text: $1.00 October 1973 26009 #ceV YOU COMMUNICATIONS TOWER 100' HIGH, COMPARE BEFORE YOU BUY: Free-stcmding Ascom/ Universal Aluminum Tower Height 60' Wind rating 6 Sq, Ft, @ 80 MPH (EIA Standard) Erection requirement Tower weight Maintenance 1 man, 3 hr. 153 lbs. none Mfgr, sugg, list $466.20 Typical Free-standing Commercial Steel Tower 6C m 3 Sq, Ft, @ 80 MPH (EIA Standard) m 3 men, 8 to 12 hr. 571 [fas annual << $590.00 'jg&JK \ '/ Now— can you think of one good reason to buy a steel tower? ^ UNIVERSAL ALUMINUM TOWERS ascom electronic products 12435 Euclid Ave., Cleveland, Ohio 44106 RM640DURACELIBYMALI.ORY. 1,4V 500 m AH MERCURY CELL. FRESH: V50e 8K OF 8 BIT BYTE CORE MEMORY PLANES BY RCA ON A PLUG-IN CIRCUIT BOARD. SELECTION DIODES ARE INCLUDED ON THESE BRAND NEW BOARDS S49 50 3AG FUSE POST. LtTTLEFUSE 342 MOUNTED ON A METAL I BRACKET NEW, UNUSED £.30 DUAL 16VCT TRANSFORMER. (2) 16V, |A WINDINGS AT 1 15 VAC, 60HZ INPUT. PERFECT FOR USE IN YOUR DUAL OP AMP SUPPLY. 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ALL ORDERS POSTPAID, PLEASE ADD INSURANCE magazine for radio amateurs #157 OCTOBER 1973 EDITORIAL STAFF Wayne Green W2WSD/1 Keith Lamonica W7DXX/1 RonSubkaWA9FPP/1 Yvetre Grimes WA8ULU/1 ASSOCIATES Gus Browning W4BPD Mike Frye WB8LBP BilJ Roisington K1CLL Dave Ingram K4TWJ Jim KyleKSJKX Harry Simpson A4SCF Bill Turner WA0ABI PRODUCTION Ruihmary Davis Karen Hebert Biff Mahoney Pen Mahoney John Miller Janet Ox ley Lynn PancieraFraser Philip Price Bill Suderman Bill Sundherg BUSINESS Knud E.M. Keller KV4GG/1 CIRCULATION Barbara Block Jackie Garner Dorothy Gibson TRANSPORTATION Kurt Schmidt Jinx Town send PROPAGATION John Nelson DRAFTING T.M, Graham W8FKW Bill Moiello Waynp Peelei K4MVW FEATURES 1 Table of Contents 2 Never Say Die W2NSD/1 4 Fantastic Code Tape Offer 5 SSTV Scene 6 Slow Scan Program Contest 7 DX Footnotes 7 Social Events 8 Repeater Update 8 Contest Announcements 8 New Products 10 QSL Contest 1 1 Caveat Emptor 1 1 1 Phase Lock 112 Ad Index 112 Propagation CONTENTS 13 Converting the G.E. Pocket Mate . , , . WB4DBB Transform a pocket transceiver into a pocket transceiver! 17 Frequency Measurement at Microwaves . . WA9VFG Be prepared for equipment with tiny knobs. 21 2m Front End Using One IC K1CLL A high performance 6 transistor design. 29 Instant Replay for your Tape Recorder W6FPO A tape recorder is a must for Slow Scan. 31 2KW PEP Building-Block Linear W2EEY Module design leaves room for improvement. 39 Yet Another Wattmeter . . K5CXN Did you build your first one yet? 43 Meter Legerdemain WB2PAP Pull a rabbit out of a broken VOM. 49 Europe's DX Repeater W2EEY Is 2m WTW a future possibility? 57 Two Band Balanced Dipole W20ZH Another high -wire act for your back yard. 61 A Digital "HI" Generator WA6JMM Even a Chevrolet can learn CW. 67 Oscillating Ring Counter ...*... Weinstein October foolishness. 69 Frequency Multiplication with Transistors ........ . K1CLL Bill Hoisington turns down his thumb at the standard circuits. 77 Amateur Rules and Regulations, Part V FCC This month the watertight compartments of the Titanic are explained in detail. 73 Magazine is published monthly by 73, Inc., Peterborough, New Hampshire 03458* Subscription rates are $6 for one year; in North America and LIS, Zip Code areas overseas, $7 per year elsewhere. Three years, $14, and $16 overseas. Second class postage paid at Peterborough NH 03458 and at additional mailing offices. Printed at Menasha, Wisconsin 54942 U.S.A. Entire contents copyright 1973 by 73 Inc., Peterborough NH 03458. Phone: 603-924-3873. Microfilm edition of 73 available from University Microfilms, Ann Arbor, MI 48106. Magnetic tapes available from Science for the Blind t 332 Rock Hilt J?d. t Bala CynwydPA 19904. OCTOBER 1973 MISQUOTED The editor of a small DX publication — a sort of newsletter for contest ops — took me to task for the July article on the repeater regulations. Normally I would ignore something like this, but the technique is all too familiar and I would like to point this out in case someone mentions the piece to you over the air In this editorial I was accused of holding that it is illegal to experiment with antennas which are to be used for repeaters — that it is illegal to operate a repeater on reduced power when necessary — that it is illegal to use the same station for auxiliary link and remote control and forbidden to have more than six control operators for a repeater. Not one of these things did I say in my article — not onel From thene the editor proudly goes on to disprove my statements. Big deal. What I did say is on pages 59-60 of the July issue of 73 and has little resemblance to the statement by the editor. Obviously he was counting on his readers not reading my article - and he is probably right as 73 does not cover contest activity in depth and there probably is little overlap, Since many readers do not take the time to read through things like this carefully, and thus may be confused about the above points, let me point out that it is not in any way illegal to experiment with antennas — as long as you don't do it on your repeater* Your repeater antenna must be the one that the FCC has okayed for your repeater. If you are going to change it even for a short while, you should apply to the FCC for permission and include the horizontal and vertical patterns of the new antenna, unless it is an accepted commercial antenna, in which case you merely refer to it by its nomenclature. When you get the official word from the Commission to change, then you change- I realize that this sounds insane, but this is the way Walker wants it and the way HE reads HIS regulations — and this means that this is what we are stuck with for the time being. It is difficult to keep up with the ever changing interpretations of the rules. Walker was ad amen t at first that the control operator must have some system for keeping the repeater on the EDITORIAL BY WAYNE GREEN air with a pulse or something that would indicate that he was in active control. This seems to have been dropped - thank heavens. Walker has not relaxed much on his position on a maximum of six control operators. This is not in the FCC rules, it is just a Walkerule, but it still has caused quite a few repeater applications to be rejected; nevertheless. Walker does say that if there are serious extenuating circumstances that he might accept more than six control points. As far as operating the repeater with less than the power applied for on the license application, the Walker approach is that any changes in the parameters set up in the application must have official FCC sanction before being made. The repeater power obviously is one of these parameters and there is nothing in the rules about being able to operate with lower power with no notification. And Walkerules state that notification MUST be before the fact, not after, and that sanction must be received from the Commission before changes are made. These things are all idiotic and the sooner we are able to get rid of the paperwork garbage the better. In the meanwhile the less squabbling there is in the ranks the better. The editor who backs up the FCC to the hilt like that is no real friend of amateur radio. JOHNSON BLASTS FCC FCC Commissioner Johnson, whose term officially ended July first, but who is serving until Nixon finds a successor, lashed out at the Commission recently in an article in the Yale Law Journal. Johnson said the FCC is "manipulated daily by the industries it is supposed to regulate and by its staff." Certainly amateurs have seen that happening in recent months, with the deluge of new Walkerules and the 224 MHz CB band that seems to be wanted by only the Electronics Industry Association — the Washington lobby for the CB industry. Money talks. "As a result," Johnson continued, "the commissioners often make precedents which return to haunt them." Like the 27 MHz CB band, perhaps. NASA NIXES HT With a bonafide ham aboard the next to the last Sky lab trip, it seemed a natural to have him pack along a little hand unit for some two meter FM work. The space and weight were no problem — but the politics was* Owen W5LFL was already in the clean room a few days before departure when K3GKB managed to get a little four channel hand unit through to him via Owen's wife — only to have NASA officials turn thumbs down on the basis that they didn't want to have any possibility of anything being said from Skylab that they couldn't censor before release. Some amateurs have gotten reprimands from NASA for tuning in the down link and giving the information to news media or letting it go through local radio stations. NASA wants complete control over everything coming from space. Pity. Imagine the pileups on 34/94! And 52/521 Plus he had one 147 MHz channel set up for simplex that Clegg users would be able to jump on right away. Pity. REPORTS NEEDED Though radio amateurs are intimately involved in virtually every serious disaster, not one in a hundred are written up and sent in for us to use in the newspages or in our letters to congress, Please give us the news to use for these valuable services. Most ops who get involved in emergency work put their all into it and then figure that once the job is done the job is done. There is still a responsibility to help amateur radio by making known what has happened so you can reconstruct the story later and know that you have it straight. While only 73 and OST are into this type of news, I can assure you that both of these magazines will appreciate knowing what has happened. 73 gives you the extra advantage of knowing that your story has a good chance of being told to congress — and might get into the Congressional Record. FCC HEARING Plans are well along for a public hearing before the FCC Commission- ers en banc on the matter of the FM repeater rules. The hearing seems to be coming as a response by the FCC to the 73 editorials and pressure to re-examine docket 18803. The en banc hearing was suggested by FCC Chairman Dean Burch in a phone call to 73. A position paper is in the works which will explain the problems with the new rules, why these rules present 73 MAGAZINE CONSIDERABLY SPECIAL CONSIDERING THE SPECS 2 METER FM TRANSCEIVER Frequency Model SRC-146A * » » ■ 143-149 MHz (2MHz spread) Number of channels , . . . , 5 Supplied with 146.94 simplex, 146.34 A 94 (same plug in crystals as SR-C826M ) R.F. output 2 watt minimum Sensitivity , . # * .better than 0.4 uv/20 DB Q,S. Audio output , 500 mw Meter monitors battery voltage on Tx, S Meter on Rx Current drain ....*... 620 ma Tx t 15 ma Rx standby Size. ,.8 3 /s" high x3" wide x 1 s /8"deep Weight .......... 24 oz. t less batteries Options: Private channel (CTCSS), external mic T or mic-speaker, stubby flexible antenna, desk top charger, leather case. Suggested Amateur Net Price NEW 2 METER REPEATER SCA-RPT-1 All solid state, 2M, 10W T FM REPEATER. Built-in C.O.R., adjustable carrier delay and time out timer. Write tor complete specifications and cost. Standard L COMMUNICATIONS CORP. 213/775-6284 ■ 639 North Marine Avenue, Wilmington, California 90744 OCTOBER 1973 problems, and what amateurs re- commend be done to improve the rules. This paper will be provided lo the Commissioners and other interest- ed parties (Walker?) before the hear- ing. Representatives of many of the major repeater groups will participate in the hearing. Since time will be very limited, this will probably be kept down to perhaps a dozen at the most. Every effort will be made to have intelligent, well informed and erudite men to answer for all of us at the hearing. The last thing we need is some egomaniac taking the floor to create a bad impression and waste the whole hearing for us. > .and, as you may realize, amateur radio has more than its share of these critters. The ARRL was granted a hearing by the Commissioners on July 9th and the reports are that they created a favorable impression with their pre- sentation of the good aspects of ama- teur radio, Unfortunately they appar- ently did not get around to explaining why amateurs are so uptight with Walker about the new rules — so this job is still ahead of us. It is hoped that the result of this hearing will be a re-writing of the repeater regulations. There are many of them that are in bad need of elimination or serious change. Con- sidering the degree of self-regulation of amateur repeaters, it would seem beneficial to have all of the antenna restrictions removed, power limita- tions removed, crossband restrictions removed, control restrictions remov- ed, map coordinates and height calcu* lations removed, block diagram re- quirements removed, band limitations removed, power calculations and an- tenna pattern requirements removed, multiple repeater interconnection re- strictions removed - and things like that. Amateurs, based upon their fantas- tic record of achievement and service, deserve to be set free to experiment and develop in whatever way they desire. Once we are able to back Walker down on his Walkerules and Walker- interpretations, perhaps we can get to work on bringing other recent rulings into line — such as the third party traffic restrictions. The FCC handed out a notice of violation to an ama- teur in a drive-in theater who revealed the price of admission to someone on their way to the drive-in I This insanity has to stop too! The original rules prohibit pecuniary interest and per- haps that is where it should stop. If a chap in Bolivia wants to know where the devil his antenna rotor he ordered from an outfit in New York is, we should be able to call in for him and find out* The fact is that Ma Bell makes out just fine with most phone patches and darned few ham messages cut into any possible phone revenue* Ma is doing very well anyway, and her major problem is in keeping up with service, not trying to hog it. We'll try and bring a full report on the FCC hearing - hopefully with some good news on possible rule changes. Repeater councils that are interest* ed in helping support this hearing should immediately prepare a paper outlining the rules that should be changed - why they should be chang- ed and how they should be changed. Councils who have provided this paper have a right to send a representative to the hearing. Please send the paper to 73 Magazine — and let us know who your representative might be and how to get in touch with him (or her?). In answer to the editors and ama- teur radio officials, elected and self appointed, who took the time and trouble to point out that there was no use in complaining about the repeater regulations — that nothing could be done — that a petition was a waste of time - that we should all just depend upon the League — I would like you to realize that it is indeed possible for someone in our country to speak up and be heard. It is possible for some- one to get action. It may even turn out to be possible for rules to get changed! In this case it was Wayne Green that made the outcry — but it could just as easily have been any individual con- cerned amateur. Space is available in 73 - and possibly elsewhere for this sort of thing. If you speak up 73 will back you up. IBM TAPES NEEDED The tapes for the 73 Magazine MTST IBM composer are wearing out and we need more. Does any reader know where we can get some for a reasonable price? Help I 73 AGENT DOES WELL One 73 agent made over S300 at a hamfest in commissions — perhaps you might look into this? That's not a bad pay for a day's work, you know. Drop a note to 73 Magazine and send some references. DAYTON EXPANDS - AT LAST! The Hamvention committe has at last decided to expand the Hamvention to a full two and a half days. Thousands of amateurs will certainly cheer this decision — as will an awful lot of manufacturers. Any amateur with more than one or two interests in the hobby has had a heck of a time getting to the talks of importance. With all of the talks scheduled in one day, there was incredible overlap. DXers missed important RTTY meetings - delightful SSTV meetings — and so forth. With over two full days for meetings and talks, these things may be able to be spread out a little better. The size of the flea market has been such that no serious scrounger could possibly do it justice in one short day — there was just far too much. And the manufacturers exhibits were so packed with hams that only about one in five Hamventioneers could break through to ask a question. The odds should be a little better next year. This will be better for the manufacturers too — for they will have a chance to talk personally with more prospective customers — and make more sales — the basic reason for the long trip to Dayton. The largest hamfest in the country can only get larger with this move- CASSETTE TAPE CODE COURSE 73 is offering a cassette tape code course that is so simple that the average person can learn the code fast enough to pass the Novice or Tech exam in a few hours. One of the beauties of cassette tapes is that you can take them with you anywhere — at work for lunch break — in the car while you are driving - cassette re- corders are simple and inexpensive - and are useful for dozens of ham applications. This cassette code course will teach the International Morse code at five words per minute — all letters, num- bers and punctuation. The tape not only gives all of these characters, but gives them in a very simple order so you can start copying code within one minute of hearing it. This has got to be the easiest way to learn the code ever invented. The cassette actually has the code being sent at about 6 wprn, allowing a margin for operator panic when the chips are down and the real exam is at hand. It makes the 5 wpm code sound a whole lot slower — and that is a help. And wait* 1 1 you get a look at some of the stuff you'll be copying on this tape — pure Wayne Green, of course. You may lose your place the first time through when some of the stuff hits you. There's no reason why copying code shouldn't be fun — right? Send now for the 73 Morse Cassette Code Course — only $3.95 postpaid from 73. WAYNE 73 MAGAZINE Dave Ingram K4 TWJ Rte. 1 1, Box 499, Eastwood VfL SON B/rm/ngham AL 352 10 SSTV CONTEST ANNOUNCED This winter promises high Slow Scan activity, and we're kicking it off with a Slow Scan Program Contest It works like this: Make up your prize winning program (6 minutes maxi- mum) on a cassette, and send your entry to 73 Magazine. They will be compiled and reviewed, then forward- ed to another "anonymous" judge to be reviewed again! Firrai results and prize winners will be published. Selec- ted frames from winning tapes will also find a prominent place in these pages. All entries will be judged on origi- nality, with technical aspects counting in the scoring. This contest begins now and ends December 31, 1973. Be sure to include return postage for your tape. The purpose of this contest is to get more fellows thinking and acting in terms of good purposeful programs, not just I Ds and CQs. Last month I briefly described some basic scan conversion techniques from the aspect of both solid state and dual gun (lithocon) electron tubes, I also mentioned Don W9NTP, and Art SM0BUO, were developing a converter unit that used the Thompson TME 1238, a single gun storage tube. Since this tube is rather unique, [only one electron gun is used) I have a brief description this month. Figure 1 is a simplified sketch of the tube. First the Slow Scan video is fed in on Grid 1, and stored on the mosaic target. Next, Grid 1 (writing grid) is biased to give a constant electrong flow. The electrons now repelled by the "reading" Grid 5, and can be fed to a video amplifier Since the reading grid does not affect the target (because it doesn't scan it) it is SLOW SCAN I IDEA INPUT umu i ■ ■ ■ ■ SILICON MOSAIC TARGET _ t. ■* "T> T ^ j: * ■ ■ iMot-ei itrlr? in manner 1 I ■ ■ ■ ■ ■ ■ Rudciuil GRID GRID 5 FAST SC AIM Fig. 1. Simplified sketch of a single-gun storage tube. considered a nondestructive readout device. In fact, Don turned on his unit two weeks after the Dayton Demonstration, and his last picture was still there! {Of course it wouldn't last this long if rt had been constantly "read/') Our thanks to Dr. Miller for the previous info on the Thompson CSF tube. I understand Don replaced the bad video transistor that caused the noisy pictures at Dayton, and now the unit is working well. Incidentally Don agrees, like many others, digital pro^ cessing is probably the better way to approach scan conversion from a "standstill/' In fact, 3 MOS shift registers, driven by red, green, and blue Slow Scan information could be used to give Slow Scan displayed on a color Fast Scan TV in real time, This is probably 2 or 3 years away yet. A couple of the fellows suggested this MOS shift register method over my "crt/dichroic mirror" color scheme, and I agree this is better. However, for the next few years, the tubes and dichroic mirrors (advertized in the July issue for $4,95 each) should be less expensive. Here's some more info on the weather satellite I mentioned last month whose facsimile transmissions might be of interest to Slow Scanners. At this time the four main satellites of interest are ESSA-8 (137.62 MHz), NOAA-2 (137.50 MHz), ATS-1 and ATS-3 (both on 135.60 MHz). ESSA-8 and NOAA^2 are orbital satel- lites, with an orbital period of 114 minutes, inclination of 101 degrees, and an altitude of 906 miles. (Orbital info is given on W1AW bulletins.) ESSA-8 transmits only while the spacecraft is in daylight areas, and cuts off when it enters a dark area. NOAA-2 is said to be transmitting continuously. ATS-1 and ATS-3 are fixed position (geosynchronous) satel- lites. ATS-1 is approximately 4,000 miles above Venezuela (70 a West/0 " latitude). Both of these satellites scan (and can be received by) about 1/3 of the world. You can get a rough idea of this coverage by placing an object 4,000 scale miles above Venezuela on a world globe, for example. Then look at the globe from that point, and you'll see what the satellite sees. If it's "line of sight" (use a piece of string from your QTH to satellite) you should be able to receive it. ATS-1 transmits daily at 0130 to 0215 GMT, and again at 1400 to 1445 GMT. ATS-3 transmits daily at 0730 to 0815 GMT and again at 2045 to 2130 GMT. AH of these satellites (except NOAA-2) transmit primarily on fac- simile using an amplitude modulated 2400 Hz tone. Maximum amplitude (80 to 100%) corresponds to white, and minimum amplitude (30 db below this) is black. The horizontal line rate is 4 per second, (240 lines per minute) and a total frame lasts approximately 208 seconds. NOAA-2 differs only in that it has a 48 line per minute rate. For satellite copy on a surplus deskfax unit, simple video inversion is necessary. (Because maximum ampli- tude gives the darkest line on current sensitive fax paper.) Then we increase the drum speed from 180 rpm to 240 rpm. There are several methods of accomplishing this like, for example, dividing the 2400 Hz received signal by 30 and using this resultant 80 Hz to run the motor, thus giving 240 rpm. Another method of copying pic- tures from the satellites is with a converter (for obtaining proper hori- zontal and vertical timing, a video demod/amplifier, and "front end" limiter) feeding a 'scope or Slow Scan monitor. A camera is then used to photograph the screen (three minute picture. . .strictly Sloooow Scan!}, thus reproducing the picture. Special thanks go to Bob WA7MOV, for his QTH ANGLE OF ELEVATtOM - -^ SATELLITE LOBE MILEAGE SCALE Fig. 2. Setup for measuring satellite antenna positioning. help in compiling much of the above info. I've also received word from R. L. Drake's Service Manager, Their 2 meter gear should receive okay on 136 MHz, although they have not tried it. Possibly the 2 meter rig's crystal oscillator coil may need slight retun- ing. (Why shouldn't it work. Many put crystals in 2 meter rigs to pick up Police calls on 150 to 160 MHz.) Mr. Frost of R, L. Drake says crystals are $7.50 each for the TR-22 and are not returnable. Also the TR-22 bandwidth is 20 kHz. ,. fine for satellite copy. Say — how about a Bearcat "scanner" set up to copy all the satellites. Barry VK5BS, recently vacationed in the Fiji Islands, carrying quite a bit of SSTV info in hopes of getting some of their hams on slow scan. (Two packs of info I sent him arrived just a couple of days before his departure!) Hopefully, we will soon know the status of SSTV in Fiji. And finally, the Independent Side- band boys are gathering on Tuesday nights between 14.230 and .240 kHz for I SB SSTV operations. If you Ye interested, here is the place to be to get in on the action. , . .K4TWJ OCTOBER 1973 ■ --'-»£$&ixsnmM!i!*i «.. i. . -. magazine's a single frame of your RULES: ^tlflplc (IT yCfl /? flfl m ^ minute maximum time length longer enough — you 've got more talent than that nows your chance to prove it? First Prize ROBOT Model 61 Fast Scan Viewfinder Other prizes to be announced. Subject matter is limited only to your imagination — anything goes. Label cassette with your return address and include sufficient re- turn postage. All programs will be returned. Decisions of the judges will be final. Contest starts now — entries must be mailed before December 31, 1973. Use only enough time to effec- tively bring across your idea. An idea that is best expressed in 2 minutes will turn into a horrifying bore if interspersed with 4 minutes of filler. Don't repeat frames except for a purpose — the closed-circuit quality of tape makes repeating unnecessary. Please do not send a script or explanation of your program. Since Slow Scan is a visual media, every- thing you want included in your program should be on your tape. Send your entry to: Slow Scan Contest, 7 3 Magazine, Peterborough, NH 03458. 73 MAGAZINE Gus Brown) ng W4BPD Drawer "DX" Cordova, SC 29039 SOME QSL INFO: A26AC via 4S7YL AP2MR via Callbook address C29ED via VK3TL CT2AZ via W0 JHY EL7D via DK3IA EL0 Q via LA9GG EL0S via YU3RCZ ET3USD via WA4HVQ F0ALN via K4II FBflZB via F8US GC5AGA via K4II HB0AVB via DK3ST HW3UIT via F9QE JW4EJ via SM5BCS JW7FD via U\3UC JX6VO via LA IRQ JX9TM via LA9TM SVPWY via WApVPX M1C/D via I4FTU TJ1BG via K4WQS TY7ABM via DL7JJK WI9ANG via WA9DZL WF20C via W2HAQ WS4SKY via WA3NAN 3D2JA via W2QVC 5Z4KL via GM3VLB 7W3ITU via 7X-buro " 9X5MV via DJ2AZ If you want to see more DX QSL info each month let me know because I can give you a lot more than the above. WTW VERIFICATION POINT: I wish to announce that we have a FB DX Club that has volunteered to act as our WTW {and 73-73-73. too) verifi- cation point for all of W/Kl, W/K2, W/K3 land. More or less centrally located too; The Thomas A, Edison Amateur Radio Assn. c/o WB2FVO Club QSL Manager William W, Inkrote, Jr. 52 Elliot Place Edison, N J. 08817 - US.A. Be sure to send them all your cards to be checked. Send along the $ 1.00 to help the expenses for your certificate, and also send along enough extra for the class of postage to return your cards to you. They will give you very fast service I am sure - I will mail you the certificate that you qualify for when they notify me that your cards have been checked and that you have qualified O.K. We still need more verification checkpoints, how about your club ? I am at last getting things fixed up here and will be seeing all of you on or near 14220 sometime between about 2200 to 2400z. 73 till next month - de, -^U4- B P D RATARAMA The Mount Airy VHF Radio Club, Inc., presents the annual Pack Rat Hamarama, Sunday October 7, 1973, at the Warwick Fire Co,, Jamison, Pa. The Warwick Fire Co., is located on Rt. 263 North of Philadelphia. Activities include a giant flea market, auction, and an amateur TV demon- stration. Festivities begin at 10 AM. Food concession on premises. Regis- tration is $1.00, flea market tables or tailgate safes, $2.00. Talk in on 146.52 and 52.525. For furthern in- formation contact: Dave Zimmerman W3ZD, 520 Centennial Rd., War- minster PA 18974. MIDWEST CONVENTION The ARRL Mid-West Convention is being sponsored by the Lincoln Ama* teur Radio Club this year. It will be held on October 6 and 7 f 1973, at the Villager Motel and Convention Center in Lincoln, Nebraska. It promises to be one of the largest in the Mid-West, drawing on radio amateurs in a four state area and more. For information contact: G3UGH/W0. c/o Lincoln Amateur Radio Club, Inc., P. O. Box 5006, Lincoln, Nebraska, 68505, MID-SOUTH HAMFEST The Mid-South ARA is holding its 1973 Hamfest on October 6 and 7, at the State Technical Institute in Memphis TN. There will be a MARS meeting, FM Symposiums and other activities. Contact: Harry Simpson W4SCF, c/o Mid-South ARA, 1830 Macaulay Ave., Memphis TN 38127. CHAUTAUQUA AUQTION The Chautauqua County NY FM Association's third annual auction will be held October 13, 1973, at Shore Acres Boat Yard, Bemus Point NY. For further information write to Robert Greenwald WB2YQO, Rte. 2, Box 76, Jamestown NY 14701. OCTOBER REPEAT A special meeting of the Illinois Repeater Council will be held on Saturday, October 20, at Southern Illinois University- Hosted by WR9ABU, all Illinois and adjacent repeater representatives are cordially invited. Contact; Kontact Kim King, Sec. IRC, 1618 Linden, Des Plains IL 60018,312-824-8419 TAMPA BAY Seven Tampa Bay Area clubs have joined forces to present, perhaps, the largest ham gathering in the State of Florida. Over $2500 worth of prizes will be awarded by drawings. First prize will be a complete Galaxy 500 station. Registration is S2. It will be held on October 6 and 7, 1973, at the Electrical Building, Florida State Fair- ground on N. Boulevard, 2 blocks north of Kennedy Boulevard, begin- ning at 8 AM local time, inquiries may be sent to Mr. George Dixon WA4VQT, 12915 Veronica Ave., Tampa FL 33612, In addition, we an? providing an information station on the air Monday, Wednesday and Fri- day, 7 - 7;30 PM EST and Sunday, 10 - 10:30 AM on 7280 kHz. ADRIAN HAMFEST The Adrian Amateur Radio Club Inc, of Adrian Michigan, presents their fall Hamfest, Sunday October 14, 1973, from 8 AM to 3 PM, at the Lenawee County Fairgrounds on Dean St Talk in on 1812 kHz - 3935 kHz - 52.525 MHz - 146,46 MHz - 146,52 MHz - and 146.94 MHz. All buyers, sellers and visitors are welcome. Plenty of refreshments and prizes. Cost $1.00 in Advance, $1.50 at the gate. Tables $1.50 per half table. For information on tickets or tables write to the Adrian Amateur Radio Club, P. 0. Box 26, Adrian Ml 49221. FAR-OUTing The Foundation For Amteur Radio will hold its annual Hamfest at the Gaithersburg Fairgrounds, Gaithers- burg MD, on Sunday October 21, 1073. Featured is a large flea market, food service, exhibits, ladies events, supervised children's program and many prizes. Main events are all in- doors. Picnic grounds and free parking available. Will be held rain or shine. Participation fee $1.50, sales space $5/00, Talk-in service provided. Near- by motel rooms available. For info write or call Bill Miller K4MM f 10919 Woodfair Rd., Fairfax Station VA 22039. 