during the entire QSO party, then count an additional power multiplier of two. Final score is the sum ot OSO points times the total multiplier. AWARDS Special certificates will be awarded to the winners of each category. Regular cer¬ tificates for country, US state, and Cana¬ dian province winners ENTRIES Logs must show datefttme (GMl), station QSOed RS, mode, band, SSBer number, US state, VE province, or country, and period of rest time. Summary sheets show states, Canadian provinces, countries, YL/OM teams, DXANK teams, and partner con¬ tacts. Send logs and summary sheets to Rick and Minnie Connolly (K6RDJ and KAflALX). Star Rt 1, Crocker MO 65452 prior to June 1st. Be sure to indicate who your DXANK partner is! RESULTS 1982 NEW JERSEY QSO PARTY New Jersey Stations Station OSO Points Sections Score WA2QNW 1018 72 73,296 W2ZO* 534 62 33,108 N2AEW 260 48 12,482 Out-of-Stata Stations Station Contacts Counties Score N3RJ 77 21 1,617 W5WG 47 19 893 KC4HN 47 18 846 New Jersey Counties Station Score Station Score Atlantic Monmouth WD4SIG/M 234 W2GSA* 11,562 Bergen (Operators: WB3HUPIM 8 KN2B, KA2F, Burlington WA2SSH) W2XQ 3.475 KF2T 2,508 WD4SIG/M 209 WD4SIG/M 132 WB3HUP/M to Moms Camden WD4SIG/M 324 WD4SIG/M 88 WB3HUP/M 54 WB3HUP/M 8 Ocean Cape May N2AEW 12,480 W2YC/2 4,060 WD4SIG/M 192 WD4SIG/M 143 Passaic Cumberland KC2PL 3,000 W2ZY 3,536 WA2ASO 561 WD4SIG/M 192 WB3HUP/M 30 Essex Salem WD4SIG/M 54 WB2KMR 918 WB3HUP/M 30 WD4SIG/M 56 Gloucester Somerset WD4SIG/M 72 WD4SIG/M 70 WB3HUP/M 25 WB3HUP/M 9 Hudson Sussex WB3HUP/M 72 W2RO 112 Hunterdon WD4SIG/M 112 WA2HCC 3,000 WB3HUP/M 9 WD4SIG/M 70 Union WB3HUP/M 4 WB2DND 1,045 Mercer WD4SIG/M 72 W2ZQ* 33,108 WB3HUP/M 2 WB2PKG 4,350 Warren WB3HUP/M 4 WD4SIG/M 72 Middlesex WA2QNW 73,296 WB3HUP/M 16 WD4SIG/M 49 WB3HUP/M 2 Out of State Location Station Score Location Station Score CT KFlB 143 KY WA4EBN 231 W2CC/1 1 VA KC4HN 846 ME N1PL/1 364 K0RI/4 782 WBlGLH 25 WA4PGM 247 E. MASS KA1CLV 228 LA W5WG 893 E. NY K2POF 592 N. TX KX5U 9 W2WSS 187 S. TX W5PWG 646 W. NY WB2IPX 442 AZ AK7J 30 DEL N3ARV 180 OH WOBOYF 264 E PA N3RJ 1617 Wi K9GDF 30 (Worked 21 Counties) CO N0CKC 225 KB3ZF 688 ONT. VE3KK 595 W3SK 420 VE3DIF 120 (Operators: AA3B) DX JA2YKA 1 W. PA WA3JXW N3COR 216 216 (Operators: JR2GMC, JJ1BTC, JH2QXG) N. FLA WD4ITK 144 • = Mufti-operator 2ND ANNUAL RTTY WORLD CHAMPIONSHIP CONTEST Starts: 0000Z February 26 Ends: 2400Z February 26 SPONSORS: 73 and The RTTY Journal MISCELLANEOUS RULES: The same station may be worked once on each band. Crossmode contacts do not count Single-operator stations may work 18 hours maximum, while the multi-oper¬ ator stations may operate the entire 24-hour period. OH periods are no less than 30 min¬ utes each and must be noted in your io$(s). 73 Magazine • February, 1963 119 OPERATOR CLASSES: (A} Single operator, single transmitter, phone only, (8) Multi-opera tor, single trans¬ mitter, phone only. ENTRY CATEGORIES (At Smgie band. iB} ASIband, 10-80 meters EXCHANGE: Stations within the continental 48 US states and Canada must transmit an RST report and state, province, or territory All other stations, including Alaska and Ha¬ waii, transmit RST report and consecutive contact number. 0S0 POINTS: t QSO point is earned for each valid contact. MULTIPLIER POINTS, l multiplier point *s awarded for each of the 48 continental US states, Canadian provinces of territories, and OX countries worked on each band. FINAL SCORE Total QSO points times total multiplier points equals claimed score CONTEST ENTRIES: Entries must include a separate log for each band, a dupesheet. a summary sheet. a multiplier checklist, and a list of equip¬ ment used. Contestants are asked to send an SASE to the contest address for official forms. ENTRY DEADLINE: All entries must be postmarked no later than March 26. 1983 DISQUALIFICATIONS: Omission of any required entry form, op¬ erating In excess of legal power, manipulat¬ ing of contest scores or times to achieve a score advantage, or failure to omit dupli¬ cate contacts which would reduce {he over¬ all score more than 2% are all grounds for immediate disqualification AWARDS - Contest awards wifi be issued in each en¬ try category and operator class in each of the US cail districts and Canadian prov¬ inces and territories, as well as in each DX country represented Other awards may be issued at the discretion of the awards com¬ mittee. A minimum of 5 hours and 25 QSOs must be worked to be eligible for awards CONTEST ADDRESS: Send an SASE to RTTY World Champion¬ ship Contest, do The RTTY Journal, PO Box RY, Cardiff CA 92007 Chod Harris VP2ML Box 4881 Santa Rosa CA 95402 FROM EASTER ISLAND TO CHRISTMAS ISLAND The Pacific adventures of DXpeditioner Eric Sjoiund SM0AGD were mentioned in the August. 1982, edition of this column. The saga of how a copy of that column caught up with Eric reflects the hectic nature of his recent six-month journey. Fellow Swede (SM5HIH—and how's rhaf tor a CW callsign*) picked up a copy of the August 73 while firs ship was m Houston.. SM5HIH sent the article to Eric Edberg W6DU. who maintained daily schedules with SMCAGD as the latter prowled the Pacif¬ ic. W6DU fired the column off to Eric on Tarawa, in the Kiribati Islands One month later, the letter arrived in Tarawa postmarked Taiwan and marked. "Not in Taiwan" Well, some of the letters are the same Meanwhile, Eric had completed his two- week operation from T30CB and was in Pago Pago in American Samoa. The letter containing the copy of the column was for¬ warded to Pago Pago, but once again Eric was on the high seas before the letter caught up with him, this time heading for Christmas island. The letter missed Eric again at Christmas, but the next forwarding to Hawaii did the trick and Eric f malty got to see the column mentioning his "forthcom¬ ing DXpedition" at the very end of that trip Your OX reporter caught up with world- traveler Eric on his way home to provide this update on one of the most successful amateur radio Journeys in many years Eric reviewed his odyssey for the benefit of 73 readers. "After the International OX Convention in Visaiia, California. I headed for Rarotango in New Zealand's Cook Islands to meet my yacht We sent the generators and beam antennas ahead by air freight to make sure they would arrive on time, but they didn’t show up. The skipper was anxious to leave, so we sailed to deserted Suwarrow Atoii. where I operated as ZK1AF. "Before he died, a hermit had been the sole occupant of the atoll for years. I used the desk from his hut as my operating table, bul i had to move it to the shore of the lagoon to get away from the trees around the hut. it was the most beautiful operating position on the trip: looking out over the long wire and Wlndom antennas stretched across the blue water We made two more stops in the North Cook Islands, at the in¬ habited atolls ol Manihiki and Pukapuka “I left my transportation in Fiji since the skipper was heading for New Zealand and would miss the other Pacific islands. 1 spent a month in Fiji looking for a yacht go¬ ing m the right direction, while operating as 3D20X And although the island has no television, i received TV! complaints, it seems the neighbor's video players were sensitive to my low-band operations in the evening. Fortunately, the telecommunica¬ tions official handling the problem was the person who issued my amateur license and he took my side. "It was just as well that f spent the time in Fiji. The poor propagation and solar flares would have made for frustrating DX ing. 1 finally found a yacht heading north i put T36CB on the air from Tarawa, where i stayed with a local ham T38BY I didn’t feel guilty about spending a lot of time fishing and seeing the island, as T30is not too rare. "In Tuvalu I received my T2AGD callsign in a couple of hours and spent about a week operating. I was the only passenger on a seaplane to Wallis Island, but I had no trou¬ ble getting on the air as FW0AG. “I finally caught up with my generators, TH2 beam, and transportation, and we sailed for Atafu Atol in the Tokelau Islands This was my favorite stop on the entire trip; I on¬ ly wish i had been mere without radios. The island is unspoiled due to its lack of a good anchorage. The natives were extremely friendly, throwing feasts and dances *n my honor. 1 had to explain that the pileups were waiting and 1 had to return to the radio. They all thought I was a bit crazy to sit and operate the radio all day and night. I never got to see much of the islands, and I think I would like to go back to really explore them, without a radio—or at least with only a very small one. "After four wonderful days we sailed on to Kanton Island, the rarest spot on the trip. Kanton was once a military base, so old buildings and antennas abound. Unfortu¬ nately, I could not use the huge log-peri¬ odic antennas because we had no power to turn them. Kanton’s two dozen residents enjoy Joint administration fey the United Stales and Kiribati. Thus, i could use two callsigns: T31AD and SMCAGOfKHI To reduce the confusion and to give out as many contacts as possible, i alternated callsigns, changing them daily at 2400 UTC It was very confusing for me. so I hung up a sign with my call. At 2400Z, I would turn over the sign and change the call Eric’s dedication to his DXing is evident in the impressive statistics he rolled up on Kanton; 19,000 contacts in six days of operation under each callsign. He worked 80 meters between 1100 and 1300 UTC, sunrise across the US, to give all operators their best chance to work him. even though this was the middle of the night in Kanton. in fact, Eric got by on only a couple of hours of sleep each mght during his two-week stay "There were no social distractions on Kanton," Eric relates, "but I did get a little tired the second week." Eric operated the radio nearly all the lime he was on Kanton. except for a single afternoon that he spent bird watching. Eric's last DXpedition stop was Christmas island where he operated for six days as T32AJ When he finally flew Into Honolulu at the end of the voyage, he deposited his rig in a locker at the airport so that he wouldn't be tempted to turn it on. After a week on the beach at Waikiki, Eric, headed home for Sweden, Behind him he left thousands of pleased DXers. Among the 47,600 -contacts were thousands of new ones and many more thousands from mew- band countries. DXers from the 30D-coiintry level to the newcomer worked Eric, many at every stop. Even long-time DXers com¬ mented on the excellent handling of the pileups. saying that it was always a pleasure to work Eric. "He gives everyone a fair shake: you know you will get through eventually, and he almost never misses a callsign, no mat ter how bad the pileup." QSL CARDS Those who made one of the 47,600 con¬ tacts with Eric will undoubtedly be locking for their QSL cards. So far. in my series on OSls and OSLmg i have covered the design of the card, filling out the card., and mailing *1 to the proper person Now let’s look at the most fun part of OSLing: How do we get the card back? If you are in a hurry {and who isn’t?!, the fastest way to get your return OSL is by sending a self-addressed, stamped enve¬ lope (SASE) with your card, Let’s look at the finer points of using SASEs Your first step in preparing an SASE is to choose an appropriate envelope. The envelope should be large enough to accept standard-sized cards without folding; try a few of your larger cards first. If you are ex¬ pecting a return card from outside the US, use an airmail envelope with the little col¬ ored slashes around the edges. In the place for the return address, put the call of the DX station. Neatly address the envelope to yourself,, including your callsign, and be careful to in¬ clude "USA" at the end of your address. Use a separate envelope for each contact —or at least for each different callsign Hot Tip: Write the QSO information from your OSL card on the inside of the return envelope flap. For example: T30CB 13X82 0435Z 14003 kHz 2xCW 599. Then if the envelope gets separated from your card, the DX station or QSL manager can fill out and mail you a card based solely on the envelope. If you are mailing your card and SASE to a stateside station or QSL manager, you can include a US stamp for return postage. (Watch out for postage-rate Increases, and include enough postage to- pay for the return.) But what if you’re mailing your card to Eric's QSL manager, SM3CXS, in Sweden? You can’t get Swedish airmail stamps at your local US post office, so how do you supply sufficient return postage? Most amateurs turn to the Internationa! Reply Coupon (IRC) The tiny IRC has many mysteries ol its own which we'll explore in a future column, but we'll keep it simple for now. In theory. Em Sioiuno SM0AGO fright) recently completed a sin-month DXpedition in the Pacific, mak¬ ing 47,600 contacts Friend Erie Edberg W6DU (left) helped Eric stay in touch with Europe during the poor propagation last summer 120 73 Magazine • February, 1963 you can buy International Reply Coupons at any US post office. However, I have got¬ ten a blank stare at some of the smaller branches when I asked for some IRCs. The cost of the IRC goes up frequently, but they were selling for $0.65 each at last count. You might be able to purchase IRCs for less through your local radio club or from QSL managers and DX stations which re¬ ceive a lot of IRCs. Ask around. A typical ask¬ ing price might be $0.40 each, in lots of 100. The International Reply Coupon forms a sort of internationally-recognized currency for hams. IRCs are seldom cashed in at a post office. Since each is worth one unit of international surface postage in exchange, you would get one $0.30 stamp for each IRC turned in. At $.65 each, this is quite a loss. The IRC has several advantages in DX QSLtng. It is universally recognized, even in countries where they are not directly useful, such as communist countries. Eastern Europeans, for example, cannot buy or exchange IRCs within their coun¬ tries, but they can send out any they receive. The chief drawback to the use of IRCs is their expense. Many operating aids for the DXer specify the number of IRCs necessary to return your envelope and QSL via airmail. This number ranges from 2 to 5, so It might cost as much as $3.25 in IRCs to get your card back from Sri Lanka, not counting the cost to get your card and return envelope to Sri Lanka. Because of the high cost of IRCs and the poor exchange rate at the local post office, some DX stations suggest a “Green Stamp” instead of IRCs. No, not a real Green Stamp, but a US $1.00 bill. It costs less than 2 IRCs, is almost as universally recognized as the IRC, and usually is worth more in exchange. The money is certainly useful to the DX station and often is used to finance future DXpeditions. However, “Green Stamps” have their own problems. First, they are easily lost or stolen before the money ever gets to the DX station. Also, some DXers question the ethics of asking for money, especially over the air. The ARRL will not accept QSLs from stations which insist on a cash “donation” for a QSL But many stations “suggest" rather than insist on cash. Finally, a hoard of US dollars could get hams in some coun¬ tries in trouble with the local authorities. If you are in doubt, stick with IRCs. There is a third method of arranging for return postage for your QSL; Supply stamps which the DX station can use di¬ rectly to return your card. In other words, if you send your card to SM3CXS, you put Swedish airmail postage on your envelope. All you need is a source of small quantities of mint airmail stamps from countries all over the world. You might try the local stamp and coin dealer, but he is unlikely to have much of a selection, and he’ll want a stiff premium on what he does have. Wouldn’t it be nice if some ham bought such stamps In quantity and packaged them for individual DXers? Fortunately, someone has! Send an SASE (you know how to do it right, now) to DX Stamp Service, 7661 Roder Parkway, Ontario NY 14519, for their current price list. The use of these stamps has several ad¬ vantages. The cost is comparable to IRCs (and can be cheaper when 4 or 5 IRCs are re¬ quired). The DX station returning your card does not have to dispose of the IRCs at a loss nor arrange to sell them He doesn't even have to go to his local post office to buy stamps to return your card. He merely fills out your card, sticks it in the envelope, and throws it into the mailbox. By making the QSL return so easy for the DX station, the QSL-return rate increases. And isn’t that the point of this whole opera¬ tion, to get your card back as quickly as possible? So try using the DX Stamp Ser¬ vice and see what it does for your QSL returns. Next month we'll talk about QSL bureaus. Until then, good DX! LETTERS ) THANKS TO ALL In response to the notice you put in the 73 Magazine "Ham Help” column for me, requesting a schematic for a Phllco 89 radio, I have so far had no fewer than 16 of¬ fers of help. I’ve written to each one thank¬ ing them and would like to say thank you to you, too. Hams are certainly helpful people! Charles Owens Durham NH BOOTLEG COMMENTS When the early morning hours of Mon¬ day, September 6th, produced some of the finest auroral curtain reflections I’ve ever heard on VHF (and a dazzling visual light show as well-one of the hottest ever seen in New England), I began to wonder how in¬ experienced or uninformed operators would react to this bizarre propagation phe¬ nomenon and its ghostly northern echos. Naturally, I tuned my receiver down to the il¬ legal “bootleg band” (27.6-28.0 MHz) that lies between CB and ten meters for a first¬ hand look. The band was hot with auroral reflection and my hunch was confirmed in spades! A hop across the band produced these howlers, which deserve to be logged for posterity: From an unidentified source: “How come everybody in skipland sounds like they're gargling with Listerine? This has got to be the worst outbreak of bad breath I ever heard. 10-4?” From a station in New Jersey. 'O.K., Massachusetts, but there’s ‘lots of QRM from a station in North Carolina—he really be booming in OFF THE BACK SIDE (sic) of this here beam!!!” From two stations in Maine: “10-4 on Old Orchard Beach. . we re about 50 miles apart but you're peakin’ off the SACK of the beam.. .1 had to turn north to pull you In, and you're right dead off the back of the antenna. I don’t know what to make of it.” The next time someone talks to you about the advantages of lowering or eliminating licensing standards for the amateur service, just reflect for a moment 122 73 Magazine • February, 1983 about the consequences of turning emergency communications services over to a gang of operators who don’t even know which way to turn an antenna to work an auroral curtain—let alone (God help us!) the reasons why. I’ve never had a heartier laugh, nor met a better argument for keeping licensing stan¬ dards exactly as they are. Dave Beauvais KB1F Amherst MA THANK BASH, WAYNE I have subscribed to your magazine since 1977. In that time you have consistently vil¬ ified incentive licensing (something we WDs and KAs would not have thought to question). For the last year or two, you have been attacking the Morse code require¬ ment. In your October, 1982, editorial, you demean Bash. With at least the passive connivance of the non-hams running the FCC, Bash has given you exactly what you asked for. In¬ centive licensing is now a joke. (Wanna up¬ grade? Send a check.) I received a catalog in the mail last week which offered Bash tapes of the code tests. Now knowledge of Morse is irrelevant. Wayne, where is your gratitude? Your sermonizing and lobbying just filled edito¬ rial space. Bash has accomplished your stated purposes. How can you attack him for that? I don't believe incentive licensing has ever bothered newcomers to amateur radio. Incentive licensing irritated a bunch of geri¬ atric AM operators by crowding them up the band among the sidebanders. If the Feds ever caused a slump in new hams, it was probably by terminating Con¬ ditional licenses. The Bash hams of today are the sons of the Ws, Ks, and WAs who got their licenses by buying a new rig from the right guy. I don’t see how turning licensing over to radio clubs can be much of an improvement over the old Conditional system. I saw the Bash booth at the Cedar Rapids conven¬ tion; there were enough people standing around, presumably licensed amateurs, to form a club. Possibly hams could learn from the rela¬ tionship the National Rifle Association en¬ joys with the Army. The military should be well funded for at least the duration of the Reagan administration, and it has a vested interest in rule 97.1(d). Today’s armed forces, particularly the Navy and Air Force, have a far greater need for electronics and communications experts than for skilled riflemen. Reserve, National Guard, and ROTC units are conveniently located close to population centers and should be eager for a chance to show their best side to young electronics enthusiasts. The FCC should be glad to give up the ex¬ pense of the testing program, and the mili¬ tary should want a program that actually determines proficiency in electronics and communications skills. Robert A. Wiley WD9FQD Solon IA INCENSED AND LICENSED As a new amateur, 1 enjoy 73—even bought a subscription. But after 2 issues I became incensed after reading comments from your other readers. Hams apparently are a big bunch of hypocrites when it comes to code and licensing. The consensus—at least judging from your magazine—Is that CW is: 1. A sacred cow: “I got mine, so everyone else must also suffer." 2. CW keeps yo-yos off the ham bands. 3. Every ham constantly uses CW. 4. Bash is destroying the tradition of hams for understanding radio. Well, I say bull! First, if code is so sacred, then current hams would not mind taking a retest at renewal time to prove proficiency. Betcha a lot of Extra class would become Novice, maybe! At a recent ARS auction, the auctioneer, in selling a bug without suc¬ cess, asked if anyone uses CW. The laughter spoke for itself. Second, it appears to me that the only ham bands that are crowded are the phone bands. The CW portion of all but the Novice bands are unused by comparison. And please tell me what General, Advanced, and Extra are doing on the Novice bands sending at 18-20 wpm with umpteen Watts? Now to the test. The written FCC test is a joke. I studied a complete Heath course and the ARRL manuals, memorized all sorts of formulas, and flunked the test, The questions are ridiculous. My advice is to forget Bash, or whatever, peruse a manual or two, take and flunk the test, then study. The questions don’t change. Now that everybody is mad at me, I will make my recommendations for improving amateur radio. 1. Keep the code as a license require¬ ment but set the General speed at 10 wpm. Nothing sacred about 13 that I know about. The single Item keeping more people from becoming hams is $$$ for equipment. And require a code retest with every renewal. If that’s too hard to swallow, set 10 wpm for Technician and grant phone on 40 and 80. 2. Expand the phone bands. An awful lot of our frequencies are wasted. 3. Restructure the written test to be a true evaluation of knowledge of radio telecommunications. Pete Thacher N4HQZ Raleigh NC HABLA MORSE? You're right on the mark regarding elimination of Morse code as a part of the amateur licensing process. What the FCC really ought to require is that all hams learn Spanish. You never know when someone knowing only Spanish could get into an emergency situation with only a phone- capable rig and couldn’t remember any code (only time he used it was for the test). Just the other evening I listened to two locals talking on two meters saying that we have to keep the screen tight and keep the code. Then they went on to talk about how they were working to upgrade and how nice the Bash books were. Who is kidding whom? Drop the code and keep the written, but maybe print up 10 or 20 different versions to make it memory-proof. Contrary to the No¬ vember editorial in QST, the time IS now. Charles L Kelsey WB2EDV Mayville NY LEARN TO EARN Without going totally into the debate pro or con on the code requirement and justifi¬ cation for each question on the written ex¬ am, it appears to me that both have strong and weak points, i submit that anyone who has reasonable intelligence and desire can learn the code at 5 wpm. Whether 13 or 20 wpm should be required for phone privi¬ leges, t question. Also, the theory exam cer¬ tainly has a problem, I think Bash is wrong to provide direct answers to the FCC ques¬ tions! However, I think he is right in that some questions are ridiculous. The word¬ ing and content of some questions are out¬ dated and would not lend themselves to the scrutiny of a first-year education major. Maybe H.R. 3239 will provide some change lor the better In these problem areas. Nevertheless, my main purpose in writing Is to discuss learning the code. I would like to share my experience at learning the code. This technique was used tor both the 13-wpm General exam and the 20-wpm Extra exam Now, I do not consider that I have much time available as I am a full-time employee (Texas Instruments), full-time father, full-time husband, and part- time student Oh, yes, I do have a little time left over tor a hobby Also, I do not consider myself exceptionally bright (not a member of Mensa). t purchased a battery-operated cassette tape recorder/piayer with earphone and a copy of the 7313 4 wpm tape Then I placed the tape player with pad and pencil on a table near my favorite chair Each evening as I sat down to read or rest I would copy code for 10-15 minutes (at most) Very few evenings would I miss an opportunity to copy, however Using this technique, I passed the 13-wpm test on the first try after one month. On the 20-wpm test, I studied for six weeks and passed on the first try. I used only the 73 random character tapes and trained myself to copy only one letter at a time, re¬ sponding to the composite sound Also, I concentrated only on the code and did not prepare for the written (theory) exam I pre¬ pared for that at a separate time after pass¬ ing the code The very first hurdle is to decide that you are going to team the code at the wpm re¬ quired and dedicate some time to the proj¬ ect Thus, the first problem is a psychologi¬ cal one. Also, you understand, no one is go¬ ing to "give" you a passing grade—you earn it, I consider the code as part of earning a privilege and it makes my license worth even more to me Maybe code Is outmoded and not modern, but like some of the theory, It gives me a taste for what is in¬ volved and the ability to use It when and If needed. Whether one needs to learn code at 20 wpm to get full privileges is question¬ able, but a good stiff theory exam seems appropriate. Let's keep the code, make It appropriate, and Improve the theory exam. Mike Grimes K5MLQ Sherman TX INSULTING Reference my letter to you, published In the September, 1982. 