703-893-2450. TERRY SWAP The Terry County Amateur Radio Club's 19th Annual Brownfield Free Swapfest will be held on October 14, 1973 in the National Guard Armory, Brownfield, Texas. Doors open at 6:30 AM and Swapfest activities last until 3:00 PM. No registration or admission fees! Door prizes. Largest Amateur Radio flea market in Texas! AH exhibitors, amateure, CBers and families welcome. Free parking and trailer camping in Coleman Park a& jacent to the Armory, OCTOBER 1973 f REPEATER UPDATE LISTENING §4 76 88 73 70 64 82 AL WR4ACK Oritur 145.40-14700 At WR4ACB B'tmiafum 14fi.tG-14-G.76 14B.13-I4fi.7fi CA WR&ACB Li Hibra Hit 146.11H46.70 CA WR6ABX Wttodlmd 146.37-146.97 CT WR1ABA Sftniburv 146.2214612 CT WR1ABC Tflfiififton 223 06224.66 FL WR4ACV fioci ftllon 146.22-145 82 IA WRIABS Ofrtflport 1462214682 IL WR9A9X Rock Iriind 146.34- 146.94 III WH9A8P ImJunipolis 14C.1 6-146.76 III WR9A9W KobofflG 146JM46.91 KS WfllABO PrTBbwrf 145.13 146.73 KV WH4ACQ Asttlifid 146.34 146.94 MA WRIAiO Worcerttf 146JM46.97 MA wniAtv Witthtrn 140.04 146,54 MA WHlAlK F onfall ra 146.31 -146.91 MD WR3ABQ Hirmiitf PL 443.55-4W.95 MO WRiABC Bonn* Ttm 146 29 146 96 NY WR2ABF Rochrttti 146,19146.79 OH WRQASA ML Vprnon 146 T9 146.79 OH WH6A9C Draltnd 146,16-146.76 OH WRIABF Dayton 146 34 146.94 OH WHBABG Springfield 146.13-146,73 OH WH5ABH Hudson 14611446,61 OH WRtABJ Mmrcomentown 146 16-14676 OH WRBABO Chtlltcacht 146,261 45.85 OH WRHA&P Cincinun 146_2S 145.86 OH nnflnoR Diitwtff T46.37-146J7 OR WR7ABJ Wettport 146.1B-145.7fi PA WR3ABF Valley f Offf Plinned PA WH3ABG V*II«Y Foifi Planned PA WR3ABH ViMty FofOf 222,34223,94 PA WR3AB! ViHty Forgt 14634 146,94 TX WRSABM Brownftild 146.2 2- 146. 82 VA WR4ACW Richmond 146.29146,88 Wl WR9ABV tikt Ginavi 146J7146,97 Wl WR9ABS Mifwoukee 146.25-1 46.85 CONTESTS ~z 3ET Tom DiBiase WB8KZD 708 6th Avenue Steubenvttie OH 43952 Oct. 6-7 Oct. 6-8 Oct. 13-14 CONTESTS Sept 29-Oct. 1 Delta QSO Party New Mexico QSO Party California QSO Party RSGB 21/28 MHz Telephony Contest Oct. 20-21 RSGB 7 MHz CW Contest Oct. 20-22 North Carolina QSO Party Nov, 2-5 CHC/FHC/HTH QSO Party RSGB 7 MHz Phone Contest QRPPCWQSO Party Nov. 34 Nov. 5-1 1 Month New Mexico QSO Party From 220 GMT October 6 to 0100 GMT October 7; 0200 GMT to 0600 GMT and 1800 GMT to 2200 GMT October 7, 1973, Frequencies are 65 kHz up from the bottom of each CW band, phone near the edge between General and Advanced frequencies, Novice near the middle of each Novice band. Only NM stations call CQ Contest near these frequencies, Exchange QSO number, RS/T and QTH (county for NM, state, province or country for others)* Stations may be contacted only once on each band, and again if he changes counties. Intrastate NM contacts are valid. Score 1 point per QSO. NM multiplier is total states, provinces, countries and NM counties, Non-NM use total NM counties for multiplier. Appropriate awards. Full log data, including exchanges, should be sent to Bill Wageman, K5MAT, 35 San Juan, Los Alamos NM 87544 by November 1, 1973. California QSO Party From 1800 GMT October 6 to 0600 GMT October 7, and 1500 GMT October 7 to 0300 GMT Octber 8. Same station may be worked once per band/mode. Exchange QSO number, RS/T and QTH (county for California, ARRL section or DX country for others), California stations work anyone. Non-California work California only. Score 1 point per QSO. Multiply total QSO points by total California counties worked or total ARRL sections (including California) and DX countries worked. Frequencies are 3560, 7060, 14060, 21060, 28060, 3880, 3980, 7280, 14280, 21280, 21380, 28580, 3725, 7125, 21125, 28125. Appropriate awards. Logs must show date, time, band, mode, exchanges sent and received. Logs can't be returned. Be sure your call is on each page. A summary sheet is required showing counties, ARRL sections and DX countries worked, breakdown of QSOs per band and scoring. Include your name, call and address in large block letters. Mail logs before November 7, 1973, to John Minke, W6KYA, 6230 Rio Bonito Drive, Carmichael, California 95608. Include a large SAS for results. Comments are encouraged and appreciated. North Carolina QSO Party From 1800 GMT October 20 to 0600 GMT October 21 and from 1300 GMT October 21 to 0200 GMT October 22, 1973. Each station may be worked once per band/mode and again if operated portable or mobile, and with each county change. Exchange QSO NR, RS/T and QTH (county for NC; state, province or country for others. NC score 2 points for out of state QSOs, 1 point for QSOs with other NC stations, multiply total points by number of states and provinces worked. Out of staters score 2 points per QSO and multiply total by number of NC counties. Frequencies are 3575, 7090, 14070, 21090, 28090, 3710, 7110, 21110, 28110, 3810/3900, 7290, 14290, 21310, 28510 (all are plus/minus 10 kHz). While on 3575 try not to QRM the Carolina's traffic net which meets at 2300 GMT and 0200 GMT near that frequency. The entire 6 and 2 meter bands can be used, and repeater QSOs count. Appropriate awards. Mail logs before November 25, 1973 to Charlie Wells, K4SK1, Rte 8, Box 414, Greenville NC 27834. By the shadow on the wall I see that it's time to wrap up another column. Until next time, "CQ Contest, CO Contest, CQ Contest/' Tom WB8KZD NEW PRODUCTS SBE Scanvision The W2NSD/1 Scanvision package being tested with special zoom lens. SBE has come up with a beautiful slow scan system — complete with a built in cassette tape recorder. This system makes it duck soup to put together your own tape programs, . .and let's face it, this is the way slow scan has gone. With tape reproduction of a slow scan usually identical with "live" camera work, it is only logical that most ops have opted for using tape. It doesn't take long sitting still for eight seconds in front of the camera — and then jumping up to refocus (which isn't all that fast a process unless you have a fast scan monitor too) on a menu board for giving your name, location, signal report, and perhaps a QSL — before you are thinking seriously in terms of tape* Unfortunately, many of the cheaper recorders are not adequate for the job 8 73 MAGAZINE REPEATER OWNERS Don't Take Chances. SENTRY offers custom made crystals made exactly to your specifications. When it comes to crystals for your repeater, BUY THE BEST -SENTRY. .'.■.'.'.Vi'.'lViViVrVA , Vfc"| , B"-l , B a | , -"| , -"l - ' ■ ' ' ' ■ .-.-.'.■ ■■l'd' y< ■ ;■ :>:£*# REPEATER USERS If you want reliable access to the repeaters in your area, you want and need SENTRY CRYSTALS. SENTRY CRYSTALS are custom made for your rig. We don't stock a large quantity of crystals for a certain frequency and hope you can tweak them to frequency in your rig. We do offer FAST service on crystals made especially for you and your rig. If you want reliable, on-frequency operation, INSIST ON SENTRY. SENTRY MANUFACTURING COMPANY Crystal Park, Chickasha, Oklahoma 73018 PHONE: (405) 224-6780 TWX -9 10-830-6425 OCTOBER 1973 mm and there are little squiggles which result from not too steady tape drive mechanism. Once you are set up with a good recorder you can start putting together short tape programs — a view of your shack — picture of you — your wife - with titles. You can tape the OTH and CQ calls. You can work up a short program showing some of your other interests than amateur radio — which is r.ot only interesting to viewers, but affords plenty to talk about if you match an interest with someone else. You can put together a program of your QSLs for each country worked, unless you are one of the real slow scan DXers with 73 countries worked, in which case it would take about ten minutes at one card per frame, to show the bunch. Even so, that might be a little better than some of the dumb cartoons that are being shown- The SBE Scanvision camera has one very handy feature — an automatic contrast control. The less controls you have to diddle with the better. There •S a manual over-ride for knob twisters. After using the Scanvision for several weeks, there are several things that stand out — the ease of hooking it up for use — the beautifully sharp picture — the convenience of the built in tape deck — and {most of all) the fun of actually seeing the fellow you are working. The Scanvision manufacturer also makes commercial broadcast television cameras and this is obvious when you open the camera and take a look at the construction techniques. . .beautiful! This shows up in the picture too — just take a look at a grey scale on this monitor and see how much more you get than you might expect. Linear Systems is to be congratulated for making this superb slow scan unit available — slow scan will, it seems certain now, be one of the big growth aspects of amateur radio during the next few years. Once you see it in action you are hooked. TONE PADS Interface Technology has introduced a Touch -Tone generator designed to aid repeater and auto- patch users. The unit generates the 12 standard frequency pairs used for Touch-Tone dialing by the telephone companies. It is designed so that the output can be used in several ways. For one, a speaker included in the kit can be mounted internally and the unit simply held up to the micro- phone. The speaker can also be mounted in a small, remote case (not supplied) and connected by a cable to the generator. This allows the user to position the generator on a table or desk while the speaker is held up to the microphone, A third approach is to wire the unit directly into the microphone circuit, eliminating the need for the speaker altogether. There are no switches or controls on the unit other than the key pad, so no current is drawn from the standard 9-volt transistor battery until the operator touches a key to generate a tone. This feature insures long battery life and simplicity of use. The unit is lightweight and packaged in an attrac- tive black molded plastic case, For more information contact: Interface Technology, Inc., 10500 Kahlmeyer Dr., St. Louis, Missouri, 63f32. 314-426-6880 SBE SCANNERS Linear Systems has announced the introduction of a complete line of scanners which cover frequencies from 30-470 MHz. The entire line, known as the Sentinel Series, consists of six separate models. The Sentinel includes 8 channels for scanning, lock-out switches, man- ual or automatic scan operation and AC/DC capability. An important fea- ture of the Sentinels is the priority channel which assures the reception of the most important channel. All come equipped with cord/plu sets for either 12V dc or 115V ac operation* Also included is a screw-in telescoping an- tenna for VHF and where applicable a separate VHF plug -in antenna. The receivers have excellent sensitivity of .3jj V with selectivity rateo at -6db @ 9 kHz, Audio output is 4 watts and the receivers are designed to operate over the temperature range of -20 'C to +50 'C, The specific model numbers and frequency ranges are Sentinel I high-low VHF, Sentinel M high band VHF, Sentinel 111 low band VHF, Sentinel V UHF r Sentinel VI UHF high band, and Sentinel VII marine VHF. For further information contact: David K> Bradley, Vice President, Mar- keting, Linear Systems, inc., 220 Air- port Boulevard, Watsonville CA. Tele- phone; 408 722-4 177. ooxTEsrr Jane OCEANS' DE Jane Rice WA60ZS, captured the heart of our contest judge this month with her homebrew silkscreened entry. Win a one year subscription to 73! Send your QSL to: QSL Contest, 73 Magazine, Peterborough NH 03458. CANADIAN GOVT. SUPPORTS REPEATER GROUPWITH GRANT $6,772 AWARDED State-of-the-art thinking on the part of Canada's Department of National Health and Welfare has prompted a $6,772 grant to a repeater group in Courtenay, B.C. Realizing the impor- tance of VHF repeaters in providing emergency communications during times of disaster, the grant was endor- sed whole-heartedly by civil defense authorities*. The planned repeater will provide communications within a 150 mile radius. Meanwhile, back at the FCC. . . 10 73 MAGAZINE ♦:♦:♦:♦:♦:♦:#:♦:♦:♦:♦:♦:♦ Caveat Emptor? ♦:♦:♦:♦:♦:♦:♦:♦:♦:•:♦:♦:♦. Price — $2 per 25 words for non-commerciaJ ads; $10 per 25 words for business ventures No display ads or agency discount. Include your check with order. Deadline for ads is the 1st of the month two months prior to publication. For example. January 1st is the deadline for the March issue which will'be mailed on the 10th of February, Type copy. Phrase and punctuate exactly as you wish it to appear. No all-capital ads. We will be the judge of suitability of ads. Our responsibility for errors extends only to print- ing a correct ad in a later issue. For $1 extra we can maintain a reply box for you. We cannot check into each advert iser, so Caveat Emptor . . . WESTERN UNION DESK FAX trans ceiver manual: Complete theory of operation, adjustment, lubrication, preventive maintenance, troubleshoot- ing, parts list. Includes all schematics and mechanical parts drawings. $3.80 postpaid. Bill Johnston, 1808 Pomona Drive, Las Cruces, New Mexico 88001. "WANT VIBKOPLEX carrying case. Advise condition, age and price. P. O. Box 191 r Rye Beach NH 03871." 2 METER FM Brand new HR-2A 94/94, 22/82, Hustler 5/8 trunk lip r warranty, perfect. WA6LZH, 4130 Carson, Oakland CA 94619, 415-530-7187, COLLINS MP-I Power Supply, new never used, trade for 516F2, PM-2, 312B4, HT220, or ST-6. Want to buy 32S1. Fred Slaughter, WB8IJX, 3636 Douglas, Toledo, Ohio, 43613. "DIGITAL MULTIMETER - 3 % digit franklin model 500, - $60. Chart recorder, - $20. 6' x 19" rack cabinet - fully enclosed, - $40. EMC 5 MHz Oscilloscope, - $90. Sell or swap. Jim Einolf, 1218 W. Ionia, Lansing Ml 48915/ Tf FOR SALE: GE Porta-Mobile 2m, 10 watt portable with nicad, 94/94, 22/82, $300. HT-22Q, two watt, two channel with charger, $275, MQTRAC "A" model transmitter and power supply, $35. MOTOROLA pocket- receiver with nicad, $45. MIDLAND CB? - $25. Gary Eberle, WA6CW, 1655 Via Escondido, San Lorenzo, CA 94580. WANTED: Facsimile equipment, weather satellite equipment and/or information, RTTY machines 100 wpm. Ken DeBrecht, WB6NOV, P. O. Box 1086, Novato CA 94947. EQUIPMENT FROM 73 The following list of gear, unless otherwise noted, consists of brand new equipment purchased for testing purposes only. Cap-Corn 40m solid state SSBxcvr $150 Heath IB-101 counter with Vanguard Scaler $250 Clegg 27B 2m xcvr S380 IC-22 2m FMxcvr * $246 Midland 1 3500 2m xcvr $200 Midland 1 3509 220 xcvr $200 Tempo CL-220 220 xcvr $200 Clegg FM-21 220 xcvr $255 Regency H R-6 6m xcvr $1 90 HR2MS 8 channel scanning 2m xcvr $255 TME-H-LMU 16 channel rcvr $255 Digital Logiclocks $ 80 Dycom 2m repeater $425 Wilson 7 element 10 & 15m beam (pick-up only) $250 Waller 60A power supply $105 Standard sr-c 120/5 power sup. $ 44 Gladding 1 2V power supply $ 60 SBE Scannavision $650 Robot Monitor $265 Robot Camera $265 AX 1 90 amateu r rcvr $200 SX 190 SWL rcvr $200 Pickering KB-1 keyboard $200 TPL 502-B 2m Amp 1 w/40w $1 10 TPL 502 2m Amp 10w/45w $ 90 Kenwood TS-51 1 S SSB xcvr $350 Heath HW-202 w/encoder $1 80 Heath HWA-202-1 $ 30 Heath HA-2022 amplifier $ 70 FACSIMILE PAPER for Desk Fax units: $1.95 per box, 6 boxes for $10.50; for weathermap recorders; $4.25 per box, 4 boxes for $16. Jim Cooper, P, 0. Box 73, Paramus IMJ 07652. tOR SALE: Gonset III 6 meters "MINT 1 , - $100.00. Gonset III 2 meters AM and FM, excellent, - $145.00. WANT: Hallicrafters HA-2. Jim W1VYB, 53 Loth rap St, Beverly MA 01915, 617-922-3850, OPAQUE/TRANSPARENT PC/IC TAPES. SPECIFY 1X, 2X, 4X. TWO 8 x 10 Assortment sheets plus art worksheet - $3.50. Eugene Wiener, 523 Morgan No. r Minneapolis, Minn 55404. HOOSIER ELECRONICS - Your ham headquarters in the heart of the Midwest where only the finest ama- teur equipment is sold. Individual, personal service by experienced and active hams. Factory-authorized deal- ers for Clegg, Drake, Genave, Re- gency, Standard, Hallicrafters, Ten- Tec, Kenwood, Tempo, Midland, Galaxy, Hy-Gain, CushCraft, Mosley, Hustler, Ham-M, Sony, plus many more. Orders for in-stock merchandise shipped the same day. Write or call today for our quote and try our personal, friendly Hoosier service, Hoosier Electronics, R. R. 25, Box 403, Terre Haute, Indiana 47862. 812-894-1297. "Don and Bob" new guaranteed buys. Discount prices, full warranty. Write for low prices on following; HYGAIN TH6DXX, TH3MK3, 204BA, DB1015A, 402 BA; Mosley CL33, CL36, S402; Triex MW50, MW65, W51 (FOB, Cal); Clegg FM27B; Mid- land 13500, 13509-W-T; Regency HR2B r HR212; SBE 144 $199,95; SBE 450 TRC converts 2mFM to 3/4m ($179,95 list) $149,00; Stan- dard 826MA, 146A; Ham-M $99.00; TR44 $59.95; AR22R $31.95; Belden 8448 rotor cable lOrf/ft; 8214 RG 8 FOAM 17tfft; 8237 RG 8 1 5d/ft; Amphenol PL259 49c?; Hallicrafters FPM300 DEMOS, NEED FACTORY WARRANTY REPAIR $460.00 ea; Used guaranteed; Collins 75A4 $345.00; Kenwood R599 $300.00; T599 $350.00; Hammarlund HQ180 $250.00; Heath SB300 $250.00; Write Quote Swan, Eimac, Rohn tower; 3/16" cable clamps 18d; Motorola HEP 170 epoxy diode 2.5A/1000 PI V 29d, $25/100 LOT; Motorola Semi- conductor Data Series $7,50; Calrad KW dualmeter SWR-relative power meter, to 150 MHz $15.95; MOT MC 1709CG OP AMP (709) TO 5 39 tf; Write items not listed. Shipping col- lect. Madison Electronics, 1508 Mc Kinney, Houston, Texas 77002. 713-224-2668 Ni te/ weekend 713-497-5683 OLD (ANTIQUE) Radio Buffs, Re- pairers for sale, in working order. Complete (16 Vol.) repair manuals — thousands of service data, schematics, etc., almost ail makes from the Twenties to the Forties — Gernsback Official Man. Volumes 1 to 7 (1937) plus Riders Volumes 8 thru 14 (1944), plus Volume 5 (1934) and 16 (1945-1946). Atwater Kent Model 35 battery radio (1924). Majestic "B" battery eliminator (1928). Standard Metal Co. 19" upright horn loud speaker (1925). 16" cone Western Electric Model 540AW magnetic speaker (1928). Cathedral type Crosley table model radio (1932). Old books; old tubes; telegrapher's sound- er, key; etc. W. C. Motz, 219 Elm St., Pittsburgh PA 15218, 412-371-1580, MEMPHIS AREA HAMFEST, Sunday, October 7, at State Technical Institute, conveniently located on Interstate 40 at Exit 11. Tennessee Section ARRL Convention in conjunction. ARRL Forum, MARS meetings, prizes, Flea Market, XYL entertainment. Informal group dinners Saturday night. Talk in on 34-94 and 3980. All your friends will be there! COMPLETE 36 page QSL catalog, 3rd edition. New "SPARKLING" QSLs. Hundreds of cuts, ten report forms, thriteen colored stocks, 25tf. Ten sample QSL cards. Cornell son's Quality QSLs, 321 Warren St., N. Babylon, N, Y. 11704. CANADIANS - FREE 120 page elec- tronics catalog ETCO-B, 464 McGill, Montreal, OCTOBER 1973 11 *v H " . * . a mu.it for Jnv f>n»* using an inexpensive receiver or a sideband transceiver on our cto h d ed C ^ ban ci -." (73 Magazine test report} Our a-BOK audio fillet f«tur«; B.ndwltfth CONTINUOUSLY VARIABLE from 30 Hi (fllmoit 100* sharper thnn moil Ketfrtl) to 2kHa. Aetr*<r film (noaoil»|. No Imurtlon Ion. Not a breadboard, Rajidy to plug into ANY rcvr/ncvr. Onvet phon« or «xt, ipkr, omp. Full intfruttiorti. In uit worldwide. Plug one Into your ncaluar todiyl . , . Only Si 7.85 + S) tapping in U.S. JAdd SaJei Tax in Ctl.l tQ day morwvbiick guafsnlia. SEND FOR FREE LITERATURE AMD TEST REPORTS. I A1ITER ^llV ■ ■ ■■ Box 1494L, Canoga Perk, California I - i i Shipments against our orders placed months ago are arriving daily. No long wait for the world's most popular ham gear. SER VING HAMS for 35 YEA RS ELECTRONIC DISTRIBUTORS, INC I960 Peck Muskegon, Ml 49441 Tel.(616)-726-3196 HRS. 8:30 -5:30 SAT. 9 -4 KITS Ci Sub-Audible tone Decoder S9.95 i\m Encoder $8.95 Compatible with all sub-audible tone systems such as Private Line, Channel Guard, Quiet Channel, etc, G*ass epoxv PCB's & silicon xstrs throughout, Any r&eds except special dual coil types may be used. Motorola, G.E.. RCA, SDL., Bramco, etc. All are powered by 1 2 vci Use on any tone frequency 67 Hz to 250 Hz Small size 1.5 k 4 x ,75" All pans included except reed ;nd reed socket Postpaid - Calif, residents add 5% sates tax COMMUNICATIONS SPECIALISTS P.O. Box 153 BreaCA 92621 & (lhl»"MNI) EXCLUSIVE 66 FOOT "*" — "^ 75 THRU 10 METER DIPOLE NO TRAPS - NO COILS - NO STUBS - NO CAPACITORS futty Air Tested — T h ousand* Already in Use E #16 40% Copper Weld wire annealed so it handles like soft Copper wire—Rated for better than full legal power AM/CW *r SSB Gonial or Balanced 50 to 75 ohm feed line — VSWR under 1 ,5 to 1 at most heights— Stainless Steel hardware— Drop Proof Insulators— Tern fie Performance — No coils or traps to break down or change under weather conditions— Comp- letely Assembled ready to put up— Guaranteed I year— ONE DESIGN DOES IT ALL; 75 1 OH D— ONLY $12.00 A PAND» Model 75 I0HD $60. 00 Model 7520HO $50.00 $6 Ft 75 Thru 10 Meters 66 Ft 75 Thru 20 Meters Model 80 40HD $42.00 ORDER DIRECT OR WRITE FOR FULL INFORMATION (IMP"fliND Model 75-40HD $40.00 Model 40 20HD $33.00 69 Ft 80-40-15 Meter (CW) 300 S. Shawnee Leavenworth, Kansas 66048 66 Ft 75 Thru 40 Meiers 35 Ft 40 Thru 20 Meters OR THRU YOUR FAVORITE DISTRIBUTOR More CAVEAT EMPTOR WANTED: ARC-5/VHF components. Mounting Backs MT-65 and MT-71. Control Unit C-42, Junction Box J-28. Also need connectors. WB8NLM, 146 Schonhardt St., Tiffin OH 44883. DESK FAX TRANSCEfVERS as re- moved from commercial service (working). $14,95 each, or S25 pair. Jim Cooper, P. O. Box 73, Paramus NJ 07652. MOBILE IGNITION SHIELD gives more range, no noise. Everything from economical suppression kits to custom shielding. Literature, Estes Engineer- ing, 543 S West 184th Street, Gar- dens, Calif., 90248 ROCK CRUSHER - Hallicrafters HT 33A Linear $200, - HT37 $150, - SX 101A $T50, - NCX3 TR^Band $150, - NCXD $50, - HT40 $35, - WA8IYL, 419-492-2317. FOUNDATION for AMATEUR RADIO annual Hamfest Sunday 21 October 1973 at Gaithersburg Mary- land Fairgrounds. COLLINS FOR SALE: Individual prices are indicated. For package deals please write. 32S3 SN 12091 $650, 75S3 SN 14276 $600, KWM 2 A SN 1 1535 $750, 516F2 P. & $75, 312B4 station control $125, 30L1 linear amp $350. Jack Aviv, WA2KNC, 106 Glenn Avenue, Lakewood NJ 08701. WANTED: RD 92/UX fax recorder. Need several mechanical drum sub- assemblies. Don W1GBO, Box 803, North Falmouth MA 02556. "BRAND NEW: Clegg 66er in origi- nal factory carton, $145, Money order or certified check. J. A.LaTorre, P. O, Box 521, Lawrence MA 01842. MOTOROLA P33-BAC 5W Hand! Talkie, excellent condition with an- tenna, mike f Ni-Cads, 34/94 and 94/94 - $95; Heath HX 20 8a 10 meter SSB and CW transmitter, HR-20 80-10 meter SSB, CW, and AM re- ceiver, and HP- 20 AC power supply, good condition — $195. FOB, W5PNY, 25G6-A, 35th St., Los Alamos NM 87544. 12 73 MAGAZINE Recently a number of GE Pocket Mates have become available, and they make ideal walkie-talkies for 2 meter FftL They have several advantages: 1) small size, 2) extremely sensitive receivers (.3— .4 jiV for 20 dB quieting, 3) good output (1W), and 4) reasonable price. These units are a good buy provided you make sure of several things first. If all of these requirements are met, then you will be making a good investment: Make sure the unit is dual channel (if you want it) and check for Vi-lW output. Check for 1 fiV sensitivity and make sure the speaker is good, because it doubles as the microphone. The unit should squelch at a setting between 2 and 5 on the squelch control The antenna should telescope pro- perly and no corrosion should be present in the battery compartment. Check the opera- ting frequency with a counter; if it is above 160 MHz or so, some of the brass slugs will have to be replaced with green ferrite ones to lower the frequency ( It isn't a bad idea to get several extra green and yellow slugs anyway, since they are easy to break. ) To take the unit apart, first remove the screws holding the speaker and unsolder the wires. Then remove the 4 screws fastening the case to the antenna block. Next remove the small screw just inside the bottom (battery) plate. The chassis should then slide out. Using a tiny iron, unsolder the crystals and replace them with 2 meter ones (avail- able from KW Industries - they already have correlation data). It isn't a bad idea, either, to write GE and request a manual This makes it easier to find exactly where every- thing is. Now you are ready to tune it up. Tuning the transmitter is simple. Hook the two battery springs to a 14V power supply, with a 0—100 mA meter in series. Hang a 47-52fl 1W resistor from the antenna jack to ground and tune T5-T10 for maximum current. Remove the resistor, extend the antenna, and peak L10 and LI 6 for maxi- mum output. Repeak all other coils again, and adjust the drive pots for 180-190 mA (change the meter to a 0- 1 amp one). T5 and T6 put crystals Yj and Yj respectively, on frequency. When properly tuned, you Herman Cone WB4DBB/4 Route 4 f Box 493D Chapel Hill NC 27514 GETTING ON 2m WITH OCKET OCTOBER 1973 13 SQUELCH MODULE ■ ^ i — * 7 RECEIVER IF. RECEIVER RECErVER FRONT END RECEIVER CRYSTAL FILTER LOW LEVEL TRANSMITTER STAGES TRANSMITTER AUDIO MODULE DEVIATION CONTROL TRANSMITTER F\ DRIVE CONTROL F2 DRfVE CONTROL Transmitter Coils T5 — F1 osc, sets crystal (s) on frequency T6- F2osc. " T7, T8, T9 — dou biers — tune for max. current T10 — driver L10- P,A. tank L16 - P. A. output filter Tune T10, L10, L16 for max. output into 5212 load. Receiver Front End Coils L2 — rf amp L4 f 5 — front end L6, L7 — mixer L10 — osc. coil (adjust first) RLVR 1-f Coils Leave these alone unless you are sure they are off, L25 - in filter L15 — coupling T1,T2-i-f coils T3 — discriminator Accessory Jack (Hole directly above jack is for external antenna.) Pin 1 ext. mic. 5 ext. squelch 2 ext. mic. 6 not used 3 13 to 15V 7 gnd. 4 ext- PTT Receive Crystals (Sc - 18 holder) f c = fQ-10.7 Coil Slug Color Codes Receiver: Yellow: L6, L15, L25 Violet: L10 {Yellow Will Also Work) Green: L2, L4, L5, l_7 Transmitter: Yellow: T5, T6, T7, T8 Green: T9, T10, L10, L16 Transmit Crystals (Sc - 18 holder) f =L° C 8 Fig. I, Internal diagram and coil identification, should get around a watt out with 180-190 mA drain. Some units have another pot on the transmitter audio board - adjust it for proper deviation. If yours doesn't have this, it is fixed at 5 kHz. To set the deviation on these units, find the wire going from the audio module to the transmitter's phase modulator. It will have a resistor of approxi- mately 1 MQ in series with it. Decreasing this value will increase deviation. Also, some units have only one drive control, which controls both frequencies. My own is de- signed this way. The receiver is a little more difficult to align, but good results can be obtained if you have a good signal to work with. It is best to use a signal generator set exactly on your receiver's frequency. In most cases, the front end board is the only one that should be touched. A view of the unit with its case removed. 14 73 MAGAZINE KING Your finest discount antenna supplier Beat inflation. Save time and money with mail order. • NAME BRANDS • Gigantic Savings FREIGHT PREPAID MOST ORDERS 48 HOUR SHIPMENT WITH CASHIERS CHECK OR MONEY ORDER ROTORS ANTENNAS TOWERS ACCESSORIES ANTENNA KING Box A, Lomita, Calif. 90717, Phone (213) 534-"KING JUMPER ORANGE WIRES (15 K RESISTOR JS ATTACHED TO ONE) Fig. 2. Rear view of the speaker* Add a wire from the jumper to the chassis to insure a good ground connection. Carefully covering the open areas with tape gives an improved audio response. First, feed a strong signal (30-300 juV if you have a generator) Into the antenna and adjust L10 until the crystal "pops" into oscillation. This is a fairly critical adjustment and a change in noise level will be heard. Then adjust all other coils on this board for maximum quieting, reducing the input signal as you go. It should be fairly easy to get a sensitivity of less than .5 /iV for 20 dB of quieting. The filter and i-f boards are pro- bably in reasonably good alignment already, and shouldn't have to be touched. When adjusting the various coils, it is advisable to first melt the wax (if there is any) with a warm screwdriver blade, and to PIN 3 PIN7 Fig. 3. Schematic of a battery charger suitable for charging the Pocket Mate's Nicads. Starting at maximum resistance on Rl, adjust the setting for a meter reading of 15 mA and charge the unit for 10-16 hours. tune them with a flat toothpick, since the slugs are very fragile. Check to see that the coils have the appropriate color-coded slugs, since they are made of different material A vast improvement in audio quality can be had by carefully covering the back of the speaker with masking tape — this is es- pecially noticeable when transmitting. Mallory TR-136 mercury batteries (8.2V) work fine in the Pocket Mate, but for long-term economic feasibility suitable Nicads can be obtained from Alexander Battery Co., Box 1645, Mason City, Iowa 50401. . . .WB4DBB OCTOBER 1973 15 — YAESU SF101 P $59 00 5P10I 1900 FviQl S« 00 16QM tHHOUGw 1 FT 101 f«49 00 FL7IO0 Ui» 00 ijudw iff FT0K401 SS94 00 THANSCVR S*Ort PEP FV401 J99 00 EXTERNAL VPO THROUGH 10M FL 70006 SJMOO LINEAR AMP 1200W PCP I C P c v FRDA40G £299 00 RECEIVER 1A0M TMflOUGH I0M ftE3 n I FLOM400 S394 00 EXCITER 90M THROUGH HOM FL 20006 1399,00 LINEAR AM* 120CV- PEP FP2 AC POWER SUPP1V ■ FTZFEI S 279 00 144 1*H4V ion HIGH tW LOW VCJBS O »tt 00 DIGITAL COUNTER BLRLT IN PRESCALEH YOUR ASSURANCE OF PERFORMANCE & QUALITY The 5P1Q1 P Landhner provides phone patch operation as well as speaker. From panel. Patch twitch, meter, TX and RX gam controls. Rear apron: Receiver 4 ohm output, receiver 600 ohm output, monitor null switch, bal- ance control, line jack, transmitter high Z jack. The FV 101 permit* split frequency operation and control from either th* FT 101 or FTOX401. The FT 101 exciter coven 160, BO. 40. 20, 15, (CBh and 10 meters and comes complete with microphone cable and plug, fused DC power cable and plug, AC Cable with plugs and all necessary plugs are furnished- AC and OC supplies are internal. The FL 2100 Un*a' ampJifie* needs only 3 wire cable and coax cable, Con- nectors are furnished, FTdx40T features high power, super sensitivity and sharp selectivity. The FT dx401 includes: AC power supply, noise blanker, 100 KG and 25 KC cali- brators. VOX break in, phone patch terminal, coating Ian. Covers 3.S through 10 MH; plus VWVV 560 watts PEP, AM that is required to gel on the air is a microphone and speaker. The FV 401 permits split Frequency ape-ration lor the DX chaser or net opet ator Covers 30 through 10 meters FL 2000 B 1200 wans PEP. 1000 watts CW. 600 watts AM. Drive power re- quired 100 watts. Has two cooling fans and uses two 572 B tubes, FRdx4O0 includes 2 mechanical filters plus "T" notch rejection tuning, ind c rentier lor easy lero set for SSS Crystal control 1st mixer and tunable 1st IF. provides stable operation and high spurious rejection, 100 KC and 2S KC calibrators. VFO can be used in transceivt operation in conjunction with F senes transmitter FLdx400 operates SSB, I USB LSB selectable), AM, CW and FSK Circuitry can be built in lor RTTV operation, 240 watts PEP VOX, PTT\ and break in CW FL 20008 grounded grid linear uses a utiir at 5?2 B tubes. Plate meter V$WR monitor, 2 fans, built m power supply, SO through 10 meters. 1200 watts PEP with distortion product in excess of 20 DB down. FP 2 AC power supply specifications Output 135 volts. 2 amps. AG input 100H 17/220/234 vol is, Speaker 5" u 3-1/5", Portable or home bete operation can be achieved with the addition of the optional FP 2 power pack. This AC power pack provides regulated DC power for the transceiver and charging voltage tor optional leak proof rechargeable colloidal type batteries. In addition, a high fidelity elliptical style speaker is built mlo the pack. The FT 2F8 Opens the door to noise free broadcast quality 2 meter operation, and thanks to the repeater stations throughout the country, the 2 meter band n no longer restricted to Fine of sight. General coverage 144 to 148 MHi. 12 channels 13 supplied? Push to talk Receiver 3 amps, transmit 17 amps, power source 13.5 volts + 10V Dimensions 6-3/8" w, u 2 1/2" h a 10" d . weight 4 lbs. Comes with dynamic microphone, connector plug, DC cord, fuse and mobile maun! Th« FT 2 auto is a compact base or mobile VHF/FM transceiver, covering 146 to 148 MHt, featuring electronic scanning up to 8 stations between 146 148 MHi with priority channel sam pling while locked on another channel. Adjustable lone burst push-button lock on lor repeater actuation The FT 2 auto ♦$ self contained. Two power cables are supplied with ihe transceiver, including all mounting hardware, cables, connectors, and accessories required for both mobile and base installation, as well as dynamic push to talk microphone. Operates from various AC voltages or 13 5 DC, Dimensions 8-3/4" m, m *1/4" h. n 115/8" d Weight 9 ibv 5P401 P »9« 5P401 19.00 SPEAKEH'PATCH f - i € t FT? AUTO $379 00 1*4 U Cpmpltti With AC Pa*r Cold 6 Ft OCPmhi Cord 6 Fl Stfirui Tm L«d with &NC Conn«cior 3 Fl SPECIFICATIONS Enqurrev r^ngi Actu'*^* Oiii]4iv S-l*np1ir>B him 'HO**> ttrrn rttoutney Urwl Q'Ullw Input VoHt vc.ttW SHi to ,1TjMHi iSOHr Ki 20OMH/I *1>ffH frM* mlfrMy * t CiHint h Di^l 1 mdli T 7 1*£ kUi MW, Onotjty tub# 20m V— ?0Vpp MAX Input VoUjis ryot Imydanci Ll Si«eaiTv Po*pr Require nvioti C VC J«ap" eoVfm in iSV p pj HIGH T W enhrn Low 5€ ohmi Leu Ihaw fQpf ' ',' H; £>»-/ irAi'iT** 0005'. 0025*- if «1 »«C ffi - UPC WOl 1 10/ If 7 * 2O0/?2O 733V 5Q/60H; 1BV A Jl^U^^^A^ rt^ehx Tub* D'iDllv lutw tOttduClDfl Sil"tiK> diode $4litt>n Ti»nu«t»- FET IC VC 3550 J2Oirt»X»OfHjK270lOI i 8 14 W X 3 1/4 H 10 \tl i«hm 12 26 PFttCES SUBJECT fOCHANtlE WITHOUT NQTJCE FACTORY SERVICE IS AVAILABLE WHERE WARRANTY HAS EXPIRED. NIK- 160 (J60M)KIT tl€ 00 WITH XTAL PLUS LABOR, MODERNIZATION KIT MIR- 1 FOR OLDER MODEL FT101 t 70.00 FACTORY INSTALLATION ONLY. HAM RADIO CENTER 8347CH'VE flLVD ST LOUIS MO &3U2 ADIRONDACK RADIO SUPPLY IBS 191 W MAIN ST . AMSTERDAM MY 12020 ItfAafTflONlCS AMATEUft El f CTRQNIC SUPPLY 4033 BHOWIMSV1LLE flD . TREvOSE PA 19047 fi?1 COMMOMWEALTH AVE , fi. 32^03 EKTER RADIO 3Q02E ASHLASt FRESNO CA 93776 HEMRV RADIO STORES Lc» Angvlri. Anahtirn, C-Ai MAM RADIO OUTLET aurhrvBJfnr CjI GHAHAM ELECTHOHICS RACQM ELECTRONICS *33S PCMMSVLVANIA. UNDF AMAPDL^S ID 4G204 R»nlo*r W«h FfttfCK RADIO BV SUPPLY / ^0* 2&4 95&1 HutlT- Md. Aihtmllp. KC HARRISON RADIO/5V&293 7990 Fi'mmgdlU L.I V«ll«v Sl»MIH. L I N«W York WILSON ELECTRONICS Win mm N*« ED JUCE EtECTRONiCS Poil Worth. T«m AMATEUR ELECTRONICS SUPP1V M>^iuk». Wn CL«*4*r>0. Ohm W YAESU MUSEN USA INC. TWX 910 346 7624 TEL 213 6334007 VAtSU V 7625 E. ROSECRANS AVE UNIT 29 PARAMOUNT, CAL. 90723 Silas S. Smith WA9VFG 2308 McCord Murphysboro IL 62966 FR EQU MICROWAVE MEASURING AT QUENC This article is not intended to give the theory, but rather a practical solution to the building and use of wavemeters at microwave frequencies. In microwave work, frequency is one of the most important measurements. It must be understood the wave length in the devices described here is not the exact frequency wave length. A well-constructed wavemeter that has been calibrated can be very precise. They can be within 1.5 MHz at 10 GHz or less than half of a MHz at 1250 MHz. Temperature has some effect on the frequen- cy. Most commercial wavemeters are con- structed of Invar, a metal that changes very little with temperature. Some parts are of 7 SOURCE WAVEMETER INDICATOR B i LOAD WAVEMETER SOURCE rfis = LOAD INDICATOR ATTENUATOR WAVEMETER POWER INDICATOR WAVEMETER f LOAD OR LOSSY MATERIAL WITHIN CAVITY OR NOTHING AT LOW POWER Fig. 1. bi-metal construction to compensate for temperature. For the average experimenter, brass and copper will have to suffice. Al- though silver plating is desirable, it isn't an absolute necessity. Frequency at microwave frequencies can be measured by three meth- ods: wavemeters, slotted lines, and frequen- cy comparisons. All of these methods are used commercially. The frequency compari- son is usually used in the laboratory to calibrate the wavemeter and the slotted line. As a general rule, any method of frequency measurement used at lower frequencies can also be used at the microwave frequencies, but are not always practical. The resonate cavity as a wavemeter is used in microwave measurements. There are three types of cavity wave- meters: the transmission type, Fig. 1A and IB, the reaction type, Fig. 1C, and the assorption or absorption type, Fig, ID. All are resonate cavities. The way in which the wavemeter is used determines the type. All wavemeters are adjusted for maxi- mum readings except the assorption type. The assorption is adjusted for a dip in power output, The most popular wavemeter used by the beginner is the open circuited trans- mission line type, Fig. 2. This type of wavemeter is the equivalent of lecher wires, (Open circuit refers to the standing wave within the cavity, not the physical construc- tion except as it pertains to the frequency wave length.) The practical physical dimen- OCTOBER 1973 17 Larsen Mobile Gain Antenna 144-148 MHz The result of over 25 years of two-way radio experience. Gives you ■ * a ■ 3 db + gain over 1/4 wave whip ■ 6 db + gain for complete system communications ■ V.S.W.FL fess than 1.3 to 1 • Low, low silhouette for better appearance The fastest growing antenna in the com- mercial 2-way field is now available to Ama- teurs. It's the antenna that lets you HEAR THE DIFFERENCE. Easily and quickly ad- justed to any frequency. Hi-impact epoxy base construction for rugged long life. Silver plated whip radiates better. Handles full 100 watts continuous. Models to fit any standard mount. Available as antenna only or com* plete with all hardware and coax. Get the full facts on this amazing antenna that brings signals up out of the noise , . . provides better fringe area talk power. Write today for fact sheet and prices. Sold with a full money back guarantee. You hear better or it costs nothing! also available . * . 5 db Gain Antenna for 420-440 MHz and 440-460 MHz Phased Col linear with same rugged construe* tion as Larsen 2 meter antennas and 5 db gain over reference 1/4 wave whip. Models to fit all mounts. Comes with instructions. Write today for full fact sheet and price. hi TO - Larsen Antennas 1 161 1 N.E. 50th Ave. ■ Vancouver, WA. 98665 Phone 206/695-5383 Fig, 2. sions are not many. The inner circumference of the main tube should be less than one wave length at the highest frequency to be measured. The rod should be small com- pared to the tube. If inductive coupling is used, the inductive coupling should be close to the shorted end. For probe coupling, the probe should be close to the middle. The open circuited transmission line is generally used in two ways. This type can be used "in line' (Fig, IB) as it has very little loss when it is resonated. However, it should be re- moved from the line before transmitting, as it will act as a narrow band filter. The half wave length is the measurement between the two successive points at which the generator will load to maximum, as the rod is inserted or withdrawn. Another method in the use of the open circuited transmission tine calls for the use of an additional circuit, as in Fig. 3. The circuit is a simple crystal diode detector connected to a microampmeter. The diode and condenser are usually built into the connector, as the leads should be kept as short as possible* The half wave length measurement is made on the rod between two successive maximum readings on the meter, as the rod is inserted or withdrawn- See Fig. 1A and IB for the setup. CRYSTAL DIODE MICROAMMETER DH* t /j\C R Fig. 3, The quarter wave coaxial cavity is actual- ly a shorted coaxial line one quarter wave length long (Fig. 4, 5, 6), As illustrated in these figures this type makes a very good cavity to use as a standard. To calibrate, a chart is made of the micrometer settings at different frequency wave lengths from a 18 73 MAGAZINE calibrated source generator. Don't tell them so, but the Public Relations Department of the Telephone Company may help you here, if they have any microwave technicians close by. The quarter wave coaxial cavity can be either physically open or closed. If closed, the closed end should extend at least a quarter of an inch beyond the center con- ductor at its lowest frequency. The closing of the end will lower the resonate frequency. Probe (capacitance) coupling as used for coupling in Fig. 5 will shorten the center conductor, and loop (inductive) as used in Fig. 4 will lengthen the conductor. In Fig. 4 we change the length of the center conduc- tor to change its one quarter wave length. In Figs. 5 and 6 the center conductor remains the same, and we change the resonate frequency by capacitance. This method makes it necessary to construct the center conductor very short as compared to the full quarter wave length as in Fig. 4. These devices are not longer, so caution must be used when calibrating. The closed wavemeter as indicated in Fig. 7 is a shorted coax line at each end. The wavemeter uses a shorting plunger which is movable along part of its length. If used as the quarter wave coaxial cavity, the center conductor must be longer than a quarter wave length. Up to this point we have covered most of the wavemeters that could be used from around 144 MHz up to approximately 3000 MHz. 1000 MHz to 3000 MHz are usually called the lower microwave frequencies. If the inner circumference of the outer tube is kept less than one wavelength, these wave* meters will operate in the desired TM mode. There are four ways to couple energy into a wavemeter, loop (Fig. 4), probe (Fig. 5), direct (Fig. 6) and slit (Fig. 8). The most commonly used is the loop, as it has very little effect upon the electric field. The usual methods for changing loop coupling is to change the size and orientation of the loop. Loop coupling is usually placed in the high current area of the wavemeter. Capacitative coupling is changed by the size of probe and the distance from the center conductor. Capacitative coupling is usually placed at the high voltage portion of the wavemeter. As in Fig. 5, a small probe - say Vi in. piece of No. Fig. 4. Fig. 5. 22 wire, for example - may require an external voltage amplifier. The smaller the probe, the less effect on the resonate fre- quency of the wavemeter. In direct coupling as in Fig. 6 the primary concern is imped- ance. To increase the impedance, move the coupling up the line away from the shorted end. To decrease the impedance, move the coupling down the line toward the shorted end. Slit coupling (Fig. 8) can be a small hole or a series of small holes or a slit. Its purpose is to allow a certain amount of leakage. In all forms of coupling, it is desirable to use loose coupling, as the wavemeter will have less effect on the system, and the Q of the circuit will be higher. Fig. 6. Fig. 7. Above 3000 MHz, usually only the tunable wavemeter is used. The cavity is one quarter wave length long. The cavity can be coupled in three ways: loop, probe and slit. Because of the high frequencies, the slit is usually used, and the meter is most often OCTOBER 1973 19 Fig. S. kept as an assorption meter. In the assorp- tion method, the wavemeter should be de- tuned when not in use. Some of the cavity wavemeters have a little lossy material added to absorb some of the energy, as in Fig. 7. Lossy material can be made from graphite impregnated cloth in epoxy* There is one other type of wavemeter thai can he briefly mentioned; it is the reference wavemeter. The reference wave- meter is of any design as described, but would be constructed more like Fig. 6. II can be locked when adjusted to a selected frequency and used as a reference standard. The micrometer assemblies can be made from any micrometer with additional parts welded on. I constructed one using an oversized tube over the main cavity, and dimpled it at various places around its circumference until it fit smoothly over the cavity, and 1 used a piece of 3/8 threaded brass pipe as the main adjusting screw. I am sure you can come up with a good one without any backlash. This wavemeter spread the 1250 MH2 band out to over 100 inches by rough measurements, 1 haven'l calibrated it> so I can't say for sure just how far. There are three nice veeder root count- ers in the APX 6 which would make ex- cellent wavemeters plus sliding contact ma- terial- One could even use the entire cavity. The last method of microwave measure- ment that we will look at is the slotted line Fig. 9 (Fig. 9). The slotted line is a section of coax line along which is cut a slot. A probe, which is a simple crystal detector with a one quarter wave length shorted stub for a dc re'turn path, is moved along near the center conductor of the slotted section. In this case we are looking for two successive minimum readings along the line. The distance be- tween these readings is one half wave length, A slotted line should also be calib rated. If calibrated at one spot near the intended frequency to be measured, a chart will not have to be made -just a K factor obtained. The distance between two successive read- ings times the K factor should equal the frequency half wave length. There are a few accessories that can be either built in or used Fig, 10 externally. One is a coax attenuator shown in Fig. 4. It will slide in and out of the other half. It too can be calibrated if one wishes. A 5 OH resistor can be used for an impedance match for 5012 lines if inductive coupling is used such as in Fig. 10 and when the loop is Fig. 1 1 - small. The line stretcher (Fig. 11) is useful with the slotted line. It merely consists of two coax sections, one sliding into the other. • . .WA9VFG 20 73 MAGAZINE Bill Hoimngton Kl CLL Farover Farm Peterborough NH 03458 Fig. 1. Build a complete receiver front end with the RCA CA3102E integrated circuit. Truly it is said, "Nothing succeeds like success/' and the RCA lads in Somer- ville NJ are to be congratulated on this latest achievement of theirs in building an IC which works well as a complete 2 meter front end in corpora ting rf stage, mixer and oscillator. This article concerns the RCA IC CA3102E in a 14 pin in-line case which contains six 1000 MHz semiconductors. Bear in mind, please, there is a large difference between integrated circuits for digital work and those for rf work. This article, like most of mine* is not just a construction article. It deals with the design and philosophy of the components and the circuits shown because I believe amateurs should have the opportunity — if they wish — to learn as much as possible while building. There is a perfectly valid philosophy which concerns "Connect a short red wire between point A and point B." 1 have done lots of these myself, but always found I had to force myself to forget all I knew about radios and become a true know-nothing while doing it. The RCACA3102E This little gem has two independent differential amplifiers inside, with its sche- matic shown in Fig. 1. Each of the six transistors has an Ft in excess of 1 GHz, making this IC useful to 500 MHz. Special care has been taken in the internal chip layout to assure good freedom from reaction between the two independent amplifiers. Inasmuch as I seldom write about anything I have not tried out, 1 have some running here and they work well. Since the true home -brewer is always interested in possible applications of what he spends his hard-earned money on, the I — vw o + RF IN> + 12 -^ tf* > RF OUT + O Fig. 2. Differential amplifier connection, RCA CA3102E (pin view). See Figs. 3 & 4 for represent- ative values. OCTOBER 1973 21 RF IN > 0+ 12 + 12 O^^WV C4 -^^- > RF OUT Fig. 3. Cascade connections, CA3102E. For tuned circuit values, see LI in Fig. 4. following list of CA3102E uses is included: VHF amplifiers , mixers, multifunction com- binations such as rf/mixer/oscillator, con- verter/i-f, cascode amplifiers for i-f, or dif amps, product detectors, doubly-balanced modulators, balanced quadrature detectors, cascade limiters, synchronous detectors, balanced mixers, synthesizers, balanced cas- code amplifiers, sense amplifiers (whew!i and others. The age of the VHF-UHF ICs is being opened up by these I GHz beauties. Dif Amp and Cascode Details Inasmuch as the LC is formed by a cascode amplifier, and the mixer section has an rf amplifier in it, a few words on the use of this chip in both modes is timely. Figure 2 shows one half of this versatile little chip of 1 GHz capability in the dif amp mode, where Ql is a grounded collector amp driving Q2" a common base amplifier, Q3 acts as a constant-current source. This is the configuration that is best if strong signals are present, as in metropolitan areas, or other areas where amateurs may be in close proxi- mity to each other. This dif amp mode has slightly less gain than the cascode mode, but this need not be considered unless you are trying to minimize components, often a false concept. Two stages with lower gain, such as dif amps, are often much better and easier as well to build and line up then one of higher gain. Noise figure goes down with current, another reason for two stages. Circuit Referring to Fig. 2, the rf arrives at the tuned circuit L1-C2 from the input matching capacitor CI. A tap about one turn from the ground end goes to the base of Ql, a common collector amp. Ql is emitter- coupled to Q2, a grounded base amp whose collector circuit has C3 and L3 for tuning. See rf section for details and component values. Constant-current Source The makers of these IC rf circuits use a lot of transistors in these tiny chips for this sort of thing. Making them mainly for commercial users, they put in, for example, Q3 ? which does not appear to do anything at all. It does however do nice things if you look a little deeper. When the temperature varies it tends to maintain a constant current on the amplifier and therefore lessens any detuning effect that might otherwise occur and other nuisance effects. Just use it as shown. It helps for a better circuit, especial- ly when you can take it out in your car in the winter right out of a heated room or garage. After all, it only costs the maker a fraction of a cent to photograph it in there, so why should you worry? Cascode Connection Figure 3 shows connections for the cas- code configuration, which has the highest gain but cannot handle strong signals like the dif amp. The rf goes through the series matching cap CI (referring to Fig, 3), then to the tuned circuit L1-C2 and then to the low impedance base of Q3, a grounded emitter stage. This stage is cascode coupled to the emitter of Ql, and the signal goes out on the collector to the tuned output circuit C3-L2 and on out through C4. Q2 is not used in this mode, and simply floats for dc, with external connections 4 and 14 bypassed 22 73 MAGAZINE to ground for stability purposes. Keep LI away from L2, and use a shield between them if needed. Put the shield more or less in line with pins 5 and 1 2, as shown in Fig. 3. More details in the rf section. Internal Feedback and Stability The compound (internally connected dif amp or cascode) connections of the dif amp or cascode are both much better for internal feedback (having less) than a single grounded emitter transistor, with the best in this respect being the cascode mode. The ratio of how much better may be as high as 1/140 at low frequencies, to perhaps 1/10 at 100 MHz. In the cascode circuit this may be as high as 1/135 to 1/1200. In any case the internal feedback is low enough so that no consideration of neutralization is needed. This reverse transconductance is sometimes labeled Yr, in case you should meet it some dark night. Just be sufe the external feed- back does not clobber the nice internal feature. Pay attention to the details and notes in this article and it won't (shielding, bypassing, etc.). + 12 AGC i The mixer gain can be easily controlled to a high degree in these versatile chips, up to 60 dB or more, by putting a negative voltage on the base circuit of Q 1 in the mixer circuit of Fig. 5. Remove R3 and put the negative going age voltage on the base at that point. You will more likely use the age on the rf amp, though- In that case the age voltage would be applied to the base return of Q3 through LI in Fig. 3. A good balance of rf amp current (minimize) and gain, as well as mixer gain, should be sought. Mixer Figure 4 shows the half of the CA3102E used as an rf amp, mixer, and L.O, buffer- amplifier. Note the grounded line between pins 5 an4 12. I am not quite sure how this is physically arrived at inside on that tiny chip, and it will have to wait for my next visit to Somerville NJ (RCA Solid State Hq), but it works fine. You would have to have a good microscope to find it! Ql is a grounded emitter rf amplifier which takes the rf signal at 147 MHz in on LI and direct couples it to 0+12 + I20 RF IN 14? MNz > A UO. IN FROM osa SECTION 136 MHz Fig. 4. One-half of CA3102E - use as a complete rf front end. Ll f 5 turns No. 20, 12mm long, 8mm diameter. Input tap at I, output tap at IJS. L2, 15 turns No. 20, closewound 10mm diameter, L3 t 2 turns over bottom of L2. Q2 } a grounded base mixer stage, Q2's collector goes out at 10.7 MHz to the i-f output transformer L2, link coupled by L3, to the output cable. Q3 is used as a buffer amplifier for the L.O, — the 136 MHz injec- tion voltage coming from the other half of the CA3102E used as the crystal oscillator. This section is quite straightforward even though an rf amp and buffer-amp for the L.O. are included, and works well due to the 1 GHz transistors used. I checked it several times against a good 3N200 FET mixer and local oscillator chain, and it has a dB or so better sensitivity, or I should say conversion gain, than the FET job. Noise Figure The noise figure of the CA3102E used as an rf amplifier is highly dependent on OCTOBER 1973 23 — m current, as indeed in most semiconductors, 2 or even 1 mA being good figures for rf amps. This noise figure runs about 4.6 dB at 200 MHz for the transistors used in the CA3102E, There is a fairly simple rule to follow with these units, as already mentioned. Use of the lowest possible total current through QTs emitter will in general give the lowest noise figure. This refers to the use of the CA3102E as rf amps also. Note the setup for tuning LI, the series cap bringing in the rf and the two tie-points serving as output connectors. This method has proven to be very efficient, both for building the first model and for layout of the PC boards later. If done correctly, each tie-point can serve as a place to drill the PC board for a lead hole, or component tie-in. It is particularly impor- tant in VHF and more and more so as you go up into 220 and 450 MHz, to furnish a layout man with exact placement detail. You can no longer leave it to him, at VHF and UHF, unless he knows a lot about rf work and particularly the IC under consider- ation. You should think this out carefully, as VHF and UHF IC's handle quite differently than af, digital, or control circuits. m 0+12 m Fig. 5. Example of base bias in the CA3102E. Base Bias Due to the direct coupling of the various transistors, placing them in series dc-wise, attention should be paid to the base bias voltages, While in general the resistors may be as in Fig. 5, these should really be adjusted with signals flowing through for checking best noise figure, gain and current- I have already done this for you, but it is a 24 11 My name is John (WB2AZT), and I'm the Amateur Products Manager for Venus Sclent if ic. By • now s you've probably scanned pur ad on the opposite page* you react as most haras do> you* re probably thinking, "That's a nice look** ing package, but who and what is Venus Scientific?** That's the purpose of this message—to acquaint you with our company, Its products, and its reputation. There's nothing like knowing that a manufacturer is able to back up his product claims* Basically, Venus Scientific is one of the country's leading manufacturers of electronic high voltage control systems for military and industrial applica- tions. Our H*V, Power supplies, were used with television cameras on the Apollo flights that sent TV pictures back from the moon* Some time ago, a group of us within the company who are all active hams, began pressuring our boss Fil Galluppi to let us get into the amateur radio market* After con- siderable urging and coaxing* including actually dragging him to several ham- fests, he too got the bug and gave us a go-ahead . So here we are with our first of many products we've planned for the amateur market- Our slo-sean monitor is in production, ready for delivery, and frankly, it's something : else again. More than Just an S.S.T.V. monitor, a flip of the switch converts the unit to the incredible Accu Syno™, an oscilloscope that clearly reads out both incoming and outgoing 5.3*1- V* signals- Other features, like our mas- ter G10 , -P.C-. Board, make the SS2 flexible and long lasting* The specs on the next page are just a few of the features of the SS2. Just remember that the ten years we've been in business designing and manu- facturing high reliability systems has brought to the ham market the quality product I think we, as hams are en-. titled to* OK t now you know a little &bout Venus Scientific. Look for our ads in the months ahead and let us know what you think of our product. And by the way, in case you r re wonder- ing/ Yes, we'll announce our companion camera in the next few months. John Lot it o WB3AZT .