73 ("Emergency Sys¬ tems^, Your reply is, to say the least, over¬ simplified and Insulting to my intelligence. I wonder how many 1C boards you worked on and whose kids work on your equipment If you can t give an Intelligent answer to the problem, why waste space and time? From all the comments on the CW issue versus comments on "Emergency Sys¬ tems," It appears that there is no interest in the latter issue, and with your funny) I need an original or photocopy of TV/. written by Dick Wiidman W6MOG and published by 73. I also need a D0-T35 or DO-T6 audio transformer, and I would like to buy MBO 201 or MBD 301 hot-carrier di¬ odes in lots of 10 Please write and state your price before sending material Gordon La Grange W5AKQ 318 East Circle Dr. Baytown TX 77521 124 73 Magazine • February, 1963 useless/stupid comment, the problem will never be considered seriously. Of course, Wayne, there won’t be any problems be¬ cause the enemy will give us plenty of advance warning so we all can discon¬ nect our antennas, and when your equip¬ ment gets blown away, you can find the kids to repair It. I know you won’t print this rebuttal to your stupid answer, but at least I got it off my chest. I most probably did a hell of a lot more equipment repair than you ever did. I can't find kids to do my repair work. Good luck. Wayne. In your old age you are getting very sarcastic. Arnold D. Samoais KH6COY Ocean Shores WA Old age may have made me sarcastic (no. I've always been sarcastic—It's /usf that you are getting old enough to recognize it at last,X Amokt, and l don’t doubt tor a mo- ment that I have insulted your intelligence, i also don’t doubt that you've done a lot more repair work than t.I did train in the Navy and did the electronic repair on the USS Drum during the war ; keeping the radar ) radio, and sonar running despite every effort of the submarine tenders to screw it up. And I spent ten years or so building ham gear tor RTTY, sideband, and soon... managing to twist my hip permanently from standing on one lag at the workbench. But you’re right—I’ve gotten away from servicing and even buiiding, much is the pity, doing it only when there is no alternative. However, before I wrote my “lunny/useless/stupid” response to the letter, I did my homework. It you do yours, in return, you will find Out what I know. . .and that is that it Is the youngsters who are the real hot shots at re pairing today’s circuits. The best service person we've ever had here was a teenag¬ er. .. and the worst were some older hams. The Drum is still around, so I did okay — Wayne. SOFTWARE NEEDED I don’t have to tell you about the growing Invasion of microcomputers into the ham shack. Many of your editorials show your awareness of this. I would, however, like to bring your attention to the expanding popu¬ larity of one computer In particular the Commodore VIC 20. Many people don't realize how fast this machine's popularity Is growing. For example, I know about nine¬ teen hams who own computers. Out of these nineteen, two own the Heathklt H 89. One owns an Apple, two own a Radio Shack Color, five own Model Is (Radio Shack), and nine own the Commodore VIC 20. And why not? The VIC 20 is an easily expandable computer with a fairly powerful Basic (CBM V2.0). Also, it is rf-tight. It’s perfect for be¬ ginners in computing who are trying to learn and, right now. that is a lot of hams. Unfortunately, there is one problem I am a Gl stationed in Europe and a soon to-be Novice I need a schematic for a Yaesu FT-401D (same as the FT-DX401) Also, can anyone teil me now to hook up my fre¬ quency counter to the FT-401 to measure the receive frequency? I will, of course, pay post¬ age and copying costs for this information. David Granholm HHD, 69th Sig. Bn. APO New York 09178 which, If let go too long, may cause the computer to be self-defeating. Because so many beginners are buying the machine, there Is a shortage of good software, in fact, that Is the one big reason many hobby¬ ists may have for not buying the VIC. Naturally, I don't want to see the death of such a fine computer. The solution to this problem, as I see It, is not so much to make available packaged software as It Is for magazines, such as 73, to publish software along with articles which explain how and why this software works. This would not only make software available but also would supply other VIC 20 owners with a better understanding of their computer so that they. In turn, could write programs to be published. I have written a number of programs which would be of interest to hams, such as RTTY and Morse programs, programs which track OSCAR, etc. Also, many VIC owners don’t realize how simple It is to in¬ terface a Model 33 ASCII teleprinter to their computer to serve as a line printer. I'm sure that if you investigate this a bit further, you will find that printing this infor¬ mation could be profitable not oniy to ama¬ teur radio, but to 73 as well Jim Archer KF1T Warwick R! ANTI-SEMITIC? In your November, 1982. editorial regard¬ ing how hard work pays off, you wrote, "given equal opportunity, the US would be as proportionately populated with wealthy Chinese as it Is wealthy Jews " I was shocked and surprised to read such an obvious anti-Semitic statement. Did you take a survey asking bank balances and re¬ ligious persuasion? How about wealthy Catholics? Or wealthy Protestants? Why did you single out Jews? How in good con¬ science can you perpetrate this ugly myth and stereotype and In doing so Inflame the fires of anti-Semitism? As a former New Yorker, you must be aware of the many needy unfortunate Jew¬ ish families In the lower East Side of Man¬ hattan. Did you take them Into account In your survey? Your point would have had the same ef¬ fect If you had deleted "Jews" and substitut¬ ed the word "people." By noting yourcom- parlson to "wealthy Jews," It showed you as a narrow, unthinking person who may profess to be free of bias but In reality Is not. Mike Hettoetman KM2F New York NY While I've never been entl-Semitic before, I think In your case I might be able to make an exception. You, sir, appear to have a very serious inferiority problem. At eny rate, I gather that you are trying to make a case that there is something wrong with being successful. Well, that's a good rationaliza¬ tion tor your personal failure to be as suc¬ cessful as you feel you should. No, I'm not antf-Jew, enti-Chfnese, anthCatholic, anti - WASP, and so on * and I have thirty years of editorials to back me up, . plus a wide range of personal friends of every known persuasion and color I'm known, i think, not to be anti-Arab— which may taint me in your estimation Now, I must admit that I do have my preiudices, being anti-drugs (which includes fobacco), antiestabhsh ment (and moat of you know what govern¬ ment agencies I am referring tok anti-lazi¬ ness, antHUiteracy . and so on. t have a strong record as being pro-success and I think i can point with pride to the intelli¬ gence and success of Jews, the Chinese (where they have not been screwed by the communist political system), and the Japa¬ nese,—Qoy Green. KEEP THE GOOD STUFF QST and Ham Radio were my steady diet of amateur radio magazines for as many years as I care to admit—at least since the inception of Ham Radio. But in one way or another, these magazines changed (as magazines tend to do) and I became disen chanted. Being the inquisitive experiment¬ er type, new excitement was needed. What seemed to have been lost, I found in 731 I like your editorial philosophy of includ¬ ing the type of arttcies in 73 which, accord Ing to some publishers, do not belong in amateur radio magazines. Hogwash! For example, one of these days (and sooner than most of us believe), the ham fraternity will have access to its own geosynchro nous satellite, complete with microwave band transponder* (See Westlink Report September 10,1982.) Over the years, I have authored about 22 ham magazine articles, not the least of which was the popular coffee-can feedhorn (Ham Radio, May, 1976). In fact, in 73 for Oc¬ tober, 1982, John Franke WA4WDL says, "The first antenna I tried was the popular coffee-can horn. Since then it has become my standard to which ail other antennas are compared.” Seeing testimonials like this from fellow amateurs gets my adrenalin pumping! Makes life seem worthwhile! But, alas, one can’t have everything. I fear few persons know about the 1976 article or who authored it. TVRO will never be the same since that article was published You probably know that rectangular horns were the “in" thing originally, but not anymore I like to think I should take a teeny bit of credit for that, too. It seems to me both the amateur and non-amateur stand to gain from articles of this kind; it works both ways. Keep the good stuff coming. Maybe I'M even renew my 73 subscription! And I might even find time to write an article or two for 73. Norman J. Foot WA9HUV Elmhurst (L P.S. My consulting business Is to a large de gree an outcome of my amateur radio activ¬ ities over the years. Your editorial covered such a possibility very well. BEST ISSUE EVER The November issue of 73 is the best am¬ ateur magazine I have ever seen—simply outstanding in Its variety of construction projects. The power-supply project by WA6TTY is so good I can't believe it—even to an offer of help for an SASE! The step-by- step instructions are what are so sorely needed. I have, 2 years ago, written to QST and said that this is what we need, but I'm afraid the letter was given a stock reply and there it ended. But there are many of us who are not technical wizards who want to learn and construct. Weil, Ken Wyatt has done a great service for us, and I do hope that you can encourage him to contribute again How about a 66-foot 4- or 5-band cheap dipole—simple, yes, but isn't that what will get the new ham Into making rather than buying? A cursory glance through the ham ads will show you how many hams buy their dipoles. Well, anyway, If you never produce another issue fix a year, the November issue is worth the annual price Keep that up and let OS T keep on with the dreary con¬ test rules/winnersIDX clubs, etc. I could write pages of congratulations. I'm so pleased with that issue. Eric Stabler VE3IS0 Ontario, Canada Bill Gosney KE7C Micros, Inc. 2665 North Busby Road Oak Harbor WA 98277 40-METER HOOT OWLS There is another Hoot Owl network, which has been in existence since 1967. This net was started by W3CDH and others, meeting on 40 meters at 06002 on Saturday mornings. Various frequencies have been used over the years but now they meet on 7.274 MHz, plus or minus QRM, and have check-ms from ail across the country. To call in, merely say "hoot hoot/ and after five regular check-ins, an award will be mailed to show participa¬ tion The type of rig, power output, antenna system, or genus of operator has no bear¬ ing on the degree of Hoot Owl classifica¬ tion. Hoot Owi capability is based solely on the licensed operator's ability to stick with it on the 40-meter band at least two hours beyond his sensible bedtime. An associate membership may be is¬ sued to operators who qualify in some re¬ spects but operate in the wrong frequency band or, tor some other reason, told up and are unable to hack it. There's even an women's auxiliary! Any fe¬ male stayer-upper attempting to qualify who is thereby hollered at by her father or hus¬ band shall be designated a Mmt-Hoor‘ Dues tor the organization are $10.00, which keeps a Hoot Owl in good standing for a period of ten years It not paid within the ten-year period, the former Hoot Owl becomes a "Chirp," which means he no longer gives a hoot. Oh yes, the password, we must not for¬ get that! Any Hoot Owl can easily be iden¬ tified by another member when the pass¬ word "hoot hoot" is injected at the point of contact. Do you give a hoot, or not? CANADAWARD The Canadian Amateur Radio Federa¬ tion is pleased to announce the following awards available to all radio amateurs worldwide. A colorful certificate will be issued to any amateur who confirms two-way con¬ tact with all Canadian provinces and terri¬ tories All QSOs must be on one band on¬ ly. Separate awards are issued for each band on which the applicant qualifies. Canadian provinces and territories in¬ clude: V01/V02 Newfoundland/Labrador; VE1 Prince Edward Island; VE1 Nova Sco¬ tia; VE1 New Brunswick; VE2 Quebec; VE3 Ontario; VE4 Manitoba; VE5 Saskatche¬ wan; VE6 Alberta; VE7 British Columbia; VE8 Northwest Territories; VY1 Yukon Ter¬ ritories. Note; V02. Labrador, is part of the province of Newfoundland and therefore counts for a Newfoundland contact. A mode endorsement is available if all QSOs are made on the same mode (CW, SSB, RTTY, SSTV), Contacts made after July 1,1977, only will count for this award. All amateur bands may be used. Each dis¬ tinct satellite mode {432/144, 144/29, or 144/432 MHz respectively! will count as a separate band. To apply, submit the twelve QSL cards with $2.00 (Canadian or US funds) or ten IRCs plus sufficient funds ($.60) for return postage for your cards CARF members need only send funds for return postage as the award is free to ail CARF members. 12B 73 Magazine • February, 19B3 A special plaque is available to any am¬ ateur who confirms two-way contact with all Canadian provinces and territories on each of five separate bands. Submit your 60 confirming QSL cards with $25.00 (Ca¬ nadian or US funds) plus sufficient funds for return postage to: Canadawards, PO Box 2172, Station D, Ottawa, Ontario. Can¬ ada K1P5W4, WBCC AWARD The Worked Broward County Cities award is sponsored by the Broward Ama¬ teur Radio Club AM amateurs are invited to apply for this very attractive and desir¬ able certificate, printed in three colors on heavy parchment stocks Applicants must obtain two way con¬ tact with five of the Broward County cities, A gold seal will be awarded for fif¬ teen cities worked. All contacts must be made from the home QTH of the applicant; QSOs with mobile or portable stations in Broward are valid. All legal bands and modes may be used, but contacts via repeater will not be accepted. Applicants should list the date, time, band, mode, and cali and QTH of the Broward stations worked Have this list verified by two fellow amateurs Send your list, together with a fee of $1.00 and two first-class mail stamps (OX applicants send US $1.00 plus 3 IRCs). to: WD4RAF Awards Manager, 1921 NW 41st Street, Oakland Park FL 33309 Gold seals will be issued for a seif-addressed envelope or one IRC The following Broward County cities apply: Coconut Creek, Cooper City, Coral Springs, Danla, Davie, Deerfield Beach, Fort Lauderdale, Hacienda Village, Hal¬ landale, Hillsboro Beach, Hollywood, Lau- derdaie-by-the-Sea, Lauderdale Lakes, Lauderhill, Lazy Lake, Lighthouse Point, Margate, Miramar, North Lauderdale, Oakland Park, Parkland, Pembroke Park, Pembroke Pines, Plantation, Pompano Beach, Sea Ranch Lakes, Sunrise, Tama¬ rac, and Wilton Manors. THE VKS WHISKEY CHARLIE AWARD This award was originally created to commemorate 25 years of the club's exis¬ tence and is still an awaid hunter's challenge For the first 23!6 years of VKSWC's ex¬ istence, it was the only callsign author¬ ized from Woomera, a now small Austra¬ lian community and former home to the European Launch Development Organiza¬ tion (ELDO). The club presently has four active HF members with several other members awaiting their reciprocal calls. VK50L, VK5MQ, VK5AH, and VK5LA can be heard operating from the village as well as the club's station itself. The award is available to all licensed amateurs throughout the world who can show proof of two-way contacts with club station VK5WC and two club members, or four different Woomera stations who are club members. Any authorized frequency or band, in¬ cluding crossband and VHF, UHF. or satel¬ lite repeater, and any mode or combination of modes for which the stations concerned are licensed are permissible. Contacts may be claimed retroactive to May 3,1978, which is the date the use of individual call- signs was authorized within the Woomera village community. To apply tor the award, submit a copy of all eligible log entries signed by the claim ant and certified by either the cosignmg of two other licensed amateur radio opera tors or, In the case of an isolated claim¬ ant, certified by a justice of the peace or a notary public. In case of dispute, local log entries at Woomera shall be accepted as proof conclusive of whether or not a con- tact took place. Claims for the award are to be submit ted in writing to the Award Manager, Woomera Amateur Radio Club, PO Box 538, Woomera, South Australia 5720, Aus¬ tralia, accompanied by $2.50in Australian currency (or equivalent), preferably by bank check payable to Woomera Amateur Radio Club. Award Account. The award is an enlarged version of the club s QSL, with black, red, and blue printing WORKED VK8 AWARD Work or hear eight stations in the VK8 area, irrespective of applicant s QTH Any band, any mode, GCR applies Award fee is $3.00 Australian or ten IRCs Send log data with fee to: Awards Manager, PO Box 40318, Casuarina 5793, Northern Territory, Australia. TASMANIAN DEVIL AWARD Applicants must establish contact with a number of VK7 stations depending on their QTH: Australia. 50 contacts; Oceania and Antarctica, 30 contacts; Asia and North America. 20 contacts; Europe and South America, 10 contacts: Africa. 7 con tacts. Band and mode endorsements are available as well as special endorsements for making all contacts with Novice stations. Claim logs with applicant s call and fuff name are to show station contacted, date, time, band, and mode The claim is to be signed by the applicant and counter¬ signed by two other amateurs. Spot checks will be made with contact stations in VK7 for confirmation. QSLs are not re¬ quired. Contacts made on or after January 1, 1978, are valid. The award fee is five IRCs or equivalent for Australian appli¬ cants, ten IRCs for overseas applicants Apply to: Tasmanian Devil Award, VK7 QSL Bureau. PO Box 3710, Hobart 7001 Tasmania, Australia. ZONE 29 AWARD To qualify for this award, rt is necessary to contact 25 amateur stations located in zone 29. Zone 29 includes the VK6 and VK8 call areas Only contacts after 0800 GMT on January 1, 1952, are valid No crossband contacts are permitted. Mini¬ mum acceptable exchange of reports is RS33 or RST338. QSL cards are not required as proof of valid contacts but the applicant must show that the log extracts have been ex¬ amined and verified by two other ama¬ teurs. A simple declaration that the appli cant's station has conformed to all licens¬ ing regulations related to his operation is mandatory The fee for t he award is $1 00 Australian or five IRCs Apply to: Awards Manager, Zone 29, W1A (VK6 Division), PO Box N1002. Perth 6001, Western Australia, Australia THE VK1 AWARD This award is available to any amateur or SWL who submits details of valid con¬ tacts with the required numberof VK1 sta¬ tions. On HF, VK stations require 20 VK1 contacts, others require 10 VK1 contacts On VHF, 10 VK1 contacts are required. A log extract is required, showing for each contact claimed me GMT date and time, band, mode, callsign of the station worked, and reports or cyphers ex¬ changed. SWLs must show callsigns of both stations in the QSO and the reports or cyphers given by each station. The award cost is $2,00 Australian or five IRCs. Applications should be forwarded to: Awards Manager, WiA (VK1 Division), PO Box 46, Canberra 2600. Australian Capital Territory, Australia. THE SOUTHERN CROSS AWARD This award is granted to amateurs and SWLs who obtain the required number of points from working or hearing members of the Eastern and Mountain Districts Ra¬ dio Club of Melbourne, Victoria To quali¬ fy. Australian amateurs and SWLs require fifteen points, New Zealand amateurs and SWLs require ten points and all other am¬ ateurs and SWLs require five points. A point ts awarded for each club mem ber worked or heard The club callsigns VK3ER and VK3BNW each count two points, but only three points can be claimed it both callsigns are included in any one application for the award. The award will be issued for multiband and multimode or specific band or mode as requested at the time of application. To obtain the award, a General Certifi¬ cate Log and the award fee of $.50 Austra¬ lian or three IRCs should be sent to: Awards Manager EMDRC, PO Box 87 Mitcham 3132, Victoria, Australia The General Certificate Log Rule means that any officer of a recognized amateur radio club or society, any two li¬ censed amateurs, or any CHCer may certi¬ fy a copy of the applicant's log tn this way, you do not have to submit your origi¬ nal log. THE NAVAL POSTGRADUATE SCHOOL AMATEUR RADIO CLUB The Naval Postgraduate School Ama¬ teur Radio Club in Monterey. California, will operate a special-event station K6LY during the 42nd Bing Crosby National Pro Am Golf Championship The station will be located near the eighteenth green at Pebble Beach, Operating hours will be 1800Z-24QGZ dally, February 3-6 1983 K6LY wilt operate on the lower part of the General class phone band on 15 & 40 me¬ ters. Stations contacting K6LY and wish¬ ing to receive a commemorative Crosby Pro-Am QSL card should send their QSL card to WB6ZSB, 831 Avalon Place, Mon terey CA 93940. An SASE is not required. NORTH OKANAGAN RADIO AMATEUR CLUB We of the North Okanagan Radio Ama¬ teur Club are going to be having a special station set up during our winter carnival again this year. Our station will be operat¬ ing during the week of February 4-13, 1983, from 2100Z to 2400Z. daily. The fre¬ quencies that we will be on are 28.575, 21 375, and 14 295. plus or minus QRM. The cost of our award is either $1.00 or an SASE sent to North Okanagan Radio Ama¬ teur Club, Box 1706, Vernon, British Co^ lumbia VlT 7T9. Canada. This award, catted the Vernon Winter Carnival Award, is available year round by working our club station (VE7NOR) or 3 Vernon area stations. The Vernon area is defined as Vernon, Armstrong. Winfield, Oyama, Lumby, and Enderby DEALER DIRECTORY Culver City CA Juru Electronic*. 391U Srpulvwla Blvd., Culver Oh CA 90230. 390-8003. Trudts 4G3-I886 San Diego. 827-5732 ((Imi NV>. Fontana CA Complete line* I COM. DenTron, Ten-Tec. Mirage, Cubic. Lunar. over 4000 eteutamit* prod nets for hobbyist, techntdan, exjserimenier. Also CB mlk*,. landmofaUe. Fontana SJtctrenfcs. S62S Skrra Aw., Fontana t A 92335. 822-7710. New Castle DE Factory Authorized Dealer! Yaeui, IOOM, Ten- Tec. KDK, Ardntt, YEA, Kantmnxsu Santee. FuB tine of Aoecsmrkfc No Sale* T*t in Onr mile off 1-95. Debt ware Amateur Supph. 71 Meadow Road. New Cattle DE 19720. 32S-772S. San Jose CA Bay anu s, newest Amateur Kudin store New tn used Amateur Radio mb* 6c nenlce. We feature Kenwood, ICOM. A/.den. Yaisti. Ten-Tec, San- l»s N many more. Shaver Radio. Inc.. 1378 So, Bascnm Ave.. San Jose CA 95128. 998-1103. Smyrna GA For your Kenwood, Yati*ui. ICOM. Drake and other amateur need*, come to m» iiv Britt's Twee Wav Radio. 2506 N Atluntu Rd.. Srnvma i.\ 30080. 432-8006. Preston ID R» WB7BY7! has the Larijwt Stuck at Amateur Gear in the Intemmiltfailt W«*s ami the Res* Prices. Cal! n» hw ad! ywr ham needs.. Rov. Dktrihwtms. 78 St*. Stair., Ptrsloo ID *83*83. 852-0830. Bloomington. IL BOHN TOWERS-Lttp ttwk plus all I'N.AK CO ROHN item* availal.de tm last drop vhijv merit*. Wholesale prices to all users. Also whole- siih distributor for Antenna Spceiulbts, Ftagencv, and Wilson, Hill Radio £503 G.F.. Road Bos 1405. Bloomington. 11,61701 963-2141 Terre Haute IN Your ham headquarter* located in the heart of the midwest. H nosier Electronic*. Inc.. *9 Meadows Center. P.O. Ben 3300. Terre Haute IN 478001. 238-1456. Littleton MA The Reliable Ham Store Serving N. E Full line of ICOM a Kenwood. Vhsu IFTY. Drake. Dam a. B&W accessories,. Curtin & True tenters.. I.arsen. Hustler, TefetTly-Csin products. Mirage amps... Astron P.S.. Alpha Delta protectee*. ARBI.. & Kantronict imtniction aids.. \Vhntler radar detec¬ tors . Full line of com fitting. TEL-COM Elec¬ tronic ( i»mmunKa?Wfm 675 Croat Rd. f Rl. 1191. Littleton MA 01460. 617-486-3400/3040. Ann Arlxir MI See us for products like Ten Tec. R. L. Drake, DenTroo and many more. Open Monday through Saturday. 0830 to" 1730. WB8VCR. WBSUXO, WDSOKN and W8RP Ixthind the? counter. Pur¬ chase Radio Supply, 327 E. Hoover Aw,, Ann Ar¬ ia* Ml 48104. 668-8696. Hudson NH New England's Distributor and Authorized Ser¬ vice Center for all Major Amateur Lines. Tufts Radio Electronics. Inc.. 61 I nwvll Road. Hudson Ml 03051, 883-5005. Somerset NJ New 1 Jersey's only factory-authorized ICOM and Yatsu distributor. Large inventory of new and used sjtedulv Must major brand* in stock Com¬ plete service and facilities Radios Unlimited, 1760 Easton Avenue, P.O, Bov 347. Somerset NJ 08873, 469-4599, Buffalo NY WESTERN NEW YORK Niagara Frontier's cmly full thefting Amateur dealer. Aho Shortwave. CB. Scanners, Marine. OminrfrtaJ. Operating diqrfays featuring Ken¬ wood ami <:4hers... Tower*. Antenna*. Sales and Smxr DX C c na aaB katiata, 32l4Traroit Road, West Seneca NY. (S6S-SS73. Amsterdam NY UPSTATE NEW YORK Kemem*!. ICOM. Drake, plus many other lines.. Amateur Dealer lor over 35 years Adinmdadk Ra¬ dio Supply. Inc.. 183 West Main Street, Amster¬ dam NY 12010. 842-8350. Syracuse-Rome-Utica NY Featuring; Kenwood, Ymu, ICOM, Drake. Ten- Tec, Swan, DenTron. Alpha. Robot, MFL Tem¬ po, Astron, KLM. Hy-Gain. Mosley. Larsen, Cnsheraft, Hustler, Vfini Product*, Yon won't be disappointed with ihju i p men tV M»rvice Radio W orld. Oneida County Airport-Terminal Build- ing, Oriskanv NY 13424. 736-0184. Columbus OH Tin* biggest and Inst Haris Store in the midwest fiatuiinjt qualit* Ketmmxi product* with work mg dtvpuy*. WV -all onh the lw*j, Airtborizrd Kmwund Setvk*?. Enht rsal Amateur Radio Inc . 1280 A»i* Or.. Revnoiddmrg t niumbin. OH 43068. 866-4267. Philadelphia PA/ Camden NJ W avygukle Ac Otaxial Microwave 13 & Equipment, laboratory Grade Test IminunniU, hmvt Snjijfks, Buy. Sell Ac Track* all jjojHiiar make**- lil\ GR, FXK, ESI, Sorwmm, Singer, etc. I ax trunk Research Lata*. 1423 l f em Ave.. Camden NJ 08104. 541-4200 Scranton PA ICOM, Bird, Cushcraft, Heckman, Fluke, Lur- sen, Hustler, Antenna Specialist.*, Astron, Avanti. Bidden, W2AU/W2VS. CDE, AKA, Vlbroplex. Hum-Key, CES, Amplienol, Sons. Fanun/Coori- er, B&W Arneto, Shore I jRue Electnmks. 1112 Grandview St , ScrantiMi PA 18509,343-2124. San Antonio TX Amateur. Oumsettial 2-way. Selling Afttetusa Speeiahs,!:*. AvtantL Atsden. Bird. Hy-Gain. Stan- aard,. VRuunin. MkMand. Hrnn, Cushcraft, Dii-kira. Hustkr. ICOM. Mf f. \ve, Sfiim.-. Cubic, Tttaa, Ten-Tec and other*. AppUai** A Equipment (k, Inc. 2317 \anec }«Gmi Road. San Antonia TX 78213. 734-7793. DEALERS Your company name arui message can contain up to 25 words for as little as $150 yearly (prepaid), or $15 per month (prepaid quarterly). No men¬ tion of mail-order business or area code permitted. Directory text and payment must reach us 60days in ad¬ vance of publication . For example , advertising for the April, *S3 issue must he in our hands by Feb 1st . Mail to 73 Magazine, Peterborough NH 03458. ATTN: Nancy Ciampa. DEALER DIRECTORY ■ . "~i J. H Nelson 4 Plymouth Dr. Whiting NJ 08759 EASTERN UNITED STATES TO: GMT: oo or 04 06 on jo 12 14 ie jb 20 22 ALASKA m s B! m m m HI HP! m HP ARGENTINA m m B59 K9 HI m Hi IHj Hi Hi HP HP AUSTRALIA Si B9 7g, El HI HI m Hi Hi H! Hi CANAL 2ONE iw m 'Hr! _ 1 HR HR ■n Hi IjjfB Hi Hi Hi ENOLANO m m H! H9 m Bi Hi HW HI H HAWAII 2lh 14 7B HR HI Hi HP Bi INDIA m ■1 H9 m 7n 7T Hi Hi HI Hi JAPAN 21 A K3 m E3 7 r 7B 7B 7B _14 Mi*(CO 22 7A _z 7 ? 7 ■■■A? 21 a 2 ta| 2 T a Ifi 159 K9 755 , TfL 7ft TV JB 7H j Kw€«TO RICO 24A ? 1 7 7 7 14 21 5ia 2 U UlA | SOUTH AFRICA 14 7 7 _ 1 HI H HP! H5 Hi HI HI U S & ft 7 m m HP HP! HW HI Hi WEST COAST 21A 14 ■ K ■ ■ m IB Bi Bi Bi CENTRA! . UNITE! 1 STATES TC ): ALASKA 21 H! HQ m 3A ^T7 7 14 21A| 21 A ARGENTINA 21A mr\ BS! KS9I EH _2 B5R5 R5I 21A, 21A IdSZZQElB m Ifi Ei! E8 m EH HI 141 HI Hi ISSSEZS wn\ ■5 m m HR m El HI H5 21 & Bi Hi ENGLAND ■> j 1 1A 7 7 7 153 H5 2| HI m HAWAII 55 m E5 7 7 7 7 7 HI 2tA Hi INDIA wr\ m E9 HI BI R5 HI 7B, HI Hi JAPAN 21A 14 ED El El g HQ El HI HI MEXICO 2T 14 1 7 7 7 14 •»t 2J A PHILIPPINES m Wf\ B5 HI d HI Hi Hi ■1 HI PUERTO BiCO 144 L7 A HQ m HI HI H5 HI Wf\ S HR HU IE m Bi Bi HU 1 U.S.S. ft.. L 2 B. 1 JA iA 7B- 7B 14& a 1 7B ALASKA 21 14?v ?A 7 3A ? 7 H ARGENTINA 21 A 14A, 7g 7T 1 7B. 14X 22A. ?y ? . 71A AUSTRALIA ZlA .14, UB. 7ly Lmj 7ft 7B 1.4 14 ?! 21 ft CANAL 2ONE 21. ? 7 7 7 7 14A. 2lA 21A. ENGLAND -ZB, _za _2 _I 7B _za 14R 2.JA la 7a HAWAII ■ 21Ai l2M 14 Jih 7 7 7 14 21A ?lft INDIA -2B 14A 14 7B 7B 7B 7B| 7a. I4n 7PI 7ft 7ft JAPAN 21A _2i 14 7U 7B _I 7R 14 71A MEXICO 21 14A 7 7 7 14a 21A 21A ?] A PHILIPPINES 7-1A 2 LA 14 7B _2a ...IB ?a 1 _L 7ft 7ft 14A PUERTO RICO 14A M 7 _7 7 14 21A 21A 21A ?1A SOUTH AFRICA 14 7B 7 7B 7B 7B 75 14 21A 21A 21 UIS R _2B| -2a 3A ..X4 7B Lie 1 A a U Uft 7ft EAST COAST 21A 14 7 T?! _7 3A 14 m 21A 21A ml A = Next higher frequency may also be useful. B = Difficult circuit this period. First letter = night waves. Second = day waves. G = Good, F = Fair, P = Poor. •= Chance of solar flares. # = Chance of aurora. NOTE THAT NIGHT WAVE LETTER NOW COMES FIRST. FEBRUARY SUN MON TUE WED THU mi SAT 1 12 3 4 5 F/F F/G F/G G/G G/G 6 7 8 9 10 ti 12 F/G F/F G/G G/G G/G G/G G/G 13 14 15 16 17 18 19 GIG GIG F/F* P/F* P/F F/F F/G 20 22 23 24 25 26 F/G F/G G/G G/G GIG F/G F/G 27 28 F/F GIG | 146 73Magazine • February, 1963 March 1983 $2.49Vi Issue #270 Amateur Radio’s Technical Journal □a Wayne Green Publication 8 New And Useful Projects! Home-Brew II Contest Winner ’age 10 Tearing Into Ten-Tec’s Corsair ’age 105 Coffee-Can Cavity Filter >age 74 OSCAR Gear From Junk >age 18 VI ore Simple Circuits E E RTTY Tuning: The New Solution This simple tuning indicator whipped the competition and took first place in 7J's Home-Brew l| Contest WB205Z 10 Uncover Equipment for OSCAR Phase III S Lurking in flea markets and |unk boxes is everything you need to work OSCAR K6KLY tells what to look for and how to make it woik.K6KLY 18 Up and Coming: Direct-Broadcast Satellites Part II looks at the technical problems with communications at 12 t <\ 1 1 which mav be offset by the advantages N8RK 26 The Fun-Vac: A Synthesis of Old and New This one-tube transmitter combines the circuits oi the fifties vuth the tech¬ nology of the eighties It also keeps your coffee warm WA0RBR 32 Adventure in Sarawak 1 wo DXpeditioners journey to the land of headhunters —and send a signal to the rest of the world. VK9NI 42 Put 2 Meters in Your Shirt Pocket S Radio Shack s Pocket Weatheradio makes a dandy 2-meter receiver A few quick modifications will get it right on target K3PIG 46 The Secret Telemetry of OSCAR 8 Do those numbers from the skv mean any- thing/ You bet K50M 52 Scandinavia: The 2-Meter Dream Vacation Licensing, frequencies, and procedures — it s all here All vou need w a plane ticket WA60CW 58 Twisted Remote Control H This circuit is easy to build and easy to use. The twist is that you probably own the most important part WDSjWV 64 RTTY Tuning—10 Take Your IC's Temperature Like people, solid-state devices get sick it they get too hot W3KBM provides a wav tn answer the burning question. How hot is hot?’ W3KBM The Q-Master Cavity Filter A high-Q filter that uses no copper and no silver-plating —just coffee cans and some ingenious thinking KB6AL Push Your Radar Detector to the Limit E E Without this simple modification, you won l know what vou are missing — un¬ til it s too late W5LFM Personalize the M800 RTTY Program 1 1 A Now you can design and save your own version of this popular software pack¬ age All ii takes is a POKF: or two VF 4AFO 70 74 86 94 Sarawak 9M8—42 Never Say Die—6 Ham Help—95, 97, 100, 103, 109, 117 Social Events—96 Contests—98 Review—104 Awards —108 Circuits —110 Reader Service —114 Satellites—115 Fun! —116 Corrections—117 RTTY Loop—118 DX—118 New Products —120 Letters —122 Dealer Directory—146 Propagation—146 W2NSD/1 NEVER SAY DIE editorial by Wayne Green THE CONNECTICUT CONTEST, CERTIFICATE, AND CHOWDERHEAD CLUB There are three items on my agenda which may be of less than great importance to you. One has to do with some won¬ drous changes wrought by the International Amateur Radio Union, wherein, I was told by sev¬ eral of the assembled at the re¬ cent Bangkok hamfest, the ARRL was finally dumped out of the driver's seat. There was an un¬ seemly amount of rejoicing among our supposed friends overseas. While the League has gra¬ ciously permitted foreign ama¬ teur radio societies to belong to this illustrious organization, HQ always insisted that they have complete control of it. Unrest has 6 73 Magazine • March, 1983 been brewing for quite a few years over this, with a growing number of malcontents foment¬ ing revolution over the high¬ handed, low-action management by the League. Oh, there goes that miserably crotchety old Wayne Green, grip¬ ing about the League again. . . right? Well, you probably believe in the Tooth Fairy, too, so who am I to suggest you take off your smoked glasses and see what your bumbling voting record at ARRL elections has cost you. But, if you even have a shred of question about how our beloved League is perceived overseas, then for heaven’s sake try to find your old rig up there in the attic and get on the air for a day or two.. .make some DX contacts ...and, after you’ve gone through all the usual drivel ... probably mercifully covered up by QRM... ask ’em what they think. You’ll get an earful from a bunch of ’em. At any rate, there was general rejoicing at Bangkok over the freeing of the slaves as news of the vote to move IARU headquar¬ ters from some almost totally unknown town in Connecticut to Geneva was spread. Who knows, perhaps the IARU will now be able to develop some clout! Item two has to do with the re¬ cent director election wherein Mary Lewis eked out a win by less than ten votes,..raising hell with the morale of the en¬ trenched chauvinists at HQ. They’d said for years that, dam¬ mit, this was a man’s hobby and they didn’t need any women on the board of directors. One ex¬ president of the outfit said that hell would freeze over before they’d let a woman get on the board. I wondered about that, so while in Bangkok I made a visit to Hell (a well-known Bangkok res¬ taurant) and found that it had not, in fact, frozen over. Well, so much for ex-presidential predic¬ tions. No wonder they dumped him. Then there was the defeat of poor Don Miller out in Indiana. Don has had a rough time of it. First the HQ gang did all they could to keep him from being elected the first time. Then they trumped up a bunch of baloney and scared him into resigning, threatening to put on the pres¬ sure to get him fired from his job. Knowing that HQ had been able to get Mary’s job, he panicked. With Dannals and Baldwin out of the driver’s seat at HQ, Don ap¬ parently thought he might be able to make it back into the di¬ QSL OF THE MONTH This month's winning QSL is from Lutz Hannig DL9GI of Berlin. West Germany. Lutz’s unique design depicts a confused-looking Red Baron flying Into the center of a multl-coiored radio wave. The card cleverly focuses your attention to the center by moving from the black background to the bright yellow and red of the middle. The rapid shift in hue lends depth to the scene, making It appear as if the aviator were flying into the maw of some great creature. Lutz’s callsign, emblazoned in white at the bottom, ensures that the viewer knows where this card is from If you would like to enter our QSL card contest, put your QSL in an envelope with your choice of a book from 73 "s Radio Bookshop and send it to 73. Pine Street, Peterborough NH 03458, Attn: QSL of the Month. Entries which do not use an envelope or do not specify a book will not be considered rector’s chair again. Well, one thing no one at HQ wants to have to live with Is a director who starts asking questions and shows any initiative at really di¬ recting. They have their short yearly meeting, vote on every¬ thing unanimously, and go home. Do not rock the boat, please. Remember that we here at ARRL are all one happy family and that Wayne Green is a kook. Close, but no cigar.. .actually I’m a cook... love to cook. So Metzger is your Midwest Di¬ rector and those who voted for this chap are welcome to him. Some of the other directors like him, others sneer and call him a toadying turkey. That sort of talk is ill-becoming of directors, even if it might be true. I try to look at the bright side.. .the more all this politics screws up the League, the more interesting things I can write about. Since most of the older timers at the League have bailed out, the attitude has improved a bit. The old-timers’ perception of the membership was as a bunch of nitwits who could easily be led in¬ to anything they wanted. Unfor¬ tunately, there was more truth in this perception at times than was comfortable. For every thinking ARRL member, there was a coun¬ terbalancing group of blind fol¬ lowers, eager to buy whatever the latest party line demanded. The laughter was uncontrolled at HQ when they came out with incentive licensing. This was their plan to disenfranchise 85% of the hams from the phone bands, returning us to the pre- WWII licensing system of two classes, one with phone bands and the other without. Would you believe that almost 50% of the ARRL members bought the idea ... mostly on the basis of the nice name they’d given ft. Who could be against incentive licens¬ ing? Only those who bothered to read the fine print, which turned out to be a minority. And a lot of those opposing it were fighting it because they didn’t want to have to go down and retake the test all over again rather than because the whole idea was ridiculous. The few firms still left in the amateur radio industry are waiting to see some positive moves by the new management of the League. There’s not much left of the industry any more. 95% of the manufacturers are long gone...and 95% of the dealers are gone. We used to have nearly a thousand ham dealers around the country sell¬ ing 73 over their counters! Now there’s a few score. You know this when you look around for some place to go to see a new rig. A few years ago, ham stores were almost everywhere... today they aren't. There’s just one or two left in all of New England, for example. THE CODE Which really brings us to a discussion of the Morse code. Just what you really wanted, eh? Yes, I know the League is dedi¬ cated to preserving the code. And, believe me, I have heard all the old saws about the code be¬ ing the only thing protecting us from the hordes of CBers and keeping the ham bands from be¬ ing like the CB bands. What a crock of.. .er.. .stuff. Frankly, I’m not at all convinced that if we set up booths on the street and gave away ham tickets to any passerby, we could attract anyone to our hobby. There is now a rising call for getting older people into ama¬ teur radio, our having failed to interest kids any longer. Just what we need. Sure, the hobby is great for oldsters. It would keep them from getting lonely. It would give them something to do in their twilight years.. . ker- chunking repeaters and jam¬ ming nets. Why save all that fun for just the Extra-class hams, eh? Of course, we aren’t going to provide our country with much in the way of technicians, engineers, and scientists this way.. .or electronic fodder for our war machine, should we de¬ cide to save the world for capitalism again. But we would be able to sell some rigs, there¬ by enriching the lives of the Jap¬ anese manufacturers. I say let's get at it. Let’s get into the old folks homes and set up dub sta¬ tions... give licensing classes ... and call in Bash so faltering memories won't even have to learn any theory. Word from the underground has reached me that the outfit selling the FCC Morse-code ex¬ ams at Dayton was run by none other than a very well-known California ham. We really have to see that those tapes get bet¬ ter distribution so that old peo¬ ple, who have more trouble than kids with the code, are not dis¬ criminated against. Why should we penalize old people just because they can’t learn the code? As a matter of fact, if we are going to go along with the modern morality, we should set up a system whereby anyone who has shown proof that he has seriously tried to learn the code, yet failed, would get a li¬ cense. In today’s world, it is not the answer to the question Continued on page 101 Well... I Can Dream, Can’t I? by Bandel Linn K4PP “It’s the FCC! They’re not just renewing your license—they’re also giving you a Caribbean cruise!” 8 73 Magazine • March, 1983 John L angrier WB20SZ 115 Stedman Street Chelmsford MA 01824 RTTY Tuning: The New Solution This simple tuning indicator whipped the competition and took first place in 73's Home-Brew II Contest. W hat is your favorite method to tune in a radioteletype (RTTY) sig¬ nal quickly and accurate¬ ly on an SSI3 receiver? A dual ellipse on an oscillo¬ scope? Light-emitting diodes (LEDs) activated by mark and space filters? A sig¬ nal-strength meter? By ear? Here is a new one that might make you change your mind Background/The Problem When Teletype® signals are sent through audio chan¬ nels, they are usually con¬ veyed by switching between two tones with a different timing pattern for each of the characters. During peri¬ ods when no characters are being sent, a steady tone, called the "mark" tone, is present The other tone is called the "space" tone. A device called a "termi¬ nal unit" (TU) extracts these two particular tones from any background noise and produces a digital signal suitable for a printer or computer If this audio signal is com¬ ing across a telephone line or an FM radio link, the fre¬ quencies of the tones at the receiving end will be the same as at the origin How¬ ever, there can be a problem when using an SSB receiver, because a slight mistuning will change the frequencies Photo by Mark Hood Photo A Appearance of the display for a correctly tuned signal. 10 73 Magazine • March, 1983 of the tones heard and the terminal unit will not work Over the years, various methods have been devised to indicate when the proper tones are detected. Here is a new one. A New Solution As shown in Photo A, the circuit displays its output with a row of 20 LEDs. Each one will light up when the strongest audio frequency present is within its particu¬ lar range. The two with the pointers over them corre¬ spond to the mark and space tones. A constant mark signal is tuned proper¬ ly when the LED under the left marker is lit When char¬ acters are being received, the LEDs under both mark¬ ers will be lit. If the tones are low in frequency, LEDs to the left of these positions will be lit. Higher frequen¬ cies activate LEDs farther to the right It's as easy as tun¬ ing an FM broadcast receiv¬ er with a tuning meter! Theory of Operation The simplified block dia¬ gram in Fig 1 illustrates the basic principle involved Each time the input signal completes a cycle, the cur¬ rent content of the counter is captured in the latch. Af¬ ter a brief delay, the counter is reset and resumes count¬ ing for another cycle of the input signal Meanwhile, a decoder is looking at the output of the latch and se¬ lects one of the LEDs based upon it For example, let's sup¬ pose we had a clock of 200 kHz and an input signal of 2 kHz. During each cycle of the input signal there would be 100 clock pulses, so the counter would contain 100 when the latch grabs the counter's output. If there was an LED corresponding to a count of 100, the decod¬ er would cause it to light up until a different count was obtained from the counter. A higher frequency input would result in a shorter pe¬ riod, a smaller count, and a different LED Keeping this simplified model in mind, let's look at the actual circuit (Figs 2 and SAVE COUNTER CONTENT 3j latch 11 Fig. 7. Simplified block diagram. H *4 6 Z ti Fig. 2. Main circuit for tuning indicator. 3) and see how it differs Starting from the audio in¬ put on the left, the first thing you will notice is the 565 phase-locked loop I initially tried some experiments with bandpass filters and a Schmidt trigger. This worked great with a nice clean waveform from a signal gen¬ erator, but was pretty use¬ less with a noisy signal from a sideband receiver The phase-locked loop does a good job of following a sig¬ nal through the noise and providing a nice clean square wave of the same fre¬ quency for later logic cir¬ cuits. The two diodes before it provide protection against large signals that could damage the 1C Next we have a couple of one-shots (IC2) to generate timing pulses at the end of each cycle. Four separate steps are involved: (1) Stop the clock so the count isn't changing during latching. (2) Capture the contents of the counter in the latch (3) Re¬ set the counter (4) Restart the clock. When the counter is reset. it is set to ~~ 3 rather than zero as you would probably expect. (See pins 9,10,1, and 15 of the counters ) This is to make the mark and space tones fall in the middle of the frequency ranges for the corresponding LEDs. When the most signifi¬ cant bit of the count (IC5, pin 7) is 0 and the next bit (pin 6) is 1, the count is in the range of 64-127 This is the region where the display is enabled If the counter con¬ tent reaches 128, IC6 is dis¬ abled through pin 4 and counting stops. This pre¬ vents overflowing and a false display for a very low frequency input. Under the latch (IC7), you will notice a 7485 magni¬ tude comparator. Each time the latch is clocked, it com¬ pares the counts for the cur¬ rent and preceding cycles. When the low-order four bits are the same, the dis¬ play is enabled for the next cycle. This blanks the dis¬ play during changes, result¬ ing in a much cleaner ap¬ pearance and dimming with only noise present. High- order bits could also be compared with another chip but I doubt it would have much effect because counts for consecutive cycles dif¬ fering by a multiple of 16 are probably quite rare MV 57 I 64 Fig. 3. Display portion of tuning indicator. 73 Magazine • March, 1983 11 10 REM™ RTTY TUNING INDICATOR DESIGN PROGRAM. 20 REM-- 30 REM - MB20SZ* APRIL 1982 40 REM**~ 50 REM— M9 AND S9 ARE DESIRED COUNTS FOR MARK 1 SPACE LEDS. 60 REM- 70 M9*91 80 S9*=84 90 REM- 100 PRINT *UHAT IS MARK (LOWER) FREQUENCY * f 110 INPUT M 120 PRINT *UHAT IS SPACE (HIGHER) FREQUENCY*I 130 INPUT S 140 IF H>*5 THEM PRINT 'HARK MUST BE LOWER FREQUENCY.* V STOP 150 REM- 160 REM— CALCULATE COUNTER PRESET VALUE. 170 REM- 180 P»XNTC(H9SM-$9*S>/<M-S>+«5> 190 IF ABS(R>>63 THEN PRINT * INVALID PRESET COUNT.* \ STOP 200 REM- 210 REM— CALCULATE THE CRYSTAL FREQUENCY. 220 REM*— 230 X»((M9“P)*M+(S9~P>*S>*8 240 REM-. 250 REM— PRINT CALCULATED VALUES FOR CIRCUIT AND 260 REM— PRODUCE CHART OF FREQUENCY RANGES FOR EACH LED. 270 REM- 280 PRINT ’WHERE WOULD YOU LIKE THE OUTPUT (TERMINAL IS DEFAUL T 1 * * 290 INPUT 0* 300 IF OS*** then o*~*tt:* 310 OPEN m FOR OUTPUT AS FILE 11 320 PRINT • 1 » * MARK FREQUENCY »**NJ*HZt SPACE FREQUENCY **?SS*HZ* 330 PRINT *1 340 REM— 350 PRINT %1 360 PRINT *1♦•COUNTER PRESET ® *SP»* (BINARY *1 370 N®128 380 P2= 5 P 390 IF P2<0 THEN P2®P2E256 400 IF P2<N THEN 440 410 PRINT #I**1*1 420 P2»P2--N 430 GO TO 450 440 PRINT •1»*0*» 450 N=N/2 460 IF N>*1 THEN 400 470 PRINT *!»*>* 480 PRINT lit "CRYSTAL FREQUENCY * * ) X/l. OOOOOL»06 i * MHZ * 490 PRINT #1 500 PRINT #1 510 PRINT #1 530 B-127,5 \ GOSUB 620 \ GOSUB 680 540 B^ 111.5 \ GOSUB 620 \ GOSUB 680 550 FOR B 95.5 TO 79,5 STEP -1 560 GOSUB 620 \ GOSUB 680 570 NEXT B 580 B-71,5 % GOSUB 620 V GOSUB 680 590 B~63.5 X GOSUB 620 600 CLOSE •! 610 STOP 62.0 REN— 630 REM— PRINT AUDIO FREQUENCY BOUNDARY. 640 REM- 650 F=INT(X/16/(B-P)+.5) 660 PRINT #l»t»*-* IF 670 RETURN 680 REM- 690 REM— PRINT •#' REPESENTING A LED. 700 REM-— APPEND 'M' OR 'S' FOR MARK AND SPACE TONES. 710 REM- 720 CI^M* 730 IF B~.5-M9 THEN C#«C*+* M* 740 IF B-.5=S9 THEN Ct*Ct+* S* 750 PRINT tltfC* 760 RETURN Fig. 4. Basic program to compute crystal frequency and counter preset for given mark and space tones. Construction and Adjustment As shown in Photo A, the LED displays and three de¬ coder chips are mounted on a small piece of perfboard which can be installed on the front panel of a terminal unit The rest of the proto¬ type was constructed with wire wrapping for ease of modification during devel¬ opment You can reduce the cost by using solder-tail sockets with point-to-point wiring or making a PC board With no input applied to the circuit, adjust R3 so that the LED just to the left of the center line is lit Power requirements are + and — 12 volts at about 25 milliamps and 5 volts at about 350 milliamps. Modifications The crystal frequency and counter preset value shown in the schematic are for the standard RTTY tones of 2125 and 2295 but can easily be changed for a dif¬ ferent pair of tones in the same neighborhood. The Basic program in Fig 4 com¬ putes these values from Parts List Semiconductors C7,8 20-pF, mica 2 x .26 IC1 NE565 $ 1.00 — 01-uF, disc ceramic (to bypass IC2 74221 1.25 + 5 volts to ground) 5x .10 IC3 7404 .22 Other IC4 7493 .52 ICS, 6 74191 2 x .85 XI 3.195-MHz crystal, FT-243 holder, IC7 74273 1.25 .01% tolerance, 32-pF load capaci- IC8 7410 .19 ty (available from Jan Crystals) 3.00 IC9 7485 .65 solder-tail 1C sockets, 14-pin 7 x .14 IC10-12 7445 3 x .69 16-pin 4 x .16 D1, 2 1N4148 or 1N914 diode 2 x .20 20-pin .29 21, 2 1N4735A 6.2-V, 1-Watt zener 2 x .30 perfboard 1.59 LED1, 2 MV57164 10-segment bar-graph total about $28.00 display (Radio Shack part number 276-081) 2 x 3.79 Obtaining Parts Resistors p/i-Watt unless noted) The only unusual components in this device are the 10-seg¬ R1, 2 Ik 2 x .07 ment LED bar-graph displays. As indicated in the parts list, R3 5k 15-turn trimmer 1.25 these are available at your local Radio Shack store. If there is R4, 5 220-Ohm, Vz-Watt 2 x .07 not a Radio Shack in your part of the world, use 20 separate R6, 7 4.7k 2 x .07 LEDs Instead. R8 330-Ohm .07 1 happened to use a crystal in an HC6/U holder. If you don't R9 470-Ohm .07 mind the size and appearance of an FT-243 holder (like Nov¬ RIO 82-Ohm .07 ices used in the old days) you can save a couple of bucks by getting a crystal with only .01% tolerance which is still more capacitors than adequate. Cl, 3 ,1-uF, disc ceramic 2 x .15 Everything else is quite ordinary and available from vari¬ C2 .001-uF, disc ceramic .10 ous dealers who advertise In the back of 73. The circuit C4 .047-uF, mylar™ .15 Is not at all critical and minor substitutions should not C5, 6 33-pF, mica 2 x .26 affect performance. 12 73 Magazine • March, 1983 CES INTRODUCES THE NEW 510SA “SMART PATCH The State of the Art Simplex Interconnect Communications Electronics Specialties introduces the CES 510SA “Smart” Simplex Autopatch, with many important new features never available before: * Three digit control codes with user programming. * A sophisticated toll restrict provides positive long distance lock out. • Time-out and COR activity timers with warning beeps and digital pro¬ gramming * Rotary or DTMF dialing. • Phone line in-use detector prevents interrupting a call in progress, and sends unique CW sequence • Phone ring detection logic enables unique CW sequence. • Digital programming of the sample rate and width, and noise gate sensitivity control, for easy interfacing with most radios. Simple and direct connections to radio. Options available: * Smart CW identifier with unique CW messages for each patch function. • FCC type accepted phone line coupler, • Special tone squelch kit to operate patch through repeaters. i» ' egg “flbwFa PIT CONNECT 1 ■ SHIRR T FATQit ; cm*CCfgk, CES The 510SA — the newest advance in interconnect technology, from the innovators at: Communications Electronics Specialties, Inc. Post Office Box 507 • Winter Park, Florida 32790 (305) 645-0474 * Toll-free (for orders only): (800) 327-9956 -4<e ALL IN ONI RTTY DEMODULATOR KIT FEATURES ON W3ARCI TOWER SUPPLY AFSK GENERATOR, PROVISIONS TOR LOOP SUPPL Y , ACT t VC F I LTIERS OR OPT tONAL TCRROIO FILTER, AUTMT AH T , ANT 1 SPACE pcb kit no n-tm «B «0 St A0. as RTTY SPEED CONVERTER CONVERTS *0,71 A too *PM BAUDOT CODE TO tOO WFM CODE FOR BAUDOT MACHINES REVERSES SAME FOR SENDING FEATURES SELCAL, BUFFER(NO AND INTERFACE FOR BAt/DOT PTR PCS KIT *31018 *09 03 BAUDOT ? ASCII CONVERTER MICRO BASED RTTY CONVERTER CONVERTS BAUDOT TO A SC I | FOR RECK I V* ASC 1 1 TO BAUDOT FOR TRANSMITING FEATURES SELCAL, BUFFERING A?® 1NTgftrACE,FOR ItO BAUD PTR PCS KIT 11 lilt lit.«S AUTOCW-tO KIT FEATURES ON BOARD TEN MINUTE TIMER WITH TTL. PLUS/MINUS It INTERFACE AND UP TO II DOT*. DA SMEW OR SPACES PCS KIT NO 33 1 7*1 4-1/ 2X6 Ul 13 ONE AMP POWER SUPPLY KITS BELOW 3 KITS 22 EDGE CON 4 - t/2X6 TU/LOOP SUPPLY PCS 2J-I72S *57 99 * a - 12V * *8 PCS 23-7.1 IS *35,90 LOOP SUPPLY PCB 23-2D2S *33.09 BELOW 2 KITS NOT ABOVE FORMAT + * 12V « FS 2-1/2 X S FOR PLL TU It PIN EDGE CONN.PCB 23-1716 *26.95 7 OR 5 TO 2 4V (SPECIFY POLARITY ANO VOLTAGE) PCB 23-05(2 2X4 1 / 0 *14,95 RTTY DEMODULATORS DM 60 ACTIVE OR OPTIONAL TORROID FILTER AUTOSTART. ANT 1 SPACE . S I MOLE SHIFT lUP OATEO ST 0 ON ONE BOARD 1 PCB KIT NO 21-1712 *59 03 DM 30 PLL TU DESIGN WITH ACTIVE FILTER TRONT END.PCB 23-1718 *29,95 AFSK GENERATOR FOR RTTY ROCK SOL 1D CRYSTAL CONTROLLED AFSK GENERATOR V ! RTUALLY DR 1 FT FREE TWO POPULAR SIZES specify size PCB KIT TO 21- 1 71 7 2- 1 /2X5 *28 *5 PCB KIT TO 21-1710 4 1/2X6 *11.95 ■ TU BANDPASS FILTER ■ ACTIVE FILTER AFH ■ PCS 33-3718 * 8.8$ 1 TGRHOI O F I LTTP CM** 9 ■ PCS : M 191 lit 9 S LOG! Ci'CWL i TCH PROBE rwrasut* NIOM speed PUUME 07* LOGIC LVL PCS 7*170* *i *.a* RS2 3 2 L t ME MONITOR MON! TORS 9 COMMON RS232 LINES W/LED PCS 23-3707 StS 55 1NTERFACE KIT 1 OPTO RS 7 13 JUST* ■ LOOP TO TTL 1 TTL TO LOOP ■ PCS 2 1 - t 722 *1 X *3 ■ 1 ONE KC SOURCE KIT I”""" ,,M AUS to AMPL t FEW KIT PC* 33-1731 * *.** TONE CONTROL RELAY PCS 21-*710 * 1.55 pulse generator f i rl PCS 2 3- 1732 S 1 »sl CABINETS f * * *, « ;; ■? ! * «! J-WJ 5 * is T *si 1 /‘i iiiiii iiil I«-SS1 7:1 \\ 5yj31 UNIVERSAL CIRCUIT BOAROS N«*R Slavs * r .AS, c DRY TRANSFER pj a-taiy GATAMAtf* SETS ggggggM TV AMD Ml Ft 21-0-9*8 *3 . * i • *•«*»*'* HAM RADIO * C* it -83*5 *2 . *9 ♦•"►w"""-* EXPER 1MENTER X 3 0<9«» *!.*• TEST a i no?, rtii jj-aa«t *2 *« . MARK a SWITOM If OH1 *2 . *0 ALPM * MJMRESFSl *1-49*3 C* *9 — 3/8 IN A3JPMMCT 2I-6068 *2 10 1/2 IN ALKMMET 31 -80** *2 SC TITLES FOR ELECTRONIC *3*713*. 2 1 -5583 1ILACK TITLES Si •« *4CTE» DIAL KIT 21-09** *» *5 0»TWCO*.T SPRAY SEALitaS GLOSS.21-4*7? *4 21 MATTE.i*--4L7* *4.15 OQNT MISS OUR IS SI CATALOG WITH OVER i 2 »® t tens senes u.ao i refundable ; ON FIRST ORDER} FOR OUR CATALOG. OR SEND A TWO STAMPS FOR OUR FREE FLYER ALL KITS INCH LOT PARTS FOR PRINTED CIRCUIT SOAR© ONLY . PLEASE ADO *2.88 FOR SHIPPING. AOO 55 ADDITIONAL FOR LWBERS fJ®ES 3? CMCeKS - MASTER CARO - VISA - COD Daytapro Electronics, Inc . 