-. . •'•;■• ■ • . .: Venus Scientific brings ten years of space-age technology development to the production of the latest breakthrough in HAM Equipment . . .the SS2 Slo-Scan Wlonitor. The following unique features of the SS2 have been designed to offer the HAM operator the maximum functional performance in SSTV. These advances include: ACCU SYNC? a diagnostic and tuning aid which converts the SS2 Monitor to an oscilloscope by the flip of a switch that monitors incoming and outgoing video; LED SWEEP INDICATORS, go-no-go lights for ease of servicing CAMERA ADAPTER provision to accept Polaroid Color Pack Camera or Polaroid Square Shooter, which enables you to take pictures right off the air; SIMPLIFIED INDEPENDENT CONTROLS. For the full story on how VENUS' $S2 monitor has become the 2nd Generation of Slo-Scan and a list of accessories, write or call today. Amateu r net pri ce $349 N. Y. State residents add sales tax. >: > <:■> ■ . BRIGHTNESS Automatic CRT Bum Protection CONTRAST Independent Contrast Control 'C.AMffe.A SOURCE SELECT JKCC¥ $TWC '</Q(H ►1***1 «-KAW M£t£P CABINET Zinc Die Cast Front with Extruded Alum Sides 1Q3V'Wxl3''B x5V 2 "Ht TILT STAND Collapsible Bail VENUS -. . i. nm ■— ■■ PERSONALIZED IDENTIFICATION PLATE Your cafl sign CAMERA ADAPTER Mounting^ Bezel OPTIMUM PICTURE for POLAROID ireproductfon ACCU SYNC© Diagnostic Oscilloscope Tuning [ViOEO/VOICEl SELECT BE- SCAN Vertical Retrace The company that put high voltage on the moon t now brings you expanding amateur radio technology. 399 Smith Street Farmingdale, MY. 11735 Phone 516-293-4100 TVtfX 510-224-6492 ■i mm good thing to iearn about. There is also quite naturally a certain amount of interplay between Rl, R3, R6 and the current con- trolling emitter resistor R5. The optimum values are not critical or touchy, but will be seen to be quite responsive to best values. I generally use a 5K pot at the Rl , R3 and R6 places to start off with, and a IK pot as R5, The proper values are soon determined with that arrangement, and you are not left guessing if you have the right values or not. Remember that monolithic photo-built tran- sistors have quite a wide range of parameters at times. Naturally I ran the mixer when finished, with an outboard oscillator as well as the internal one, to see if there was any reaction between the two halves of the CA3102E when used as rf, mixer and oscillator, but could not find any. It seems to be a "natural." ■i 7-100 pF TWEAKER ARCO 423 ■i TUNE TO 136 MHi C£ 5-80 pF ARCO 46£ Jfi* > TO MIXER 1 (PIN 7 t 01 OTHER HALF) + 12 Fig. 6. Interna/ schematic, H RCA CA3102E, IC used in the cascode connection as a crystal oscillator. LI, 5 turns No, 20, 12mm long, 8mm diameter. Crystal tap at 1 tectums, output tap at 1 *£ turns. I have recently developed an IC tuneable, LO.j which also goes very well with this unit. Disable the internal L.O. by pulling out the crystal, and plug in the external vfo cable to pin 8, the base input of Q3. The unit was described in the July 1973 issue of 73 Magazine, A. B. a Fig. 7. 136 MHz crystal operation. Crystal Oscillator on 136 Direct Referring to Fig. 6, we see the rf signal from the crystal entering Ql at the base, Ql is the grounded emitter portion of the cascode amplifier forming the oscillator. Note the crystal used is cut for 136 MHz direct, without multiplication of any kind. Some have expressed surprise at this, but it should be known that today control crystals are available up to 250 MHz direct, not only for two meters. Such crystals are commonly referred to as *' overtone," which to my mind smacks of obscurantism, the real functioning of that precious little piece of "glass" being as shown in Fig, 7. This gives you a rough idea of what is going on inside that little tin can. You can also see that only odd numbers can be used- If you try to use the even number combination in Fig. 7C, you will of course get no ac out of it. Never forget that 26 73 MAGAZINE INPUT SH5. GEN. INPUT C 7,5cm STRAP 10 cm BOX IN295 DIODE r>h ^^ 25 pF d-ce ADAPTER r)\> J AF OUT l — i ] DC OUT V. INSULATED WIRE Fig. 8. Oscillator frequency check-out circuit. a crystal operates on sound waves and that only certain numbers can be used. If this sounds to you like quantum mechanics, good for you, you're getting warm! A piezo-electric chip, if cut right, gives off electricity, positive on one side and negative on the other when compressed, and that is good old dc if you hold it that way! Madame Curie's brother used to demonstrate this nearly one hundred years ago by hitting a piece with a hammer and demonstrating to the entire hall a spark therefrom. What you need first is that the oscillator be running, and if it's a good oscillator, it will be as soon as you throw the switch. It has to run, it's a law of nature. So, as shown in Fig. 5, the oscillator voltage enters the base of Ql on pin 2, a grounded emitter amplifier. This is internally connected (direct coupled) to the emitter of Q2, a grounded base amplifier, the two-transistor compound forming a cas- code amplifier good to 450 MHz, Here it is used at 136 MHz. The output of Q2 goes to a tuned circuit Ll-Cl, tuned also to 136 MHz. In this circuit, LI has two taps, one for the output going to C2, and then to the mixer in the other half of the IC The full gain of the cascode Ql and Q2 is used and needed, Crystals on 136 MHz are not to be taken lightly. They must be matched as to ac impedance fairly well into and out of the cascode. The input, base of Ql, is sort of a natural, as the base impedance is quite low and the matching can be helped by adjust- ment of both the base bias and the emitter bias, which I have done for you. The output match of Q2 into the crystal is done by tapping down on LI, and is also seen to be low in impedance. It is also possible to couple into the crystal by a two turn link, wound in the same direction as LI, and placed over or inside of LI. I generally tune up such an oscillator with a 5K pot as R2, and another as R4, These are not at all touchy but you can make the oscillator run better that way. To check out and tune up — not only for frequency but also for good starting, absence of squegging,- noisy hysteresis jumps either in frequency or power and proper base biases — a tuned diode detector is very handy. A one or two turn link around the cold end of LI with a cable into a diode trough-line cavity does the trick. You must know if it is really on 136 MHz. Figure 8 shows a helpful setup to do this. Set up the tuned diode detector and check for good, smooth, quiet power out, using both meter to measure and af to listen. Then bring in a wire, as shown, close to or around the diode tuner center conductor as shown in Fig. 8. Tuning the signal generator very slowly over the region 135 to 137 MHz, you should be able to hear the desired heterodyne resulting from the crystal oscilla- tor beating with the signal generator on 136 MHz. If you do not, something of course is wrong. Do not, as I have said many times before, use a sensitive receiver for these Test operation should include good, clean tuning of CI (Fig, 6) with the oscillator coming on and off with a nice "plunk" in the af speaker indicated in Fig, 8. The meter should also come up and drop off with the proper action. Marginal operation is to be avoided like poison. For example, the oscil- lator may be just working, and the next time it won't come on at all. So there you are. If you build this IC front end as shown, it will work and in good style, I have done it here and it works fine. The operation is stable and secure not marginal. You can put any rf stage in front, or use another CA3 1 02E as the rf stage. . . .K. 1 CLL OCTOBER 1973 27 * Self-supporting With A TrUBander (A) * 32 1 - 40' - 48' - 56' * 3 Mounting Bases * Heavily Galvanized (A) Limited to JR TriBander, unless guyed, on 56* towers. 32 FOOT TOWER II THE BEST TOWER VALUE!" ASPIRE CONSTRUCTION iruivft.N tftefM] Heavy steel ' 'beaded' 1 channel design for ex- ceptional strength -much stronger than tubular of same weight. "X" bracing & bridge type construction for exceptional torsional stability. Positive riveted construction & heavy galvaniz- ing makes it exceptionally durable for minimurtir maintainance. Tapering design provides "nesting" shipment at lower cost to you, as well as lighter sections as yog go higher, making it easier to erect, THREE BASES: Rigid concrete (recommended base is 3x3x3' in firm soil, 32/40' models, and 4 1 deep on 48/56' models. Hinged con- crete base provides option of lay-over, pro- viding you have suitable "gin-pole" and tackle facilities. And the EARTH ANCHOR base requires no concrete and holds well in firm {day, etc) soil and may be relocated later. A custom drilled rotor plate is provided that accepts all CDE rotors (AR22R, .TR44, HAM-M) and also the HY-GAIN 400 with slight enlargement of bolt holes. A friction thrust (lateral) bearing is included* u HI-SPIRE rr towers shipped truck collect from Indiana , TOWERS WITH RIGID CONCRETE BASE 69C09K - . « . .32' 133 lb». $ 79*95 69C09Z 40' 175 lbs >., 104.95 69C093. .... .48' , .243 lbs 144.95 69C137. . 56' . - 308 lb* 189.95 TOWERS WITH HINGED CONCRETE BASE 69C055 32" 147 lb* $ 89,95 69C056 40' 189 Ibi 1 14,95 69CQ57 -48* 248 Ibi 154.95 69C138. . . . . 56' . ■ . - - . 313 lb* 199*95 TOWERS WITH EARTH ANCHOR BASE 69C094 32' ....♦• 191 lb* • -$119.95 69C095 40 1 ..... . 233 lb* . . . • ■ 144,95 69C096. .... .48' ...... 390 lb* . . . * ♦ 239.95 49CI39, .... .56' 455 Ibf 284,95 &9C100, M T H wrench to drive anchor! (8 Ibi.) ,«♦,.. 9,95 Include! anchor bate and anchor! (anchor bases require no concrete). Earth anchors screw into the ground and" Hold wel in firm toil. May be removed and relocated later* The Best Ham Tower For 15 Years When you need "ham" gear & accessories call H.I. ! efCoBBtf fj industry CALL:Tues. /Sat.-Noon/5PM Al McMillan W0JJK (712) 323-0142 WRITE: HOBBY INDUSTRY Box 864 Council Bluffs, Iowa - 51501 28 73 MAGAZINE FJ. Bauer W6FP0 P.O. Box 1086 Feiton CA 95018 INSTANT REPLAY FOR YOUR TAPE RECORDER At times a tape recorder can be a useful accessory to any amateur station. One obvious use is relaying information directly to another phone station on the net. Instead of laboriously repeating or paraphrasing the message, why not record it on tape and retransmit it to the other station? The simple control box described in this article makes this procedure a cinch. It has the following operating features: 1. Off-the-air recording may be monitored on the receiver speaker or earphones at any audio level without affecting the recording level 2. Recorder output may be monitored either for cuing in or transmitting purposes TO HEGH SIDE OF AUDIO GAIN POT MIC W/PTT 6 6 MOM I TOR TRANSMITTER RECORDER TRANS MIKE MIC W/PTT RECEIVER "J TO HIGH SIDE OF AUDIO GAIN POT MONITOR Fig. 1. Tape recorder control box interconnec- tions — all cables are shielded. without tying up either the transmit or receive function, 3. Recorder output is reduced to the same level as average microphone output during transmit so that it is unnecessary to readjust microphone gain when switching from microphone to recorder. 4, No modification of the tape recorder or other equipment is required other than adding a short audio cable to the audio gain control of the receiver or transceiver. A block diagram of the setup is shown in IN-0U1 J! si — o- REC ■»*- ;vr AUDIO J3 RECORDER J2 OUT TRANS Rl 470K f— 3 MON =LJ4 MIKE MIC TAPE *R2 33 «1 AUDIO J, PTT 3 MIC PLUG TO XMTR Fig. 2. Control box schematic. Value of R2 should be adjusted so that recorder output is approxi- mately the same as microphone output. Fig. 1 and the schematic diagram of the control box in Fig. 2. SI switches the recorder from receiver to transmitter, and S2 switches the transmitter microphone input from microphone to recorder, as required. Resistors Rl and R2 form a voltage divider that drops the recorder output to approxi- mate microphone level. High impedance earphones are directly connected to the high side of the voltage divider for cuing in and monitoring purposes. Generally speaking, there are two types of tape recorder interconnections available. OCTOBER 1973 29 MM Most tape decks have separate inputs and outputs, but many of the older tape decks have only one connection which serves as both input and output, depending upon whether the recorder is in the **record" or "play" mode. If your recorder has an "in-out" termi- nus, switch SI must be operated along with the recorder when changing from "record" to "play". If your recorder has separate inputs and outputs switch SI should be left in the REC position at all times. The recorder will then always be properly con- nected when switching to "record" or "play" at the recorder. Monitoring while recording may be done conveniently by listening to the receiver speaker or earphones. On playback, the recorder is monitored with earphones con- nected directly to the recorder output. My unit was housed in an old meter case. This presents a pleasing appearance and also permits mounting the controls at a con- venient angle. The meter hole is covered by a small aluminum panel upon which the con- trol switches are mounted. The microphone and monitoring jacks are mounted in the 2 - Meters . * * Need we say more ? DIVISION 3050 Hempland Road Lancaster, Pennsylvania 17601 meter case binding post holes after reaming them out to size. All other remaining cables and connectors are brought out on the rear of the meter case as shown in the photo- graph. Front and rear views of control box. Photo was taken before the "trans mike" cable and plug was installed through grommeL Wiring of course is simple and not critical, since this is only an audio switching device. However, make sure all connectors are pro- perly grounded to avoid hum problems, A gadget such as this ordinarily does not get much use around the station, but when it is needed it is a real operating convenience. It surely beats haywiring the tape recorder with clip leads and riding the gain, trying to maintain proper output level to the transmit- ter. There is no reason why this or a similar arrangement couldn't also be used for SSTV, CW f or RTTY. . . ,W6FPO 30 73 MAGAZINE John Schultz W2EEY 1829 Cornelia St. Brooklyn NY 11227 2 KW PEP BUILDING BLOCK LINEAR A simplified construction approach to homebrew a high power single or multiband linear. Many amateurs have undoubtedly shied away from the construction of a high power linear because they felt the cost or the mechanical work involved in building such a linear would not be justified. After I had built my first few linears, I would have tended to agree with this viewpoint. How- ever, after having built many more linears over the years — and of widely different types — I find that with a small amount of advance planning the construction of almost any power level linear for the HF bands can be attempted by the home brewer using relatively simple hand tools. I should say not only "attempted" by the home brewer, but attempted witn a very high probability of success. The amplifier described in this article is a particular case in point. It illustrates a particularly simple construction technique and illustrates more than just the construc- tion of a specific linear. By selection of the number and types of tubes used, an ampli- fier of anywhere from the 200 to 2000W PEP level can be constructed. The cost is very low on a watts to dollar ratio and can easily approach 20W of input power per dollar of material cost- Planning the Linear If one looks at the overall diagram of any linear, it presents a rather complex picture; that is, perhaps not so much in terms of electrical functions of the various parts but in terms of mechanical construction when one starts to consider in detail how the amplifier will be built and how to arrange all the components on a chassis, do the mechanical work to mount the various com- ponents, etc- It is usually at this point that the home brewer starts to falter and forget about the entire project as being too com- plex and, particularly, too risky. The risk factor comes into play since if one assembles all the necessary parts — tubes, cabinet, chassis, transformer, etc, and then the am- plifier project doesn't work out, one will be left with a fair amount of money expended for no real return. The risk in construction can be almost completely eliminated if one looks at the construction of the amplifier from a differ- ent point of view rather than as a complete whole. As shown in Fig. 1, the amplifier can really be considered to be made up of three main "sub-blocks" - a power supply, a pi- network output circuit and a sub-block containing the actual tube circuitry with the antenna switching. The power supply sub- RF IN \ i POWER SUPPLY AND FAN AMPLIFIER AND SWITCHING PI- NET CIRCUIT i F RF OUT Fig. I. Most grounded-grid linears can be visualized as consisting of three main constructional blocks. OCTOBER 1973 31 TOUCH- TONE DECODER Dual tone decoder decodes one Touch-Tone digit. Available for 1, 2, 3, 4, 5, 6, 7, 8, 9, #, * and other dual tones 700-3000 Hz. Latch and reset c a p a b i I i t y built-in. • COR control built-in. • Relay output SPST y2-amp. ■ Octal plug-in case. • Compact 1-%" square, 3" high. • Free descriptive brochure on request. T-2 Touch-Tone Decoder ". $39.95 PPD, Specify digit or tone frequencies. (Include sales tax in Calif.) EHGIN BOX 455, ESCONDIOO. CA 92025 super sensitive START HEARING the WEAK ONES JAN EL makes a preamp tor improving the performance of almost any receiver. All are resistant to overload and fully diode protected. Top quality construction. APPLICATION MODEL FfteaueiHicv OSCAR VI 3QPB 29.5 MHz 6 Meters 50PB 50 5 MHj 2 Meters 544PB 144 MHi 2 Meter FM 147PB 147 MHz 220 MHi 220PB 220 MHz: Aircraft 120PB ] 08 140 MHi FM lOOPB BH 1U8 MHi TV TVPB Ch2 13 iSpscirvl Miuli B<jr>d 1GQPB 145 174MH* 432 MHz 432PA 432 438 MH? 440 ATV 432PA T 435 445 MHz 450 FM 432PA-F 440-450 MHz UHF FM H32PA-U 450-4 70 MHz PB models are only SI 9-95 and the 432 PA models are only $23.95. All are in aluminum cases, have BNC connectors (others available), require 12 vdc p and are postpaid and guaranteed. Specify model and frequency when ordering. Other models are available with AC power supply. Write for details. JANEL can also supply a wide variety of receiving equipment for industrial applications. A quote to your specifications will be sent promptly. *W 9 n laboratories BOX 112, SUCCASUNNA r MJ 07876 Telephone: 201-584-6521 Top view of amplifier sub-chassis shows how tubes are circularly arranged around plate choke, block should really present no problem. Any number of power supply circuits are avail- able which have been thoroughly proven in operation and one can even purchase rela- tively inexpensive high power capacity power supplies on the surplus market or used equipment market. Any amateur should be capable of building a simple bridge type rectifier power supply. The pi-network output circuit sub-block should present even less of a problem. Pi-network circuits for single band or multiple band use using conventional components or using toroid coils have been thoroughly described in many handbooks and articles. With a bit of patience, anyone can find the correct tuning conditions and component values to use with a pi-network circuit on any given band. However, it is the tube circuitry or actual amplifier sub-block that is at the crux of the whole linear construction project both in an electrical and in a mechanical sense. If this sub-block can be electrically complete so that the only other electrical wiring that is necessary is the power supply and the pi-network circuitry and if this amplifier sub-block can be easy to construct, almost 70 to 90% of the work in building a linear is done! Of course it will still take patience to complete the linear and to tune it s but one can then have confidence that the linear will work. To take a very conservative approach, one need invest initially only in the compo- nents necessary to build the amplifier sub- block without risking a total investment in all the linear components that might not be used should one decide to give up the project. 32 73 MAGAZINE A 6KD6 Amplifier Sub-Block This article describes in detail the con- struction of a linear amplifier sub-block designed for use with one to five 6KD6 tubes. Other tubes can be used as well, using the same construction ideas. Five 6KD6 tubes can provide a maximum input of 2 KW PEP on SSB. The rock-bottom price I could find for these tubes was $1,50 each. They are available new from almost any discount tube dealer for around $3,00 each. Wherever these tubes, or other TV sweep type tubes for use in a linear are purchased, be sure to obtain tubes of the same manufacture, This applies also in case a tube needs to be replaced. The question of distortion products might be raised when beginning to describe any linear amplifier using TV type sweep tubes. Rather than get involved in this subject, which is not the purpose of this article, it is sufficient to say that the linear described will have 3rd order intermodula- tion products of -25 to -30 dB. Also, the purpose of this article is not so much to emphasize the use of a particular tube type as to emphasize a particular construction technique. If extremely low intermodulation proudcts are an overriding consideration, one can easily use regular transmitting tubes in place of the 6KD6's* 572B's, for instance, would lend themselves nicely to the type of construction presented here. Sub-Block Circuitry If one extracts from a linear amplifier all the circuitry which can be combined to make it as complete as possible except for the power supply and output circuit, the result will be the circuit of Fig. 2. In this case, the antenna switching circuitry has been included in the sub-block. The antenna relay used is a triple pole type so it can also switch a 1 2V zener regulator in during transmit to bias the tubes properly. During receive the tubes are cut off by the higher unregulated bias voltage to prevent noise generation. The sub-block contains within itself all the external connections needed except the power line connection for the power supply (assuming the power supply will be in the same overall enclosure as the FEEDTHRU TO PIN 2 ANY TUBE (CATHODE) 150 r si -L20 — ■♦■ — ■vw- i 47K T TJN34 47K 1N34 ** -• ALC OUT <k-VW * + 20V I ±_5K ALC ADJ. I OPTIONAL CIRCUIT (ALC) Fig, 2. Amplifier sub-chassis diagram, Up to 5 tubes can be wired in parallel Ll r L2 and L3 are discussed in text. amplifier). The pi-network output circuit need only be connected between the plate circuit and the feed-through insulator which connects to the antenna relay. The power supply requirements to the amplifier sub- block are: a high voltage from 800 to 900V (at 200 mA peak for each tube used), a filament voltage of 6,3V (at 2.8A for each tube used) and a bias voltage (unregulated) from -25 to -100V at 50 mA. The bias voltage is not critical as long as it is more than 25V so the tubes are completely cut-off during receive. The series resistor for the 1 2V zener will have to be adjusted according to the bias voltage so that the zener regulates properly without undue heat dissipation. The above are the only external power supply requirements, for the antenna relay is powered by the bias supply line. A monitor- ing circuit for relative power output is included in the sub-block which would be used to drive a I mA meter via a 25K series connected variable resistor. These compo- nents would be mounted on the front panel OCTOBER 1973 33 of the overall linear enclosure. This meter plus an ammeter (0—1 or 0— 1.5A) connec- ted in series with the plate supply (the ground lead, if possible, for safety) will suffice for metering of the amplifier, A cooling fan is necessary if the amplifier is to be used at its maximum input rating. This can be simply connected across the primary of the power transformer so it is activated at the same time as the power supply is turned on. A 1 1 5 V fan which is popular is a Barber Coleman D YAF 761-110 with their AYFA-403 fan blades. The larger electronic mail order houses can supply this item. Other suitable surplus type fans can also be used, but there must be a good flow of air (about 100 cfm). The 6KD6 tubes run hot and I have seen several removed from TV sets where under normal operating condi- tions the glass envelopes have started to distort due to heat problems, The external connections for the amplifi- er sub -block consists of the usual rf input and output connectors, a relay connection for switching the linear to transmit via the exciter, and an ale connector for use with the exciter. The latter is an optional feature which can be used if the ale voltages needed by the exciter from the driven linear are known. The actual circuitry of the amplifier sub-block is extremely straightforward. The 6KD6 tubes operate class AB in a grounded grid configuration. The tubes are not indi- vidually current balanced and this is not necessary as long as the tubes used are of the same manufacture. The input circuit to the cathodes of the tubes contains a low-pass filter (LI and the 100 pF capacitor). This filter helps to prevent further amplification of harmonics from the exciter used and improves the overall distortion rating of the linear. L2 is an rf choke which will pass the cathode current of the tubes while still keeping the cathodes above rf ground. The choke is quite easy to construct and consists simply of close wound turns of #24 wire on a 1.25 cm by 7 cm long ceramic or high temperature plastic form. L3 is the plate rf choke. One has the choice of using one of two simple approaches to construct a suitable rf plate choke. The choke I used is wound on a 9.5 x 2 cm ceramic form with #24 wire. It consists of five sections, each section separated by about 1 cm. The top section consists of 1 1 turns and the follow- ing sections are 16, 27 s 33 and 43 turns. A somewhat simpler rf choke can be made if desired, but then two chokes have to be used in series. The first choke is wound full with #24 wire except for 0.5 cm at the top and bottom. The second choke is an Ohmite Z-50. The .001 juF plate bypass capacitor is used after the Z-50 choke, not between the two chokes. Construction The amplifier sub-block is fully contained on a standard 5 x 7 x 2 in. aluminum chassis. The tube sockets are arranged in a semi- circular fashion with the rf plate choke in the center. The circle is arranged so the center of the end tube sockets are about 2.5 cm away from the side of the chassis on either side, This will permit the tubes to be separated enough to allow good air passage while not allowing the rf leads to become too long. The rf plate choke is about 2.5 cm away from the edge of the chassis also. The tube sockets are oriented so that the number two pin (cathode) on the socket always faces the center of the semi-circle. At the rear of the chassis, the connectors used are a SO-239 for the rf input, phono jacks for the relay control and ale output (if used), and another SO-239 for the rf output. The ale adjustment potentiometer is also located on the rear panel of the chassis. The use of Rear view of amplifier shows arrangement of connectors. Single hole mounting SO-239's are used to facilitate bolting of amplifier sub-chassis into an overall enclosure. 