1030 H WE JMItl LN . AXUNGTON MfS ILL *600* ■■■■f 3?T-*7©-«S5S ^312 the tone frequencies and prints a chart (Fig, 5) indicat¬ ing the frequency range for each LED. Mark frequency = 2125 Hz, Space frequency = 2295 Hz, Counter preset =-3 (binary 11111101), Crystal frequency = 3.19532 MHz m m m ## m ## m m ## m m m ## ## ## s m m ## m ## ## Fig. 5. Output of program in Fig. 4 for standard tones of 2125 and 2295. — 1530 —1744 -2027 —2048 —2070 —2091 —2113 —2136 —2159 —2183 — 2207 —2231 -2257 —2282 —2309 —2336 —2363 —2392 —2421 —2681 —3003 Use and Conclusion The circuit requires a min¬ imum of 10 millivolts peak- to-peak for good tracking of the input signal Acceptable results can be obtained by connecting the tuning indi¬ cator directly to the receiv¬ er's speaker, but a cleaner signal will produce a more pleasant display. If your ter minal unit has a bandpass filter, connect this circuit after the filter, but before the limiter. If you den t have a bandpass filter, I suggest that you build one (see 73, September, 1977, page 38) or buy one such as the Flesher PS-170. It's simple, inexpensive, and makes a big difference when trying to copy RTTY under noisy conditions For a couple decades, most people agreed that a dual ellipse pattern on a CRT was the best way to see when a RTTY signal was tuned in properly Try this circuit and you might not be one of them anymore ■ 14 73 Magazine • March, 1983 Uncover Equipment for OSCAR Phase III Lurking in flea markets and junk boxes is everything you need to work OSCAR. K6KLY tells you what to look for and how to make it work. MHz, I would have to go down in frequency with the 28-MHz exciter. This was too confusing to try to handle while tracking a satellite, so I looked fur¬ ther and found in the data my friend sent me a sche¬ matic on a unit, model 4ET24A1 or All, which cov¬ ered 406 to 420 MHz. This was perfect. When you want 435 out and you are putting 28 MHz into a mix¬ er, you need a 407-MHz lo¬ cal oscillator to make the mixer work correctly. This 4ET24A1 was in the right fre¬ quency range. I started look¬ ing around at the swap meets and asking my friends who were into old FM equip¬ ment to keep an eye out for this model for me. I found out later that GE did not make too many of these A1 - type strips as compared with the A2-type strips. I finally found a 4ET24A1 strip at an FM-equipment auction and paid $20 for it, complete with all the tubes. After cleaning the dirt off the unit and making sure it had not been modified or robbed for parts, I started the conversion. My first task was to order a crystal from the ICM crystal company in R. Bentson K6KLY 3432 Lodge Drive Belmont CA 94002 T his article is for the ama¬ teur who wants to get on OSCAR Phase III inexpensive¬ ly. This can be done by con¬ verting a surplus GE UHF transmitter strip to a 435-MHz SSB mixer. With the upcoming launch of OSCAR Phase III, I was looking for a way to get on the 435-MHz input inex¬ pensively when I found some old GE Progress-line UHF transmitter strips at a ham flea market. I asked a friend who had a GE data file to send me a copy of the schematic, which he did. After reviewing all the material he sent me, I found that I had a 450-to-470-MHz transmitter, model 4ET24A2. It could be modified to be a mixer for 435 MHz, but it would be upconverting in frequency with the local oscillator frequency on the high side of the wanted out¬ put-signal frequency. Thus, the sideband signal would be inverted and when I wanted to change frequency in an upward direction on 435 Photo A. Overall view. Notice orientation of the crystal oven. 18 73 Magazine • March, 1983 Photo B. The coax from the 28-MH/ exciter is soldered to pin 4 of the last 6907 tube right under the variable capaci¬ tor, Cl 7 L Oklahoma City Since we need a 407-MHz local oscil¬ lator and the transmitter strip has a multiplier of 36, the crystal frequency needed is 11.3055 MHz. When order¬ ing the crystal, tell ICM that the crystal is for a CE model 4ET24A1. If your strip has a crystal oven or if you can get a GE crystal oven, tell ICM that the crystal will be used in a GE oven Modification The modification of the transmitter strip is very easy. First, remove the cover over the three large tubes in the caged-in area This is done by removing one screw next to the MULT-4 test point (see Photo A) Next, pull off the cover, starting with the end over the 2E26 The far end of the cover fits under a notch in the output filter Then, find Cl 71, the PA grid- tuning capacitor of the last tube, a 6907 Drill a 3/16" hole in the plate that Cl 71 is mounted on, halfway be¬ tween Cl 71 and the edge of the plate closest to the red test point, PA CATH (see Photo A). Next, using a small pair of wire cutters, cut off the capacitor and wire going to pin 4 of the 6907 tube. Pin 4 is right under C171. Prepare a three-foot length of RG-58-type coax by stripping off 2 inches of the outside rubber jacket, fol¬ lowed by one and one half inches of the coax braid. Next, remove V* inch of the inner insulation from one end of the coax. Prepare the other end of the coax to ac¬ cept a PL-259 coax fitting with the adapter ring for the RG-58 coax. Push the center conductor of the coax through the 3/16" hole in the plate and then wrap and solder the center conductor to pin 4 of the 6907 tube under Cl 71. Push the coax braid down around the 3/1 6" hole and solder the braid to the plate. Find the cover and, using a reamer or a set of drill bits, enlarge the vent hole in the cover that is closest to being right over where the 3/16- inch hole is in the plate when the cover is replaced Enlarge this hole to about V* inch, which is big enough to allow the coax to pass through it. Feed the coax through the hole and re¬ place the cover on the cage Solder a PL-259 with the adapter to the end of the coax cable you prepared earlier Find a 28-MHz rf choke coil such as a Miller RFC28 or Ohmite Z28 Solder this rf choke inside another PL-259 coax fitting One end of the rf choke goes to the center pin of the PL-259 and the other end goes to the outside rear edge of the PL-259. Using a UHF coax T-fitting, connect the new cable from the mix¬ er unit and the coax fitting with the rf choke inside it to the T-fitting. Later, the coax from the 28-MHz exciterwil! connect here also. Caution: The rf choke must be connected or dam¬ age could result to your ex¬ citer Check the rf choke with a VOM to be sure it is good, after soldering to the PL-259. Locate the socket the crystal oven plugs into and cut off the ground wires go¬ ing to pin 5 If there are any other wires going to pin 5, cut them off pin 5 also and solder them to ground points. Next, remove VI08, a 12AU7/ 6680 tube It will not be used. If any other tubes are missing, replace them per the following list: VI01 6BH6/6661 VI02 6U8 VI03 6CL6 VI04 2E26 VI05. 106 6907/6252 VI07 12 AU7/6680 Install the crystal in the GE oven between pins 4 and 8; then plug the GE oven in¬ to the 8-pin socket on the mixer. If an oven is not used, plug the crystal into pins 4 and 6 on the 8-pin socket Power Supply Power supply connec¬ tions are as follows: • Pins 1 and 2 are not used. Audio input for FM. • Pin 3 to ground Oscilla¬ tor-select channel 1 on All model. • Pin 4 is not used. Oscilla¬ tor-select channel 2 on All model • Pin 5 to +6 volts dc keyed on transmit, if anten¬ na relay is used • Pin 6 to 6 volts ac or dc fil¬ ament supply (not used if 12- volt filament supply is used). • Pin 7 to ground (filament- return lead for 6-volt fila¬ ment). (To 12 volts ac or dc if 12-volt filament supply is used ) • Pin 8 bias supply, —22 volts dc, adjustable. • Pm 9 B+ final, 450 volts dc, keyed on transmit • PinlOB-F multiplier, 300 volts dc, keyed on transmit. • Pin 11 B~f oscillator, 200 volts dc. This transmitter strip is normally used with a GE model 4EP4A power supply. This is the same supply that is used on GE Progress-line repeater stations. Since many older 2-meter and 440-MHz repeaters are go¬ ing to solid-state equipment, some of these power sup¬ plies are showing up at auc¬ tions and flea markets now The 4EP4A power supply is selling for about $30 to $40 in working condition See the photos of the complet¬ ed mixer mounted on the power supply to help you recognize the power supply at the flea markets. When using the 4EP4A power supply, the bias-sup¬ ply section will need to be modified to a voltage-multi¬ plier-type power supply in order to get the required - 22-volts-dc bias See the ARRL Handbook under power supplies for circuits. This requires only the addi¬ tion of two capacitors and two diodes. Here are the terminal- strip connections on the 4EP4A power supply: • Terminals 1, 2, and 4 not used Audio lines • Terminal 3: key to ground on transmit PTT line • Terminal 5: 250 volts dc "caution." • Terminal 6: to ground channel A select on model All • Terminal 7: ground • Terminal 8 6 3 ac fila¬ ment line • Terminal 9: one side of 110-V-ac input • Terminals 10 and 11: other side of 110-V-ac input • Terminal 12: not used. Channel B select on model All. • Terminal 13: not used Transmit light line • Terminal 14: not used. Rec mute line • Terminals 15 and 16: not used Spares. 73 Magazine • March, 1983 19 28 MHl INPUT Fig . 7. Schematic. If you have a model A1 unit and want to modify it to be an All-type unit so you can switch between 432 and 435 MHz at the flip of a switch, send me an SASE for a schematic. Install a 10-Ohm, 2-Watt resistor in another PL-259. This will replace the PL-259 with the rf choke for the bias setting in the alignment pro¬ cedure only. Alignment Replace the PL-259 with the rf choke in it with the PL-259 with the 10-Ohm re¬ sistor in it on the T-fitting. Connect a voltmeter (2.5-volt scale) to where the exciter 20 73 Magazine • March, 1983 should connect on the T-fit¬ ting. Turn on the power sup¬ ply and, after a few minutes warm-up, turn on the B + voltages. Adjust the bias supply until you just start to get a reading on the volt¬ meter. This indicates that the mixer tube is just start¬ ing to draw cathode current. Remove the B+ voltages and replace the PL-259 with the rf choke in it. Do not connect the exciter yet. Turn the variable resistor on the side of the cage to fully counterclockwise. Caution: Do not key the transmitter for more than 30 seconds at a time during the entire alignment procedure. Connect the negative lead of the voltmeter to the MULT-1 test point and the positive lead to ground. Key the B+ voltage and you should see a reading of about 1 volt. This shows the oscillator is working. Move the negative lead to the MULT-2 test point and ad¬ just the two transformers be¬ tween the 6U8 and 6CL6 tubes for maximum voltage on the voltmeter (approxi¬ mately .75 volts). Move the negative lead to the MULT-3 test point and adjust the two transformers between the 6CL6 tube and the end of the transmitter strip for the maximum volt¬ age (approximately 1.5 volts). Move the negative lead to the MULT4 test point on the top of the cage next to the 2E26 tube. Using a nonconductive screwdriv¬ er, adjust Cl26, the 2E26 plate-tuning capacitor, for maximum voltage on the meter (approximately 2 volts). Move the negative lead to the test point marked PA GRID. This is near where the new coax cable is coming out of the cage and the test point is green in color. Using a nonconductive screwdriv¬ er, adjust Cl29, the plate¬ tuning capacitor of the first 6907 tube, for maximum voltage by putting the screwdriver through the hole in the cage cover and down about an inch to en¬ gage the plate-tuning capac¬ itor. This is a very sensitive adjustment. With the nega¬ tive lead in the same place, adjust C171, the grid-tuning capacitor of the mixer tube, for maximum voltage on the meter. Cl 71 is the capacitor right next to where the new coax cable comes out of the cage cover. You should repeak C129 again. Connect a load to the out¬ put of the transmitter and connect the exciter to the coax T-fitting. You may want to connect a good UHF watt¬ meter between the trans¬ mitter and the load. I sug¬ gest a Bird wattmeter with a 25-Watt 200-500-MHz ele¬ ment. Connect the volt¬ meter with the negative lead going to ground and the positive lead going to the test point marked RF at the end of the cage area. Re¬ member, do not key the transmitter for more than 30 seconds at a time in CW mode or you could burn out R132, a 6.8k V 2 -W resistor connected to the screen pin of the mixer tube. Apply about 10 Watts of 28-MHz energy from your exciter and turn the BH- volt¬ ages on. Tune Cl72, the mix¬ er-tube plate-tuning capaci¬ tor, for maximum voltage on the meter. Be sure you use a nonconductive screwdriver and place it down through CONTROL IN BASIC FOR $169.95 No Need For -Assembly Language -Development Station -Expensive Test Gear . . Just a Terminal THE JARR Z8 BSC CONTROLLER INCLUDES: ‘Tiny Basic Monitor *RS-232 Serial Line *Timer/Event Counter *14 Parallel I/O Lines *4K User Eprom or Ram 'Expandability! 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JARR Z8 Controller Peripherals: 'Eprom Programmer/Cassette Interface (Model # Z8-ECI) *24 Line Parallel I/O Card (Model # Z8-PIO) *8 Channel Relay Control Card (Model # Z8-RCC) *2 Channel Temperature Sensing Card (Model # Z8-TSC) 'Breadboard Interface Card (Model # Z8- B1C) 'Speech Synthesizer Card (Model # Z8-SSC) Call, Write or Circle reader service number for detailed information on the JARR Z8 Con¬ trol Family. JARR CORPORATION “We Make Control Easy” 9127 Benavides SW Albuquerque, N.M. 87105 (505)831-0221 ^209 the hole in the cover of the cage to engage with Cl 72. This is a very sensitive ad¬ justment. Adjust the two controls on the output filter at the end of the cage area, by the antenna relay, for maximum voltage on the voltmeter or maximum out¬ put on the wattmeter. Go back and readjust Cl72 again for maximum output. I suggest that you take the output power right from the filter output connector with¬ out going through the anten¬ na relay. You should go back and adjust Cl 71 (PA GRID) again for maximum output. Turn R135, the variable resistor on the side of the cage, fully clockwise again. Increase the 28-MHz input power up to 20 to 25 Watts and you should get between 8 and 12 Watts out of the mixer at 435 MHz. This com¬ pletes the alignment pro¬ cedure. Operation You may connect the mix¬ er directly to the antenna or run the output of the mixer into an amplifier. I have used this mixer on 432 MHz with a 4CX250B amplifier to win many ARRL VHF con¬ tests in the Pacific Division. I have also used its prede¬ cessor, the A2 version of the transmitter strip, to make over 500 contacts on OSCAR 7, mode B. As you can see, this is an inexpensive way to get a 435-MHz SSB signal on the air to input OSCAR Phase III If you would like to use this same unit on 432 SSB, sub¬ stitute a crystal with a fre¬ quency of 11.2222 MHz and follow the same alignment procedure as before. I hope this article will help many more stations get on OSCAR that would not have be¬ cause of the high cost of new equipment ■ AT LAST! This service will be available nationally. Lab tested & time proven modifications professionally installed in your amateur Handy-Talkie 2M, 220, 440, MH2 transceiver by Henry Radios warranty technicians (KNOWN AS “A&W PRODUCTIONS”) HAVE ALL PL TONES AVAILABLE AT YOUR FINGER TIPS Outboard the dip switch! Have it neatly inlayed into the back cover of your Handy-Talkie making all 32 PL Tones Selectable at a moment's notice. $25 Got your own PL? Send it to us with your Handy-Talkie unit and we do the professional installation for you. $55 We wilf install a new PL and intay the dip switch into the back cover of your Handy-Talkie ready to operate. Send us your Handy-Talkie unit and a check or money order plus $3.50 for shipping and hand¬ ling payable to A&W PRODUCTIONS, INC. ForTEMPO units the dip switch is inlayed into the Push-to-Talk bar. The TEMPO S-15 will have the dip switch inlayed into the back cover. $45 We will install a NEW BATTERY BEATER in your TEMPO S-1, S-2, S-4, S-5 READY to operate Your New Battery Beater will use the same jack as the charger with no new holes and regulation circuits built into unit. Comes with Cigar Lighter Adapter svith internal luse. CONTACTAHW PRODUCTIONS FOR SPE¬ CIAL MODIFICATIONS YOU MAY WANT TO HAVE DONE. WE SPECIALIZE IN THE TEMPO HANDY-TALKIES. WE ARE AN OFFICIAL •TEMPO" REPAIR STATION ALL WORK GUARANTEED FOR 30 DAYS. SEND YOUR HANDY-TALKIE AND A CHECK OR MONEY ORDER TO. £\ A tPRODUCTIONS VV 3305 Pico Blvd,, Santa Monica JKr mr California 90405 <213) 828-9310 22 73 Magazine • March, 1983 Up and Coming: Direct-Broadcast Satellites Part II looks at the technical problems with communications at 12 GHz, which may be offset by the advantages. Timothy Daniel N8RK 7 Peabody Drive Oxford OH 4505 6 H ams love a challenge Why else would they erect 200-foot towers, en¬ dure cold mountaintops, or spend hours designing and building the ultimate receiv¬ er? The current generation of satellite television was a natural attraction for hams. Dedicated to doing more with less, electronics hobby¬ ists took on the TVRO chal¬ lenge and ended up creating a new home-entertainment industry Will the 1980s version of spacecasting, Direct- Broadcast Satellites (DBS), offer the same kind of op¬ portunity that beckoned TVRO pioneers like W5KHT, W6HD, K4AWB, and N6TX? The first part of this article, in last month's 73 , concluded that DBS holds a different kind of promise. The presence of large, technically-advanced companies is likely to dis¬ courage garage-style entre¬ preneurs. But what about the basement tinkerer? For him, DBS could be a challenge par excellence. This is not a "how to" arti- cle With DBS service planned to begin in the mid to late 1980s, it would be premature to start manufac¬ turing circuit boards But if you have already mastered the reception of present-day 4-GHz satellite signals, then consider taking on the chal¬ lenge of receiving 12-CHz signals from one of the "communications" satel¬ lites already in orbit or soon to be launched. Though no hobbyist has publicly an¬ nounced such an accom¬ plishment, an examination of the technical parameters will show that it is doable. Why 12 GHz? The choice of 12 GHz for DBS is not as baffling as it may first appear. Perhaps the most important reason behind 12 GHz is the need for small, inexpensive re¬ ceive antennas. Fig 1 shows that a dish, one meter in diameter, has roughly 30 dB of gain at 4 GHz, making it far too small for catching satellite TV signals on that band. The same dish has about 40 dB of gain at 12 GHz. A dish antenna's gain at a particular frequen¬ cy is proportional to the reciprocal of the wave¬ length squared, hence the increase of 10 dB A second argument for 12 GHz centers on the ability to use larger bandwidth* DBS proponents have sug¬ gested using signals with band widths as wide as 400 MHz The tenfold increase over 4-GHz signal band- widths holds some exciting possibilities. We might be treated to high resolution video and have our choice of several different audio channels! The technical attractions of the 12-GHz Ku-band are accompanied by some sub¬ stantial drawbacks. While much of the theory that works at 4 GHz holds true at 12 GHz, actual Ku-band components require another magnitude of precision Consider that a Ku-band sig¬ nal has a freespace wave¬ length that is less than one inch long. At these frequen¬ cies, hardline gives way to waveguide and suitable mi¬ crowave transistors, when available, cost in the hun¬ dreds rather than the tens of dollars. The Satellites DBS planners have laid the groundwork for a multi¬ satellite network Depend¬ ing on the proposal, there will be either three or four geosynchronous spacecraft, each one beaming to a separate region of the US The multi-satellite approach offers two advantages over DIAMETER IN METERS Fig , I, The gain of a dish antenna depends on the frequency of operation and its efficiency . A one-meter dish has 10 dB more gain at 12 GHz than it has at 4 GHz , provided efficiency remains the same. 26 73 Magazine • March, 1983 the current system of using a single satellite to blanket the country. First, by concentrating the satellite's signal on a smaller area, the cost and complexity of receivers can be lessened. When the an- tenna-size limitation, re¬ ceiver-noise performance, and the substantial path loss (approximately 205 dB) are weighed against the need for snow-free pictures, it be¬ comes clear that the new satellites must have an ef¬ fective radiated power far greater than the 30- to 35-dBW signals emanating from the 4-GHz satellite-TV birds Ku-band DBS signals will probably exceed 50 dBW and may even ap¬ proach 65 dBW A satellite capable of covering the continental US with that kind of signal would need close to 1000 Watts of out¬ put power, severely taxing the weight and power- supply limitations for spacecraft How do spacecasting transmitters generate high- powered microwave sig¬ nals? The answer is, very carefully. Traveling-wave tube amplifiers (TWTAs) are used, often in groups of two or more since the largest single unit can generate no more than a couple of hun¬ dred Watts. TWTAs, like amplifiers for ham radio, can fail at the worst time. The world's first direct- broadcast satellite, a Japa¬ nese experimental space¬ craft, had a shortened life due to TWTA problems. The push is now on to build high¬ er power TWTAs and im¬ prove satellite power gener¬ ation and cooling systems A second drawback to the single-satellite approach stems from biannual eclipses where the Earth pre¬ vents the sun's rays from reaching a satellite's solar cells. The satellite must cease transmitting or rely on heavy and expensive stor¬ age batteries. Rejecting the second alternative, it may be possible to place the sat¬ ellite in an orbital location that causes the blackout to occur at an hour when few people expect television ser¬ vice. But, as Harley Radin pointed out in the August, 1982, issue of Satellite Com¬ munications, such a location would be over the Pacific Ocean and impractical for east coast reception. With the single-satellite approach presenting prob¬ lems at every turn, planners have suggested a multi-satel¬ lite system where each craft would serve either one- fourth or one-third of the continental US. In arguing for the three-satellite ap¬ proach, Radin questions the need to match program times with the national time zones, a feature of the four- bird proposal. Instead, he suggests that using only three satellites will reduce the overall cost (satellites are expected to cost in the $100-million range) and make better use of the fre¬ quency spectrum and or¬ bital space. Should DBS become a money-maker, two addi¬ tional problems may devel¬ op. First, there is a limited number of ways to launch a satellite. Companies that counted on the European Space Agency's Ariane launcher are beginning to have second thoughts, and the best alternative, the US Space Shuttle, is almost completely booked through the mid-1980s If a large number of satel¬ lites do end up in orbit, it could present problems on the receiving end. Dish an¬ tennas are limited to a very narrow beamwidth—about 3 degrees—and may need to be rotated to receive signals from different satellites if motorized antennas prove too costly, an electronically- steered "flat" array could be introduced. Receiver Performance The plight of satellite-re¬ ceiver designers is best ex¬ pressed by the old saying, "He robs Peter to pay Paul " Fig. 2. The NHK Corporation of japan receiver, described in the january/February, 1982, issue of High Technology, uses direct conversion for low cost and a reasonably good noise figure. The tradeoff is between re¬ ceiver-noise performance and antenna size. It boils down to getting acceptable performance at a reason¬ able cost Acceptable per¬ formance is usually equated with a carrier-to-noise ratio (ON)of at least 10 dB While 10-dB ON may not be studio quality, it does ensure reasonably snow- or spark- lie-free pictures. DBS back¬ ers realize that their signals must compete favorably with conventional broad¬ casting and cable TV if they are to stand a ghost of a chance. For an in-depth look at the "rob Peter, pay Paul" di¬ lemma, read Stephen Gib¬ son's "How Big a Dish?" in the November, 1981, 73 . The culprit, as Gibson points out, is noise. In his article, "Direct Sat- ellite TV: The 12-CHz Challenge" ( High Technolo¬ gy, January/February, 1982), James Fawcette outlined three approaches to build¬ ing receivers. The first and perhaps most startling meth¬ od (shown in Fig. 2) is direct conversion, developed by the Japanese broadcasting giant, NHK. Akin to the simplest of ham receivers, the NHK design features a very low manufacturing cost. The signal goes from the antenna to a diode mixer via waveguide. There is no low-noise preamplifier stage. Fawcette cites an NHK claim of a 3.4-dB noise figure and 300-MHz band¬ width! A more traditional ap¬ proach to receiver design centers on a low-noise pre¬ amplifier circuit operating at 12 GHz. Like the current 4-GHz gear, several gallium arsenide (GaAs) field-effect transistors (FETs) are chosen because of their minimal noise contribution to form a preamplifier before the mix¬ er stage. GaAsFETs are, however, expensive and dif¬ ficult to use. Designers must pay close attention to the transition from waveguide to printed circuitry and use isolators to insulate the FETs from high swr These addi¬ tions can add to the receiver noise level and require a lot of individualized alignment The result, while expensive, should be better than that which is achieved with the direct-conversion approach Hobbyists who want to roll their own 12-GHz low- noise amplifier might want to consider the Mitsubishi MGF-1403 This GaAsFET, offered by at least one 73 advertiser, has a Ku-band noise figure of less than 2 dB. If your pocketbook per¬ mits, you might want to try for an even better noise figure. Manufacturers hope to avoid the cost of discrete GaAsFET front ends by fabricating GaAs integrated circuits. It is conceivable that the entire receiver could be on one chip. But until GaAs technology is refined and yield levels are boosted, receivers probably will employ hybrid circuitry using discrete front ends and integrated circuits for intermediate frequencies and signal processing Siemans A.G., a European 73 Magazine • March, 1983 27 Fig. 3. ANIK C3, a Canadian satellite , may be the first source of North American 12-GHz television broadcasting. Its foot¬ print will favor the northern United States. (Illustration from Satellite Communications, )uly, 1982.) Fig. 4. By using a 4-GHz TVRO dish, front-end module from Plessey Corp. and integrated circuits for the i-f and signal¬ processing stages , a 12-GHz receiver could be within the reach of many hobbyists. For dyed-in-the-wool do-it-your¬ selfers, there are suitable GaAsFETs for building a 12-GHz low-noise amplifier, and a Gunn-diode oscillator could be used with a passive mixer for the downconverter stage. corporation, already has in- consider getting in on the troduced GaAs ICs that ground floor. In late 1980 a would follow the mixer satellite built by Hughes Air- stage in a DBS receiver. craft was put in a geo- A number of companies synchronous orbit of 106 de- have finished prototype re- grees west. Operated by Sat- ceivers and are laying the ellite Business Systems groundwork for manufac- (SBS), the spacecraft has turing them in 100,000 quan- ten-Ku-band transponders tity levels. European and and is used by large corpora- Japanese companies like tions for high-speed data Plessey, Philips, Sony, NHK, communication, and Siemans seem to be in The all digital-time divi- the forefront. The late entry sion multiple-access data by American firms may be format will make it difficult due to the lengthy FCC- for hobbyists to receive any approval process and lack meaningful data from the of 12-GHz satellites for SBS signals, but what the testing. Just who will satellite does offer is a dominate the US market re- steady source for testing an- mains to be seen. The ability tennas and receivers. The to keep costs to a minimum transmitter footprint is said could be the deciding fac- to be in the 43-dBW range, tor. favoring the east central and western United States. SBS Getting Started recommends that users If you have read this far have a 5.5-or 7.5-meter dish, and like a challenge, then The first North American 28 73 Magazine * March, 1983 satellite to carry 12-GHz video on a regular basis will probably be ANIK C3, which was launched from the Space Shuttle last No¬ vember. (See Fig. 3.) Built by Hughes Aircraft for Telesat Canada, ANIK C3 has 16 12-GHz transponders that can accommodate data traffic or two FM TV chan¬ nels each. Telesat Canada plans to lease most of the transponder space to US companies, including sever¬ al interested in experiment¬ ing with direct broadcasting. Although ANIK C3 transmis¬ sions aren't as strong as future DBS signals, they should be easier to receive than those from the SBS satellite, especially if you live in the northern US. Finding suitable 12-GHz hardware will be the biggest problem facing pioneer tink- erers. One logical starting point is the dish antennas for 4-GHz TVRO reception. Some manufacturers even claim that their antenna will work just as well at the higher frequency. Whether you build or buy, remember that any dish antenna's per¬ formance is severely degraded if flaws in the sur¬ face accuracy exceed .1 times the wavelength of op¬ eration. For 12-GHz work, this means a tolerance of less than a tenth of an inch! When choosing an anten¬ na, pay close attention to the feed since it plays a big role in determining an an¬ tenna's efficiency. Remem¬ ber, the feedhorn designed for a 4-GHz satellite system is not what is best for 12-GHz experimentation. Choosing receiver com¬ ponents could be tough. If you have the necessary experience and test gear, you can roll your own 12GHz LNA. Otherwise, you'll have to scour the sur¬ plus markets or save up enough money for a com¬ mercial-grade unit. Engi¬ neering evaluation models are starting to become available; Plessey Corp., for example, offers a complete receiver front-end module. Hams who have experi¬ mented with Gunn-diode- based oscillators may want to try building their own local oscillator and diode mixer. The secret seems to be keeping the local oscil¬ lator's frequency stable and reducing unwanted side¬ band noise. Once you have perfected the preamplifier, local oscillator, and mixer stages, you can rely on prov¬ en intermediate-frequency and signal-processing de¬ signs. Fig. 4 shows one possi¬ ble approach at assembling a working 12GHz terminal. Does all this sound tike too much—-an impossible feat? Then think about the not-so-distant past when Bob Coleman K4AWB built a 4GHz satellite terminal using a few hundred dollars worth of surplus "junk" and a VTVM. For him, satellite TV was an opportunity rath¬ er than a roadblock and there was no need to wait for someone else to lead the way. Who will be the first to master the 12-GHz DBS challenge? Author's Note Since the legality of un¬ authorized reception of sat¬ ellite signals has not been decided, readers are urged to use discretion in de¬ coding or disseminating any information they might receive. ■ References Aviation Week & Space Technol¬ ogy, December8,1980. 73 Magazine, “How Big A Dish?,” November, 1981. High Technology, “Direct Satel¬ lite TV: The 12-GHz Challenge,” January/February, 1982. Satellite Communications, “Satellite Notebook 16,” July, 1982. Satellite Communications , “Sat¬ ellite Notebook 17,” August, 1982. Satellite Communications, “More Is Not Better: The Case for Three DBS Service Areas,” Au¬ gust, 1982. Mark Oman WAORBR 528 Deinm Court ft Collins CO <80525 The Fun-Vac: A Synthesis of Old and New This one-tube transmitter combines the circuits of the fifties with the technology of the eighties. It also keeps your coffee warm. Ed. Note: PC boards for this project are available from the author for $7.00 ppd. T he response to my series of articles on Fun home¬ brew gear has indicated that there is a diverse group of people butlding gear today* Without question, the one central and overwhelming theme of the response has been about simplicityl The emphasis in home¬ brew products has changed dramatically over the years Nearly everyone has as his main rig a factory-built transceiver which is good on today's crowded bands* However, the lure of home- built gear seems to entice even more hams than be¬ fore, quite possibly because they are building for tun and challenge and not because of necessity or lower cost The "Fun-Vac," the 2-to-5- Watt 40-meter CW transmit¬ ter described here, is in re¬ sponse to requests from both old-timers and new¬ comers for a different kind of transmitter—a tube trans¬ mitter Believe it or not, I did say tube (hence the "Vac" for vacuum) What a chal¬ lenge it was to design and build a tube transmitter based on the Fungear prin¬ ciples of no adjustments and all parts coming from Radio Shack! It really was fun to return to the early days of my ham career (mid¬ sixties) and work with vacu¬ um tubes. However, modern construction practices and the 1980s philosophy of home-brew gear were used in designing this very simple, very reliable, one-tube, 40-meter transmitter Why use a tube? First, it is nostalgic for the many who entered the ham-radio field before the seventies. Second, many older hams have stopped building due to the extinction of tube cir¬ cuits, This project hopefully will bridge the gap for them between current transistor¬ ized gear and the older, massive, point-to-point con¬ struction-type tube rigs which required hours and hours ot wiring, sheet-metal work, and critical adjust¬ ments Third, many new hams have virtually no experience or education regarding tubes, and a simple one- tube project is a good way of discovering our tube heri¬ tage (which may help in un¬ derstanding transistor cir¬ cuits). Fourth, it is just plain fun to integrate the fifties and sixties home-brew ideas with the home-brew philosophy of the eighties! I firmly remain, however, a proponent of state-of-the- art gear Transistors are much more efficient with their use of power, and 12 V 32 73 Magazine • March, 1983 to 24 V is much, much safer to work with than 300 V! Objectives My main objective with this rig was to design a tube transmitter that fit in with the entire Fun series of sim¬ ple, low-cost gear It would be worthwhile to review the entire series, particularly the article on the Fun-Mitter (73 Magazine, February, 1981; see also "Fun-Equipment Revisited" in the January, 1983, issue). The Fun-Mitter is a 5-Watt, 80- through 15-meter solid-state trans¬ mitter The characteristics of the Fun gear are: small size, simple construction, no adjustments, and all parts available from Radio Shack. The objectives of the Fun- Vac were, in addition • PC board construction with the same size board as other Fun gear(2!4 " X 3") • a cost less than $25 • easy assembly • 2 to 5 Watts output All of these objectives were met Even a 300-volt power-suppiv design is in¬ cluded here. Circuit The basis of the transmit¬ ter is a 6BQ5, a 9-pin minia¬ ture beam-power pentode available from Radio Shack. The 6BQ5 is a rugged device capable of dissipating 10 to 15 Watts under a 50% CW duty cycle The 6BQ5 functions as both oscillator and amplifi¬ er The oscillator uses FT243 fundamental crystals in a Pierce configuration Cl and C2 provide feedback be¬ tween the control grid and cathode. The oscillator is keyed by breaking the cath¬ ode-to-ground connection. LI, R2 t C3, and C4 comprise a wave-shaping circuit to eliminate clicks and sluggish starting of the oscillator The big power-waster of this circuit (as with all tube circuits) is the filament A tube works by heating the cathode to jar electrons loose from its specially- coated surface. This is the function of the filament (or heater) which actually glows orange, warming the cath¬ ode. The 6BQ5 requires 6.3 V at .75 Amps applied to the filament. (This is about 4'A Watts, or as much as the total output power of the tube!) The plate operating volt¬ age (250 to 300 V) is applied through plate choke L2 In order to meet the objective of using Radio Shack parts, L2 was required to be 100 uH This is somewhat less in¬ ductance than the normal value of plate choke, but ab¬ solutely no problems were encountered Rf output is taken from the plate through C7 and applied to the match¬ ing network, L3, L4, C8-C10. This network serves two pur¬ poses and is different from the norm in tube circuits Its first purpose is to match the impedance of the plate (about 2500Q) to a 50Q antenna load. This is accom¬ plished by C8, C9, and L3. The second purpose is har¬ monic filtering, which is ac¬ complished by both sec¬ tions The matching network is actually two pi networks combined One matches 2500Q to 50Q and the other is a 50Q-to-50Q match Although the pi network is a standard method of matching impedances in a plate circuit, this network is different in one aspect: it is fixed-tuned Normally, a variable-load capacitor would be used at CIO to ad¬ just for an antenna load of between 30Q and 70Q All of today's equipment is fixed- tuned for a 50Q antenna load, and with antenna transmatches in abundance, the necessity for a variable load control no longer ex¬ ists. Another norm in tube circuits is to use a vari- able-tune-control capacitor at C8 By designing for a somewhat lower Q, this capacitor was made fixed No tuning adjustments are required! The entire trans¬ mitter can be built on a small PC board just like to¬ day's solid-state rigs, with no Photo A. Front view of the Fun-Vac . bulky front-panel variable capacitors! The matching inductors, L3 and L4, are made from Ra¬ dio Shack 10-uH chokes as has been done with al I previ¬ ous Fun gear By removing the required amount of turns, the needed induc¬ tance is easily obtained These chokes make for small and easy-to-make induc¬ tors—again, something quite unusual in a tube circuit The LED, CR1, was includ¬ ed to provide a method of monitoring plate current. The LED is wired in series with the plate voltage and lights brightly when the plate current passes through it Because of the very low voltage drop across the LED, no power is lost in it. (It also is fun to use a modern solid- state device to monitor cur¬ rent in a tube rig!) Power-Supply Circuit The Fun-Vac operates from two power-supply volt¬ ages, 6.3 volts ac and ap¬ proximately 300 volts dc. The 6.3-V-ac filament volt¬ age is somewhat critical in value, but the high voltage can vary between 200 and 350 volts. These voltages can be obtained from an ex¬ isting supply or a supply can easily be built and incorpo¬ rated into the same box with the Fun-Vac PC board I chose to include power sup¬ ply and Fun-Vac in one box, as shown in Photo B. How¬ ever, the voltages can easily be "stolen" from a tube- transceiver supply or a simi¬ lar supply by using the ap¬ propriate connector on the Fun-Vac chassis. A simple circuit to obtain the needed voltages is shown in Fig. 2. An attempt was made to design a supply that also met the Fun gear objective of obtaining all parts from Radio Shack. The design shown meets that ob¬ jective although it repre¬ sents a rather unorthodox approach. By using two step-down transformers Fig. 2. Fun-Vac power-supply schematic . 73 Magazine • March, 1983 33 FROM FUNOSCILLATOR PHONO JACK >- LA: 3 TURNS WOUND OVER ENTIRE BODY OF LB ? S: SPOT SWITCH (275-326) TO PC BOARD CRYSTAL CONNECTION }: SI8 FUNVAC SWITCH I50K 1/2 W 271-0*7 CRI 12V ZENER 276-563 CR2 12V ZENER 276-563 RELAY control (VOLTAGE TO FUNAMP Fig. 3. Using the Fun-Oscillator and Fun-Amp with the Fun-Vac. The Fun-Amp relay-control voltage is needed due to the methods used with the Fun-Mitter . Mount resistors R1 and R2 very close to SI. back to back, a secondary ac voltage of 117 volts is ob¬ tained. This is possible be¬ cause of the relationship of the turns ratio of the trans¬ former. (It is an old trick, used in the past to obtain a negative bias voltage for tube rigs.) The 117 volts ac is applied to a full-wave volt¬ age doubler which provides 2.8 times the rms voltage (2.8X117) to provide about 320 volts dc. This arrangement is not extremely efficient and the parts shown do not provide a very "stiff' high-voltage supply. This results in less power output than the tube Fig. 4. PC board. TO 6.3 VAC (FILAMENT) TO Jl (KEY) — R2— Li cl c ? h C2 I C! L3 ! I C7 — C8— 7 8 9 - <4 ^C5 C6 -R3- 1 C9 I I CIO L2 is actually capable of, but the parts are easy to obtain and the circuit is easy to build. The transformer wind¬ ings must be connected in phase in order to add volt¬ ages. If, after the supply is wired, no ac output occurs at T2 secondary, then re¬ verse the connections at T1 secondary. Using the Radio Shack parts shown does make the power-supply portion of the Fun-Vac nearly as expensive as the rf circuitry. It may be possible to substitute for the filter capacitors by using the junk box or buying from a local TV repair shop. A val¬ ue of 50 to 100 uF will work fine, and even less capaci¬ tance can be used at the ex¬ pense of less filtering and regulation. Also, the trans¬ formers can be replaced by any transformer that can supply the needed voltages. L4 TO SIA (RF OUTPUT) TO CRYSTAL SOCKET TO B + (HIGH VOLTAGE) Construction Before beginning the ac¬ tual construction of the Fun- Vac, a review of safety prac¬ tices with high voltages is necessary. The high voltage used in this circuit can be lethal! When voltage is ap¬ plied, never touch anything on the PC board or in the box. Always keep one hand away when making any measurements. Using PC board construc¬ tion for the Fun-Vac greatly simplifies building the rig and makes it as simple to build as solid-state gear. PC board use also eliminates wiring errors. All of the parts except the jacks, switches, and the plate-current LED are mounted on the board. The 6BQ5 tube can be soldered directly to the PC board without a tube socket. This makes the load¬ ed board shorter, which is important in mounting. If you purchase a new 6BQ5 from Radio Shack, there should not be a need to re¬ place the tube, rendering the usual practice of using a tube socket unnecessary. FT243 crystals and sock¬ ets can be obtained from a number of sources and are quite inexpensive. Mount the socket on the front panel to facilitate easy changing during operation. The plate-current LED should be mounted in a hole on the front panel and glued in place. Route the wires to the LED carefully since these wires carry the high voltage. If possible, don't leave bare wire exposed anywhere in the high- voltage circuit. The sheet-metal work necessary with the Fun-Vac is much simpler than it was in a comparable tube trans¬ mitter from fifteen years ago. Before, heavy metal was used, often even steel, and it had to be punched for tube sockets, variable ca¬ pacitors, and large coils. Us¬ ing the Radio Shack cabinet makes sheet-metal work easy. The light-gauge alumi- 34 73 Magazine • March, 1983 Fig. 5. Component layout. Photo 8. Inside view of the Fun-Vac. Photo C. PC hoard for the Fun-Vac. num is easily worked using a hand drill and a knife Mounting of the PC board in the cabinet should be done with care If the Radio Shack cabinet is used, it will be necessary to mount the board at right angles to the case, as shown in Photo B If desired, the bottom of the board can be covered with electricians tape to keep fingers from accidentally touching the high voltage The wiring used is not par¬ ticularly critical. The fila¬ ment wire should be at least 22 gauge. All rf wiring should be with coax, and RG-58 will work fine. After the power-supply section is completed, do not connect the voltages to the Fun-Vac PC board This will be done after proper opera¬ tion of the supply is vended Vfo and Amplifier Use The Fun-Vfo (2/82) and Fun-Amp (5/82) can be used with the Fun-Vac easily Us¬ ing the Fun-Vto requires the addition of a step-up trans¬ former to match the output impedance of the Fun-Vfo to the high imp€*dance of the control grid of the Fun- Vac. The vfo signal is ap¬ plied to the crystal socket. A switch can be used to switch between vfo and crystal Details of the im¬ pedance transformer and 36 73 Magazine • March, 1983 possible switching arrange¬ ment are shown in Fig 3 The Fun-Amp is easily added to the Fun-Vac. It re¬ quires a control signal to control the Fun-Amp relay; this can be brought out of the Fun-Vac through a pho¬ no jack. The Fun-Amp will provide around 20 Watts of output power from the Fun- Vac. Details of the Fun-Amp use are given in Fig. 3. Adjustment The safety factor cannot be overemphasized . During adjustment, with the case open, it is very easy to ac¬ cidentally touch the high voltage Whenever the cover is off, always be aware of where the high-potential voltage points are. The only adjustments of Fun-Vac Parts List (with Radio Shack numbers) Cl 4.7 pF 272-120 C2 100 pF 272-123 C3 .01 H F 272*131 C4 .47 m F 272-1071 C5 .005 350 V 272-1051 (Two In series) C6 .005 350 V 272-1051 (Two in series) C7 .005 350 V 272-1051 (Two in series) C8 94 pF 100 V 272-121 (Two 47 pF in parallel) C9 940 pF 272-125 (Two 470 pF in parallel) CIO 470 pF 272-125 CR1 LED 276-041 J1 Phone jack 274-252 J2 SO-239 ant. jack 278-201 J3 SO-239 ant. jack 278-201 Lt 100 uH choke 273-102 L2 100 uH choke 273-102 L3 Remove 7 turns from 273-101A choke L4 Remove 17 turns from 273-101A choke R1 47k, 1/4 W 271-1342 R2 100, 1/4 W 271-1311 R3 15k, 1 W 271-040 (Two in parallel) SI DPDT 275-1546 VI 6BQ5 Y1 7-MHz FT243 crystal Case 270-253 the Fun-Vac are really not adjustments at all, they are checks to ensure proper op¬ eration If possible, obtain a voltmeter capable of mea¬ suring ac and dc voltage of greater than 300 V At this time the two power-supply voltages should not be hooked up to the Fun-Vac With the power on, carefully measure the high voltage. The reading should be be¬ tween + 250 volts and + 350 volts. Next, connect the fila¬ ment-voltage wire to the PC board. Switch the voltmeter to the ac range and measure the filament voltage. It should be around 6 3 V If it reads more than 7 volts ac, a filament-voltage dropping resistor may need to be add¬ ed— R = (V -6.3)/ 75 At this time, with 6 3 V at on the fil¬ ament, there should be an orange glow from the tube, indicating that the tube fila¬ ment is working. Next, w ith power off, con¬ nect the high voltage to the circuit board through the front-panel plate-current LED Also, hook up a dum¬ my load to the antenna con¬ nector and insert a key in¬ to H Turn the power switch on and wait at least 30 seconds tor the filament to warm up Cl Fun-Vac Power Supply Parts List (with Radio Shack numbers) Each capacitor should be about 25 mF at a C2 voltage rating of at least 200 volts. This can CR1 be done by wiring four 272-1044 100-^F 50-volt caps in series for each. 400-V, 1-Amp diode 276-1103 CR2 400-V, 1-Amp diode 276-1103 R1 103 Vt W 271-001 R2 10G Vt W 271-001 SI SPDT switch 275-324 T1 Transformer, 12.6 V ac, 1.2 Amps 273-1505 T2 Transformer, 12,6 V ac, 1.2 Amps 273-1505 Fuseholder 270-365 1/2-Amp fuse 270-1271 Line cord 278-1255 With a 40-meter crystal in¬ stalled and the receive/ transmit switch set to trans¬ mit, close the key The front- panel plate-current L i D should light, indicating the plate current of around TO to 50 mA This indicates proper operation If a watt¬ meter is connected between the antenna jack and the dummy load, a power out¬ put of between 2 and 5 Watts should be observed, with the key closed For vfo operation, merely substitute the Fun-Oscillator for the FT243 crystal and proceed as above If problems are encoun¬ tered. a logical analysis should reveal the trouble If power-supply voltages are correct, then the problem can be isolated to the Fun- Vac PC board Measure the voltages at the various points around the board cor¬ responding to the indicated voltages on the schematic If your voltages vary signifi¬ cantly from those given, then check and recheck for improperly soldered con¬ nections, miswiring, or faulty components. Operation Using the Fun-Vac for contacts is almost as much fun as building it! As with the Fun-Mi tier, a 50Q reso¬ nant antenna must be used. This usually will provide an swr of 1 to 1 which is a good method of monitoring load conditions With today's sta¬ tions, the necessary 50Q- load antenna probably al¬ ready exists due to the prev¬ alent use of transmatches. Allow the Fun-Vac to warm up for at least 30 sec¬ onds before use. In some ways, the soft warm glow of the tube as you operate is a reassuring feeling— reminis¬ cent of days gone by. Inci¬ dentally, the heat generated by the soft, warm glow of the tube literally will keep your coffee warm —a side benefit of the Fun-Vac To operate, merely select the correct operating fre¬ quency, switch SI to trans¬ mit, and begin keying. The receiver is connected to the receive antenna jack on the rear panel of the Fun-Vac.. The low power of the Fun Vac eliminates the necessity of a sidetone or receiver mute control since the ac¬ tual signal can be listened to on the receiver without overloading Conclusion The Fun-Vac provides a means of experimenting with tubes using modern methods, (If other band cov¬ erage is desired, refer to the Fun-Mitter articles) It's amazing how simple those massive old rigs can be Happy nostalgia!® GET COMPETniUE...GET DATONG! World’s finest accessories for the serious operator FL-3 = FL-2 + AUTO-NOTCH That’s right! What you have been asking for is here. Combin¬ ing the knife-edge selectivity of the FL-2 with the unique auto-notch feature of the FL-1 has produced our most effective multi- mode audio filter ever. Double-notch capability (one manual and one auto) for when that se¬ cond whistle appears. ASP - RF SPEECH PROCESSOR Installs in MIC line, RF clipping with speech shaping from 0 to 30 db in 6 db steps. Frequency response 400-3400 Hz ± 3 dbs. Total harmonic distortion at 1 KHz, at 30 db clip level — 1/2%. Accepts Hi or Lo im- pedence MICs. RFA-RROADRAND PREAMPLIFIER Strengthens signal re¬ ception of any transceiver/ receiver between 5 and 200 MHz. 9 db gam + low noise and 3rd order inter¬ cept of ~f 20 dbm RF switched Requires 12 dc @ 40 ma “G4MH MINIREAM ANTENNA" High performance, miniature anten¬ na has 6' turning radius. Built from quality materials for durability in the worst weather. IT element/5' boom. Weighs 14 lbs Operating frequen¬ cies: 20m. 15m, 10m. Kit “$139.95. • ALL DATONG PRODUCTS CARRY A 90 DAY WARRANTY • VISA-MASTERCARD WELCOME D AD lATO fMG on- t oM ics am Technical Products Corp. ^329 877 S. Adams Road P.Q. Box 62 Birmingham, Ml 48012 Phone (313) 644-5698 * March. 1983 38 73 Magazine Adventure in Sarawak Two DXpeditioners journey to the land of headhunters — and send a signal to the rest of the world. Kirsti jenkins-Smith VK9NL PO Box 90 Norfolk Island Australia 2899 lim at the rig. 42 73 Magazine • March, 1983 S arawak—the land of the Hornbills, in Northwest Borneo: It is a country of rain forests, rivers, and unex¬ plored areas. It is also a country of culture, arts, and handcrafts. Once the do¬ main of headhunters, Sarawak is now the largest of Malaysia's 13 states. So reads the caption on our QSL card from this oper¬ ation. The idea of visiting Sarawak during our holidays came to us early in the year. It did not seem to appear on any of the guided-tour brochures which came our way, and as we are not very tourist-minded, this made us look into the possibility of visiting and also doing some operating from there. There were no problems regarding travel and visas. Modern jet-liners connect with Kuching daily, and for us it was a matter of travel¬ ing Norfolk Island —Syd¬ ney—Singapore—Kuching. We had contacted Paul 9M8PW beforehand and he was most helpful in arrang¬ ing accommodations for us in the Anglican Church hostel. Here we were able to rent a small flat and thus be independent. This is necessary in this sort of venture since not ev¬ eryone appreciates their houseguests staying up through the night making cups of coffee and shouting into a mike. And hotel ac¬ commodations—apart from being expensive—present a problem in that hotel meal¬ times do not coincide with the times of the day when band conditions are down to nothing and it is most suitable for the operators to take a meal. In fact, they have a way of serving dinner and breakfast at peak operating times. So the hos¬ tel was ideal in many ways. It also was central and close to shops and restaurants. We had applied for our li¬ censes months before, and on arrival in Kuching were informed that these would be issued for the period of time we were visiting the country. This was good news indeed, as we were well a- ware of the reluctance to issue guest-licenses in Malaysia. It now was a matter of proceeding to set up our op¬ erating quarters and station. Jim got busy with the multi¬ band dipole which we even¬ tually were able to hang from under the roof of the building across the yard and make fast in a suitable tree. Paul had a beam he was not using which he lent us. It needed some repairs and handiwork done to it, and Jim got busy with this chore. At the same time, we were making enquiries as to where we might be able to obtain a steel water pipe to mount the beam on. We were met with a strange re- The battery setup after the lightning strike. Our water-pipe antenna , overlooking Kuching. luctance which we did not get to understand until over a week later, hut we decided to find pipe for ourselves. Nowhere did we see such an item, but after making our way through nooks and crannies in the shopping center, we finally found a shop where they said that they could help So across the street we went; a large storage room was unlocked, and there within were literal¬ ly hundreds of pipes. We se¬ lected a 20-foot piece and asked if it could be brought home to us. "No, no (with an apologetic smile)!" Well, by this time we thought we had wasted enough time on the project and the main thing was that we had the pipe within our reach So reso¬ lutely we picked it up be¬ tween us and paraded home through the streets to the vast enjoyment of the lo¬ cals. Once home, there were no more difficulties. The caretaker and one of the gardeners came along, of¬ fered to help us put it up, and the job was done in minutes. Later on, visiting the po¬ lice museum at Fort Mar- guerita, we realized why we had experienced some re¬ luctance in "operation water pipe " There on dis¬ play were several guns and mortars homemade from water pipes which had been confiscated from terrorists. We hasten to say that Sara¬ wak is a well-ordered and safe state at present, but ob¬ viously they have learned from history and are not tak¬ ing any chances We were now in business. We had decided to concen¬ trate on CW contacts as this mode was more needed from East Malaysia We did not have a thundering suc¬ cess that first day We had the dipole only up to the first floor and there was a CW contest on that week¬ end. So, unless people were looking for us, we could not break through on the busy bands. We also found that propagation was not the best to America and Europe, but was excellent to Asian countries and the Pacific. It took a couple of days to get the antennas erected to their full potential, but gradually we worked our way into the rest of the world. Openings to America and Europe continued to be a bit tricky, but with cooperation from the people calling, we were able to work pileups giving such reports as 529 and even 429. This is not possible unless there is some restraint on behalf on the ones awaiting their turn. The bands usually opened prop¬ erly for a few hours from midnight on and the path would be open to the USA and Europe, which created some tremendous pileups. The Europeans are not known for their patience and restraint in these cir¬ cumstances, so it was plain hard work It was, on the other hand, a pleasure to work a pileup of JA-boys Their operating manner is above reproach Anyway, we continued in this manner for the first week and were looking for¬ ward to the weekend when lots of people who have only weekends available for their hobby would be around. On Saturday after¬ noon, however, there was a tremendous flash of light¬ ning simultaneous with a deafening crash of thunder Jim was outside making im¬ provements to the antennas and was holding the 40-me¬ ter dipole in his hand at the time. It was lucky that he es¬ caped being sizzled That the power supply to the rig died instantly is really of minor importance in com¬ parison However, we were effectively shut down for 24 hours while we tried to re¬ pair the power supply. We were able to buy some of the components we knew had blown, but after struggling until 2:00 am Sun¬ day replacing these and still not making it work, we real¬ ized we were going nowhere unless we could gain access to a good ham shop With one resident ham in the country, the shops did not stock ham gear We finally arranged to hire a battery and charger which gave us 25 Watts, and by borrowing Paul's linear, we could bring this up to 100-150 Watts and continue operation The second week was mostly a continuation of the first week The number of QSOs crept upwards, and it was nice to meet old friends in the pileups. We had real¬ ized by now that checking into nets we usually checked into from Norfolk Island was virtually