34 73 MAGAZINE single hole mounting SO-239 connectors and phono connectors greatly simplifies the mechanical work involved. At the underside of the chassis the antenna transfer relay is mounted on one side wall above a tube socket and close to the front paneL There is no need to mount the relay in any exact position but it should be mounted nearly as pictured so the length of the wire between the rf output connector to the pi-network is as short as possible. This is to minimize coupling between the output line and the rest of the amplifier circuitry. A short piece of coax is used to go from the relay to the input connector. The zener diode for bias regulation may be mounted in any convenient location near the relay. The cathode of the diode is directly bolted to the chassis, as the chassis functions as a heat sink for the diode. The wiring of the cathode circuitry of the tubes deserves mention. This wiring should be kept as short as possible and an insulated terminal post is mounted for this purpose in the center of the ring of tube sockets. The post can be held in place by the same screw which supports the rf plate chocke on the top of the chassis. The cathode choke, L2, is mounted on the side wall of the chassis opposite the relay. The low pass filter coil, LI, is wired between the relay contact and the cathode terminal post in the center. Also the 100 pF capacitor associated with the filter is wired in beneath LI and utilizes the bottom of the center terminal post for ground, You can also use the ground post of the small terminal strip located in the middle of the inside front panel. This latter terminal strip supports the few components for the relative rf output level circuitry. The 100K resistor in this circuit can be seen going between the relay and the terminal strip. Each cathode pin of the tube sockets is connected with an equal length lead to the center terminal post. 0.5 cm wide copper material is preferred, but large size wire such as -1 2 or larger can also be used, simplify the wiring of the chassis is to wire the tube sockets as fully as possible before mounting them, then complete the wiring of the sockets on the chassis, mount the rest of the components on the chassis and then complete the final wiring. The whole process may sound a bit involved, but actually once the chassis has been drilled and the compo- nents assembled the whole wiring can be completed in an afternoon. All the pins on the tube sockets are wired to ground via the ground lugs on the sockets before mounting the sockets on the chassis except pins 2 (cathodes), 12 (filaments), 5 and 9 (grids) and 7 (internal tube connec- tions). The two ,01 bypass capacitors associ- ated with each socket are wired in at the same time. Once mounted on the chassis, the filament pins (12) and grid (9) are wired together from socket to socket. The wiring to the power supply leaves the chassis via a grommet on the side wall opposite the relay. The mechanical working of the chassis can be done completely with hand tools if desired. The only large holes which require work are the ones for the tube sockets and the SO-239 connectors. These can be made with a punch or with a nibbling tool and round fiie. There is little sense in investing in a punch if one is not likely to use it again, but a nibbling tool can be used for a variety of chassis work, Pi-Network Circuits A number of pi-network circuits have been tried which will work properly with the amplifier. If the linear is to be used on only one or two bands, the pi-network circuitry becomes quite simple and one need only experiment with the component values that produce the highest power output. Extract the single band component values from the Bottom view of amplifier sub-chassis showing wiring of cathode leads to a central terminal point Note also placement of 3pdt relay on side of chassis. OCTOBER 1973 35 it wasn't easy. . .but Kenwood improved the 599 & T-599 THOUSANDS HAVE PROVEN THEMSELVES THROUGH DAILY USE. EVERYTHING THAT MADE THEM THE BEST REMAINS, BUT NOW KENWOOD DID THE IMPOSSIBLE BY MAKING THE "TWINS" EVEN BETTER. THE R-599A IS THE MOST COMPLETE RECEIVER EVER OFFERED... MANY FEATURES WHICH ARE "OPTIONAL AT EXTRA COST" IN OTHER RECEIVERS ARE STANDARD the R-599A Solid state . . , low power consumption, superbly reliable, small and lightweight • Full amateur band coverage . . 10 through 160 • CW, LSB, USB, AM, AM.N, FM reception » Selectable AGC . . . slow or fast • Built-in calibrator • Monitor T-599A frequency to calibrate transmitter • Squelch circuit • 1 KHz frequency readout. . , smooth VFO action • Versatile cross channel operation with T- 599 A • Automatic or manual selectivity selection • Built-in SSB/8 pole, CW/8 pole and AM filters • RIT circuit with RtT tuning separate from RIT switch • Five built-in fixed frequency channel positions * Provisions for installation of 2 and 6 meter converters* Stable, accurate VFO • Built-in power supply for 115/230 VAC operation or 12 VDC operation • Built-in WWV reception • Built-in S- meter • Excellent sensitivity —.5 uv • Easily adaptable to use with Kenwood TS-900 • Modern, beautiful design New Features: New easy read dial, same 1 KHz readout . . . same smooth VFO action • Excellent built-in noise blanker • Improved 2 and 6 meter operation with optional accessory converters, easier installation • Continuous RF gain control replaces stepped attenuator • Built-in 11 meter coverage • AGC The R-599A by Kenwood turns off if desired • VFO indicator light for cross channel operation • The R-599A . . . $439.00 ♦ Converters . . - $31.00 • S~ 599 Speaker .,.$18.00 the T-599A Mostly solid state . , . only 3 tubes • Built-in power supply • Full metering: ALC, lp, RF output* high voltage • CW, LSB, USB T AM operation * 1 KHz frequency readout, smooth easy VFO action • Built-in VOX, with delay, sensitivity and anti-VOX adjustments • Built-in semi-automatic CW with sidetone * Built-in calibrator function when used with the R-599A • Full amateur band coverage > . . 10 through 80 • Versatile cross channel operation with the R-599A • Stable, accurate VFO • Modern, beautiful design • ALC feedback • Maximum TVI protection • 200 watts PEP input nominal • Tube saving TUNE position • Built-in cooling fan • Selectable low or high microphone impedance New Features: Front panel MIC Gain control • Front panel CAR LEVEL control • Improved, easy read dial, same smooth VFO action • VFO indicator light for cross channel operation • New high reliability final amplifier layout • Improved keying characteristics • New chain drive * The T-599 A.., $459.00 Prices subject to change without notice. Why buy from Henry Radio? Over 40 years experience, No finance charges if paid with-in 90 days, tow interest contracts - 8%/yr add on (14% annual rate) - as long as 24 months. 70% down or trade-in down payments. Good used equipment. Most makes and models. Used equipment carries a 15 day triai 90 day warranty and may he traded back within 90 days for full credit towards the purchase of NEW equipment. Write for bulletin. Export inquiries invited. i 11240 W. Olympic Blvd., Los Angeles, Calif. 90064 213/477-6701 931 N. Euclid, Anaheim, Calif. 92801 714/772-9200 Butler, Missouri 64730 816/679-3127 Available at Kenwood Dealers throughout the US multiband circuits shown in Fig. 3. Under properly loaded conditions and with 800-900V on the plates, the CW plate current will run 200—220 mA per tube used. For the full five tube circuit, the plate current for CW can be loaded up to between $.. and 1,1 A. The key-down periods must be kept to 1 seconds or less. If an 80 to 10 meter multiband pi- network output circuit is desired, Fig. 3 presents two good possibilities. The first circuit has an advantage in that it requires only a conventional 2 pole, 5 position switch for all of the capacitor and coil switching functions. The second circuit avoids the use of auxiliary fixed capacitors for the lower frequency bands but the plate tuning capaci- tor shaft requires an insulated shaft coupling and mounting above ground. In any case, the final coil tap positions should be experi- mentally peaked up for maximum power output on each band. The plate tuning capacitor in either circuit should have 1000— 1500V spacing while the output load- ing capacitor need only be a broadcast band type. The fixed capacitors should be mica or ceramic types rated from 1 to 3 kV. Ceramic transmitting type capacitors such as the Centralab 850S are preferred if one can find them surplus at a reasonable price, ? 250/ tKV SPACING C0IL:5CM DIA.5CM LONG BAND TAPS 40 -7T 20- 3T 15 - 2T 10 - IT ANT, Jf 1000 TO # 1500 MAX, Huh ROLLER INDUCTOR n~^ ~x -U00 \J 1000 MMF/ SECTION ANT PLATES I £ I500MMF Fig* 3, Two good pi-network circuits which can be used with a 5 tube 6KD6 amplifier for all band operation. Vfan J AMPLIFIER SUB-CHASIS RECTIFIER/ FILTER Fig m 4 M There are many ways the amplifier sub- chassis can fit into an overall enclosure to fit almost any taste m Build the sub-chassis first and then integrate it into an overall enclosure. Final Enclosure Assembly Exactly how one wishes to finish up an amplifier in an enclosure depends to a good degree on how fancy an appearance is wanted, so this part of the project is pretty well left up to the desires of the individual builder. Certainly, if the power supply is ready, the amplifier chassis finished and the parts for the output circuit secured, the grouping of these items in an overall enclo- sure is not a big problem. Although not one of the fanciest ap- proaches, but certainly a simple and ade- quate one which I have used for a number of amplifiers, is the use of standard large size metal utility cabinets (Bud CU or AU series, Par-Metal MC series) as the overall linear enclosure. These enclosures are inexpensive ($5 to $6) and come in black wrinkle steel finish or bare aluminum. The black steel cabinets are attractive in that they need no further painting. These enclosures are typi- cally square looking with removable top and bottom covers. The mounting of the ampli- fier sub-chassis in such an enclosure is particularly simple since the connectors on the back of the amplifier sub-chassis can be used to secure the sub-chassis to the en- closure. Figure 4 shows how the total linear might be assembled in such an enclosure. For ventilation purposes, a series of holes should be drilled in the two side walls of the enclosure which are in the path of the air flow produced by the cooling fan used. > . .W2EEY OCTOBER 1973 37 LOOK INTO OUR CRYSTAL AND SEE BEYOND 2 METERS The new 220 MHz Clegg FM-21 transceiver has a unique triple-duty crystal feature and offers you a chance to get away from to- day's 2 meter crowd. The FM-21 uses just 1 crystal in any channel. One crystal gives you a separate transmit and receive frequency plus automatic 1.6 MHz programming in** the repeat mode. Our Crystal Saver Frequency Control is just one of the big pluses you get with the FM-21. another ail-American made quality rig from Clegg. For the whole story, see your Clegg Dealer or call or write us now for detailed data sheet an escape from the 2 meter crowd. Amateur Net $299.95 Gm. CHECK THESE SPECIFICATIONS GENERAL POWER REQUIREMENTS: 12 to 14.8 Standby Current: 120 Ma. Receive Current: 450 Ma. Transmit Current: 1 .5 Amps. Max. FREQUENCY RANGE: 220 to 225 MHz Power output down less than 2 db at 220 MHz DIMENSIONS: 7" wide x 2%" high x 9" deep. cpfC RECEIVER SENSITIVITY: , 25^ (Max.) for 12 db SINAD SELECTIVITY: Adjacent channel (40 KHz) down 50 db AUDIO POWER: 1.5 watts at 10% THD to internal or external speaker SQUELCH: Noise actuated, adjustable threshold. .2 to 2/iV min. range MODULATION ACCEPTANCE: ±7 KHz POWER OUTPUT: 8-10 watts (min.). MODULATION: PRE-EMPHA5IZED FM with deviation adjustable from to 7 KHz. Adjustable speech clipping up to 10 db. DIVISION 3050 Hempland Road Lancaster, Pa. 17601 Tel: (717) 299-3671 Telex: 84-8438 John A. Meissner K5CXN 2223 48th Street Los Alamos NM 87544 T ANOTHER WATTMETER Many VHF operators would like a cheap, accurate instrument to mea- sure rf power. The same desire is frequent- ly expressed by operators of the HF bands. Here is a very simple wattmeter which when used with a SOfi transmission line or load has all of the following desirable characteristics: 1. Easily calibrated to good accuracy (±5%) with your multimeter and a variable dc source; 2. Perfectly flat from dc to 450 MHz; 3. Insertion VSWR less than LOS 4. Power readings in the 2 to 50 watt range (higher power can be measured with slight design changes); 5. Cost of approximately $20,00, assuming the use of a surplus micro- ammeter. The operating principle of this watt- meter is stark simplicity. A pilot lamp across the rf line senses a small portion of power in the line and glows brighter with increasing power. An appropriately located photovoltaic cell connected to a micro- ammeter measures the light output which is proportional to the power flowing in the line. Of course a good deal of nonlinearity is involved in the various elements — both the lamp's resistance and its spectrum output change with heating; output of the photovoltaic cell varies considerably with both the amount and frequency of the light shining upon it. Some of these factors tend to cancel out however, because the photovoltaic cell produces some current with only infra-red lamp output at low power levels before the lamp even produces a visible glow, and the cell tends to saturate, increasing its output quite slowly at more intense illumination levels. if the resistance of the lamp filament is very large when compared to the line impedance. In general, a factor of 15 or more times the line impedance is suffi- ciently large to produce negligible effects. In the case of the suggested 10V, ,014 Ampere pilot lamp, the mismatch produced in the line gives a VSWR of 1.05:1 at the power level of 1 watt. This mismatch decreases rapidly with increasing power. It falls to well below 1,01:1 at 50 watts. Another point of interest with regard to this particular choice of lamp is that it is a long-life type with a life expectancy of 10,000 hours. This implies two advantages: (a) The lamp will operate at well over its rated voltage without burnout (50.0V at 50 watts), and (b) the interior of the lamp envelope will resist darkening which would negate the wattmeter calibration- In addi- tion, the filament structure of this type of Probably the biggest single requirement of any wattmeter is that it must be capable of being inserted into a transmission line without disturbing the operating conditions in the line (low insertion VSWR). It might be argued that hanging a lightbulb across a transmission line will seriously affect the line impedance. Ordinarily, this is true, but the undesirable changes can be minimized and indeed approach an insignificant level UG-J07A/U UHF COAXIAL "TEE" RF IN RF OUT / / l\ DIALCO LAMP WO. 39J0 g7t *BASE REMOVED) z^^ RS NO. £76-115 PHOTOVOLTAtC CELL 20^i A DNNECTORS SDl j MIN1BOX - BUD NO. CU-3000-A COAX CABLE OR TWISTED PAIR Q lo 50 10- WATTS MAX-RI'95U.IW 50- WATTS MAX- flZ- 20ft r 100ft. t/4 W IN PARALLEL 50 f 3 f RZ r Fig. 1, Schematic diagram. OCTOBER 1973 39 lamp is a single-strand straight tungsten wire. The coiled type of filament structure introduces undesirable inductance into the circuit which can distort wattmeter read- ings in the UHF range. The wattmeter shown is constructed in two boxes for the sake of convenience. The sensor can be located in the transmission line at any point and the meter can be placed beside the transmitter. For test work, the whole unit could easily be put into a single box- Coaxial fittings and cable were used for interconnection, but since dc only flows in this circuit, any type of wiring would be satisfactory. The photovoltaic cell used in this watt- meter is a unit obtained from the local Allied/Radio Shack store. (Catalog No. 276-1 15.) Output of the cell is rated ,5V at .6 mA in sunlight. Since the cell generates considerably more than 20 mA under moderate illumina- tion, a switching arrangement is incorpora- ted into the wattmeter to shunt it into progressively higher current ranges with increasing power. Alternatively, a 50 or 100 milliammeter could be used with less switching at a sacrifice of sensitivity in the 1-3 watt range. Calibration of the wattmeter is a simple process. By solution of the formula P = V /R for voltage, the following tabulation is made for a 5 Oil line impedance: VOLTAGE POWER (rms or dc) (Watts into 50J2) 7.07 1 10.00 2 12.24 3 14.14 4 15.71 5 17.32 6 18.71 7 20.00 8 21.21 9 22.36 10 31.62 20 38.71 30 44.71 40 S0.00 50 Using the tabulation, fasten a metered variable dc supply into the wattmeter ac- cording to the following diagram. Now simply note the reading on your wattmeter for each of the selected voltages in the table and tabulate this reading with the corresponding power in watts in a table of your own. It may even be possible to remove the front of the meter case and mark new calibrations directly on the dial. This was not possible with some hermeti- cally sealed meters. It is best to disconnect the wattmeter from the antenna feedline for this calibration- If the meter is left with a transmission line attached and the an- tenna happens to be fed through a balun device with near zero resistance, the power supply, and perhaps the balun, will suffer. UHF TEE AC INPUT VARIABLE VOLTAGE DC SOURCE OP£N END TO METER VTVM OR MULTIMETER Fig. 2, Calibration diagram. It must be pointed out again that this power meter is intended for use either with 50J1 coaxial line systems with low VSWR or with 5012 dummy loads. A coaxial line that is not "flat*' (unity VSWR) or a dummy antenna that does not look like" 50fi, which is the case with most HF loads used at VHF or UHF, may cause distorted power readings. If you have doubt about your transmitter's power out- put when using this meter, you should check it while using a known 50O load rated at the transmitter's output frequency. 1 mentioned before that this power meter was easily adaptable to higher power readings. To upgrade the meter, the only change required is to insert the correct higher voltage pilot lamp having low cur- rent, long-life specifications. Suggestions for some of these are the following Dialco Lamps: Part No. Max Power Level (Watts) 24CS 1 00 48CS 200 60PSB 340 120PSB 800 . . .K5CXN 40 73 MAGAZINE SCAN- VISION SCANVISION SLOW -SCAN ■ iflT Fully meets all accepted SSTV standards. Compatible. Exclusive! Built-in, casette-type recorder* Ready Instantly Now — unexcelled picture performance with exclusive- feature equipment of highest quality in which the most advanced SSTV techniques are expertly ap- plied — Sit Scanvision* Here, carefully considered design has simplified operation to the point where the non-engineer radio amateur can have his SBE Scanvision monitor connected and start enjoying slow scan in just a matter of minutes. Most of the many hundreds of SS TV'ers now active on the air agree that the full excitement and enjoy- ment of SSTV can best be realized only when a tape recorder is part of the system. Incoming pics are taped for future viewing on SS monitor — pre-taped pictures, scenes, l-D — can be transmitted, So — ex- clusive! — every SBE Scanvision monitor has a cas- sette-type tape recorder built-in — wired — ready to go and selectable with panel switch. Here is the ultimate in convenience. Scanvision is conservative — reliable, with pic- ture-proved circuitry and is all solid-state except for the scope tube in the monitor and the videocon pic- ture pickup tube, heart of the SB-1CTV camera, Both tubes are standard types with predictable character- istics^ — not surplus- High quality is everywhere evident — throughout, the to-be-expected SBE approach — fastidious — profes- sional- The SBE Scanvision, S8-1 MTV Monitor, com- plete with casette recorder and SB-1CTV Camera with f/1,9, 25mm lens, connect with patch cable to com- prise ft system- Units are also separately available* SEE SCANVISION AT YOUR SBE DEALER Audio in,., and out NO MODS!! if=i. 1 Available- camera with high quality videocon for "live" or "still" pics. Camera is supplied with quality f/1. 9, 25 mm lens. No extra charge. Monitor con- nects to spkr or phones for receive— to mic input for transmit. "Live" SSTV pic photo- graphed from monitor, Un- retouched. 1SBEI LINEAR SYSTEMS, INC. 220 Airport Blvd. Watsonvilie. CA 9SQ76, you like METER YOU'LL LOVE OUR 15 OR 1 WATT POWER OUT/ SWITCH SELECTABLE/ FULL 12 CHANNEL TRANSMIT AND RECEIVE CAPABILITY Youll like the crystal clear transmit and receive performance of this compact, 2 meter unit and so will those listening. The 12 transmit channels are provided with individual trimmer capaci- tors for the optimum in point-to-point and repeater applications. A HI/LO power switch provides 1 watt output or full rated output. The receiver has an audio output of 3 watts at excellent sen- sitivity, Solid state, American made quality at a low price. $229 00 AMATEUR NET k * frftt nam* I in iplid ftrtf Wl l includes plug-In ceramic mike, mounting bracket and transmit and receive crystals for 146.94 MHz. THE FM LEADER IN 2 METER AND 6 METER... AND NOW 220 MHz J. K. Bach WB2PAP Ivy Hill Road Walden NY 1 2586 ^DEMAIN Nobody in his right mind would fix a meter by choice, any more than he would operate on his wrist watch. But fate, which seems to be a generalization of Murphy's law, determines that sooner or later you will be faced with the necessity. One day you are minding your own business and your boss sidles up to you like an affectionate bison, mumbling something about how easy it would be for you to fix this (heh heh!) meter in your spare time. Or it's your own meter that went ape on a weekend. Whatever the motivation, you de- cide to take a hack at it. I had never fixed clocks or watches, but I had reversed a tuning meter or two to read up-scale, so meters held no terrors for me. The first time I was handed one to fix at work, I started out with a show of jolly self-confidence and proceeded to lose my patient — irretrievably — within minutes- The second worked if you tapped it continu- ously and held your mouth right. The third and fourth I don't remember, but the fifth worked as good as new. By this time I had made most of the more stupid mistakes, learning a bit from each. A meter repairman would laugh himself sick at my methods. Were I in his position, with his facilities and skills, I would laugh too. Vd laugh even harder watching him work on a meter with my facilities. He has to work fast to make money and has all the parts he needs. He replaces whole assemblies, as an automobile mechanic does. I have to straighten the kinks out of hairsprings, but I have lots of time. My boss gives me the job because when he sends any meter to any shop he knows how long it takes to get it back. This is true of all shops all over the land. Even buying a new one takes a lot of time, which is why so many of us are volunteered to fix them* The tools are very simple. A good light, such as a desk lamp, is very useful but not essential if you have young eyes, I haven't. The next thing is to provide a spread newspaper to work on. Meter magnets will attract steel filings and steel wool fuzz from incredible distances. These have to be swabbed out of the air-gap with Scotch tape- One session of this will teach you to spread a clean newspaper. The second lesson is, no magnetic tools. You naturally try to use your familiar long-nose and screwdriver, but at best you can't control them closely enough near the magnets and they are hazardous besides. What you need is a non-magnetic toothpick. It can be round, like the one in the photograph, or the old square kind. You can Fig. la. Top view of a healthy meter spring. i ^P Fig. lb. Side view with indicating needle added. cement two together to make a tiny fork for straightening needles and unkinking hair- springs. By all means get a magnifying glass if you can. Older guys tend to keep them in their toolbox. One of the handiest kinds is the jewelers* loupe with the steel spring head- band on it. The monocle type will cramp all the muscles from your big toe up, with the effort of keeping the silly thing in your eye. Use your own judgment. Duco or other plastic cement is handy, hut do not use it directly. If you have to cement a needle, transfer an invisible dab of cement with the end of a toothpick. Get just one drop of cement in a hairspring and no amount of any solvent will ever get it out. The only cure is to take the meter in your right hand, take a good wind up and let fly eastward. This will save you an ulcer in the long run- All this talk and nothing about the actual work yet? Patience! Watch a good machinist at work — two hours and a half on setup, and two minutes for machining, that's his rule. The beginner reverses these times and strikes out with ruined work. Meter fixing is like this - utter despair can be followed by delirious delight within a few seconds. Nearly every hairspring trouble is fixed very suddenly or not at all. And all the other troubles taken together are few. One more warning; the PAP syndrome (WB2PAP). This is not to be confused with the PAP test which is entirely unrelated. The effect is a spasmodic jerk of the hand which, by Murphy's law, invariably stretches the hairspring to its full length and ruins it. This nervous jerk is brought on by fatigue, and I believe it is due to the loss of feedback to the brain, which tries to locate the hand position and reset it, with disastrous results. I don't fully understand the mechanism — who does? — but I know a good way to prevent it. Never work free hand. Take a look at the photograph which illustrates this. See that third (fiddle count) or fourth (piano count) finger touching the meter magnet? With it, or any other finger or part of the hand touching, the brain knows right where the hand is, and keeps it there. Also the movements are measured in millimeters, not inches, and finger contact helps with this. It also helps impose gram forces instead of ounce forces. There, I've saved you one meter already. Another warning - leave the jewels and pivots alone. With a brand new meter, fresh out of the box, you can move the needle along its length a full thirty-second inch, a clearly visible amount. You can even feel the motion of the pivots in the jewels. Every- body has a thing about pivot adjustments, and so did I, once. The natural thing is to take all the slack out — just. But meter pivots should be left sloppy for the least drag. If you must take meters apart beyond the minimum possible stage, you will need some- thing to put the little screws and nuts and insulators in. I like a baby-food jar. A heavy ash tray is good too; or both. But keep the parts in the jar until you have to put the meter together again, else you may hit the ash tray with your elbow and shower itsy- bitsies all over the place. And tweezers — sound good? Like the idea? Ever "shoot" a little nut or screw clear across the room and into the nap of the rug? Maybe you have the requisite skill to use tweezers, but 1 want no part of them. 44 73 MAGAZINE At last — the broken meter. Take the front case off. Is the winding open? Blow the needle to full scale a few times and see how quickly it restores to zero. Now short the terminals and repeat. If the needle restores as fast as before, either the air-gap is very wide or you have a wiring trouble. It figures to be the coil, but several times I have found it in the shunt or multiplier resistances, or other wiring. Now if the needle is stuck, make sure it really is the needle. It can actually stick to one of the stops (rare), scrape on the scale, hook over a scale-screw, or be biased off low mechanically. In any case the needle must be okay before any other source of drag can be located. The air-gap may have filings in it, or the hairspring tangled. If the air-gap is fouled up, take a short length of Scotch tape and swab it clean. It isn't fun, but it can be done. If the hairspring is tangled or distorted in any way, the best thing is to just look at it from all angles, in all kinds of light, under the glass (low powered one will do). Try to figure out just how in thunder any normal very difficult to see unless you have experi- ence. Someone before you has had the meter open and touched the hairspring not quite gently enough. He has put a permanent set at the outer attachment, bending it toward the shaft right where it is soldered, along the horizontal plane of the spring. You can work at this for hours, making it worse and worse. But once you know exactly what the trouble is, you take the non-magnetic toothpick and bend it in the exact opposite direction, removing the "set" and restoring the original set. But don't apply the restoring set all at once, and directly against the arrow in the figure. Rather, engage the sharpened tip of the toothpick between the 3rd and 4th loop of the hairspring and run it back and forth a few millimeters - maybe an eighth of an inch — along the spring, but angled very slightly outward. Magic! That spring, under the glass, is one of the most beautiful things you will ever see! Or take Fig. 2b. By great good fortune, I managed to get something like this in the photograph, I was working left-handed at arm's length with a commercial photo- grapher, tripod, Hasselblad, and speed-flash S* Fig, 2a. Spring is bent at outer attachment. human being could get the hairspring in such shape — but don't touch it yet, just look at it. This will save you a lot of time. Figure la sketches a view of two moving paits-h air spring and shaft with side-lug. Also shown is the zero adjusting fork, which also revolves around the same axis as the shaft and pivots. Figure lb is the same thing from the side, with the indicating needle added. No fixed supports or anything else are shown. All this for comparison. Now look at Fig. 2a - what causes the bunching at the bottom of the coils? This is Fig. 2b. The outside loop is hooked over the spiral all between me and what I was doing. The only way I could tell that I was contacting the hairspring was that the meter needle quivered a little from time to time. See that little loop up past the outer turn of the hairspring? That's how it looks, except that it stays there by itself and hangs the meter movement up. Same remedy here: move the sharp tip of the toothpick a little further back this time until the spring jumps clear. Imagine you are petting a microbe; this will help you use a minimum of force. This, by the way, is the only trouble that ever clears OCTOBER 1973 45 . .■ . m ■ • METER ANTENNAS . jj FROM THE WORLD'S LEADING |4w^ MANUFACTURER OF VHF/UHF COMMUNICATION ANTENNAS (A) FM GAIN RINGO: The mosf p 0pu | ar _ high performance, half-wave FM antennas. 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A 147-22 10 Q0 watts 146-148 MHz $56.50 {E) 4-6-11 ELEMENT YAGIS: Tbe standar d of comparison in VHF/UHF communications, now cut for 2 meter FM and vertical polarization. 