impossi¬ ble due to lack of propaga¬ tion at those specific times. So, we carried on with the pileups, still concentrating on CW, Jim with his fancy electronic keyer and I with my old faithful straight key. (I want to go down in history as the only DXpeditioner stubbornly sticking to a 1940-model straight key in 1982, hi.) We had by now been in Sarawak long enough to have spent time sightseeing and getting the feel of the place. Kuching is a fascinat¬ ing city with all its old-world charm intact. There are the old narrow streets lined with shops absolutely spilling goods of every description out onto the footpaths There were the handmade souvenirs made from local materials, and there were 73 Magazine • March, 1983 43 The author stayed at the rig when the aerial fogging to kill A typical shop in Kuching, mosqu itoes hega n. the friendly people, hard¬ working and cheerful. We spent many hours in the museum, learning a lot about the culture and history of the country. And not far out of town was the jungle, practically undisturbed. We also were aware now that the dreaded dengue fever was around. We swallowed anti-malaria tablets against malaria and kept our fingers crossed against cholera, but as far as dengue was concerned, we just did our best to keep the mosquitos at bay by spray¬ ing the rooms and burning mosquito-coils through the night. We still became covered with bites and just hoped it was not the dengue-carrying kind of mosquito that had feasted on us. The authorities had an on¬ going eradication scheme against this particular beast, and one rule was that if someone contracted dengue, every house in the neigh¬ borhood was treated with a sort of spray. So it was that on one fine evening there was a whirring sort of noise outside, and the next thing we knew the flat started filling up with a dense fog. (See photo of the author at the rig at the beginning of the fogging process.) It got so thick that we could not see at all at a distance of 2-3 meters. We could not breathe, either, so we agreed there was a limit to how devoted one can be, hi, and we would not be much use to our fellow ama¬ teurs if we suffocated. There was also the fact that we did not know exactly what the fog contained and just how harmful it might be to humans. So it was a matter of QRT and escape down¬ town for a meal. (The frogs were particularly noisy that night. We think they were kicking up a row because their favorite food had been done away with!) All things come to an end, and so also did our stay in Kuching. We had settled in properly and were most re¬ luctant to leave. We took one last look out the win¬ dow at the view of tile-cov¬ ered roofs, charcoal smoke rising amongst them, and one last admiring look at the orchids growing in a hedge along the footpath. Then a quick good-bye and au revo/r to Paul's family and Paul drove us to the airport. We really had not wanted to go, but we had received the good news that we had been successful in charter¬ ing a vessel, the Cheynes II, for our January, 1983, Heard Island DXpedition. So, al¬ though we had an unforget- able holiday and made 10,500 QSOs in Sarawak, we knew that loads of work regarding our Heard Island trip would be waiting for us at home and we just had to move on. Afterthought: It was very hot in Kuching. There never seemed to be any breeze to relieve the heat of the day. And as the bands closed in the middle of the day, this was when we emerged out¬ side for sightseeing and shopping. Strange how that old tune kept coming into my mind all the time: Mad dogs and Englishmen go out in the midday sun It could just as well read: Mad dogs and ham-band-fans go out . . etc.! ■ PROGRAMMABLE CTCSS ENCODER All 37 EIA Tones • Quartz Accurate Less than 1 inch square AVAILABLE FOR IMMEDIATE DELIVERY For more information call TOLL-FREE (800) 828-6884 ^218 NY: (800) 462-7242 CANADA: (416) 884-3180 FERRITROHICS n^gara fYlIs nv 1430 , MOBILE DATA SYSTEMS (716) 282-7470 TLX 64 6303 44 73 Magazine * March, 1983 Put 2 Meters in Your Shirt Pocket Radio Shack's Pocket Weatheradio makes a dandy 2-meter receiver. A few quick modifications will get it right on target. tester Kolb K3PIG PO Box 161 Lebanon OR 97355 ^\uality, simplicity, and low price make this shirt-pocket two-meter re¬ ceiver surpass anything on the market, if indeed such a compact gadget with these features is available The heart of the FM moni¬ tor is a "Pocket Weathera¬ dio" which is listed in Radio Shack's 1982 catalog for $12 95 and measures less view rnm parts sjche than 4 x 3 X 1 y< inches. Originally covering the 162 40-162.55-MHz weather- band, the state-of-the-art cir¬ cuit features of the Weath¬ eradio make it an ideal choice for conversion to two-meter FM. The frequen¬ cy modification consists of simply adding three 5-pF ca¬ pacitors across three induc¬ tors. This modification alone makes a dandy moni¬ tor, but the addition of a simple squelch circuit puts icing on the cake. Weatheradio Circuit The schematic included with the radio shows a sim¬ ple, well-designed circuit consisting of a zener-regu- lated, three-transistor front end followed by a 4 5-MHz ceramic filter and a total of two ICs for i-f amp/FM de¬ tector and audio amp The local oscillator is tuned by a varicap diode, and a 10k pot serves as a tuning control. The rf amp is not variably tuned since the small fre¬ quency range does not re¬ quire it. Selectivity and fre¬ quency stability are excel¬ lent for a tunable VHF re¬ ceiver, but don't expect top sensitivity Disassembly Snap the plastic cover off the Weatheradio case. A cardboard insert over the circuit board is firmly glued to one of the electrolytic caps. Carefully remove this Fig. 1. Weatheradio compo¬ nent layout 46 73 Magazine • March, 1983 TO CENTER TAB OF VOLUME CONTROL 1C2 -^\u * R3. R4 OPTIONAL : R4 * I00K iOK ■ r - Jr 1 m ■ AUDIO (6 TURNS) 0!, 02 GERMANIUM DIODES; IN60, IN 34, ETC. 2to» Fig . 2 . Hybrid squelch circuit insert from the cap to have a look at the board The card¬ board insert can be cut off permanently except for the nine-volt-battery area With a miniature phi I lips screw¬ driver, remove the two screws holding the volume and tuning knobs to their shafts. Also remove the two screws from the circuit board and the one anchor¬ ing the whip antenna. Re¬ move the whip through the top of the case and take out the circuit board Unsolder the leads from the speaker itself to avoid errors when reconnecting. Use small clip leads to the speaker while testing Frequency Modification All that is required to cov¬ er two meters is the addition of a 5-pF capacitor (parallel) directly across inductors LI, L2, and L4. The locations of these coils are shown in Fig. 1. No existing parts are re¬ moved. After soldering these caps into place on the foil side of the board, recon¬ nect the speaker, slip the board back into the case, and install the knobs and whip for final testing. Re¬ connect the battery, set the tuning knob to mid-position, and with a toothpick or pointed nonmetallic tool, spread or compress L4 (local oscillator) until you hear a local repeater signal or de¬ sired center frequency from a signal generator. L2 and LI (rf amp) should be spread or compressed in the same manner for maximum quiet¬ ing, which can be accom¬ plished only with a weak signal, preferably from a sig¬ nal generator. Even though coupling between the local oscillator and the rf amp is very light, peaking of L2 for maximum sensitivity will shift the receive frequency slightly, so keep retuning on¬ to frequency as L2 is being peaked; an increase in noise may be a shift off frequency rather than a decrease in sensitivity. Strong signals can be received even with¬ out adjustment of L2 and LI, but peaking (especially L2) is recommended for best sensitivity. Hybrid Squelch Drilling holes or adding controls and switches to an otherwise attractive custom case is both difficult and un¬ sightly, With this in mind, I came up with a novel idea which I call a hybrid squelch; the volume control doubles as a squelch con¬ trol The squelch engages at (and remains engaged above) any preset volume level suited to preference by varying the squelch sensitiv¬ ity setting of R2 (Fig. 2). Once this R2 level is set, it needs no further adjust¬ ment. Although the most sensitive volume/squelch setting is just at threshold, a moderately strong signal will open squelch even if set at full volume. The use of the volume control as a squelch control is accom¬ plished by coupling the in¬ put of the 741 op amp di¬ rectly to the center tab of the Weatheradio volume control with a 240-pF capac¬ itor Thus, the input level to the noise amp/squelch switch varies with the vol¬ ume setting. Fig. 2 shows the complete squelch circuit. The 741 (DIP) op amp serves as a high-gain noise amplifier. Germanium diodes D1 and D2 provide a dc voltage which mutes the Weathera¬ dio audio amp (JC2) at pin 2 when no signal is present The 240-pF coupling capaci¬ tor helps eliminate passage of voice frequencies. How¬ ever, if you find that, at high- volume settings, heavy mod¬ ulation activates the sensi¬ tive squelch during voice peaks, reduce squelch sensi¬ tivity R2 until a compromise position is reached. To save space and eliminate the need for a subminiature pot, I adjusted R2 to the desired level, measured the resis¬ tance on each side, and sub¬ stituted fixed resistors as a divider. An alternative would be to substitute a fixed 10k resistor for the R2 pot (connecting C2 to the junc¬ tion of R2 and pin 6 of IC3) and to lower the gain of IC3 Circuit modifications . by reducing R1 to anywhere between 6.8 and 2.2 meg¬ ohms. For this approach, I found the optimum value to be somewhere between 2.2 and 4.7 megohms. R3 and R4 on pin 3 of the 741 are stan¬ dard practice, but optional; mine functions perfectly without them. Construction Notes Store all tiny screws and the knobs in a cup, they have a tendency to wander off All parts for these modi¬ fications were soldered di¬ rectly to the foil side of the Weatheradio board, each supported by its own leads or short lengths of thin but rigid wire. Space is limited, requiring Vi-Watt resistors and other parts of miniature variety. The 741 DIP was mounted against the foil side of the board, leads up, between IC1 and the imme¬ diate side edge of the board, with leads trimmed short Keep parts placement near the board edges, as the speaker magnet area has the least room for clearance The protective coating on the foil can be scraped away at points needing the solder connections. Watch battery polarities and note that the Weatheradio schematic chassis symbol designates nine volts positive. Be sure to connect the positive lead of the squelch circuit to a point after the on/off switch so it does not draw current when the radio is turned off A circuit modification or er¬ ror on the Weatheradio schematic has pins 2 and 3 of audio amp IC2 reversed Squelch output (from D2 and C3 of Fig 2) goes to ac¬ tual pin 2 of IC2. As each part is added to the board, it is a good idea to seat the board into position in the plastic case to check for parts clearance and to avoid shorting leads to the metal speaker. Care and patience cannot be overemphasized. It is quite easy to make opti¬ cal reversals while looking at both sides of the board for circuit points of induc¬ tors and 1C pin numbers. Tri¬ ple check. Insert a milliam- 73 Magazine • March, 1983 47 THERE IS A IN QUARTZ CRYSTALS International’s leadership in crystal design and production is synonymous with quality quartz crystals from 70 KHz to 160 MHz. Accurately controlled calibration and a long list of tests are made on the finished crystal prior to shipment. That is why we guarantee International crystals against defects, material and workmanship for an unlimited time when used in equipment for which they were specifically made. Orders may be placed by Phone: 405/236-3741. TELEX: 747-147, CABLE: Incrystal * TWX: 910-831-3177 * Mail: International Crystal Mfg. Co., Inc., 10 North Lee, Oklahoma City, Oklahoma 73102. meter in series with one of the battery leads after the completed unit is in the case. If it draws more than 25-30 mA, recheck for shorts or solder bridges. Final Touches Frequency coverage of the tuning range can be in¬ creased or decreased by in¬ creasing or decreasing (re¬ spectively), by a few picofar¬ ads, Cl 8 which couples the varicap tuning to the local oscillator. I made no modifi¬ cation here, as frequency coverage was adequate for the repeater portion of two meters. A tiny dot of white paint or nail polish on the tuning knob, with frequency- reference dots on the case, will prove useful. If you want to turn this into a de¬ luxe model, drill a tiny hole on top of the plastic case and install a subminiature LED for an on/off indicator. At the expense of a slight in¬ crease in current drain, this feature will remind you to turn the radio off at night and might save you a bat¬ tery. If space can be found to neatly install a small bat¬ tery cut-off jack for an ex¬ ternal nine-volt supply, it would do wonders for your budget; nine-volt batteries are not noted for their lon¬ gevity. With a little ingenu¬ ity, the local oscillator could even be converted to single¬ channel crystal control. My FM monitor keeps me in touch with what's going on without my having to pull my rig out of the car ev¬ ery evening. For a while, it also kept me from jumping in on every QSO. Eventual¬ ly, I broke down and built a 50-mW companion FM trans¬ mitter which easily hits the local repeater. It measures only*]'A X 1 X 1 inches. So now I have a $25 hand-held, but —you guessed it —no matter how hard I tried, I couldn't squeeze it into the Weatheradio case.H MORSE COG Try the All Ne ! AEA BT-1 ~ Basic Trainer F Morse Cede EA, hi conjunction with ETS (Educational Technology and Service?}*, has eioped the BT-1 Code Trainer. ETS methodology, tiaaed upon research by a mlnent mid-west university, has demonstrated that a typical student using this tern and the BT-1 can learn Morse code to speeds of 20 WPM fh four weeks ed upon two 20 minute daily training sessions. he preprogrammed BT-1 computerized trainer wHI allow you to acheive prof I* icy in Morse code faster than any other known method, lo prior knowledge ot Morse code is required to use the .BT-1. There are no as to purchase or wear out. The BT-1 operates from a 12 VDC source or from AEA 117 Vac wall adapter unit, AC-2. For portable use the BT-1P is available i Nicad batteries and comes with a charger that operates from 117 Vac. The ! can also be used in mobile settings via the 12 VDC system. jcatlon Technology & Services, see page 81 October 1981 issue bt Haro Radio Magazine. e s and Specifications iect To Change Without Ice Or Obhgatlon. See the BT-1 at your dealers or write: Advanced Electronic Applications, Inc . P.O. Box C2160 Lynnwood, Washington 98036 (206) 775-7373 Telex: 152571 AEA INTL 48 73 Magazine • March, 1983 FOURTH GENERATION SATELLITE RECEPTION NOW! With D.C.E/S 70 MHZ VIDEO PROCESSOR BOARD FEATURES: I.F. Strip Includes S. A.W. BP Filter Discrete 70 MHZ PLL Demodulator Full AGC & AFC Normal/Reverse Video On Board Power Supply Regulation The most advanced Satellite Video Processor Available KIT.1324.00 ASSEMBLED. ..$448.00 DigiCom Engineering, Inc. P.O. BOX 1656 ►-'225 KODIAK, ALASKA 99615 <907)486-5118 ORDERING INFORMATION: Check, M.O or C.O.D/s ac cepted Airmail shipping costs within U.S. included in price <allow I week for delivery) Foreign orders include 15.00 for shipment by air The Secret Telemetry of OSCAR 8 Do those numbers from the sky mean anything? You bet. loe Magee K5QM 3928 Tacoma Irving TX 75062 D o these numbers mean anything to you: 101, 245, 376, 449, 549, 601? Well, this is the data I re¬ ceived from OSCAR 8. Since first learning about amateur satellites with sig¬ nals I could hear on my Kenwood R-599, I have of¬ ten copied this type of data. The above sequence, when decoded, says that the total solar-cell current MA was 0 mA, the battery cur¬ rent was — 285 mA, the bat¬ tery voltage was 15.85 volts, the base-plate and battery temperatures were 23.28° C, and the Mode j power output was 0 mW. The math is pretty simple, so the numbers are easy to calculate. A pocket calcu¬ lator does the job in no time. The data comes from OS¬ CAR encoded into six differ¬ ent number groups. These groups are assembled into a certain order by OSCAR be¬ fore transmission. Each number group is called a channel and the assembly is called a frame. Thus, the numbers above are consid¬ ered as one frame. Each frame is separated from the rest by "HI." So, the frame above was actually copied as "101 245 376 449 549 601 HI." Notice that each channel is composed of a three-digit number. The first digit tells what channel is being sent and the next two digits are the data for that channel. Each frame will always have all six channels. The data is encoded in each channel. Since two digits can have only 100 dif¬ ferent values, equations must be used to decode the data into something useful (see illustrations). In addi¬ tion to the equations, graphs are presented so that you can get approxi¬ mate values. You can lo¬ cate the received values on MODEJ power out PjT *23N MW **C Fig. 1(d). Channels 4 and 5. the horizontal axis and find the decoded values on the vertical axis —as is shown in Fig. 1(b). Knowing the numbers still doesn't tell you what they mean. For instance, the Ixx sequence gives so¬ lar-cell current. Above, it was 0, but sometimes you may copy several se¬ quences and the Ixx may change. This happens when OSCAR goes from light to dark or dark to light. Since this happens rather quickly, one should notice a dramat¬ ic change. Once OSCAR is in the sunlight, a more subtle change should be noticed. The solar cells that are used to charge the batteries are mounted on the faces of the satellite. Thus, as it turns, the solar-cell output current will vary correspond¬ ingly. On April 17, 1979, during orbit 5683 (for exam¬ ple), I monitored the telem¬ etry. I plotted the solar-ar¬ ray current (Fig. 2). The pas¬ sage into the sun is clearly evident. Before passing into the sun, the Ixx data should be 00, 01, or 02. The 01 or 02 results from voltage offsets and counting errors. (Each channel is subject to a 1-count error.) Also, note any changes in the current resulting from the spin. As the sun shines on a corner, two sides are lighted, result¬ ing in more current than if only one side were illumi¬ nated. Also, since there are four corners, there will be four current peaks per revo¬ lution. By looking at the graph in Fig. 2, we can see that OSCAR 8 was rotating once about every four or five minutes. Channel 2 is a measure of the battery current. It tells how much current is flow¬ ing into the battery. When in the dark, with no solar¬ cell current, it will show how much current is being used by the satellite. This value, in conjunction with Channel 3 (battery voltage), can be used to determine the Mode A power output. Simply determine how many Watts the battery is delivering and then sub¬ tract 3 (the power con¬ sumed by the rest of the sat¬ ellite except the Mode A transmitter). In my original example, the Mode A pow¬ er is about 1.52 Watts (15.85 V times .285 A minus 3 Watts). As mentioned, Channel 3 is the battery voltage. Out of curiosity, I plotted it along with the solar-cell current in Fig. 2. The rises in battery voltage correspond¬ ed to the peak current from the solar array, as one would expect. Channels 4 and 5 mea¬ sure temperature. Channel 4 is the base-plate tempera¬ ture and 5 is battery tem¬ perature. The base-plate temperature will stay fairly constant when OSCAR is in the dark and will become Fig. 1(e). Channel 6. warm in the sun. This warm¬ ing will occur at various rates, depending on the an¬ gle of the sun in relation to the satellite. The battery temperature can vary much more rapid¬ ly. As nicads are over¬ charged, their temperature rises. When in the sun, OS¬ CAR will warm up from the sunshine and perhaps from battery heating as well. Bat¬ tery temperature is impor¬ tant because high tempera¬ tures will cause cell dam¬ age. In space, there is no shade; thus, if the batteries start to overheat, some¬ thing must be done to re¬ duce charging current. This is most easily accomplished by putting the satellite into a high-power mode, such as Mode J, which draws more current from the battery. Finally, Channel 6 is a measure of the Mode J power output. Naturally, it will show 00 (or 01 or 02 as does Channel 1) when in Mode A. Working with the num¬ bers once you have them isn't half as much fun as getting them. You must lis¬ ten to OSCAR 8 as it makes a pass within range of your QTH. This procedure is cov¬ ered well in other places, but if you are in the US, any evening Sunday through Thursday (except Tuesday) will be a Mode A night. Now, turn to the Table of Contents of your 73 Maga¬ zine and find the page num¬ ber for Satellites. By turning to that page you will find a listing of refer¬ ence orbits for each day of the month (remember that INPUT PARAMETERS 101 . 44'?! 549. 60 1 . COMPUTED RESULTS IT HR I BAT VBHT TBP TBAT PJT Fig. 3. Output of program. 73 Magazine • March, 1983 53 these dates and times are GMT). In general, you can hear two or three passes in any one evening. On Mode A, the telemetry is on 29.40 MHz. (The actual received frequency may vary a few kHz due to Doppler shift) As OSCAR is approaching, the frequency will be high; it will be low as it is depart¬ ing. If your QTH is close enough to a particular orbit to hear OSCAR 8, you should hear some activity within one to five minutes after the predicted crossing time. The length of time that OSCAR is within range will vary, from less than five minutes to nearly twenty minutes. One big problem with OSCAR is that it is addic¬ tive! I am torn between lis¬ tening to either the teleme¬ try or to QSOs. To help make the telemetry more fun, I wrote a program for my TI-59 calculator to per¬ form the math needed to decode the data. For added interest and experience, the program that I wrote used the PC-100A print cradle with its 20-column thermal printer, providing an in¬ formative and permanent printout The printout of the data in the first para¬ graph of this article is shown in Fig. 3 Fig. 4 is a listing of the program. It is made up of three sections. Section 1, lines 000 through 029, is used to enter the data into the calculator memory for later use. In Section 2, lines 030 through 164, the OS¬ CAR data is converted to the proper value Lines 375 through 390 are a subrou¬ tine and are used to deter¬ mine if the Ixx and 6xx val¬ ues are very small, in which case they really should be 0 * The last part, lines 165 through 374, is used to print out the answers This is where the alphanumeric ca¬ pabilities of the TI-59 are used. When printing out the •Glassmeyer and Harris, QST, July, 1978. 063 17 17 128 05 5 194 03 0 Fig. 4. TI-59 program listing. 064 54 129 93 195 00 0 065 95 = 130 08 8 196 01 1 000 76 LBL 066 42 STD 131 75 - 197 07 7 001 1 1 0 067 21 21 132 01 1 198 03 3 002 42 STD 068 7 6 LBL 133 93 199 07 7 003 1 1 11 069 3'3 X 2 - 134 04 4 200 69 DP 004 91 R-'S 070 05 5 135 08 8 005 76 LBL 071 07 7 136 65 X 201 03 03 006 12 B 072 65 X 137 53 f 202. 01 ! 007 42 STD 073 53 i 138 43 RCL 203 07 7 008 12 12 074 43 RCL 139 15 15 204 03 3 008 91 P •■ / S 075 12 12 140 75 - 205 05 5 010 76 LBL 076 75 - 141 05 5 206 03 3 011 13 c 077 05 *r 142 00 6 207 06 6 012 42 810 078 00 o 143 00 0 208 00 0 013 13 13 079 75 - 144 54 > 209 00 0 014 91 R 080 02 2 145 95 = 210 00 6 015 76 LBL 081 00 0 146 42 STO 211 00 0 016 1 4 B 082 00 o 147 25 25 212 69 DP 017 42 ST0 083 54 148 43 RCL 213 04 04 018 14 14 084 95 =■ 149 16 16 214 69 DP 019 91 R/S 085 42 STD 150 75 - 215 05 05 020 76 LBL 086 22 22 151 06 6 216 9$ hBV 021 15 E 087 Ci C; . 152 00 0 217 43 RCL 022 42 STD 088 01 1 153 00 0 21 g 11 11 023 15 15 089 65 X 154 95 = 219 99 PRT 024 91 PS 090 53 •: 155 71 SBR 220 43 RCL 025 76 LBL 091 43 RCL 156 34 rx 221 12 12 026 16 ft 1 092 13 13 157 02 2 222 99 PRT 027 42 ST0 093 75 - 158 03 3 223 43 RCL 028 16 16 094 03 3 159 65 X 224 13 13 029 91 p-’S 095 00 0 160 43 RCL 225 99 PRT 030 76 LBL 096 00 0 161 17 17 226 43 RCL 031 10 E * 097 54 •• 162 95 227 14 14 032 69 DP 098 «-.«£ 4 163 42 STD 228 99 PRT 033 00 00 099 08 8 164 26 26 229 43 RCL 034 43 PC L 100 93 165 98 hBV 230 15 15 035 11 11 166 00 0 231 99 PRT 036 - 101 02 2 167 00 0 232 43 RCL 037 oi 1 102 05 5 168 00 0 233 16 16 038 00 0 103 95 = 169 00 o 234 99 PRT 039 00 0 104 42 STD 170 02 2 235 98 ftI»V 040 95 = 105 23 2 3 171 04 4 236 00 0 041 71 SBP 106 09 9 172 03 3 237 00 0 042 34 r>: 107 05 5 173 01 1 238 Oil 0 043 77 6E 108 93 , 174 03 3 239 00 0 044 45 V 109 08 8 175 03 3 240 01 1 045 00 o 1 10 -?rr - 176 69 DP 241 05 er 046 42 STO 111 oi 1 177 01 01 242 03 3 047 21 21 1 12 93 . 178 04 4 243 02 2 048 61 GT0 113 04 4 179 01 1 244 03 3 049 33 1 14 08 8 180 03 3 245 00 0 050 76 LBL 115 65 181 07 7 246 6S* DP 051 45 yx 1 16 ICO 182 00 0 247 01 01 052 07 7 1 17 43 RCL 183 00 0 248 03 3 053 93 . 1 18 14 14 184 03 3 249 03 ;T; 054 01 1 119 75 - 185 03 3 250 04 4 055 05 *r 4 120 04 4 186 01 1 251 01 1 056 65 121 00 0 187 03 3 252 03 3 057 53 < 122 00 0 188 69 OP 253 07 7 058 6 i i 123 54 > 189 02 02 254 Ot 1 059 00 o 124 95 = 190 03 3 255 07 7 060 01 i 125 42 STO 191 05 e- 256 oi i 061 75 126 24 24 192 01 1 257 06 6 062 43 RCL 127 09 9 193 03 3 258 6*9 OP 54 73 Magazine • March, 1983 input data, a header is print- data is output this way in ed. This is accomplished by lines 287 through 373 (236 filling the print buffer with to 285 are used to print the 40 numbers that corre- output header). This is done spond with the 20 charac- by putting the eight num- ters that are to be printed bers which correspond to (two numbers per charac- the characters in the sub- ter; sorry, not ASCII) and script into the right-most then issuing a print com- segment of the print buffer, mand (lines 166 through recalling the data from 215). In lines 217 through memory, and then printing 234, the values are recalled the line, and printed. I am glad that I had to Another handy feature of tell the T1-59 how to do all the TI-59/PC-100A is the this only once! From now ability to print 4-character on, I will just read the pro- subscripts. The calculated gram in on a mag card.® 259 02 02 43 RCL 260 oo o 3 2 6 23 23 261 00 0 327 69 DP 262 0 3 3 323 06 06 ns S 3 2 9 ft 3 3 264 01 1 3 3 0 07 7 265 07 7 331 01 1 266 0 ? 3 332 04 4 £ K l' 0 6 6 333 U 3 3 2 * z - 8 04 4 334 0 3 269 01 1 335 00 o 270 69 OP 3 3 6 00 o 271 0 3 0 3 337 69 QF‘ 273 07 7 43 RCL 274 0 3 3 340 24 24 275 07 7 341 69 □ P 276 0 3 342 06 06 277 06 K 343 U3 3 2 7*S 00 0 344 07 7 279 0 0 0 345 01 1 2S0 ilLL) o 346 04 4 281 00 0 347 01 1 2S2 69 OP 348 0 3 3 20 -J 04 04 349 03 3 2S4 69 OP 350 07 7 2 £; p; 05 05 351 69 □P 2 8 6 90 HDv 352 04 04 2 0 7 02 2 353 43 RCL 2 2 a 04 4 354 25 25 209 03 3 355 69 □P 290 07 7 356 06 06 291 0 3 3 357 03 3 292 00 0 358 0 3 3 293 01 1 359 02 2 294 0 3 360 05 5 295 69 □ P 361 0 3 3 296 04 04 362 07 7 297 43 RCL 363 00 o 293 21 21 364 00 o 299 69 □ P 365 69 DP 300 06 06 3 6 6 04 04 301 02 2 3 6* 7 43 RCL 302 04 4 368 26 26 303 01 1 69 DP 304 04 4 370 06 06 305 01 1 371 98 HDV 306 0 3 3 372 98 RDV 307 03 3 373 98 HDV 308 07 7 374 92 RTN 309 69 □ P -? ej 7 6 LBL 310 04 04 376 34 rx 31 1 43 RCL 377 42 STD 31 2 313 69 □ p" 3 7 9 1 7 03 1 7 314 06 06 380 32 x: t 316 317 04 4 381 43 RCL 01 T 903 17 1 7 GE 31 0 04 4 384 OCj 1/X 319 01 1 •I; p er 00 0 320 0 3 3 3 8 6 42 STD 1 *7 32 1 07 7 388 i > 76 LBL 3 2 3 69 OP 389 35 1 - X 324 04 04 390 92 RTN 2300 MHz ______ CONVERTER PI III r antenna D w 11— ■ POWER SUPPLY how Z7.90 LC IT PC BOARD ■ V I I ALL PARTS DOWN CONVERTER NOW $ 12.95 BISK YAOI ANTENNA COMPLETE KIT WITH PVC AND MOUNTING BRACKET f POWER SUPPLY ^ Variable 4 to 15 volts ALUMINUM CABINET ANODIZED black with brushed rnhh ALL HOLES ARE PRE-PUNCHED BUILT CONV BOARD BUILT P/S A CABINET COMPLETE SYSTEM BUILT I THIONMXi[ « 6219 COFFMAN RD ^104 SHIPPING & HANDLING INDIANAPOLIS. INDIANA 46268 NO COD 317 291 7280 PHONE OR MAIL ORDER $ 15.95 $ 6.95 $ 22.50 $ 34.95 $ 77.90 AE H S » ©CjB-flllF. ■ 111 We re ChsncrinQ Whether you re a repeater owner, . . . control op. or user, the RC-850 wnat repeaters controller offers you capabilities can do... for YOU! you've only dreamed of. Like natural sounding speech synthesis ... easy, remote Touch-Tone programming ... talking meter readback... synthesized remote base operation ... and an autopatch with features you have to hear to believe. Most important of all. upgrade through software, prevents obsoles¬ cense. Which lets us bring you new features, like our scheduler, for automatic changeover of repeater status by time and day of week ... And our mailbox, for leaving messages for your friends. Plus much, much more! The RC-850 Repeater Controller—The New Standard in High Performance! Ask anyone that owns an RC-850 controller. Or ask us for our demo tape, so you can hear for yourself. CICC advanced computer controls 10816 Northridge Square 1 Call or write for detailed specifications on the RC-850 Repeater Controller. ^124 Cupertino. CA 95014 • (408)749-8330 See List of Advertisers on page 114 73 Magazine • March, 1983 55 Chuck Pereiman WA60GW 9777 WHshire boulevard , Suite 700 Beverly Hills CA 90212 Scandinavia: The 2-Meter Dream Vacation Licensing , frequenciesand procedures —it's all here. All you need is a plane ticket P ack your bags for a great Scandinavian va¬ cation! The land of the mid¬ night sun beckons and it's more fun with 2 meters. If you want to take that rig with you, plan in advance. Getting Your Licenses You need sufficient time for processing through the FCC, the Scandinavian au¬ thorities, and for any inter¬ national mail delays. Allow h months if possible. Send the ARRL (225 Main Street, Newington, Connecticut 06111, Attn: International TO: (See ielow tot Addressee) »ir*ct«*r»t« of Poet end Telegraph* Iat Technical Office 17 , Fe*¥*rg*d*» let floor 0%-USQf Copenhagen t tflWMAl* Swedish T#l«c<*aia»U*U*s» Adalftl■ t rat taa *•41-9 Depart ment, Stockholm tlemeelsg Section $-123 *6 FUST A SWEDES Affairs) an 8Vi” by 11" SASE and they will send you application forms for each country. If time is short. Fig. 1 is a form which includes all of the neces¬ sary information for each country The address for each licensing authority is also given For each country (except Finland, where the form is sent directly to SRAL), send the completed form to the FCC requesting endorse¬ ment and forwarding. En¬ close a stamped airmail en- Korveglaa Telecommunication* Administration Faetbok* 6701 St. Oleve pi. Olio l, SOSWAT SWA! f.0. So* 206 SF-00101 Seielnki 10 riWLAWD velope addressed to the proper foreign authority If you furnish an SASE, the FCC will confirm the date on which your papers were mailed Send to FCC, PO Box 441, Gettysburg, Penn¬ sylvania 17325 Denmark Application should be filed at least a month before the requested license period. Attach a pho¬ tocopy of your license Within a few weeks you will receive the license and a payment form When you arrive in Denmark, go to the nearest post office, pay the fee (only 20 kroner for a short stay), and your license is then valid. A temporary li¬ cense will be issued for up to three months. REPEATER CHANNELS Channel # Receive Frequency R0 145.600 R1 145.625 R2 145.650 R3 145.675 R4 145.700 R5 145.725 R6 145.750 R7 145.775 R8 145.800 R9 145.825 •Transmit 600 KHz down SIMPLEX CHANNELS 145.250 to 145.575 at 25-kHz spacings 145.500 used as caiiing frequency 145.550 mobile channel 145.525 and 145.575 probably most used simplex channels other than 145.500 Fig, 2. Two-meter repeater and simplex channels most frequently used. In Copenhagen, there is 24-hour service at the post office in the Central Rail¬ road Station This is right in the center of the city, next to Tivoli Gardens When applying for your li¬ cense in any country, if you do not know the exact dates of your arrival and depar¬ ture, allow a few extra days on each end If you have no references in the country, enter "none' on the refer¬ ence line Norway . In addition to a copy of your license, Nor- STANDARD R1 Receive* 434.600 R2 434.625 R3 434.650 R4 434.675 R5 434.700 R6 434.725 R7 434.750 R8 434.775 R9 434.800 R10 434.825 •Transmit 1.6 MHz lower RU0 SWEDISH Receive* * 437.600 RU1 437.625 RU2 437.650 RU3 437.675 RU4 437.700 RU5 437.725 RU6 437.750 RU7 437.775 RU8 437,800 RU9 437.825 RU10 437.850 RU11 437.875 RU12 437.900 RU13 437.925 RU14 437.950 RU15 437.975 “Transmit 4.6 MHz lower Fig. 3. UHF repeater channels. Fig . F Sample form for requesting license to operate in a foreign country . Look for me on 2m as I drive around Scandinavia in April. I f m open for ham talks in Copenhagen 3-5th April; Oslo, 6-9th; and Stockholm, 10-13th. If there is any interest, please get in touch.—Wayne Green W2NSD/1. APPLICATION FOR PERMISSION TO OPKRATK AN AMATEUR RADIO STATION IN ___^(Country) 1, the undersigned, hereby respectfully apply for e temporary permit or license to operate en emeteur redlo trensmltter in llcenee period requeoteds_ Kerne In full!________ OccupetIon Address In my ovn country:_ Dete end piece of birth:_ Ketloneltty :__ Cell $lgn:__License Claaet_Expires:, Address In _:_ Vehicle Ragietretion Kusber!___ Helling Add re ee of Fixed Station:__ Object of at ays. References In _: Member of following amateur organisation:. Fleet end date:_ Signature £ . .... Opinion of epplleant end comments or endorsement by licensing authority of home country: 58 73 Magazine • March, 1983 this certification: "Each of the undersigned certifies that he has examined origi¬ nal passport No_and the amateur radio license of Charles R. Perelman and that the above are true and correct copies. Executed on_, 1981, at Beverly Hills, California, under pen¬ alty of perjury." Two signa¬ tures followed. Each country will send you a translated copy of rules and regulations. Your license will bear your home call with the appropriate country designation, for ex¬ ample: WA60GW/0Z. Low- band and UHF privileges will depend upon the class of license you hold in your home country. In Denmark, Norway, and Sweden, you way requires a "certificate of good conduct" from your local police department. This can be a letter on police department stationery stat¬ ing that you are of good character and reputation and that the police know of no reason why you should not be issued an amateur li¬ cense in Norway. Your appli¬ cation should be on file at least a month before the op¬ erating period requested. A temporary license will be is¬ sued for up to three months. The fee of 50 Norwegian kroner must be sent with your application. Buy an in¬ ternational draft or money order payable in Norwegian currency. If you send a per¬ sonal check or dollar instru¬ ment, you may cause sub¬ stantial delay or return of your application. I suggest that you staple ah of the documents together. Sweden. A police good- conduct letter is required for Sweden just as in Nor¬ way. Your application should be filed at least two months prior to the re¬ quested license period The Swedish authorities will send you a license with a re¬ quest for any fees. Fees can be paid by mail or upon ar¬ rival in Sweden at a post of¬ fice. The fee will vary with the length of the requested license period. Finland. The amateur society, SRAL, handles all li¬ cense applications. SRAL tells you to allow at least 4 to 8 weeks, more in summer, for issuance. It took me con¬ siderably longer than 8 weeks. If your license is for less than one month, a fee of 58 markka must be paid with your application. This includes the processing charge by SRAL. For a li¬ cense for more than a month, you must join SRAL and the fee is higher, The maximum temporary li¬ cense period is three months, subject to renewal. Your mailing address in Finland must be given exact¬ ly. This may be the address of your hotel. You must furnish a copy of those pages of your pass¬ port containing personal data and of your amateur license certified by two signatures. I photocopied my amateur license and the pages of my passport with my name, date of birth, etc., and my picture onto a single sheet. At the bottom I typed QTH Channel DENMARK Verhoj R0 Ringsted R1 Esbjerg R2 Alborg R2 Bornholm R2 Hvidovre R3 Yding Skovhoj R3 Odense R4 Copenhagen R4 Thy R4 Kvinsbjerg R5 Vejby R5 Ostervold R6 Lysnet R6 Lindeballe R7 Fleming R8 Arhus R9 Fredrikshavn R9 Sakskobing R9 NORWAY Oslo R0 Horten R1 Rinsaker R1 Flekkefjord R1 Grenland R2 Kongsvinger R2 Oslo stad R2 Harstad R2 Hallingdal R2 Trondelag R3 Ringkoilen R3 Sandnes R3 Arendal R4 Kongsberg R4 Drammen R5 Egersund R5 Gudbrandsdal R5 Bergen R6 Oslo, Enebakk R6 Bodo R6 Kristiansand R6 Tromso R6 Vardo R6 Trondheim R6 Sondeled R7 Stavanger R7 Sandefjord R8 Vestland, Stord R8 Tromso Fjellheisen R8 Telemark R9 Folio S. Oslo R9 FINLAND Turku R0 Helsinki R1 Pietarsaari R1 Kotka R2 Antari R2 Mariehamn R3 Lahti R3 Seinajoki R3 Jyvaskyla R4 Salo R4 Pori R5 Kuusankoski R5 Espoo R6 Tampere R6 Vaasa R6 Lappeenranta R7 Turku R7 Hameenlinna R8 Kuopio R8 SWEDEN Bjorna R3 Bollnas R2 Boras R8 Bracke R4 Backefors R4 Edsbyn R0 Fal ken berg R1 Falkoping R5 Falun R8 Gladsaxe R0 Glommerstr. R6 Gallivare R2 Goteborg R2 Hagfors R0 Halmstad R9 Helsingborg R2 Hudiksvall R7 Hallnas R2 Harnosand R1 Jonkoping R6 Kalix R5 Kalmar R8 Karlskoga R6 Karlskrona R6 Karistad R3 Katrineholrn R3 Kiruna R8 Kramfors R0 Kristi neberg R3 Kungsbacka R7 Kyrktasjo R5 Linkoping R8 Ludvika R5 Lulea R8 Lycksele R7 Lysekil R0 Mariefred R9 Motala R1 Malmo R7 Norberg R3 Norrkoping R0 Nykoping R4 Nassjo R2 Olofstrom R1 Orsa R6 Oskarshamn R5 Pitea R0 Sanviken R4 Skelleftea R4 Skovde R9 Solleftea R2 Solna R5 Sorsele R0 Stockholm R1 Stockholm R8 Storuman R5 Sundsvall R8 Sunne R7 Tanumshede R3 Tranas R7 Tarnaby R2 Ulricehamn R3 Umea R8 Uppsala R6 Vetlanda R9 Vilhelmina R4 Visby R6 Vimmerby R1 Vargarda R1 Vamamo R0 Varobacka R4 Vastervik R3 Vasteras R7 Vaxjo R4 Vannas R5 Ystad R8 Orebro R2 Ornskoldsvik R7 Ostersund R6 Note: Above are in alphabetical order. In Swedish, the letters a and o with special phonetic marks come at the end of the alphabet. I could not print these marks. Fig . 4. Two-meter repeaters in Scandinavia . 73 Magazine • March, 1983 59 are permitted to work mo¬ bile. Although local ama¬ teurs have been working dil¬ igently to obtain this privi¬ lege for visiting amateurs in Finland, at this time non-res¬ idents are not permitted to operate mobile in Finland. Gear to Pack If you are traveling other than by car, a synthesized handie-talkie would certain¬ ly be the most versatile rig. In the older crystal-con¬ trolled radios, the Kenwood TR-2200 (same as the Drake TR-22) with sockets for 12 channels will permit you to crystal up for the 10 repeat¬ er channels and two popular simplex channels. Flowever, unless you already have some of the crystals on hand, the cost of all those rocks will probably con¬ vince you to buy a synthe¬ sized rig. Scanning is useful, par- ticularly if you will be oper- ating mobile. Even though you may have looked up the local repeater frequencies, changes do occur; you may not know exactly where some of the r epeater sites are located or the extent of coverage of some repeaters, QTH Channel DENMARK Lindeballe RUO Copenhagen RUO Ringsted RU1 Alborg RU2 Esbjerg RU2 Copenhagen RU3 Fredericia RU3 Se nedan RU4 Knivsbjerg RU5 Arhus RU5 Yd ing Skovhoj RU6 Purhoj, Horse ns RU7 Hillerod RU7 Randers RU8 Copenhagen RU8 Sakshobing RU8 Abenra RU8 Nord-Fyn RU9 Copenhagen RU9 NORWAY Kongsvinger RU1 Horten RU2 Bergen RU4 60 73 Magazine • March, 1983 or you may desire to check simplex channels. I suggest that you take the following in addition to your 2-meter rig: • Mag mount and cigarette- lighter power-supply cord for mobile use. • Quarter-wave or 5/8-wave telescoping antenna for FIT. You may be in a poor loca¬ tion or want to extend the range beyond that feasible with a rubber ducky. • Shortened or flex-type rubber ducky. If you carry the FIT on your belt, both the rig and antenna are less likely to be damaged if either of these types of antennas are substituted for the regular rubber ducky. • Battery charger and transformer or solid-state converter for 220 volts to 110 with sufficient wattage rating. Conversion plug with large round prongs. Some hotels furnish a 110 outlet for shavers which can be used to charge FIT batteries. Ordinary wall outlets are 220 volts, 50 cycles require- ing the round prongs and converter or transformer. • 1750 tone burst with dura¬ tion of at least 1 second. Some repeaters are carrier- Gjovik RU6 Oslo RU7 FINLAND Salo RU4 SWEDEN Bollnas SRU2 Eskilstuna SRU10 Falun SRU8 Halmstad SRU9 Helsingborg SRU2 Hudiksvall SRU7 Hono SRU10 Karlstad SRU7 Kungsbacka SRU4 Linkoping SRU8 Lund RU5 Mariefred SRU9 Sandviken SRU4 Solna SRU5 Stockholm SRU1 Stockholm SRU2 Stockholm SRU8 Vasteras SRU7 Orebro SRU2 operated. Most require the 1750 tone burst. Length of burst required appears to be longer than typical in some other parts of Europe. You may be able to obtain a whistle from a friend in Scandinavia which will pro¬ duce the 1750 tone. It looks like a single pitch pipe. If you are a good whistler, unless your musical talents are sufficient to approx¬ imate 2 octaves higher than A (440 Flertz) above middle C, the technique is to start high and slowly descend in pitch to be sure you've covered the right frequency. This sounds something like the second part of the whis¬ tle when you gaze approv¬ ingly at one of the local beautiful blonde blue-eyed YLs. If all else fails, you can still get into the repeater after a local ham has ac¬ cessed it with the tone burst. • Earphone. There are times when people on a bus, the street, or elsewhere may not take too kindly to the sounds of the QSO you may be holding with a local ama¬ teur. This is particularly true if there is a lot of noise com¬ ing in with his signal. The earphone solves these prob¬ lems. To avoid possible cus¬ toms questions, either upon entry into one of the Scandi¬ navian countries or when re¬ turning to the US, it is a good idea to register your radio gear (and cameras as well) with US customs. Call your local customs office to find the location for this service. It only takes a couple of minutes to fill out the form which will be stamped and inserted into your passport. In Los Angeles this can be done at a little cubicle on the second floor of Los An¬ geles International Airport. Repeater Frequencies Fig. 2 lists the repeater fre¬ quencies and most-often- used simplex frequencies for 2 meters. Fig. 3 contains information on UHF repeat¬ ers. Most of these are locat¬ ed in Sweden and follow the Swedish band plan with a 4.6-MFIz separation rather than the typical 1.6-MFIz separation used elsewhere, With my Kenwood 2400, I found it most convenient to program the 10 repeater channels into memories 0 through 9. Scanning the memory channels would then locate an active repeat¬ er. As in the United States, the repeaters are busier in the morning just before working hours and in the evening than they are during the working day. Flowever, the level of activity appears to be considerably less than on a busy repeater in one of our metropolitan areas. Du r ing the summer months, working hours of¬ ten begin at 7 or 8 am and end by 4 pm. The first three weeks in July are usually an "industrial holiday," vaca¬ tion for much of the work force. This often means de¬ serting the city for a cottage in the country or at the coast. If you want to be sure to make contact with a par¬ ticular ham, by all means ar¬ range your meeting in ad¬ vance. Use the low bands or a letter before your trip to be sure of his or her location when you will be in his country. Fig. 4 contains informa¬ tion on the location of 2-meter repeaters in each of the Scandinavian countries. With the harsh winters, an¬ tennas are often damaged so that some of the stations may be off the air at times. Fig. 5 shows locations of U EH F repeaters, Enjoying Your Fellow Hams For information on every¬ thing from directions to a Chinese restaurant (yes, there are some in Scandi¬ navia) to an interesting art exhibit, try your friendly local repeater. As elsewhere in Europe, many of the hams save pins, banners, or patch¬ es from radio societies of other countries. This kind of item makes a nice token Fig . 5. UHF repeaters in Scandinavia. gift. Yaesu and Kenwood rigs are widely used and you make a friend for life by ob¬ taining a needed service manual for a Scandinavian ham. If a radio friend is con¬ templating a trip to the US, he may appreciate a repeat¬ er directory or road maps. An auto club is the best source for maps I think the most enjoyable contact in a foreign country is with a ham with whom you've talked on the low bands. When your itinerary is firm, set up a definite ren¬ dezvous You will probably learn more about life in that country in an evening than during the rest of your trip Chance contacts resulting in bending elbows together at one of the local pubs can make new friends and be a lot of fun as well However, alcohol and driving definite¬ ly don't mix in Scandinavia Penalties for driving with even a very small quantity of alcohol in the blood are severe. Therefore, expect your friend to pass up the beer for a soft drink if he is driving. In Copenhagen, don't be surprised to have Swedish stations from Maimo, Falk- enberg, or some of the other southern towns come back to you through the local re¬ peaters In Finland, the re¬ peaters in the less populous parts of the country, north of Hameenlinna, Tampere, and Lahti, may not be opera¬ tional from time to time. You should check this out through low-band QSOs if you are planning to travel in the more northerly areas Two meters can be your key to opening up better paths of understanding of the beautiful countries and people of Scandinavia Plan ahead, make new friends on the low bands, and have the fun of eyeball QSOs far from home. You will learn more, have more fun, and have some unforgettable memories through the pow¬ er of amateur radio ■ 2300 MHz VARIABLE D O W N C O N V E R T E R ******************************************************* **************************** ANTENNA KIT PARTS I CONVERTER $1B9S i2 WASHERS V 31 SPACERS PU • MOUNTING BRACKET r 6” RG 174 COAX 1 *F CONNECTOR • 35’* ROD x 4" P.V.C. PIPE 2 DRILLED END CAPS POWER SUPPLY kit POWER TRANSFORMER P.C. BOARD COURSE TUNE POT. RF CHOKE FINE TUNE POT. KNOB 3 4 F CONNECTORS WIRE RESISTORS & CAPS 2 SWITCHES LED WITH HOLDER 4 DIODES TERMINAL STRIP LM 317 REG. WOOD GRAIN CABINET WITH SILK SCREENED front and back $1045 Extra BUILT POWER SUPPLY $34.95 HARDWARE Complete Down Converter System INCLUDES ANTENNA KIT POWER SUPPLY KIT CONVERTER KIT SPECIAL $49.95 QUANTITY DISCOUNTS Any Price in Adv. 10 pcs 12% ofi 25 pcs 18% ofi 50 pcs 25% ofi 100 pcs 30% ofi 1000 pcs 35% ofi No Mm mg for _Quantity Discount PARTS CONVERTER nverter P.C. Board / T ated through holes L -«** >| Converter P.C. Board Plated through holes for stability.$4.95 Power Supply P.C. Board .2.95 MRF 901 .. 2.00 NE02135 .4.95 2835 Diodes .95 .001 Chip Caps. 10/3.95 Choke Set of 4......1.95 LM 317 Regulator 1.25 ‘F r Connectors Chassis . .50 Wall Transformer 12 VAC 700 MA.4.95 ‘U r Bolt ...95 BALUN 75 to 300 ohm ...1.95 BALUN for rabbit ears . .2.95 *RG 59/U COAX WITH CONNECTORS FACTORY MADE m P.C. BOARD PRE-DRILLED SOLDER PLATED WITH PLATED THROUGH HOLES FOR A MORE STABLE PIC¬ TURE. n .... hot rtffwv. • 2 HP 2835 Diodes 6 .001 Chip Caps. 9 Resistors 4 Prewound chokes 1 Electrolytic Cap. 1 Pre Made Probe <§>®<§>®<§> <§><§>##<§> ★ WIRED P.C. BOARD TEST¬ ED, READY TO CONNECT TO CAN WITH PROBE & CABLE CONNECTOR ATTACHED. $24.95 We will tune conver¬ ter board for $12.50 trouble shoot add ..7.50 trouble shoot power supply .$12.50 plus any parts needed We will accept telephone orders for Visa A Mastercard No C.O.O. Orders TO ORDER CALL 317-291-7202 TU UKUfcK CALL 000.428-3500 Complete kit weighs 10 lbs. Please add sufficient postage 6254 La Pas Trail Indianapolis, Indiana 46268 ELECTROniC RAMSOUJ l 62 73 Magazine • March, 1983 Dennis Pharr WDSjWY 3521 SE. 45th St Oklahoma City OK 73135 Twisted Remote Control This circuit is easy to build and easy to use. The twist is that you probably own the most important part. D escribed here is a simple and inexpen¬ sive remote-control system, the major component of which you probably al¬ ready have on hand: an AM- FM receiver, either portable or table model As with any remote-control system, it has many uses. It may be used as a television com¬ mercial killer, to turn on or off a distant light, etc. If you have tried to build any of the light-operated-re- lay type of remote-control devices in the past, you must surely have noted two distinct disadvantages of that type of system: 1) They are usually very sensitive to ambient light levels and therefore difficult to adjust, and 2) You must be able to see the device in order to control it. Since this system uses radio waves as the con- trolling medium, these drawbacks are readily over¬ come Receiver-Transmitter It is certainly not difficult to generate a low-power rf signal that can be used for remote control, but the dif¬ ficulty begins when trying to design and build a receiv¬ er with sufficient gain to amplify the low-power sig¬ nal to a usable level. To cir¬ cumvent this problem, a conventional table model or portable-type AM-FM re¬ ceiver can be used along with a tone-modulated FM wireless microphone to generate the control signal Switching Circuit With the problem of the receiver-transmitter solved, all that is needed is a switching circuit that can be operated by an audio tone taken from the receiv¬ er. The circuit shown in Fig 1 does this job very nicely. The heart of the switch¬ ing circuit is U2, the CMOS 4027 J-K flip-flop. This par- ♦6-I2V0C ticular type of flip-flop has the unique characteristic that if both the J and K in¬ puts are held in a high state and a clock pulse is applied to the clock input, the out¬ put will toggle to a high or low depending on its previ¬ ous state. The output will continue to toggle back and forth as long as clock pulses are applied to the clock input. Referring to Fig. 1, as¬ sume that the output of U2 is in a low state and Q2 is off. Also assume that the primary of T1 is plugged in¬ to the earphone jack of an FM receiver tuned to the operating frequency of the wireless microphone. When the transmitter (wireless mi¬ crophone) is momentarily turned on, an audio pulse is applied to the primary of T1 This audio pulse is then rectified and used to for¬ ward bias Q1. With Q1 mo¬ mentarily turned on, a neg¬ ative-going trigger pulse is seen at the trigger input of U1 (used here as a one-shot). This trigger pulse causes the output of U1 to switch to a high state where it will remain for a period of time determined by the series combination of R1 and C2 (in this case about 1 second). This positive-going pi Fig. 1, Schematic diagram of the switching circuit The transistors and transformers used in both circuits are 2N2222 or Radio Shack 2009 and Radio Shack 273-1380, respectively. 64 73 Magazine • March, 1983 pulse at the output of U1 is applied to the clock input of U2, causing the output of U2 to toggle to a high state which turns on Q2 and ener¬ gizes relay K1. The output of U2 will remain high until another pulse is applied to the clock input, at which time it will toggle back to its original low state. Since the limiting action of most inexpensive FM re¬ ceivers is not what it should be. Cl (connected across the Q1 collector resistor) is included to prevent possi¬ ble false triggering caused by noise spikes from the output of the receiver. No power supply is shown in Fig. 1, since these have been extensively covered elsewhere in the ham literature. As shown, any voltage from 6 to 12 volts will work The amount of supply voltage you de¬ cide to use will depend up¬ on the voltage rating of the relay you purchase, or that of one you may have on hand. It should be mentioned here that the receiver you use must have some type of external antenna, and an earphone jack. If your re¬ ceiver has no earphone jack, one must be added, which is simple to do using a three-conductor phone jack. Transmitter Circuit The FM wireless micro¬ phone circuit shown in Fig 2 was originally published in the April, 1969, issue of Popular Electronics . The cir¬ cuit, as shown in that issue, used an RCA KD-2114 linear 1C for the active device but discrete transistors were used here since they were more readily available The circuit is shown here with one modification; the mi¬ crophone input network has been replaced with a simple tone-generating cir¬ cuit composed of R1, Cl, Q1, and T1. It has an output of about 800 Hz and pro¬ vides the necessary control signal. 66 73 Magazine • March, 1983 Fig. 2. Schematic diagram of the transmitter. See text for LI dimensions. Switching Unit and Transmitter Construction The switching unit can be built most easily using perf- board construction, and sockets should be used for both U1 and U2, in case re¬ placement becomes neces¬ sary. The unit may be en¬ closed in any type of case you may have on hand. Perfboard construction also may be used for the transmitter, although I have used the PC board square block method with good success. This means using a hacksaw to cut the foil side of a piece of PC board into squares and mounting the components on the squares. Placement of parts in the transmitter is not too criti¬ cal, but an orderly in-line layout ought to be used The connections in the rf portion of the circuit should be kept as short and as direct as possible. Coil LI consists of 6 turns of #12 tinned copper wire with an inside diameter of 5/16 inches and spread to 3/4 inches in length. The an¬ tenna tap is made one and one-half turns from the cold, C3, side, and tuning capacitor C2 is soldered di¬ rectly to the top and side of the first and last turns of the coil. Coil LI should be mounted as firmly to the board as possible to en¬ hance frequency stability The antenna can be fash¬ ioned from a piece of heavy-gauge copper wire, and can be anywhere from 3 to 12 inches in length. A plastic case similar to those sold by Radio Shack can be used for housing the trans¬ mitter. Test and Adjustment First, the transmitter should be tested and ad¬ justed to a clear operating frequency. To do so, turn on your FM receiver and tune for a clear spot on the dial The afc should be turned off, if possible, to prevent the receiver from tuning automatically to a strong adjacent channel. Once a clear spot is found, apply power to the trans¬ mitter and adjust tuning ca¬ pacitor C2 until an audio tone is heard from the re¬ ceiver. Now, either contin¬ ue adjusting C2 or vary the tuning of the receiver until the purest tone possible is obtained The switching unit may now be tested for proper operation. Plug PI into the earphone jack of your FM receiver and apply power to the switching unit At this point, the volume control of the receiver should be set at some low level Each time the transmitter is mo¬ mentarily activated, the re¬ lay on the switching unit should energize and stay energized until a second pulse is transmitted, at which time it will return to its normally-closed posi¬ tion. The volume control may have to be increased a small amount to ensure reli¬ able operation at a dis¬ tance If the switching unit does not operate as just de¬ scribed, then either a wiring error has been made or one of the active devices is de¬ fective. The range of the trans¬ mitter will vary with operat¬ ing conditions and depends to a certain extent upon the orientation of both the transmitting and receiving antennas. It has been my ex¬ perience that reliable oper¬ ation can be had with dis¬ tances up to 75 feet. Summary The uses that may be found for this simple sys¬ tem are many and are limit¬ ed only by your imagina¬ tion. If you happen to own a video tape recorder and like to record movies with¬ out the commercials, then this remote-control system can be used to pause the re¬ corder and to cut them out. It could also be used as a commercial killer for the television itself. To use it this way, one of the televi¬ sion's speaker leads is bro¬ ken and connected to a set of the relay's normally- closed contacts. In fact, you might even connect your ham-band receiver's mute terminals to the relay's other set of con¬ tacts, and that way be able to listen to it while the tele¬ vision sound is off. There are, undoubtedly, many other applications that can be thought of, but whatever you may use it for, always be careful to ob¬ serve the relay's contact power rating, otherwise an expensive relay may be ruined.