4 & 6 Element models can be tower side mounted. A 147-4. 1000 watts 146-148 MHz $11.95 A 147-11 1000 watts 146-148 MHz 19.95 A 2 20- 11 1000 watts 220225 MHz 17.95 A449-6 1000 watts 440450 MHz n.95 A449 11 1000 watts 440-450 MHz 15.95 (F) FM TWIST: A Cush Craft exclusive — it's two antennas in one. Horizontal elements cut at 144,5 MHz, vertical elements cut at 147 MHz, two feed fines. A147-20T 1000 watts 145 & 147 MHz $39.50 IN STOCK WITH YOUR LOCAL DISTRIBUTOR CORPORATION 62 1 HAYWARD STREET MANCHESTER, N. H. 03103 itself, and not very often, either. I think that slamming the needle is what does it. The sharp pulse sets up a standing wave that whips a loop of hairspring outside the spiral, where it catches. Fig. 3. This anomaly was probably caused by the downward motion of the adjusting fork. • Figure 3 is interesting, too. Obviously, someone has hit the scale end of the adjusting fork, pushing it downward. So take your tool and twist it back up. These "repairs" (adjustments) take five minutes of looking and five seconds of adjusting, Or five hours if you mess it up or "fix" the wrong thing, A good visual imagination is the secret. Of course, the examples illustrated are frequently encountered and basic. But if you get any two of them together at the same time, or even a third mixed in, then the others will be more obvious and can be cleared in their turn, I never said it was easy, but you can do it, nevertheless, if you look before you poke. Most people don't. Consider: The hairspring is foil thin, it is made of phosphor-bronze, one of the tough- est metals, perfect for the purpose. It wants to go back like it was. Both ends are soldered fast, which limits the degree of possible entanglement, a sort of antithesis of Murphy's law. The worst thing is kinking and this is also due to big, vulgar, ignorant thumbs getting into the hairspring- Even these can be straightened one at a time, and suddenly the hopeless case is perfectly okay. Some traces may remain, but if the spring is symmetrical, and the eye can't be fooled in this, then by all means let it alone I Once you have sufficient clearance, twice as much isn't better, and costs in another dimension. Generally it is not necessary to remove the scale. Mount the meter level and se- cure — in a box, or something. If the meter slips and you make a grab for it and stick your highly-skilled thumb through the hair- spring, it will have exactly the same affect as if the office oaf stuck his in. You won't feel any better, anyhow. Once I got a meter in a tube tester that was supposed to stick. Impossible! It was a taut-band type, with pole clearances you could throw a cockroach through, I returned it and got it back, with the needle stuck this time. Out of the case, it came unstuck and no possible place to stick could be seen. By considerable mistreatment I managed to hang the needle up on a scale-screw. Bending the needle up a bit fixed things, A funny one: a meter with no needle at all, I was offered affidavits that the case had never been opened, but still - no needle anywhere. What could I use for one? Broom- straw, inked? Broom? Push-broom!! I plucked a horsehair from it — perfect. How- ever, 1 ironed it straight on the soldering iron, and dampness finally re curled it. I should have picked the longest and straight- est and let it go at that. How about calibration? You have re- stored the spring to its original shape, and very probably the calibration is pretty goodL You can set the zero adjustment in the middle of the adjuster range by moving the hack hairspring lever (be very careful of this one, the lever is short and you risk a Fig. 2a), Once you get the zero okay, how about full scale sensitivity? You could adjust the shunt or multiplier, or if you are lucky, there might be a magnetic shunt. This gadget is a thin leaf of magnetic material that can be slid across the poles to leak a little of the flux around the coil. For more sensitivity, slide it back over the magnet away from the pole. This forces more of the flux through the air-gap and coil, increasing sensitivity. Only the very best domestic meters have this feature. Hickok even had one around the outside of the meter case in the big Gm meter of one of their tube testers. It is usually pretty disillusioning to cali- brate or compare meters. It really shouldn't be, but even the best meters aren't as accurate as you think. If they were, they would be too fragile and expensive to use. We've been getting along with them very well for years, just as they are. And if you have to fix one — good luck! . . WB2PAP OCTOBER 1973 47 One Setting for TOTAL BAND COVERAGE... m Lowest SWR-PLUS! • Bandwidth at its broadest! SWR 1.6 to 1 or better at band edges. • Hustler exclusive trap covers "Spritz" extruded to otherwise unattainable close tolerances assuring accurate and permanent trap resonance. • Solid one inch fiberglass trap forms for optimum electrical and mechanical stability* • Extra heavy duty aluminum mounting bracket with low toss— high strength insulators. • All sections IVa" heavy wall, high strength aluminum. Length 21' 5 - Buy . . . buy choice Stainless steel clamps permitting ad- justment without damage to the alumi- num tubing. 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This range of coverage is available through the Zugspitze repeater located in the Alps in southern Germany, The Zugspitze repeater is probably one of the most unique repeaters yet to operate in the 2 meter band. Its story is an interesting one not only because of its location, technical details and the German amateurs involved but because it may well become the model for a number of DX repeaters located throughout Europe. So, although American amateurs won't be using this repeater, except perhaps when on vaca- tion in Europe, its story should be of value and interest. Before describing the history of the re- peater itself, and unless one Is familiar with southern Germany, it would be a good idea to take a look at a map of Europe and locate A panoramic view from the Zugspitze Mountain. OCTOBER 1973 49 SYNTHESIZED ! Inoue's New IC-230 . • 162+ channels, simplex or offset {600 kHz) for repeaters • All modular construction • Super hot MOSFET/helical coil AfJiV receiver • AVAILABLE NOW ! . .. only $447,50 Send QSL or check index for detailed brochure ERICKSON COMMUNICATIONS 4653 North Ravenswvood Avenue Chicago, IL 60640 (312) 334-3200 the city of Munich in southern Germany. Within a radius of 200 to 250 miles coverage around Munich are located portions of all of the countries mentioned above. These countries cannot be worked directly from Munich because of lack of height, interfering terrain features, etc. However, if one pro- ceeds southward from Munich, the country- side remains relatively flat to gently rolling hills until about 50 miles southward when one rather suddenly encounters the start of the Alps, A number of peaks rise to several thousand feet in height, One of the most famous of these peaks and one of the highest (9, 721 feet) is the so-called Zugspitze. It is not the highest peak in the Alps but it is the highest peak in the portion of the Alps which cover Germany and the peak is right on the border between Germany and Austria, A meteorological observatory as well as a hotel are located on the peak and the area is a favorite with skiers. The view of the Alps provided from the peak on a clear day is perhaps one of the most spectacular in Europe, It is reached by means of a rack and pinion railway (not too scenic because of all the tunnels it travels through) or by an aerial cablecar ride that is guaranteed to fascinate anyone. When the 2 meter FM repeater idea began to catch hold in Germany it was natural that the amateurs in Munich looked toward the Zugspitze because of its high location and its accessibility. Approaches were made to the Bavarian Weather Service which maintains the weather station on the mountain to be allowed to set up a repeater on top of the weather instrumentation tower, After some rather difficult sessions with the weather service people* the German amateurs in- volved in the project finally did obtain permission to set up the repeater. Some of the conditions involved were rather hard to take, however. For one thing, the repeater installation could not be located indoors but had to be contained in a metal enclosure outdoors. Only a power line to the repeater, which would be metered and separately charged for, would be provided. Also a liability insurance policy in the amount of some $250,000 had to be taken out to insure that should the installed equipment, antennas, etc., cause any damage to the weather installation or to a person (there is a tourist observation platform around the weather station) that the weather service would be protected. It required considerable determination on the part of the amateurs involved to forge ahead under these conditions, especially since at this point the financial support for the project would have to come solely from the amateurs themselves. It might be worth- while at this point to mention that although only a few amateurs did all the work on the project, all amateurs can use the repeater. Private or "closed" repeaters are simply not allowed on the 2 meter band in Germany. The makeup of the repeater channels in Germany has been described in other articles and so it won't be gone into in great detail here. But either because of the Teutonic characteristic for having everything done by a rule book or because German amateurs saw the mess that was developing about repeater frequencies in the U.S., when repeaters were first authorized in Germany specific chan- nels were set up for their usage. Only these channels could be used and every new 50 73 MAGAZINE A view of the weather station on the Zugspitze, The transmitting and receiving antennas are directly above and below the tubular structure on the right side of the tower. repeater that was set up had to use a channel that would be compatible with other nearby repeaters. Originally 3 channels for repeaters were allocated and this now has been ex- panded to 7 channels. The input channels for repeaters are in the range of 144.15 to 144.30 MHz with 25 kHz spacing and the output range is 145.70 to 145.85 MHz, Repeaters can have a maximum power of 15W and ±5 kHz deviation. To enter the repeater initially a tone burst of 1750 Hz is required (most will also whist le-on) and then the repeater is carrier keyed as long as no break of jnore than 3—5 seconds occur. The amateur licensed to operate the repeater also has to be able to remotely disable and enable it. However, a separate link is not required and this control function is done by a multiple tone signal on the input frequency of the repeater. There were many amateurs in Munich who contributed to the establishment of the Zugspitze repeater, but the leading members of the team were Sepp DJ9HJ, Bernd DL9ZD and Peter DJ3YB. This team was perhaps an ideal one for such a project because of their complementing interests and talents. DJ9HJ headed the organiza- tional aspects of getting the repeater estab- lished while DL9ZD specialized in digital and control circuits and DJ3YB was an experienced engineer on VHF/UHF cir- cuitry. After receiving the necessary license for the initial Zugspitze repeater in the spring of 1970, the Munich team set about to assemble the necessary equipment to get the repeater into operation as quickly as pos- sible. The emphasis at this point was to get the repeater into operation during the good weather period. Fortunately a commercial VHF transceiver intended for mobile use could be secured, and with the necessary modification for a power supply, frequency changes, a keyer for repeater ident, etc., it formed a repeater "package." Two com- pletely sealed vertical dipole antennas of commercial design and a cavity filter made up the antenna part of the package. After initial testing, the entire package was trans- OCTOBER 1973 51 OF THE WORLD'S FINEST 5i\X GOVERNMENT SURPLUS 1 ELECTRONIC EQUIPMENT And BETTER Than Ever! Address. City State Zip Mail Coupon for Your FREE Copy, Depf . 73 1016 E.EUREKA * Box 1105 • LIMA, OHIO • 45802 QUAD OWNERS The perfect marriage - your favorite tri band quad and an "H & H RING TRANSFORMER", Designed specifically for quads, this balun offers the optimum impedance match using a single 50 ohm co $* feed line. 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The entire repeater is located outdoors. ported to Garmisch, Germany, in August 1 970, where it was loaded on the cable car for transport to the Zugspitze- The station package except for the antenna had been assembled in a metal container intended to remain outdoors. Over a day was required for the initial setup of the repeater and all of the usual Murphy's laws applied, as it was found the metal container was too large for the space it was meant to occupy, etc. None of these problems would normally have caused great concern except that one had to work at 9,000 feet elevation and rides up and down the cable car were costing up to SI 5 each because of the equipment that had to be transported. Finally the repeater was set into operation and amateurs in southern Germany began to enjoy a unique repeater operation — but for only eight days. Then the repeater seemed to malfunction as the receiver sensitivity was greatly reduced. The cause was traced to the cavity filter used for antenna isolation. It had been constructed from 1 mm thick copper but apparently this 52 73 MAGAZINE A view of the transmitting antenna in summertime. The antenna is a completely weather-sealed vertical half -wave radiator. thickness could not remain properly ad- justed due to the temperature extremes encountered on the mountain, A look in the statistical records showed that the tempera- ture on the Zugspitze, to which the entire outdoor installation would be exposed, varied from -37 degrees to +70 degrees. The average temperature is about 24 degrees, the same as that for Greenland. The problem with the cavity filter could not be solved, but an anonymous donor came up with a commercial 5 pole filter that did the job. After solving the filter problem, the repeater basically continued in operation with only minor difficulties. The transmitter used was a tube type and had only 5W output. Nonetheless, German amateurs were pleasantly surprised to find at times Italian, Czeck and other DX stations calling over the repeater. Also, the coverage achieved in Germany was considerable, with stations being worked up to Kassel in northern Germany, The unpleasant side of thepicture was that the repeater was starting to inter- LED READOUTS Similar to MAN -I. Ji3" high. 20 mA per segment, Uith detimul pmnf. Rim] - $2.25 each Green — §3-00 LED - moUh'tl plostit: dome shape with leadx. KODAK RKL> W ratten Filters R*?d - $.25 «il4i, 5 for $1.00 Green - $.40 each, 5 for $LB5 I'crfett for tight filter over nd LElh, i " sq, M85" thie.k. $.35 each, 3 for $1.00 LM 309 Voltage Regulator IC, 5 voilx at I Amp. muw t-urrenL $2.00 each * ■ + + ■ ■ ■ ■ » * ■ ■ ■ ■ TTL IC fTuU fa ■ ■ ■ ■■ ■ P * r i 7402 .-.;*... 7404 7441 7447 ,-. 7475 i *W *^ ■ t , i ■ . ■ -■.•«. . '■'** '§:■*#'• #■ « ■' m . . . . ■ *? .'U l l l I ■ l ■ 4. ■ I fl + , FI-1-rr-.-raa-rarr- *■*#■! + 1 * + w * * i + I ■» * . M -. * . . . . +frjp . .3.F ■ Aril + »*■■-■■ VU 1 + 39 1.40 ■ ■ ■ m m m m m m a. mfkJ U w ■ ■■■■>■ ■ I .wU .......... .n5 ■ ■»■■ + *■#■ I ■ W MINIMUM MAIL ORDER $2.00 mastei charge I hi ifaM lllki HUE SEND FOR LATEST FLYER OF SURPLUS AND yEW ELECTRONICS JEFF-TRONICS 1916 Clark Avenue Cleveland, Ohio 44109 FREE CATALOGja- HARD-TO-FIND PRECISION TOOLS Lists more than 1700 iLems — pliers, tweezers, wire strippers , vacuum systems, relay tools, optical equipment, tool kits and cases. Also includes four pages ol useful "Tool Tips 11 to aid in tool selection, [^ IS JKNSEN tools ana a 4117 N. 44th S»ree1, Ph«nii, Arizona 85018 WORLD QSL BUREAU 5200 Panama Ave., Richmond CA USA 94804 THE ONLY QSL BUREAU to handle all of your QSLs to anywhere; next door, the next state, the next county, the whole world. Just bundle them up (please arrange alphabetically) and send them to us with payment of b4 each. ECM-5 FM Modulation Meter Only $75.00 It's*; batteries * Operates 30 500 Wlhz * Crystal contiolled for fast and easy operation * Peak reading * Battery p owe red with A A pencells ■ All solid state ■ Built-m antenna * Quality constructed with G-lfl px, boards Phone or write "Skip' 1 W9HAK for complete information Dial 812-476-2121 Available by tfirect ntafl only. ORDER INFO: bend check or money order for $75.00 pkis 51.00 for handing. Indiania residents scid 4^. sales tax. Crystals for 146.94 Mhz S3. 95 ea. All other frec^. S7.10 ECM Corporation 4T? N Weinbach Ave. Evansville, Indisrta 4771 1 OCTOBER 1973 53 The transmitting antenna after a winter storm. Temperatures easily drop to -37 fere with almost every other repeater in Germany operating on the same channel. Since the Zugspitze at this time was set up to be a part of the overall German repeater network and not a special repeater, the interference problem with other repeaters had to be solved. The obvious solution was taken of reducing the transmitter power to a little over ViW. This power level still provi- ded more than adequate service using the repeater throughout most of southern Germany and the repeater functioned in this manner throughout 1971. However, the vision had certainly been created in the minds of the Munich amateurs as to what could really be done with the Zugspit2e repeater if it was brought up to full power level and allowed to operate on a clear channel. A reorganization of the German repeater network channels in late 1971 made provision for the Zugspilze repeater to be set up on a separate clear channel (enter on 144,275, receive on 145.725) and planning was started on com- pletely re-equipping the repeater. The team of DJ9HJ, DL9ZD, DJ3YB and other Munich amateurs again got together and decided that rather than try to refurbish the old repeater equipment to build a completely new installation using high per- formance equipment and specifically de- signed for the environment found on the Zugspilze. Although by now there appeared to be some hope of getting the radio clubs in the southern Germany area to help defray the cost of the equipment, the initial expen- ditures were totally those of the individual amateurs concerned with the project. The equipment designs that evolved for the new Zugspitze DX repeater would deserve several articles in themselves to describe it all completely. The equipment was totally home-brewed, but with a quality I have seldom seen matched in the finest com- mercial gear. Basically the total equipment package fits in a container about T x V/i x 2" high and consists of the antenna filter, receiver, trans- mitter and control and call-sign identifier. Each unit has been tested in an environ- mental chamber to simulate the extreme conditions encountered on the mountain. The receiver consists of a FET input rf amplifier stage working into a mixer using four HP2800 hot carrier diodes to translate the signal frequency down to 10.7 MHz. At 10.7 MHz several crystal filters are used to achieve a 20 kHz bandwidth and then a phase-locked loop circuit is used as a FM demodulator. The noise figure of the basic receiver is slightly over 2 dB and the noise figure of the entire receiver side of the repeater including the effects of the antenna isolation filter is 3.5 dB, The squelch sensing circuitry operates on a dual frequency sampling basis to guard against accidental trip by stray interference. The transmitter side of the repeater, which is also fully transistorized, produces 15W output. In order to avoid the generation of many spurious signals which is usually the case when one starts with a low frequency crystal and multiplies it up to 144 MHz, a different frequency generation scheme was used. This was considered useful because the transmit- ter had to operate so closely to a very high performance and sensitive receiver. Figure 1 shows the transmitter frequency control scheme. A Voltage Controlled Oscillator 54 73 MAGAZINE TO t TX -f & VCO DIVIDER *v PHASE DETECTOR MULTIPLIER REFERENCE xtal osa \ % %. ^1 i ^ v_ ., \ FILTER K. .ATrNG ' IF )\ ' CONTROL VOLTAGE Fig. 1. Principle of operation of transmitter frequency control system. operating directly at 145,725 MHz is used. The output frequency is divided down and then compared in a phase detector with the frequency of a reference crystal oscillator which has been multiplied up in frequency. The resultant difference control voltage from the phase detector is used to control the frequency of the VCO. The VCO is directly FM modulated by an audio signal, the control voltage from the phase detector being made slow enough not to react on the modulation. The control, alarm and call identifier chores are taken care of by cir- cuitry consisting of some 24 ICs from Texas Instruments. The call repeater works on a shift register principle and is timed to send the call (DB0ZU) every 80 seconds. If the transmitter has not been keyed by a user, the transmitter is turned on just for the duration of the ident. Normally, a tone burst of 1750 Hz is necessary to key the repeater. It then remains carrier keyed for 1 5 seconds after which the tone burst has to be repeat- ed. If someone should open the repeater just as it is about to identify itself via F2 3 the ident is skipped until the next 80 second period. This is to prevent the call from a weak DX station being obscured by the repeater identifer signal. The subject of the antenna to be used with the new repeater was often debated. Since the new repeater was intended pri- marily as a DX repeater, the idea of hori- zontal polarization became popular since the repeater would be primarily used by home stations. However, this idea was eventually dropped and it was decided to leave the repeater with vertically polarized antennas so mobile stations could also easily use the repeater. Furthermore, since the antennas already installed performed without failure, it was decided to leave them in operation for the time being. The only fault with the present antenna installation is that as one can see from oiLe of the photos, the receiving antenna is partly shadowed by a portion of the weather tower. The ultimate plan is to use only one antenna for both transmitting and receiving which would be elevated to clear all obstacles, A form of ferrite circula- tor will be used to isolate the receiver and transmitter rf circuits. Such circulators are economical and provide up to 50 dB isola- tion but are quite critical as to proper termination. Damage to the antenna, for instance, which causes the swr to rise, would destroy the isolation characteristics. How- ever, that plan belongs to the future as well as the one to have the receiver bandwidth automatically controlled by the strength of the received signal — smaller bandwidths being used for weak stations to increase intelligibility. The Zugspitze DX repeater was installed in May of 1972 and has been fulfilling a repeater user's dream. Records will still be in the process of being set for some time as to how far away DX can be worked in the various countries the repeater signal covers. The debate also goes on as to whether DX via a repeater is really DX at all. But whatever might be said there is no denying that working various countries via a repeater couldn't be more fun. The Zugspitze re- peater will most certainly open up new thoughts and challenges for the usage of repeaters for years to come. . . .W2EEY OCTOBER 1973 55 I is UGuIjd f m line finest quality .US best value Jl Tempo's Commercial Line VHF transceiv- ers offer commercial performance at amateur prices. Compare these transceiv- ers with any other available. Compare their performance, their quality of con- struction, their ease of maintenance, and then compare prices. Your choice will have to be Tempo. TEMPO CL 146 The CL-146 offers operation on the 146 MHz amateur band, The price includes a micro- phone, power cord, mounting bracket and one pair of crystals. A full line of accessories is also available, • 12 channel capability • 13 watts or a power saving 3 watts » All solid state, 12 VDC • 144 to 148 MHz (any two MHz without retuning) • Supplied with one pair of crystals • RF out- put meter, S-meter, receiver detector meter • Provisions for external oscillator • Monitor feature • Audio output at front panel • Internal speaker * The Price: $279.00 TEMPO/ CL220 As new as tomorrow! The superb CL-220 em- bodies the same general specifications as the CL-146, but operates in the frequency range of 220-225 MHz (any two MHz without retuning). At $329.00 it is undoubtedly the best value available today, TEMPO 6N 2 The Tempo 6N2 meets the demand for a high power six meter and two meter power amplifier. Using a pair of Eimac 8874 tubes it provides 2000 watts PEP input on SSB and 1000 watts Input on CW and FM. Completely s«1f-contained in one small desk mount cabinet with in- ternal solid state power supply, buift in blower and RF relative power indicator. $595.00 TEMPO fmh So much for so little! 2 watt VHF/FM hand held. 6 Channel capability, solid state, 12 VDC, 144-148 MHz {any two MHzJ, includes 1 pair of crystals, built-in charging terminals for ni-cad cells, S-meter, battery level meter, telescoping whip antenna, internal speaker & microphone, $189.00 TEMPO imp Truly mobile, the Tempo/fmp 2 meter 3 watt portable gives amateurs 3 watts, or a battery saving Vi watt, FM talk power anyplace at anytime. With a leather carrying case included, tfiis little transceiver will operate in the field, in a car, or at home with an accessory AC power supply, The battery pack is included. The price: $225,00 (Accessory rechargeable battery available: $22.00) TEMPO ITPL high power 1m amplifiers MODEL NUMBER POWER INPUT POWER OUTPUT (min) BAND PRICE TPL1002 3 TPL1002 3B TPL8Q2 TPL602B TPL5Q2 TPL502B TPL252-A2 TPL445-10 TPL445-30 TPL445-30B 5 to 25W 1-3W 5W 1 to3W 5 to 15W 1 to 1W 1 to 4W 1W TCP 12A Control Head , . 1QG-135W SOW SOW SOW 3B-5BW 3W 45W 25W 2,5W 12W 30W 30W $32.00 2M 2M 2M 2M 2M 2M 2M 440MHz 440MHz 440MHz ;220>00 1235,00 1180.00 1195.00 (105.00 5 130.00 85.00 $125 00 $215.00 S235.00 Prices subject to change without notice. 11240 W. Olympic Blvd., Los Angeles, Calif- 90064 931 N. Euclid, Anaheim, Calif. 92801 Butler, Missouri 64730 AVAILABLE AT SELECT DEALERS THROUGHOUT THE U.S. 56 213/477-6701 714/772-9200 816/679-3127 73 MAGAZINE James E. Taylor W20ZH 1 25 7 Wild Flower Drive Webstei NY 14580 BALANCED DIPOLE ANTENNA The antenna described displays I he /allotting features: rf balance to ground: lightning protection; low loss ground system: multi-hand capability: and simple erection procedure. Over the years I have erected a large number of 80 meter dipole antennas embodying a great variety of mechanical and electrical arrangements. Out of these multi- ple experiences have come a fair number of features which might qualify as "good" practice. It is the purpose of this article to describe a readily erected dipole system which com- bines excellent performance with unique electrical and mechanical features. First, I wanted the radiating efficiency to be high. Secondly, since the use of this dipole in a phased array was contemplated, a predictable dipole field pattern was desir- able. This required good electrical balance at the feed point and a uniform ground system. Third, since I have had enough good luck for one lifetime regarding lightning damage (none) I wanted the sides of the dipole to be directly connected to ground for dc at all times. Fourth, since I am addicted to antenna experimentation, 1 wanted the ends of the dipole to be readily accessible for length adjustment and the entire structure easily tp*ken down for major changes. In addition, why not add 40 meters? The principal radiation from such a di- pole is in a plane perpendicular to its direction; the polar plot of field strength is essentially a circle tangent to the surface of the ground. Thus, the radiation is concen- trated at the high angles, near the vertical. The desirable low-angle radiation will in- crease as the height of the antenna is increased- In addition, the losses in the antenna and in the ground are decreased as the height increases. An effective compromise between operat- ing results and cost of the installation normally calls for a height of about 40 to 60 feet. Greater height is desirable but expen- sive, whereas at lower heights the efficiency and the pattern shape become unacceptable. It turns out that the five-section telescop- ing TV masts, available in the popular TV supply stores for about $20, are satisfactory for supporting the center of the dipole at a height of 45 feet. This mast can be assem- bled on the ground and walked up or hoisted to a vertical position. If clamped against a house or other structure at about the 15 foot level the mast need only be guyed at the top, even in the strong winds of the Rochester area. The two halves of the 80 meter dipole serve as top guys in ? say, the north-south directions, and the two halves of the 40 meter dipole (with a common coaxial feed line) double as east-west guys. For ease of erection the mast is pivoted at its base. This base support is a 5 foot length of 1-1/2" diameter galvanized steel tubing projecting I foot above the ground. A 5/16" bolt through the post and mast provides the pivoting shaft. The side of the mast is OCTOBER 1973 57 SUPER CRYSTAL THE NEW DELUXE DIGITAL SYNTHESIZER ! ! ■ fill 14 7 14 h m#-w» ■■■»■— ' o*m «* MFA-22 DUAL VERSION Also Available MFA-2 SINGLE VERSION • Transmit and R«caiv« Operation: All units have both Simplex and Repeater Modes • Accurate Frequency Control: .0005% ac- curacy • Stable Low Drift Outputs: 20 Hz per degree C typical • Full 2 Meter Band Coverage: 144.00 to 147 99 MHz. in 10KC steps • Fast Acting Circuit: 0.15 second typical set- tling time • Low Impedance (50 ohm) Outputs: Allow long cable runs for mobiles • Low Spurious Output Level; similar to crystal output PRICES MFA 22 $275.00 MFA-2 $210.00 Shipping $3.00 ^ Electronics Box 1 201 B Champaign , IL 61820 SEND FOR FREE DETAILS ACTIVE AUDIO FILTERS IC'S FOR SUPER HIGH PERFORMANCE CW FILTER (CWF2) Gel razor sharp selectivity; Mo impedance matching' BW {selectable) 30 Hi, 110 Hz, 180 H* + Center frequency F = 750 Hi, Skins 60 ctn down at ViF and 2F; 4 op amps; 2"x3" PC board; $14.95 wired, tested, guaranteed; S1295 kit CWF-2: S12.95 KIT, S14.9bWlR£D CW MINI FILTER fCWF 3) 1Vk2' + PC board; Center frequency F=750 H*; 30 db down at %F and 2F; BW 110 Hz r 2 op amps; S&95 wired, tested, guaranteed; $7,95 kit LOW PASS FILTER ILPF 1) Resistors set cutoff 500 Hz to 20 KHz; Factory set to 2,5 Khte, RoJlofr48db per octave. Input imp 1 M;GatrF*1; 5 op amps; 2 ,M *3" PC board. Sl6,95 wired, tested, guaranteed; $14,95 kit. please include 55<2 postage on all ortferV WRITE FOR FREE SPEC SHEETS'!! * * *. ## MFJ ENTERPRISES P.O. Bo* 494 C Mis* State. Ms 39762 SPACE-AGE TV CAMERA KITS A PLANS ]£■ BE k PtQNFEfi IN HOC TELECASTING' Build *<w mm TV ZMESK H*k* XT-IA, Sana D, 1116.95^ Sol* «*, S?tp-br-**tP causfiucticn tmnuoL Hi A quelrK, CatiHcH to my TV wiihvt m&iiiaiuat. laWfor lu. aerftnrfT+er»» education, nousfey, t#t. PHONi or VVRtTf for CATALOG V36; N ft ROADWAY J*"V ^^ j^ffr pom and plans amiable intltxtag ,.