■ Reader Service for facing page ^ 75 - Take Your IC's Temperature Like people *, solid-state devices get sick if they get too hot W3KBM provides a way to answer the burning question, "How hot is hot?" Alien S. Ioffe W3KBM 1005 Twining Road Dresher PA 19025 B y now solid-state de¬ vices are old hat We all know that too much heat is one good way to send such a device to semi¬ conductor heaven Since touching a hot transistor or 1C with a finger either makes for one big "ouch" or leaves the question of "How hot is it?" largely un¬ answered, here is some sur¬ plus to the rescue Digital Research of Gar¬ land, Texas, has advertised "Thermistors 5000 Ohms at 25 degrees centigrade," four for a buck. Upon arrival they proved to be Fenwal KA35J3 thermistors. A quick trip to Herbach and Rademan in Philadel¬ phia produced a surplus cabinet and a nice 200- microampere meter with a scale calibrated from 0 to 100. With the addition of very few parts, this collec¬ tion was turned into a solid- state centigrade thermome¬ ter that allows me to answer 'How hot is my 1C?" very adequately. The schematic in Fig 1 shows the simplicity of the electrical hookup. Resistors R1 and R2 of the bridge should be as closely matched in value as possi¬ ble. They can range from 4700 to 5000 Ohms; the im¬ portant part of the matter is that they be as alike in value as possible. Resistor R3 should be as close to the indicated 15k as you can get The signifi¬ cance of R3 lies in the fact that at zero degrees centi¬ grade the thermistor resis¬ tance will be rather close to this value My four samples checked out this way as in¬ dicated by a fairly good dig¬ ital meter Thus, at zero de¬ grees, the bridge will be bal¬ anced and the meter should read zero Taking this route eliminates the need for a low-end calibrating element in the circuit. I used a fresh D-cell to drive the bridge; since the current drain is very low, the useful life of the battery should approach its shelf life. My meter is 200 microam¬ peres full scale, which is about the practical limit of usable sensitivity in the up¬ ward direction That is to say, if you have a more sen¬ sitive meter, then use it, but avoid using a less sensitive meter The reason for this is that even small currents flowing through the thermis¬ tor tend to produce "self heat" which changes its ohmic value just as much as heat from a device being measured If you use a 50-microampere movement, you may have to increase the value of the variable re¬ sistor in series with the meter movement This resis¬ tor is used as the sole cali¬ brating element for the thermometer The photo shows the fin¬ ished meter with its probe and also an unmounted thermistor which gives an in¬ dication of the size of this circuit element Now for some notes on the probe construction The body of the probe was made from a discarded fiber- tipped type of marker such as a Flair or other brand The point was pulled off and the residual ink was carefully wiped out of the barrel. I say carefully as there is enough ink left to ruin several sets of clothes, soil your hands, and provide some interesting comments from the family if care is not used in this regard. The sides of the thermis¬ tor are painted with clear nail polish where the leads are attached. The same treat¬ ment is given to the first half inch of lead length near the body of the thermistor after a suitable length of cable Fig. 1. Schematic diagram of meter Photo by Ira Joffe WA3PTC Completed meter with probe attached. 70 73 Magazine • March, 1983 Has been soldered to the ex- grees on tbe meter face, meter reading by 1 ,8 and Use it for its intended pur- freme ends of tbe leads. Turning tbe calibration con- add 32 to the result to con- pose of measuring the tern- The cable is then thread- trol should allow a meter vert the meter reading to perature of ICs and discrete ed through the empty pen variation of about eight to Fahrenheit degrees as shown semiconductors. When you body and the thermistor is ten degrees total on your comparison ther- do this, I suggest that you checked for a good snug fit It may pay to make a 'big momeUer If it is RigR or low, take a small bit of thermal in tRe open end as shown in deal" out of the initial cali- make an adjustment with compound such as you tEe photo If you have to brafion so you can see that it the calibrating pot so that would use on a power tran- ream out the end a bit to works. TRe big deal is as fol- tRe two readings coincide sistor to make sure that it is achieve a snug fit, by all lows Obtain a reliable ther If you do not want to go in good thermal contact means do so When this has momefer such as a unit used through tbe "Big deal" iver- with a heat sink Place this been done, pull the fhermis- to check the temperature of sion of calibration, then use on the semiconductor or 1C for and cable out an inch or photographic solutions. Fill one of the best thermal Stan- of interest and then apply so and work some artificial a jar with Hot wafer from the dards around. That standard tbe probe tip to it so that rubber compound like QE kitchen tap. CReck its fern- is you and the normal tern- you have good thermal con- silicone seal into the end of perature with your known perature of your body, tact with tRe subject at the probe barrel Pull the good thermometer. Add a which is just about 98.6 de- hand. This should give you thermistor back in, seat if Bit of cold wafer if neces- grees Fahrenheit or 37 de- reliable comparative read- nicely, and put the assembly sary to get the water to grees centigrade. Touch the ings. You can easily see the aside to dry. You may also about 120 to 125 degrees tip of the probe to your effect of different sizes and want to use the silicone seal FahrenReit. After this ther- tongue and Hold it there un- materials of beat sinks in in the end of the probe from mometer reading has stabi- til the meter reading stabi- terms of getting rid of heat whicR the cable exits to pro- lized for about one minute, lizes. Set the calibration from the power devices, vide a bit of strain relief gently place your thermistor control for a reading of 37 Please note the use of the That is all there is to tRe probe into the water so that degrees on the meter and phrase "reliable compata- probe it just dimples the surface of you are done. This is one in- tiiwe" readings. This simple When tRe construction of the water Give the meter a strument where you will device will not put the Na- the probe and associated chance to settle to a read- never lose the source of tionai Bureau of Standards circuitry is finished, turn on mg, which may take as calibration. out of work, but it is a nice the switch and the meter much as thirty seconds to Do not use this thermistor adjunct to aid any bam should be reading some- ensure that a maximum has thermometer to take the working with power semi where about 20 to 25 de- been reached Multiply your temperature of hot liquids conductor devices ■ THE RTTY ANSWER JgtFSK-SOO.. /. N. Hendricks KB6AL 993A Thunderbird Lane Concrete WA 98237 The Q-Master Cavity Filter A high-Q filter that uses no copper and no silver-plating— just coffee cans and some ingenious thinking. A few months ago, some experimental work I was doing with a low-pow¬ er, home-brew repeater sys¬ tem required a sharp filter to restrict the bandwidth of the signal presented to the antenna terminals of the re¬ ceiver section, particularly at the transmitter frequen¬ cy. Since the cost and avail¬ ability of commercially- produced cavities were pro¬ hibitive, I decided to re¬ search the problem and see if I could make my own. Several of the amateur publications, engineering texts, and reference books in my library discussed the subject (see reference list at end of article); some even gave dimensions and bills of materials. Since I live in a somewhat remote part of the Pacific Northwest, availability of many of the materials specified and ma¬ chining services required was a problem. I decided that I should tackle the problem with the idea of us¬ ing only readily-available parts and home-brew con¬ struction techniques and see what could be done. This is the story of that ef¬ fort. First, it was necessary for me to determine just how a cavity operates and what the critical conditions were. Research showed that the cavity is merely a tuned cir¬ cuit, consisting of a quarter- wave stub centered in an enclosure. The combina¬ tion results in a well-shield¬ ed, high-Q filter when in¬ serted in series with the transmission line. As with any tuned circuit, the circu¬ lating currents are quite First coffee can soldered to the top plate, Note the telescop¬ ing tuning stub. 74 73 Magazine • March, 1983 high at resonance, so losses must be kept low to ensure high Q. The losses are gen¬ erally the result of the resis¬ tance of the materials from which the cavity is made. For this reason, most com¬ mercial units are made of brass or copper and silver- plated Coupling into and out of the cavity can be accom¬ plished by any of several means, but the most com¬ mon is inductive coupling, whereby small loops are po¬ sitioned near the inner stub and act as transformer windings in relation to it. The loops are mounted on opposite sides of the stub so that there is minimum di¬ rect coupling between them. Thus, the input loop induces the signal into the stub (which is, remember, part of a resonant circuit), and the stub in turn induces the signal into the output loop. Since the response of the resonant circuit is ap¬ preciable only at or near the resonant frequency, ap¬ preciable coupling be¬ tween the input and output loops occurs only in that range, and we have a band¬ pass filter Fig. 1 shows the low-fre¬ quency equivalent of the cavity filter, using discrete coils and a capacitor, and may help the reader to un¬ derstand the operation of the circuit. In order to build the de¬ vice with a reasonable chance of success, it is nec¬ essary to identify the criti¬ cal areas first. Obviously, the length of the center stub is critical. It must be an electrical quarter wave- Overall view of the two-meter coffee filter. One can was left un pa in ted for effect length long and, since this dimension is influenced by conducting materials near it, we must make it adjust¬ able so that we can tune it precisely to the desired fre¬ quency Also, we must minimize the losses to maintain high Q and the sharpness of the filter Silver-plating was out —for economic as well as practical reasons Previ¬ ous research showed that silver-plating at two-meter frequencies yields only marginal improvement — unless the plating is very heavy, the signal still pene¬ trates beyond it to the base metal Several articles on homemade cavities report¬ ed using brass or copper with apparently satisfac¬ tory results. Another way to reduce the losses when the housing of the device is a relatively high resistance material is to increase the spacing be¬ tween the stub and the housing, thus reducing the magnitude of the induced currents and hence the losses; however, the imped¬ ance of the circuit is also dependent upon these di¬ mensions. The question, then, was how to ensure a proper impedance match into and outof the complet¬ ed cavity filter. None of the references available cov¬ ered this point; they only gave dimensions that had been used and worked, but did not back them up with theory so that the effects of variations could be deter¬ mined A little more thought pro¬ vided the answer, though If the input and output cou¬ pling loops were made identical and mounted so that the relationship of each to the stub was identi¬ cal to the other, the prob¬ lem would be solved with¬ out even knowing what the stub/cavity combination impedance was. It would be like two identical trans¬ formers connected back to back —the load impedance would be transformed to 76 73 Magazine • March, 1983 - )! - WINDING 2 i JT^ 0U T WINDING r ! WINDING 3 SHIELD Fig . L Equivalent circuit of cavity filter whatever the stub/cavity combination required and then back down to the same impedance level in the other coupling loop. With this encouraging reasoning, construction was begun A source of brass tubing, of thin wall but $uite rigid, was found at the local hobby shop. It comes in varying diameters and 12" (30.48-cm) lengths and i$ not expensive in the quantities required I used a 1 "(2 54-cm)-diameter length for the upper section of the stub, and a V* "(1 91-cm)-di- ameter length for the lower section, so that they could telescope together, allow¬ ing the length of the com¬ pleted stub to be varied as required Since circulating cur¬ rents in any resonant circuit can be quite high, as men¬ tioned earlier, it appeared essential that the two sec¬ tions be in very good elec¬ trical contact at all times. I used some finger stock from the junk box for this purpose, soldering it to the bottom of the upper tube and another piece to the top of the lower one In this manner, when the two were telescoped together, we not only had good electrical connection, but also the smaller tube was held centered in the larger The brass tubing used, however, is sufficiently "springy" that the finger stock is not necessary. You can simply saw a number of narrow slits in the ends of the tub¬ ing and form the fingers from the resulting tabs. It is a good idea to deburr the fingers thus formed with steel wool and to form slight "hooks" in them so that the contact is not made by sharp corners that r CONTACT FINGERS ALL AROUND LOWER STUB TUBING —BRASS PLUG “Tv BRASS PLUG—; _IT threaded rod JL L UPPER STUB TyBiNG - CONTACT FINGERS ALL AROUND 7 L is Fig. 2. Details of tuning s tub construction , might bind and hinder ad¬ justment. Fig. 2 shows both the upper and lower stub assemblies in greater detail, including the homemade finger contacts Adjustment of the length of the assembled stub is ac¬ complished by means of a threaded rod from the local hardware store I chose a !4-20 size. It is secured to the bottom of the inner stub section by means of a brass plumbing fitting I chose one just slightly larger than the inside diameter of the stub tubing, I ground and filed it down to a snug fit and used it as the plug shown in the drawing It is soldered to the stub and a nut, threaded over the end of the shaft, is soldered to it, thus ensuring that the threaded shaft is fairly well centered in the stub for smooth operation when tuning. Any of several stan¬ dard brass plumbing fit¬ tings, such as adaptors to couple one size of pipe to another, will be satisfac¬ tory. Note that the threaded rod is soldered to the plug and the nut so that it may turn in relation to them A top plate for the cavity was made from some 1/16" (0.64-cm)-thick copper plate I had on hand. Any material could be used that is a good conductor, but brass, cop¬ per, or aluminum would be best The latter, however, would require different (and probably difficult) methods for making me¬ chanical and electrical con¬ nections to it; the copper or brass stock allows soldering them directly to it A clearance hole for the threaded rod was drilled in the center of the top plate and a suitably-sized nut sol¬ dered over it. The two sec¬ tions of the stub were as¬ sembled and the threaded rod screwed into that nut. The upper tube of the stub assembly was then soldered to the top plate, centered as closely as I could manage A note here about solder¬ ing these pieces together: Trying to accomplish this task with a torch or large soldering iron proved diffi¬ cult. Either I couldn't heat the entire assembly enough to get a good solder con¬ nection or it was heated so much that previously sol- Fig. 3, Top plate assembly: dered parts came loose. The solution was to preheat the material in the kitchen oven to some temperature below the softening point of the solder; then a rela¬ tively small iron could be used to attach new pieces, without heating the sur¬ rounding area sufficiently to loosen previously-made joints. The coupling loops were formed from 1/16" (0,64-cm) brass tubing from the same hobby shop source. They are formed to be 1 Va " (3.18 cm) wide over- all by 1 Vi" (3.81 cm) high, with extra material on the inner leg to protrude through the top plate, al¬ lowing for connection to the outside world. The off¬ set shown in the accom¬ panying drawings was used to provide clearance be¬ tween the loop and stub ad¬ justment screw as they came through the top plate and is Vi " (1 27 cm) in sjze. I used a Teflon 1M bushing, as shown in Fig. 3, to insulate the inner end of each loop where it passed through the top plate, but if not avail¬ able, one could be fash¬ ioned from almost any scrap plastic. Be very care¬ ful that each loop is identi- TUNING KNOB - LOWER STUB Fig. 4. Cutaway view, assem- bled cavity filter. The trim¬ mer capacitor used to insert a notch in the response curve is included. Close-up of the tuning stub, coupling loops, and shunt capacitor . cal to the other and that both are mounted in an identical manner so that the impedance transforma¬ tion for each is correct, as mentioned earlier. The two loops were sol¬ dered to the top plate, posi¬ tioned so that their inner side cleared the stub by Va " (0.64 cm), as shown in Fig. 3. It will be easier to position them accurately if a hole is drilled in the top plate where the outer leg of the loops should go and then the loops are soldered in these holes. Next, I was faced with the problem of finding a suitable outer housing for the cavity. The construc¬ tion articles in the refer¬ ences available included one calling for a 4"(10.16- cm)-diameter copper pipe for this material, 2214" (57.15 cm) long. Such pipe is not readily available in my area and has to be ordered from some distance away. Also, it is available only in much greater lengths than required and is relatively expensive. I decided to find an alternative. A search of the local hardware stores yielded nothing that would be ade¬ quate. Then, one day while doing my grocery shopping, I noticed that some brands of coffee came in one- pound cans that appeared to be about the desired di¬ ameter! Eureka! Remember the ''beer-can' 7 antennas of some years back? I had found my source of material for the cavity. The only question was if the tin¬ plated steel cans would have too much loss to be usable. I decided to try and see. I wanted new cans that weren't corroded or dented; this meant stocking up on quite a bit of coffee. I de¬ cided to try four cans, giv¬ ing an overall length of 22" (55.88 cm). After storing the fresh coffee in everything 1 could find in the kitchen, I proceeded to cut both ends out of three of the cans and leave the bottom in the other. They were soldered end-to-end, and then the open end was soldered to the underside of the top plate, centered on the stub. Fig. 5. Test setup for tuning and evaluating the cavity filter. The addition of a small aluminum box to the out¬ side of the top plate and mounting two BNC connec¬ tors on its ends allowed connection to be made to the ends of the coupling loops. Adding a second nut to the threaded shaft to al¬ low it to be locked in place after tuning and a knob to the top of the threaded shaft to make it easier to adjust completed the job. I had a cavity filter, but would it work? Fig. 4 shows a cutaway view of the entire assembly and may be of use to those desiring to build their own cavity filter. Tuning the filter and evaluating its performance showed promise of being a problem without the avail¬ ability of a well-equipped laboratory. I had an old VHF signal generator and a frequency counter avail¬ able; that combination would serve as an adequate source with precise fre¬ quency calibration. The sig¬ nal generator had an output meter so I could keep the input signal constant, and valid measurements could thus be made. But I needed a detector to permit mea¬ surement of the output of the filter. If the attenuation of the filter was anywhere near as great as it should be, I would be trying to mea¬ sure signal levels far below those readable on a VTVM with an rf probe. Finally, I borrowed a technique used by hidden transmitter hunters —I used a two-meter receiver with an S-meter and a calibrated step attenuator between it and the filter to keep the signal out of the limiting range of the receiver. Fig. 5 shows the test setup. With this arrangement, I was able to make measurements of sufficient accuracy to tune the filter and to gain a rea¬ sonable feel for how it worked. Actual tuning proved un¬ expectedly easy. Adjust the threaded rod for maximum 78 73 Magazine * March, 1983 Detail showing top plate, coupling loops , and upper por¬ tion of tuning stub. Stub in this version was soldered to a threaded fitting which in turn was fastened in a hole in the top plate . output at the frequency de¬ sired. Results indicated that the response was similar to that shown in Fig 6; I had a filter. But it wasn't sharp enough for my needs —I needed (or at least wanted) additional attenuation at the repeater's transmitter frequency, 600 kHz above the receiver's frequency. Something else was needed. Let's go back to theory for a minute At resonance, the inductive reactance is exactly equal to the capaci¬ tive reactance of the circuit and each cancels out the other; that's the very defini¬ tion of resonance At fre¬ quencies below resonance, the inductive reactance is smaller than the capacitive reactance; hence, the over¬ all result is a circuit that looks like a capacitor. Above resonance, the re¬ verse is true, and the circuit appears to be an inductor Since my transmitter fre¬ quency was above the re¬ ceiver (filter) frequency, the filter would look like a small inductor there. If I put a small value of capaci¬ tance in parallel with the fiI- ter, it should be possible to make it resonate with this apparent inductance, hope¬ fully at the frequency of the (undesired) transmitter out¬ put This would, in effect, form a parallel resonant trap in series with the re¬ ceiver input, just as the traps in many multiband an¬ tennas are formed. The re¬ sults should be similar I used a 2-15-pF air trim¬ mer. By alternately tuning the threaded rod for maxi¬ mum output at the receiver frequency and the trimmer for minimum output at the transmitter frequency, I was able to achieve results similar to those shown in Fig 7. The peak of the re¬ sponse fell at the desired re¬ ceiver input frequency, while the notch in the re¬ sponse curve fell at the transmitter output frequen¬ cy. The difference between the two measured on the or¬ der of 16 to 18 dB and, be¬ cause of suspected leakage around the cavity, is prob¬ ably greater. Since some references claimed that the maximum rejection for such a cavity is about 20 dB, I wasn't doing too bad¬ ly. I couldn t measure the insertion loss accurately, but it appears to be about 1 5 dB, which is entirely sat¬ isfactory and near the val¬ ues quoted for commercial¬ ly available cavities. Subsequent investigation revealed that at the higher end of the tuning range, the Q appeared to be substan¬ tially higher, as evidenced by a sharper filter response. This is probably due to the fact that the distance be¬ tween the center stub and the inside of the cavity is larger (in terms of a wave- curve of the cavity filter without shunt trimmer. length), so losses are re¬ duced; also, the end of the stub is further from the bot¬ tom of the cavity, also re¬ ducing losses. If I were planning to build another of these filters, I would try the larger 2-pound coffee cans and use five rather than four of them It has been many months since I built this filter Re¬ checking its tuning and re¬ sponse curve indicates no change, even though I live in a high humidity area and some corrosion was expect¬ ed; apparently it is tight enough that this will be no problem I have detected no noticeable shift in its pa¬ rameters due to tempera¬ ture excursions, although I have not subjected it to wide extremes. Fig . 7. Shape of the re¬ sponse curve of the cavity filter with shunt capacitor included. The proof of the pud¬ ding is in the eating, they say, and the proof of this filter is in the system it was intended for Without the filter, the very poor receiv¬ er I had responded to a 10-Watt signal anywhere in the two-meter band when the source was a few feet away from it; with the filter inserted between the antenna and receiver, an 80-Watt signal, at the same distance, has no effect un¬ til it is within about 30 kHz of the receiver frequen¬ cy—the bandwidth of the filter included in the receiver s first i-f. So what have we learned? It is possible, even easy, to make a cavity for your own use It isn't expen¬ sive. Flome tools and build¬ ing techniques are more than adequate. Readily- available components can be used, and most dimen¬ sions are not at all critical It is not difficult to tune up, and readily-available equip¬ ment can be used. We don't have to pay a fortune for commercial cavity filters or duplexers for low-power use. While it may be advisable to do so for wide-coverage, heavily- used machines, we can quite easily use these for low-power, local-coverage machines. By substituting a small inductor for the trim¬ mer capacitor, the notch can be moved to the low side of the response curve so several cavities can be connected together to form a duplexer; although adjust¬ ing the inductor would be more difficult than the trim¬ mer, it can be done. Maybe now we can see more of these low-power, local- coverage machines, reduc¬ ing the load on the wide- coverage systems.® References: The Radio Amateur's VHF Man¬ ual, 3rd Edition, ARRL VHF-UHF Manual, 3rd Edition, RSGB. Electronics Engineers' Hand¬ book, 2nd Edition, Fink and Christiansen, McGraw-Hill. 80 73 Magazine • March, 1983 Calvm R Graf W5UM 207 Zornia San Antonio TX 7821i Push Your Radar Detector to the Limit Without this simple modification , you won't know what you are missing—until it's too late. T he use of speed-detec¬ tion radar devices by law-enforcement: agencies as a means of enforcing speed-limit laws is becom¬ ing very controversial in the United States. A court in Miami, Florida (Dade Coun¬ ty) already throws out radar speeding cases if there is no other data presented. The State of Kentucky has a court case pending to deter mine the validity of radar as a speed-law enforcement tool If the courts later rule that radar cannot be used as a means of enforcing the The author's radar detector modified to receive signals from 5 to 15 GHz. Both receiver and audio amplifier operate off 9-volt batteries and are self<ontained. 86 73 Magazine * March, 1983 speed laws of the country, radar sets will probably not be used by enforcement agencies. The auto radar detector thus would no longer have an operational requirement What will you do with your radar detector which has accompanied you so faithfully in your auto all these past years? Extend Its Usefulness Until such time that auto radar detectors become useless/ in the sense that they may not be needed to provide an alerting function for you, a simple modifica¬ tion to almost any detector w ill let you extend your u