«*%-! bii, kem/mmL cottv vioWon 4&h, conii plan,, «' ATV Research Dakota citt, nebr 0*731 WHY FIGHT QBM? Copy code through the QRM with a NEW DE-101 Signal Dis- criminator, Built m ac Su ppi y , f actory tuned, and a one year warranty. S29,95 plus S2.00 shipping, Aid- DYNAMIC ELECTRONICS INC. bama res 7rients add Box 113 1 Decatur AL 35601 5% fax 58 hacksawed diagonally at the base to clear the supporting post. The coaxial feed line for the dipoles is inside the mast; this decreases wind prob- lems and also serves to shield the outer sheath of the coax from unwanted rf coup- ling. A balun coil arrangement is frequently used to assure balanced currents at the center of a dipole antenna. In the present instance a novel method is used which not only provides the required balance to ground but which also offers a low-resistance dc current path to ground from both sides for lightning protection. The mast itself forms the outer conductor of a coaxial section having the sheath of the feedline at its inner conductor. The length of this coaxial section inside the mast is ap- proximately one quarter wave length. There- fore, if the shield is shorted to the mast at its base, the impedance viewed from the top will be high so that it can be connected across the center feed point of the dipoie without appreciable loading. This unortho- dox arrangement is completed by connecting the center conductor of the coaxial feedline directly to the top of the mast! One half of the dipole antenna is connected to this common point, the other half to the shield and, to relieve the suspense, it works fine! The arrangement provides dc current paths to ground for lightening protection of both sides of the dipoie and it achieves balance of antenna currents through its balun action. The rf transmitting currents in either half •of each of the dipoles are conveniently indicated by means of four flashlight bulbs, not shown in the figures. Each bulb is shunted across a 3 f1 length of the antenna wire just outside of the top insulator. A 3" length of #1 8 copper weld wire is used from each side of the bulb so that the latter i& soldered in place at a corner of a 3" equilateral triangle. This area of pick up loop gives adequate brillance for tests without burning out the bulbs. The equal brillance of the two 80 meter bulbs, for example, pro- vides an excellent indication of the* balun action of the unorthodox mast connection used. In order to insure a stable dipole pattern with symmetrical ground reflection and to 73 MAGAZINE reduce ground losses, a grid of nine parallel ground wires, each approximately 200 feet long, spaced ten feet apart, was buried under the dipole parallel to its plane, A single cross-buss was placed across the middle of the grid and soldered at the cross-over points, The base support of the antenna mast was connected at the center of this ground system. The clamping hardware supplied with the mast was discarded. The mast was extended horizontally on blocks on the ground and the overlapping sections were secured against vibration by us of #18 self-tapping screws. The mast was painted to discourage rust; the color was chosen to match the shutters of the house in a gesture toward community harmony. The antenna wires and the coaxial feed line are supported at the top of the mast by a cylindrical plastic insulator. This insulator, which combines high strength with low wind resistance, is made by sawing off the grooved male portion of a 'T' fitting for plastic water pipe. There is a size which is a snug push fit over the 1-1/4" o.d. mast. The grooves serve to anchor the wires and they also provide an improved leakage path for rf currents. The details of the insulator assembly are shown in Figs, 1 and 2. All wires are #12 stranded copperweld. The "D^-shaped wire loops pass through the insulator, one above the other, as shown. There are no screw connections to loosen or corrode and, of course, all connections are twisted and sold- ered. A radiator hose clamp holds the insulator in place. The RG-8/U coaxial feed SMALL JAR CAP CEMENTED I* PLACE SOUTH SO METER WIRE EAST 40 METER WIRE 0- SHAPED WiR£ LOOPS THRU HOLES IN INSULATOR NORTH ao METER WIRE COPPEP BRAID SOLDERED TO MAST {GOES TO CENTER CONDUCT- OR OF COAX INSIDE MAST) I 1/4 M 00 MAST Fig. L Top insulator — side view. ^ CRYSTAL BARGAINS Depend on . . . We supply crystals from 16KHz to 100MHz. Over 6 million crystals in stock. SPECIAL Crystals for most ama- teur 2-Meter F,M. Trans- ceivers: $3-75 Each Inquire about quantity prices, Order direct Send check or money order. For first class mail add 15C per crystal for airmail add 20C ea. DIVISION OF BOB WHAN & SON ELECTRONICS. INC. 2400 Crystal Dr. Fort Myers Florida 33901 (813) 93S-2397 Send IOC for new catalog with oscillator circuits and lists of thousands of frequencies in stock. SPECIALS! CRYSTALS FOR Frequency Standards TOO KH; IHC13/U) tOOO KH> (HC6/UJ Almost AM C8 Sets, Trans, or Rec, |CB Synthesizer Crystal on request) Any Amateur Band in FT-243 (Except 80 meters) 80 Meter Range in FT-243 Color TV 3579 545 KH/ (wire leads) $4,60 4.50 2 50 4 for 1 50 5.00 2.50 1 .60 4 for 5 00 -rm-t — l— TWO BOOKS EVERY FM'ER MUST HAVE! I I PI How To Use FM. A ■ comprehensive introduc- 1 tion to FM that gets you | on the air fast, easily. I I 1 Atlas of FM Re- peaters. The newest most complete list of repeaters world* wide, I Please send me the book(s) checked above. En- I I closed is check or money order for $ i I Name Call I ! I I J Mail to: 73 Inc., Peterborough NH 03453 Address City State ZIP eterborougn ritt UJ4DO ■^M ^^^H ^^^W : ^^^™ ^^* ^^^* ^^^ ^^* ^* '^" OCTOBER 1973 59 Here's the book for every ham who wants to design and build a digital repeater control system (or who wants to just think about doing that). Contains sections on repeat- ers, basic logic functions, logic cir- cuit design, control systems, sup- port circuits, mobile installations, touchione, plus a special section on a "mini" repeater control system. 224 pages. Hardcover $7.00 Paperback $5.00 i — i u 73 Magazine, Peterborough NH 03458 Enclosed is $ Please send Dhard- cover ($7)/Dpaperback ($5) copies of Digital Control of Repeaters" to: Name Call I I i i i I I \ i State Address City i ZIP MAST SOUTH eO METER WIRE EAST 40 METER WIRE INSULATOR { PLASTIC PfFE ) INNER CONDUCTOR T UPPER DSHAPED WIRE LOOP THROUGH INSULATOR WEST 40 METER WIRE LOWER D-SHAPEO WIRE LOOP THROUGH INSULATOR NORTH 90 METER WIRE { CONNECTED TO TOR OF MftST OUTSIDE 1 Fig, 2. Top insulator - top view, line is supported from the 'TV-loops, cen- trally within the mast, (This feed line is cut to be a multiple of a half wave- length - approximately 82 1 2" for a 3 + 955 MHz.) A noise bridge is used for this and all other resonance measurements. The mast was hoisted to the vertical position using an inexpensive 4-pulley rope hoist attached at the 16' height. After erection the mast was clamped to the house roof at the 15' level using a steel strap and lag screws. The four halyards at the end of the antenna wires are of 1/8" nylon rope. These are supported by 2-1/2" diameter galvanized posts seven feet high. These posts are each located at a distance of 80 feet from the base of the mast and are connected to the ground system. The ropes are secured by swivel snaps attached to the tops of the posts, for ease of lowering for antenna adjustments. The dipole was adjusted to resonance, using a noise bridge, by adding equal lengths at either end. Resonance was achieved at 3.955 MHz with a length of 1 2CT 9" and an input resistance of 50^. The SWR of the antenna is quite low (approximately 1.01:1) and its response is sufficiently broad to cover the 80 meter phone band without appreciable decrease in signal strength. Results on the air have been excellent and it is a pleasure not to have to ground the antenna during lightning storms, . . ,W20ZH 60 73 MAGAZINE C. Warren Andreasen WA6JMM P.O. Box 2 926 D Pasadena CA 91105 II I 111! H GENERATOR Probably one of the most used greeting or expression in amateur radio be it a car with call letter plates passing another, or the passing of an OSCAR satellite overhead, is the simple world, "HL" 1 do not know how it all started but I know that if I want to greet another ham on the road, I want to honk "HI." Therein lies the problem. My car is one with the horn incorporated in the steering wheel rim, and it is next to impos- sible to honk any kind of code, much less the rapid succession of four dots and then two dots. This prompted me to design a circuit which will digitally produce the word "HL W The scope of this article will be to describe the basic digital "HI" generator, which can be used in any application desired by the addition of the appropriate output keying stage- Figure 3 shows a typical output stage which can be used to key the horn relay of a car. In this application, the driver would be simply required to touch a momentary contact push button type of switch and the "HI" generator will start and self-complete the word "HI." This circuit uses a total of four integrated circuits and eight discrete components, and when built will easily fit in the palm of your hand. OCTOBER 1973 Referring to Figs. 1 and 2, a unijunction transistor oscillator located on plug-in-board +SV +5V TO IC-4-1 Fig. L "HI" generator. B -C>IC-3-l2 UJT OSC FIG I 3 t -3*9 IC-4-10 c-3-12 wv- II M 74KJ7 K R Q 6 START P8-I ^'7 K) ) 5 -i TO CB-l-5 74K> ^&\ l 4 A — C>TO IC-3H PUV TO IC-MI.40) B -OTOIC-3-2 C — >TO IC-3-13 ■OT0C8H-9 ? — OTQCB-1-8 CB-I-B A 4 74*0 *>& *v H4 74i0 107 IC-3 &^~ HI Fig, 2. Basic 'W generator. CB-I generates a timing pulse which is fed into a 7404 inverter (IC-4-1) and is shaped and inverted to form a narrow, negative- DIGITALLY-TUNED RECEIVERS: R 389/URR: 15 1500 KHz. OK grid, w/book 371.00 R390: 0.2 32 MHz, OK grtd, w/oper. book 495.00 R390A adds mech, fillers, w/oper. book ,..--. 595.00 AN/WRR-2: 2-32 MHz, OK grtd, w/book . . 750.00 CV 691A SSB Conv. + 455 KHz, OK, w/book 137.50 Nems Clarke #1670 FM rcvr 55-260 MHz r w/book . . . 195,00 0CT3 TTY FSK deviat. meter/rcvr, new 49.50 WWVB 60 KHz rcvr/comparaior OK, w/book 295.00 Motorola 3 MHZ Osc^ 5 parts in lO'l 199.50 AIL 30 MHr rcvr/amphf /alien, calibrator 99,50 HIGH-SENSITIVITY WIDE-BAND RECEIVER COMMUNICATIONS •BUG DETECTION • SPECTRUM STUDIES 38-1000 MHZ AN/ALR-5: Consist* cif brand imv tuner/ cunvrrtrr CV~253/A1*R in nr^in.il faetnr? park »md jo ra used, ihi'i-kftl OK & ci-ld mdin WffiVM H-144 mudifu-d fur 1 2U v. f>0/»id h/ Tht- luner reivers the rjnge in 1 l>*±ndi«: *?*rh ImocI hd* u* "nn Typr \ Ant, mpui l J 4c-krd with earn tunrr fa ihr far lory liisn-rrinr^ rhcrkoul she^L- Thf am* w, i* upenr !■ tnr fartrirv tnsrjrrliir & rru-i rf sh.Mvrd SENSITIVITY: 1.1 u\ jl 38.4 mh/. 0.H .it 133 mh/, & jt fi.iK mh/, 4 l * al 77K mh/, 7 ai t eh/ Thf tfei i ..i LiialK .i :ki| mh/ II jmpl with aQ thai follows, including .i tlnnlr mt*u*r fur relative signal sir? net hs, ,iti aitt-n « >lihr.itrd tn H dl* st«*n$ in 74 dfi, fullowfd b\ an AVC position: Pan. k Video A AK (lutpuls; switch wriest p. .*f !2<*0 kh/ ««r t2 mh/. and SELECT AM or FM" With H.trtthook & pwr input r>lu£. jEI miK 375 00 30MHzPANAOAPTER OKgnd 295.00 Attention! Buyers, Engineers, advanced Technicians: We have the best test-equipment <£ oscillo- scope inventory in the country so ask for your needs - . . don't ash for an overall catalog . m . we also buy* so tell us what you have. Price it. R. E. GOODHE ART CO., Inc. Box 1220 GC. Beverly Hills, Calif. 90213 Phones: Area Code 213, Office 272-5707 going pulse. This pulse is fed into a JK flip-flop (IC-1) which, when allowed to run by the setting of the ^run" flip-flop, acts as a divide-by-two counter whose output is a symmetrical square wave. This square wave, which will be referred to as the clock term, is wired to two locations. The first location is the clock input of the SN7490 decade counter that "counts" the clock pulses, and the second location, the output gate, (IC-3) which uses the oppose phase or clock. This term is simply the Q side of the clock flip-flop. The purpose of the clock term driving one input of the output gate is to chop anything passing through this gate into a series of dots. Since this gate, as described thus far, will produce an endless string of dots, all we have to do is inhibit the unwanted dots and we will have the word CM IN4003 +12-0V .270 R5>l/2W FROM IC-3-6 TDHORM RSJBf 02 2N5904 04 2N49t2 Fig, 3, Typical output stage that will key the horn relay of your automobile. 62 73 MAGAZINE TIMING DIAGRAM ICH-3 CLOCK C-2-G IC-2-9 IC-2-8 IC-ZH1 P^3WW^ X» INHIBIT O A B 5 2 3 4 5 A S c 6 7 S 9 k>wait OR RECYLE CL i "BEEP" OUT PUT INMI BIT- ( ABC) + ( ABC) + CLOCK* D _ OR_ OUTPUT - CUOCK- (ABC+ ABC + ABC + ABC+ABC+ABO-T5 Fig, 4 m Timing diagram* "HP remaining. Referring to the timing diagram (Fig. 4) it will be noted that to form the word "HI" we must get rid of count zero, count five, and counts eight and nine. To do this we do not need to decode all bits; all we need is enough information to elec- trically describe the period we are interested in. You will see that count zero has a unique condition when terms A, B, and C are all low. These three terms are inverted by IC-4 so as to provide the high level needed for the 7410 to decode an AND condition of ABC In the same manner, the count of five is decoded using the terms A, B, and C, 2N3053 + 12-IBV FROM AUTOMOTIVE SYSTEM t>+5V CR4 IN4734 Fig. 5* 5 V automotive power supply for the "HI" generator. Since we do not want counts eight or nine, we use the term "!>•* which occurs only during these counts, to directly inhibit them. A secondary function of this term is to reset the "mn" flip-flop back to the waiting state. So we can now say that we will have an output key unless clock is low or D is low or zero decade is present or five decode is present. Add this all together and all that is remaining is "HI." . . .WA6JMM YAESU Newly appointed dealer for the East Coast is now taking orders on Yaesu equipment. Send for literature and free list of used equipment available. FRECK RADIO & SUPPLY CO. 40 Biltmore Avenue P.O. Box 7287 Asheville, North Carolina, 28807 Telephone: 704-254-9551, W4WL FM Schematic Digest A COLLECTION OF MOTOROLA SCHEMATICS Alignment, Crystal, and Technical Notes covering 1947-1960 136 pages ir/ 2 "x 17" ppd $6.50 S. Wolf Box 535 Lexington, MA 02173 NEW MX1A $47.50 NEW NEW MX1A MINI-MIXER $47.50 This is a plug in unit to replace the first mixer in Collins 75S 1-2-3, Designed to eliminate all but the strongest (next door) cross modulation in the S line. It uses the latest in FET design. If not satisfied, money refunded. Designed Built Backed by . . . . ANTENNA MART BOX 7 RfPPEY, IOWA 50235 >v Isolated - Pad - Drill - Mill Precision circuit board construction without etching. Fits hand drill, e lee- trie drilL Simple, fast, economical, safe. Sizes: .250, ,160 dia, $6.95 ea. Calif, residents add 5%. A F STAHLERCo PO BOX 354 CUPERTINO, CALIF 95014 THE MILLIWATT r ah about underdve watt amateur radio ** r If you've bftin wanting to try QRP. then The MMMwatt is a MUST for you!" • Conn ruction Project* • Technical Article* • Operating News • WAS fc QRPP OXCC Standing* RATES: $3 40 yaarly. Reprint*. Vol. I— $4.00; II «* III— S3 SO each (all three-t10 00> Sample 254 SUBSCRIPTIONS, to: ADE W £| 5S KiMG/g - ?]1 Fo'evL Vermillion, SD^0ti Q OCTOBER 1973 63 — — available The exciting all new 1JWOUE IC-230! rem — \ te* I'n **I5 IS? 61 tf *S \ TAKE A SLICE OUT OF THE FUTURE . . . . . and put 67+ CHANNELS* of 2-meter FM pleasure in the palms of your hands , . . with the SUPER COMPACT (2.3" x 6.1" x 9.7") IC-230. Feature- wise . . . the IC-230 is fully synthesized (with the new exclusive "Phase Lock Loop System") . . . all modular construction (servicing is a snap— in and out) . . , a receiver that is very sensitive and selective as to what it hears (better than CL4UV / 20db), with unique Inoue helical filters to eliminate intermod . . . plus a super E filter mosfet front end, making copy a pleasure. * And not a crystal to buy with the exclusive "Phase Lock Loop System'*, (That's close to $650.00 worth of xtals!\ - GRAB HOLD OF THE IC-230 AT YOUR LOCAL DEALER TODAY - Distributed by: ICOM — Dealerships Available ICOM WEST, INC. 1251 ■ nOrti St N.E. Beitevue, Wash 98008 (2061 641 0554 ADIRONDACK RADIO SUPPLY 185 West Mam Street Amsterdam. NY. 12010 ICOM EAST Dn ACS. I^c Box 331 Richardson. Tex 75080 12141 235*0479 64 73 MAGAZINE Get the entire Inoue ICOM family at one of the dealers listed below: ALABAMA Wolfe Electronics Sox 358 Foley, AL 36535 ARKANSAS Gavin Electronics 516 Rrdgeway Little Rock. AR 72205 ARIZONA Ell Dee Enterprises 12612 N, 28th Dr. Suite 3 Phoenix, AZ 85029 CALIFORNIA Alpha Sound 1 405 Dry Creek Road San Jose, CA 95125 CDS Electronics & Hobbies Unltd. 235 Mitchell Drive Atwater, CA 95301 Electro Service 240 Main Street San Mateo, CA 94401 ICOM FM Sales 6234 A, Fountain Blvd. Hollywood, CA 92023 Henry Radio Company 1 1 240 W, Olympic Blvd. Los Angeles, CA 90064 Selectronics 1709 Markston Road Sacramento, CA 95825 Sequoia Stereo 773 -8th Street Arcadia, CA 95521 Sichel Equipment Co. 245 E. Harris Avenue 5, San Francisco. CA 94080 COLORADO LEC Electronics P.O. Box 7515 Pueblo West, CO 81007 FLORIDA Amateur Electronic Supply 621 Commonwealth Orlando, FL Goldsteins Box 3561 Pensacofa, FL 32506 ILLINOIS Ertckson Communications 4653 N. Ravenswood Chicago, IL 60640 INDIANA Story Electric 2039 Fairfield Ave. Fort Wayne, IN Story Electric 441 Walnut Wabash. IN KENTUCKY Everhari Electronics 116 Sydney Street Lexington, KY MARYLAND COM Electronics 900 Cram Hwy. S.W. Glenn Burnie, MD 21061 MEXICO NOVO Mex Antonio de Mendoza N°320 Lomas Vlextco 10, d.f.* Mexico MONTANA Conley Radio Supply 405 North 24th Billings. MT 59101 NEW MEXICO Robert Foster Box 198 - Escaboss Star Rt Tijeras, NM 87059 NEW YORK R.E. Nebel Laboratories 31 Whitehall Blvd. Garden City, NY 11530 Barry Electronics 512 Broadway New York, NY 10012 NORTH CAROLINA Vickers Electronic Supply 506 6. Mam St. Durham. NC OHIO Amateur Electronic Supply 17929 Euclid Cleveland, OH H & C Electronics 6271 Hammcll Avenue Cincinnati, OH 45237 OKLAHOMA Blacks Radio Company 413 N.E. 38th Terrace Oklahoma City, OK 73106 Roland Radio Company 5923 E. 31st Street Tulsa, OK 74114 OREGON Portland Radio Supply 1234 S.W, Stark Portland, OR PENNSYLVANIA Harntronics 4033 Brownsville Rd, Trevose, PA 1 9047 Kass Electronics 2502 Township DrexeL PA 19026 SOUTH CAROLINA Accutek 420 Laurens Rd. Greenville, SC 29607 Electronic Systems Inc. 1518 Gregg Street Columbia, SC 29201 TEXAS Bellaire Electronic Supply 5204 Bellaire Blvd. Bellaire, TX 77401 Electronic Center, Inc. 2929 N. Haskell Dallas, TX 75204 Trimble Electronics 1913 Mary Ellen Pampa, TX 79065 UTAH Utah FM Sales 1365 E. 5360 So, Salt Lake City, UT 84117 VIRGINIA Northern Virginia Communications 729 N. Edison Arlington, VA 22203 WASHINGTON ABC Communications 17541 - 15th N.E, Seattle. W A 98155 ABC Communications 2002 Madison Avenue Everett, WA 98200 Eichmeyer Electronics Box 691 - Route 1 1 Spokane, WA 99208 N.H.E, Communications 151 12 S + E. 44th Bellevue, WA 98006 Progress Electronics 852 Commerce Street Longview, WA 98632 WISCONSIN Amateur Electronic Supply 4828 Fond Du Lac Ave. Milwaukee, Wl 53216 IF YOUR DEALER DOESN'T STOCK /COM EQUIPMENT, LET THE tCOM DISTRIBUTOR FOR YOUR REGION KNOW, OCTOBER 1973 65 GREGORY ELECTRONICS CORP, The FM Used Equipment People. 243 Route 46, Saddle Brook, N. J. Phone (201)489-9000 GENERAL ELECTRIC VOICE COMMANDER SEND FOR NEW 1973*/2 CATALOG Full Solid State FM Transmitter-Receiver 132-150 and 150-174 MHz/Size: 9.5' * 5.3" x 1,7" 1 watt output, .5 micro-volt sensitivity. High performance, completely self-contained two-way FM radio, Compact, lightweight easily operated and hand-carried. Housed in high-impact, 2-section case. All external hardware polished stainless steel. Top section has transmitter and receiver modules, built-in mike and speaker, antenna, carrying handle, all switches and controls. Bottom section has battery power supply. Power connections to top section made by plug and jack connection. $ 138. Crystals and tuning, add $50. Proper chargers available separately, each $15. Includes rechargeable nickel cadmium bat- tery pack and charger Lots of 5 less 10% - $124.20 Lots of 10 less 15% - $117,30 TWO METER MOBILE UNITS General Electric Progress Line 74" or 17" case, complete accessories, fully narrow band. MT/33, 12 volt, 30 watts, transistor power supply d> 1 gO with wide band receiver . . $143. MT/33 MA/E33, 6/12 volt, 30 watts, vibra- tor power supply 4iJ?R with wide band receiver ^ $73. MA/E33 66 73 MAGAZINE Martin Weinstein 414 D Kiefaber Dayton OH 45409 R ATHR OSCILLATING RING WITH INDICATING SHIFT REGISTER In past months amateurs have swung to an increasingly large-scale utilization of digi- tal circuitry in the myriad of applications borne by the creative inventiveness inherent to the minds of lazy men. Finding an easier way to get the job done is a cardinal rule among amateurs which often, alas, requires staggering amounts of brainpicking and mid- night oil burning. Being a newcomer to the digital circuitry field, I diligently applied myself to the job of relearning an old hobby. It was in the midst of one of these study sessions that it occurred to me that a venture into an interdisciplinary approach could be profit- able. My friends, if you think this a fiction penned by somebody's relative from "Feenix, Arix," please bear with me, I am going to describe an amazing circuit shortly, but I feel there is much to be learned from the kind of thinking that led to its discovery. The radio circuits developed in vacuum tube days are mostly analog devices produc- ing unquantized outputs (on a macroscopic scale) proportional to their inputs. One of the greatest tools ever developed for analog circuits was the concept of feedback. Feedback gave us greater sensitivity in our detectors when we made them oscillate; remember the old super-regenerative rigs? Another form of feedback led us to develop automatic everything control circuits. And do you remember reflex amplifiers? Negative Amplifiers Circuit designers applauded the develop- ment of the tunnel diode because it exhibi- ted a negative resistance region. Fifteen years ago the easiest place to go for a negative resistance region was a neon lamp. In addition, we could make neon bulbs sensitive to ac, dc, rf, Light levels, static, radiation, or body capacity. And an NE-2 is a pretty compact little unit. OCTOBER 1973 67 By taking advantage of the negative resis- tance region of the NE-2 in digital circuitry, we can design into a simple ring counter of a few stages many of the sensitivities of the neon bulb if we correctly choose our oper- ating parameters. We can further sensitize the circuit by many of the tricks we learned in analog days: oscillation, feedback and reflexing. Further, we can sensitize and balance the stages to the point where en- vironmental factors can influence the be- havior of the active elements, warping the count, And finally, since the neon bulb is kind enough to glow for us at certain segments of its nonlinear operation, we can utilize it to indicate visually when shifting occurs. The Circuit The schematic for the three-stage oscil- lating ring counter with indicating shift register that resulted from my experimenta- tion is shown around here somewhere. A simple line -op era ted half wave rectified power supply is included for simplicity and ease of operation. Rl is a current-limiting resistor to prevent damage to the NE-2s and to help make the counter balance less critical. ^^^^^ A-/VA v_ ) _L A*W Fig, 2, All components were mounted on one side of a small (1W T x 1%") piece of perf board. All wiring was done on the bare side of the board, using sleeving where needed. The simplest test of the circuit is to assemble it and attempt operation at room temperature under normal lighting and radia- tion conditions. A properly -operating unit will flash in a sequence of 2-1-2-1-2-3-2-1 -2-1-2-3. 117 VAC • NE-2 Fig. I. Schematic diagram of the TSQRC/ISR. CI is included to slow the circuit shifting to a reasonable rate and to help, or at least to try to help, prevent the circuit from running away as it oscillates in and out of balance. Match the three remaining 1 meg resistors fairly closely, I got away with using 5% off-the-shelf units. The lamps should be matched and mounted adjacent to one another, with the six electrodes aligned. Once the correct pattern has been estab- lished, age the unit by allowing it to operate unattended for about thirty hours. During this time, the kids will get a big kick out of watching the lights blink. After aging, the unit is ready to function as a eutectic digital-human interface device, not dissimilar to Spock's Tricorder on the fictional program Star Trek. Readout is by means of variation in the basic flash pattern. The TSORC/ISR, despite its tremendous versatility, has no capability for memory, as do its big second counsins at IBM. Although I have explained its operation rather fully, 1 have not dealt with the problem of program- ming the unit If I receive enough requests, I will include a short article on the program- ming of the TSORC/ISR in a subsequent issue. , . .Weinstein 63 73 MAGAZINE FREQU Bill Hoisington K1CLL Farover Farm Peterborough NH 03458 THE EASY WAY Multiplying to 2m with transistors is easy if you take the correct precautions. This article is not only a construction article but also explains some of the things that can happen when you set out to build a frequency multiplier from scratch. You might say multipliers are easy be- cause you don't have to worry about feed- back when the input is on a different frequency than the output. True enough, but that's not all the story. Let me quote from RCA's Transistor Manual SC-14 tfre chapter on frequency multiplication: "Various types of instabilities can occur in transistor frequency multiplier circuits, in- cluding low-frequency resonances, para- metric oscillations, hysteresis and high fre- quency resonances." Hysteresis refers to discontinuous mode jumps when either the input power, frequency, or both, is increased or decreased- And, "The transistor may behave as a locked oscillator on the funda- mental frequency." Further, on VHF or wide-band circuits, "Unless the builder has had considerable experience with these types of circuits, he should not undertake the construction of such items." That's all very well and true to an extent, but it h the same old story; how are you ever going to get that experience if you don't make a start? So RF EN L2 Fig, L Schematic of trouble circuit. (Do not build,) here is some help, After half a century in radio I am still learning every day (pretty poor day when you don't) and this is what Pve already learned this year about frequen- cy mul tip hers: The project calls for high gain because you Ye out for power while multiplying. It is always pleasant if you can get it. The more power you have in each stage, the less liable you are to have reaction or feedback into that stage from the final output stage. This is very important when you try for power like 25 W, and some people are already working on 500W output power on Two! A two-stage IC FM modulated, low-power source was used to drive the input on 24.5 MHz. This oscillator's output was kept low for stability -purposes, which didn't make things any easier to start with, but it is now working very well. The whole project de- livers some 1 — L25W output on 147 MHz with good, smooth and easy tuning — no jumps or other troubles. Figure 1 shows the complete multiplier circuit first as a guide, because in the past some readers have built a wrong circuit that was illustrated to show what not to do. Figure 1 is one of these. Troubles which occurred during design work are thus shown in Fig. 1. Do not build this circuitl The first thing I did was to use the wrong transistor. I have several new, "hot" types, so of course in they went! You need high gain — go ahead! Trouble and plenty of it showed up right away* Now this is a perfectly good circuit and can be found in most manuals. But* a fantastic set of unwanted spurious oscillations showed up which clobbered the oscillator drive, and Ql took off on its own, OCTOBER 1973 even with the drive removed. After fighting it for a day or so, putting in a trimmer for CI and changing transistors, it was better, but finally I found the cause: The lower half of LI (in Fig. 1) from the tap to the cold end resonated beautifully and maddeningly with CI and the base of Ql, producing a base-tuned collector oscillator on 147 MHz. This is not a good circuit even when used intentionally. The Cure This also is not a "new" circuit, the idea being to show when to use one or the other in order to do the right thing the first time. At 73 we try to help, because in our society today there just isn't all that time available, and this little story can save you some of that precious time. Putting a large capacitor, C3, from ground to base is the solution. Then the base of Qi does not resonate on 147 MHz, and C3 also acts as a low pass filter unit to stop oscillation at 147 MHz. The incoming 24,5 MHz is resonated by LI an^l C2, now referring to Fig, 2, the correct schematic, with the ratio of C2 and C3 dropping the impedance down to match the base of QL C3b is added to C3 for this purpose. You will find the tuning with C2 and the matching with C3 to be very smooth- Ql is a 3866 which is always a good multiplier and does a good job up to 450 MHz. In this case it is used as a tripler to 73,5 MHz. I can assure you that it or the Motorola equivalent (for medium power usage), the HEP 75, will always do a good job of multiplying for you — all the way to 450 MHz. The collector of Ql is connected to the top of Ll ? which is tuned to 73.5 MHz by C4 S with C5 matching into the base of Q2 in the same manner as the input to QI- An rf choke coil is added to the base of Q2 to keep the gain up. No plus voltage was needed on the base as there is plenty of drive from QL Always check this to be sure. No emitter resistor was needed either. Be sure to check this, too! I always have a lot of external pots lying around, 500, 5,000 and 5 0K ? and lots of clip leads for them. Very useful. Q2's collector output is tapped down on L3, as these 3866\s have a low collector impedance when being pushed for output, which is what we are doing here. The output, tuned to 147 MHz by C6 and L3, is also tapped down on L3 and matched to the cable by CI. There is about 200 mW of rf here, which lights a No. 48 bulb nicely. You will find the circuit as shown in Fig. 2 is very smooth in tuning and reliable, and will handle 1 or 2 MHz without retuning. The 1W Amplfier With 1W you can begin to talk through several repeaters in your area, so we put a little time in on an amplifier for this purpose. Figure 3 shows this unit with a 2N5913 RCA transistor, one of their newer and livelier devices designed for this work, A cable input is shown, but this may be eliminated along with either C7 of Fig. 1 or CI of Fig, 1 , as the two series capacitors are + 12 RF input 24.5 MHz LOW POWER C2 7-100 pf Ql HEP 75 -^£— I ?5K OR CI Jl 4-25pF + 12 Q 220 L2 C4 3-40 pF Q2 xl ^ HEP' ■#-. OR C5 7-IOO pF ,01 L3 > \ * i < io-iaopF i 0<: Ih Fig. 2, Schematic of the 25 to 147 MHz multiplier. LI — 20 turns No. 26 on 0.5 cm diameter form, length 1 cm. tap at center; L2 — 8 turns No. 22 on form 0.8 cm diameter, winding is 0.8 cm long; RFC — 25 turns on form 0.5 cm diameter, 1.8 cm long. 70 73 MAGAZINE m COMMUNICATIONS HAL ID-t REPEATER IDENTIFIER vjy : •:.. .-. :'.- • Circuit board wired & tested With rack w/cabinet ■ ■ . $75.00 $115.00 TTL logic. Power line frequency counter for 3 minute or less timing and control Easily re- programmable diode ROM uses only 27 diodes (depending on call) ttfsend DE "any call". Low impedance audio with volume and tone control. All circuitry, including PS on small G10 glass PC board. Write for full details. HAL COMMUIMI CATIONS, Box 365L, Urbana IL 61801 HI HOT CARRIER DIODES ZENERS LINEAR IDS: DIGITAL ICS MRU COMMUNICATIONS HPMKL . $ 9fl 12/S10.00 Malchecf b v HAL 4/$4.?5 lFV472fl(3.Gv?, lN4?33f.5.lv). 1N473f>(6 ?*). lN4736{82*t." lN4739(9.lvl. 1N474JMM. 1Nfl7«riM. 1 wan. S .75 7D9N Mr;M29G .S .76 £3 75 7Q9L riON S3 25 741N JSI.5D MC1A9&G ...S3.2b MClbS&G . . SS 60 F^L923 S 90 MCT67P S3 30 MC723P. MC&9DP WCJHflP St 30 MC88DP S3 50 MC724P, MC7ZSP. MC7B9P, MC792P MC771P ...ST n MC&7DP . S3 3Q WC9?60P ■ lillllyi fl 3« £2.00 .51. DB S&.4& DIP TTL 7400 749T 7402 74 1 D 7420 7430.1440 S 48 7404, M OS S 60 744T MM 749t S3 DO 7447 SZ.25 7472 ... .S 75 7473 7474 SI 05 M75 $2 40 7A86 ST 15 7490 749 Z 7493 S2.1D 74T7T SI 40 FETS mriMHFET. *1 « ' m1tl Si0 ™ 3819 Si * TQRDIDS Indiana General CF1D2 QB, CF102 01, CFI01 Q2 S 50 CF102 D3 . ...Si Zb CINCH ICSOCKETSr BICS 14 DIP ... .S 60 MANY DTHER DEVICES AND COMPONENTS IN STOCK.WfllTE FDR CATALOG FERROXCUfiE FERR1TE HEADS . 10/S1.25 10 ICS, 16-DIP S 70 HAL COMMUNICATIONS Box 365 L. Urbana I L 61801 • 217-359-7373 Center £ Electronic World h ^.f rs\ r & ^-.JlO & $ W VHF PRE AMP 100 to reOMHr 25 db gain 2.6 db noise figure SO ohm input and output impedance Price $29.95 VHF CONVERTER TOO to 160 MHz 2.5 db noise figure SO ohm input impedance Better than A uv sensitivity 30 db gain Price S59.50 Q-TR0N]C5j FREG. PRESCALER Up to 250 MHz Available assembled, o* kit form frtfe $96.50 a ssemhlml S69. 50 kit WANTED - HAM With General Class License or better to manage amateur radio R esU me to: C. J. Harrison Hatry Electronics 500 Ledyard Street Hartford, Connecticut 06114 depa rtment. No phone calls — by appoint- ment only. ^ Q-TRONICS 310-8 So. Meadow Lane Golden Valley, Minn, 55416 S ^ \-'- • - -y.^TtlQ. • VA^^EV^U' ~3*w"*-^fc 4V * C2 7-100 pF INPUT 24,5 MHz 200 v MILLIWATTS \ — l 4 NO, 40 I WATT fe o+rs Fig, 3, 2 meter FM amplifier that wUl deliver 1W output. LI — B turns No. 20, 0.8 cm diameter, 2 cm long. Input tap at Wz turns from low end; LI — same as LI with collector tap at VA turns and output tap at 2 turns from the low end; RFC — 25 turns Wo. 30, on phenolic form, 0.5 cm O.D., 1.8 cm long. not needed together. The base of Ql in Fig. 3 is treated in the same way as the multi- plier, and responds equally well — C2 and C3 being the impedance matching network. While not critical, the best power output is obtained at the correct tap. I used a No, 40 lamp for a 1 W load through C5, and this can be lit to about 1.25W brilliancy with every- thing working right. Even though the 2N5913 is a pretty hot item, when loaded it handles well without self-oscillation and does a great job. Conclusion So here is a good straightforward project which is very handy to have around, I use it for transmitting exactly 600 kHz lower than the receiver in combination with a 1 0.1 MHz crystal. But that is another story . . . . . JC1CLL OCTOBER 1973 71 INTERNATIONAL ELECTRONICS UNLIMITED TTL 7430 .25 7470 .50 74123 1.15 7400 .25 7432 .30 7473 .55 74145 1.25 7401 .25 7437 .50 7474 .55 74151 1.05 7402 .25 7440 .25 7475 .95 74153 1.45 7403 .25 7441 1.25 7476 .55 74154 1.75 7404 .29 / II ri£- 1.15 7483 . 1.25 74155 1.35 7405 .27 7443 1.25 7485 1.20 74157 1.50 7406 .55 7444 1.30 7486 .55 74161 1.65 7408 .29 7445 1.25 7489 3.25 74164 2.95 7409 .29 7446 1.45 7490 1.25 74165 2.95 7410 .25 7447 1.45 7492 1.05 74175 2.95 7411 .35 7448 1.50 7493 1.05 74181 4.50 7413 .95 7450 .29 7494 1.10 74192 1.65 7420 .25 7451 .32 7495 1.05 74193 1.65 7423 .37 7453 .32 7496 1.05 74194 1.65 7425 .39 7460 .30 74121 .55 75195 1.15 8000 Series 8091 FIRST TIME OFFERED 9601 Retriggerable one shot $1.15 ea movinq 10% OFF -ANY ITEM - ANY QUANTITY safe 74 L00 74L02 74L04 74L10 74L16 74L20 74L30 74L42 74L51 74L71 8093 8094 8095 8123 8214 8280 8520 8551 8810 8812 8831 8836 Low Power Devices .40 74L72 .69 .69 .69 .69 .69 1.75 1.95 .95 1.45 1.95 .95 1.25 1.95 1.25 .40 .40 .40 .40 .40 .40 .80 .40 74L73 74L74 74L78 74L85 74L86 74L90 74L93 74L95 .60 74 L 164 .60 .80 .80 .80 1.25 .95 1.75 1.75 1.75 2.95 Linear* LM300PoaVreg (super 723 V)T05 $ .95 ea LM301 Hi performance ampl TQ5 ,45 ea LM3Q2 Voltage follower T05 .95 ea LM304 Neg Volt regulator T05 1 25 ea LM305 Pos Volt regulator T05 1 .25 ea LM3G7 Op Amp (super 741 1 TOS .45 ea LM308 Micro power Op Amp TOS 1.25 ea LM3Q9K 5V 1 A power supply regT03 1.95 ea LM309H 5 V regulator T05 1.25 as LM310 Volt follower Op Amp TOS 1,45 ea LM31 1 Hi perf volr^omp T05 1.25 ea LM320 5.2V Neg regulator T03 1.95 ea LM32Q 12V Neg regulator T03 1.95 ea LM320 15V Meg regulator T03 1 95 ea LM3B0 2 watt audio amplifier Dip 1 .75 ea LM3900 Quad Amplifier Dip 50 ea LM709 Op Amp T05 or Dip .29 ea LM723 Volt reg. Dip .75 ea LM741 Comp Op Amp TOS-Dip 10/S3.95 .45 ea LM747 Duel 741 Op Amp Dip 4/53,50 .95 ea Phase Locked Loops NE565 Phase locked loop dip £2.95 ea NE566 Function Gen TOS-mmi dip 2.95 ?l NE567 PLL/Tone Gen TOS mini dip 2.95 ea LED MV10B Visible red SUPER SPECIAL .25 ea MV50 type red emitting 25 ea or 5/ 1 .00 MV 5020 type Large red .35 ea Of 3/1.00 ME4 Infra red T0 18 ,69 ea MAN 1 The Original 4.25 ea MAN 3 type 1 .95 ea, 3 or more 1 ,49 ea MAN 4 type 2.75 ea, 3 or more 2,50 ea Data Lite 707 (MAN 1 repli 4.25 ea Opto Isolators MCA 2-30 Darlington MCD 2 Diodes MCT 2 Transistor .95 ea L95 ea 1.45 ea Memories — Are Made Of — 1101 256 Bit RamMos (2501) 1103 J 024 Bii Ram Mos 74BP 64 Bit Ram TTL 0223 Programme Rom Data Included wiiri Memories 2.95 ea 7.95 ea 3,25 ea 5 9S ea MOS Shift Registers - Limited quantities 2506 Dual 100 bit dyn. shift reg, (mini) .30 ea 2509 Tristate dual 50 bit st, shift reg. .30 ea 2510 Tristate dual 100 bit st. shift reg. .30 ea 251 1 Tristate dual 200 bit st. shift reg. ,30 ea 2518 Hex 32 bit static shift reg, .30 ea 2519 Hex 40 bit static shift 2519 Hex 40 bit static shift reg. .30 ea 2521 Dual 128 bit shift reg. (mini) .30 ea 2522 Dual 132 bit shift reg. (mini) .30 ea 2524 51 2 bit recirc, dyn. shift reg. (mini) .30 ea 2525 1024 bit recirc, dyn. Shift reg. (mini) ,30 ea 2527 Dual 256 bit static shift reg. {mini) .30 ea Assortment of any 2500 IVIOS items 4/1,00 NOTE: 2500 series MOS shift registers ere factory seconds & have not been re-screened. Calculator Chips 5001 LSI (40 pin) Add, subtract, multiply & divide 12 digit Data supplied with chip 6.95 ea Data onfy Refundable Wpurchase TOO ea 5002 LSI Similar to 500t except designed for battery power Data supplied with chip 8.95 ea Data only- Refundable w/purchase 1.00 ea 5005 LSI (28 pin) Full four function mem- ory, 12 digit display and calc.7 segment multiplexed output Data supplied with chip 10,95ea Data only ■Refundable w/ purchase 1 .00 ea Digital Clock . . , on a Chip MM531 1 (28 pin) Any readout 6 digit BCD, with spec sheet 1l.95ea MM 531 2 (24 pin) Any readout 4 digit Ipps BCD, with spec sheet 8,95 ea MM 531 4 (24 pin)LEDIncandescent readout 6 digit with spec sheet I0.95ea MM5316 (40 pin) Normal alarm, snooze alarm, sleep timer 12 or 24 hour operation, with spec sheet I5,95ea Grab Bag Specials 15 Assorted DTLs (dip) 15 Assorted TTLs (dips) NOTE: Factory seconds, not tested 1,00/bag 1 ,00/bag Satisfaction guaranteed. All items except as noted are fully tested. Minimum order $5.00 prepaid in US and Canada. California residents add sales tax. Orders filled within 3 days after receipt. Please add $.50 per spec sheet for items priced at less than $1.00 each. INTERNATIONAL ELECTRONICS UNLIMITED P.O.BOX 1708 S MONTERY, CA 93940 72 73 MAGAZINE Would you believe that there are some of us who remember when 73 Magazine was only 374 a copy? (How time does fly!) At the present time our subscriptions are increasing over 1,000 per month and we're beginning to realize that 1973 is our year (obviously). In order to further accelerate this trend, we're rolling back the calendar . . . yes, back to 1960 . . . and 374 a copy. We realize that we cannot get rich this way, but who cares when you can make so many subscribers happy! Now . . . for a limited time only ... (until we regain our senses) . . . you can subscribe to 73 for only 314 a copy on a 3-year subscription. That's only $13.32 for 3 years. Subscribe NOW and have it end in '76. That's the spirit! The regular newsstand cost for 3 years is $36.00-subscribe Now and save $22.68. Q New Su bscrip tion ^Renewal or extension □ Order Form 73 Magazine Peterborough NH 03458 USA 3 y rs, $1 3.32 10-73 1 yr f $6 Name Call Address City ZIP Fascinating World of Radio Communications Novice Class Study Guide General Class Study Guide Advanced Class Study Guide Extra Class Study Guide, reduced price . VHF Projects for Amateur & Experimenter VHF Antenna Handbook How to Use FM, an introduction FM Repeater Atlas, worldwide w/maps *FM Repeater Circuits Manual * Digital Control of Repeaters, new RTTY Handbook, radio teletype A to Z ATV Anthology, fast scan VHF TV *SSTV Handbook, new, only slow scan avail Diode Circuits Handbook, galore 73 Transistor Circuits, all useful Transistor Projects, mucho Solid State Projects IC Projects v 108 Q & A, transmitting, receiving, ant TVI Handbook, why suffer Coax Handbook, cables & connectors DX Handbook, w/map World DX Map, wall size, rolled Custom DX Bearing Charts, beam headings U.S. Maps, for WAS, etc (4 ea) Call Sign Badges, for lapel, black or red Magnetic Call Signs, for autos 73 Magazine Binders, beautiful red *Hardbound versions available @ $2.00 more. 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ALPHA Alpha-70 Pfl,-70V vapor cooled linear. b rand new conri AMECQ Tfc-626fli Imsler xrritter w/ti2l VFO. Oqww Relay ■ TX-626& Jmetef Knitter BIRD 43 wati meters [new! Imw ted quant ny COL LIN S £25 1 VHP canu. K WM 1 *cvr w;Sl6F-l *C bikJ 312 0-3 Kiime at 31 2B-4. paich . SYVfl . tic. J rated; new cond. CLEGG 99-(>r£f¥i irnvi working, a* is Thor 6 *Cvr w/AC mod F M 27 A FM *cv, Nk« rsew DRAKE 2B >cvt, 2BO Q rnylifspk 2A rev?. 2AQ "Q r " mull/i0k andtaP MiNJOOOrnaschtrg network T4XB w/cu r E lom ACVipk by Duke. new cond, tn caioh SW4A gtnl CoV. rCvr , nEwcond GALAX Y FM-2l'j/wAC 210 amp, 6 *rais r mic. GLADDING GladdmgSS'w/MaPs 34/76, 94/94 h 64/64. 22/82, 2S/3S. and 1ST R*$. Our Prict 1 P 27&.00©96.00 149,00 95.00 99.00 69 00 95.00 596 00 4 95,00 495.00 395.00 59.00 29 00 16900 99.00 339.00 2B9.00 21000 179 .00 139.00 149.00 1 59.00 T39 00 4B9.00 3B900 22900 199,00 189.00 I 25,00 199.00 159 00 GONSE T 6n*l Currim IV HALLlCflAFTEFS 5"5('n'i revt lateii wiprQfi. dwt. S Ft 150 ntvF w'AC.'Hjk SK-MOrcvr, Fl SOspk, HAlOcal, <Kceiv(?s w/HT-46! SR-4 2A 2m sxer, new cortd. w/2 * lals SH-46A 6m xcvr new cond r w/4 ictais HA 265& 2 VFO HEATH H X- 10 MarHiiijei 1QO watr SSBAM xmntti HW ISCrtxtiri 0O r 4O r 15 HG 10 VFO BO 2 meurt SB- 1 1 OA 6m SSB xcvr nm/SB-SOO ?m trans v ertff & KP-23A/AC I ike new, checked by Hetth SB- 500 2m Eransv^ftef HD-1 "Q" mull w/bujlt in AC pi. SB A-300-3 6m Corw. KIVIGHT/ALLIED TR 1 0B 1 5 v«ar[ 2m *wi w/AC , DC, nuc, ijk« ii ■«.■•. AX- 190 ham revr 30-10 + WWV r 1 KC. cai. eic. MAGftlUM Magnum 6 Rf- -spfiech prricessQi lor KentAQod T 599. tHimd npvy, wairaftly Rftq. Our Pribl R*g. ur Pric* NATIONAL 119 00 69 00 NCX-Bconv. to MK-2 w/NCX-A AC/spk. 429.00 3 IDOKct^ 1 29 00 99.00 NC-155fCvr 119,00 69.00 350 00 249 00 NCX-5 MK II w/NCX-A AC^k. lOOKcc^l 45000 379.00 195.00 169,00 SWAN SW-240 W/117S AC/ps brand new cond. 22300 179,00 >4^.O0 119 00 250C 6m xt^r w/1 17XC AC/spk, VOX r 43000 309.00 roa.oo 89 00 NS-1 noise silencer, nsw cond 39 00 2900 1 |?X baiic AC- TPL/TEMPO 65.00 39 00 50? 5-1 5/36-66 waTl output 2m amp,, [wm 1 U5.O0 79 00 1B9 00 1T900 502B 1 3.'4& 50 wyii ampul 2m amp, new 130.00 99 00 9 9 00 79. UO Ll*/ T50O DumfTTV I03Q !. Jl . ,c|r r'n*iiMr n»tV nq rxi 79.00 39.00 29 CX) 43900 329 00 TC-102 24 lu O^iral clock, hew TEST EQUIPMENT 89.00 59.00 Eico 378 Lab audio gen,, Eike n^w 8900 39 00 1 2900 69 00 Cfemmons SB 83B itq gan like new 295,00 2 25,00 10O0 RCA WV-9BC Sen^of VTVM. hew 99 00 59.00 3.00 Heath 10W-1 02 solid siat« scope, new 1B900 129 00 Win^iuw megiohm meter l.me:gg*rf 150 00 59 00 99.00 79.00 LEADER mr\tu fur prjee^ fl & K wrue for prices 19 9 00 149 00 MUDA. ^854 4 [ A digit digital aulO rangiing motiimeter. new 68900 S29:00 Ml 1 OA ^^108 10H? lo 550MH; freq 95000 725 00 3 33 95 99.00 c uunler, new MIIOA preci?ron calculalor^ 59 00 ' UP COMING SOON!!! I Genavo Touch-Tone Viul Gpnave fteueatBr snd MUt'U MOUE. HKG-KNTV, TLKOG, SBR. TNOUE, GLADDINO, MIIDA, GUSH ritAFT, DATA KXG., IUK1> + OLIVKIl SWAN (KIAIK IIY- t^ATX, SAVOV. lWfcK. LEADER, KKN^VOOD, TKMI'O, TEN TKr I>X KNO*, MTM riU>1>rrTS, SWAN. MIDLAND. ET(\ r IN S'NM'K— I'LEASE WHITE FOR (H'OTE. tVICI IANUALS CX7-CX7A $29-PprJ. Wo carefully ami answering service. NO ONE ANYWHERE BEATS OUR DEAL! AMATEUR-WHOLESALE ELECTRONICS 8817 S. W. 129 Terrace-Miami, FL 33156 Telephone — days (305) 233-3631 — night and weekends — (305) 666-1347 professionally iierviee every tiling' we sel], An empUiyne always answers o\ir nielli am J weekend phone — not an IM3 u:;lep tftaryp OCTOBER 1973 75 **•*•*«" Regency HR-2MS Genave Stop GTX-10 Wasting Time looking for a good deal G=.3 Hy-Gain Thunder bird 189 J .;■* Get a good deal more at LOU GOLDSTEIN - K4LAN P.O. BOX 3561 PEN SAC OLA, FLA. 32506 Florida's newest and fastest growing dealer. 5O "If I don't have it, you don 't need it " Gladding 25 V Hy-Gain iMMAwmeMii A post card brings results - write me your needs. Galaxy 76 73 MAGAZINE CC RULES AND REGULATIONS PART 97 (V) J CONTENTS THIS MONTH Subpart D — Operating Requirements and Procedures General Sec. 97.77 Practice to be observed by all licensees. $7.79 Control operator requirements, 97,81 Authorized apparatus* 97,83 Availability of operator license. 97*85 Availability of station licen&e, 97,87 Station identification. 97.89 Points of com muni cation a. 97.91 One-way communications. 97,93 Modulation of carrier. Cbntinuing from last month the complete text of the FCC Rules & Regulations pertaining to the Amateur Radio Service* SUBPART D— OPERATING REQUIREMENTS AND PROCEDURES General § 97.77 Practice to be observed by all licensees. In all respects not specifically covered by these regu- lations each amateur station shall be operated in ac- cordance with good engineering and good amateur practice* §97.79 Control operator requirements, (a) The licensee of an amateur station shall be responsible for Its proper operation, (b) Every station when in operation shall have a control operator at an authorized control point. The control operator may he the station licensee or an- other amateur radio operator designated by the licen- see. Each control operator shall also be responsible for the proper operation of the station. (c) An amateur station may only be operated In the manner and to the extent permitted by the operator privileges authorized for the class of license held by the control operator, but may exceed those of th^ sta- tion licensee provided proper station identification procedures are performed, (d) The licensee of an amateur radio station may permit any third party to participate in amateur radio communication from his station, provided that a con- trol operator is present and continuously monitors and supervises the radio communication to insure com- pliance with the rules. O #7*70 headnote and text revised eff* 10-17-72 f and (d) further revised etf, 12-1-12; FI(7£)-iJ S 97.81 Authorized apparatus. An amateur station license authorizes the use under control of the licensee of all transmitting apparatus at the fixed location specified in the station license which is operated on any frequency, or frequencies allocated to the amateur service, and in addition au- thorizes the use, under control of the licensee, of portable and mobile transmitting apparatus operated at other locations. § 9733 Availability of operator license. The original operator license of each operator shall be kept in the personal possession of the operator while operating an amateur station. When operating an amateur station at a fixed location* however, the li- cense may be posted in a conspicuous place in the room occupied by the operator. The license shall be avail- able for inspection by any authorized Government of- ficial whenever the operator is operating an amateur station and at other times upon request made by an authorized representative of the Commission, except when such license has been filed with application for modification or renewal thereof, or has been mutilated, lost or destroyed, and request has been made for a duplicate license in accordance with f 97.57, No recog- nition shall be accorded to any photocopy of an opera- tor license; however, nothing in this section shall be construed to prohibit the photocopying for other pur- poses of any amateur radio operator license, 197.85 Availability of station license. The original license of each amateur station or a photocopy thereof shall be posted in a conspicuous place in the room occupied by the licensed operator while the station is being operated at a fixed location or shall be kept in his personal possession. When the station is operated at other than a fixed location* the original station license or a photocopy thereof shall be kept in the personal possession of the station li- censee {or a licensed representative) who shall be ?resent at the station while it is being operated as a OCTOBER 1973 77 GATEWAY ELECTRONICS 8123 25 PAGE BOULEVARD ST. LOUIS, MISSOURI 63130 (314) 427-6116 Fig. A Fig. B LED READOUTS Fig, A MAN 1 Style with diffused segments for improved visability $2,75 Fig. B MAN-1 Style $2,75 Giant 0.6 in. LED similar to Fig. B $3.95 Single LED lamp, red or clear, please specify. $.35 each, 3 for $1.00 IC SPECIALS Stereo Amp. 2 watt per channel dual in-line package w/data $2.00 Clack Chip ■ National 5314 12/24 hr 4 or 6 digit 24 pin pkg w/data $12.95 22 Pin PC card socket CU56 spacing $ .50 WE Touch Tone Pad 12 button new $19.50 5 MHz crystal miniature size w/wire leads ^ $2.50 IC SOCKETS 14 pin solder $.50 wire wrap $-55 16 pin solder $.55 wire wrap $.60 24 pin wire wrap $1.20 28 pin wire wrap $1.30 BUY TO & DEDUCT 10% THUMBWHEEL SWITCHES STANDARD SIZE - 0.5 x 2.125 x 1.78 10 position decimal $3.00 10 position BCD & compl.$4,00 End Plates (per pair) $1.45 MINIATURE SIZE - 0,312 x 1.3 x 1.3 10 position decimal $2.50 10- position BCD & eompL$3.75 End Plates (per pair) $1.00 Divider plates $1.25 $5 Minimum Order. Visit us when in SL Louis. Please include sufficient postage. portable or mobile a tat ion. The original station li- cense shall be available for inspection by any author- ized Government official at all times while the station is being operated and at other times upon request made by an authorized represent a tire of the Commis- sion, except when such license has been filed with application for modification or renewal thereof, or has been mutilated, lost, or destroyed, and request has been made for- a duplicate license in accordance with | 97,57. §97*87 Station identification. (a) An amateur station shall be Identified by the transmission of its call sign at the beginning and end of each single transmission or exchange of transmis- sions and at intervals not to exceed 10 minutes during any single transmission or exchange of transmissions of more than tO minutes duration. Additionally, at the end of an exchange of telegraphy (other than tele- printer) or telephony transmissions between amateur stations, the call sign (or the generally accepted net- work identifier) shall be given for the station, or for at least one of the group of stations, with which com- munication was established, (h) When an amateur station is operated as a porta- ble or mobile station, the operator shall give the follow- ing additional identification at the end of each single transmission or exchange of transmissions: (1) When identifying by telegraphy, immediately after the call sign, transmit the fraction-bar I>N fol- lowed by the number of the call sign area in which the station is being operated, (2) When identifying by telephony, immediately after the call sign, transmit the word "portable" or "mobile", as appropriate, followed by the number of the call sign area in which the station is being operated. (c) When an amateur station is operated outside of the 10 call sign areas prescribed in § 97.51(b) and out- side of the jurisdiction of a foreign government, the operator shall give the following additional identifica- tion at the end of each single transmission or exchange of transmissions : (1> When identifying hj telegraphy, imm edia tely after the call sign, transmit the fraction-bar 1>N fol- lowed by the designator R 1, R 2, or R 3, to show the region {as defined by the International Radio Regula- tions, Geneva, 1959) In which the station is being operated* (2) When identifying by telephone,, immediately after the call sign, transmit the word * 'mobile" followed by the designator Region 1, Region 2; or Region 3, to show the region (as defined by the International Radio Regulations, Geneva, 1959) in which the station is being operated. (d) Under conditions when the control operator is other than the station licensee, the station identifica- tion shall be the assigned call sign for that station,. However, when a station is operated within the privi- leges of the operator's class of license but which exceeds those of the station licensee, station identification shall be made by following the station call sign with the operator's primary station call sign (i.e. WN4XYZ/ W4XX), (e) A repeater station shall be identified by radio* telephony or by radio telegraphy when in service at In- tervals not to exceed 5 minutes at a level of modulation Hudicieut to he intelligible -through the repeated trans- DiiHHinn. (f) A control station must he identified by its as- signed station call sign unlesn its emissions contain the call sign identification of the remotely controlled station. 78 73 MAGAZINE (ff> An nrjxiliary link sfniion mtist lie idf-ntififd by Ita DUHijfiiM] station rati tfjsn niiJrstf it.n emissions con- tain tin* call sien of its aH*oci:iti*d Htatinn. (h) The identification re<jrtirpd by para graphs (ah (b), (c), (d), (e>, (f) f and (%) of this m-tlon ftball be (riven on each frequency lielnc utilized for trana- mission nnd shall be transmitted either hy telegraphy u*tm? the International Morse eode t or by telephony, using tho EncIiMh Uinguage. If by an automatic derire only used for identification by telegraphy, the code npeed Jilmll not exceed 20 word* p**r minute. The use of a national or internationally recognized standard phonetic alphabet as an aid for correct telephone iden- tification Is encouraged- [S97,S7{<£) amended' end rede*, an (h) and new (d) t (e) t (/), and iff) added eff: 10-f7-72; FI(7£M] §97*89 Points of communications. (ft) Amnteor stations may communicate with: (1) Other amateur stations, excepting those pro* hlblted by Apj>endix 2, (2) Stations In other services licensed by the Com- mission and with lL3 f Government .stations for civil defense imr|*nses in accordance with Subpart F of this part, in emergencies and, on a tem|iornry bnuls, for test purposes. (3) Any station which ia authorized by the Commis- sion to communicate with amateur stations* (b) Amateur stations may be used for transmitting signal*, or communications, or energy, to receiving ap- paratus for the measurement of emissions, temporary observation of transmission phenomena, radio control of remote objects, and similar experimental purposes and for the purposes set forth In | 07.9L (c) Notwithstanding the provisions of paragraph (a), no more than two repeater stations may operate in tandem, i.e., one repeating the transmissions of the other, excepting emergency operations provided for in 107,107 or brief periods to conduct emergency pre- paredness testa. (d) Control stations and auxiliary link stations may not be used to communicate with any other station than those shown in the system network diagram. [|£7.83 amended eff. 10-17-72: F/(72)-/] 897.91 One-way communications. In addition to the experimental one-way transmis- sion permitted by § 07-8$, the following kinds of one- way communications, addressed to amateur stations, are authorised and will not be construed as broadcast- ing: (a) Emergency communications, including bona- i\*U* emergency drill practice transmissions; (b) In- formation bulletins consisting .solely of subject matter having direct interest to the amateur radio service as such ; (c) Round-table discussions or net-type op- erations where more than two amateur stations are in communication, each station taking a turn at trans- mitting to other station (e) of the group: and (d) Code practice transmissions intended for persons learning or improving proficiency in the International Morse Code, § 97,93 Modulation of carrier, Except for brief tests or adjust incuts, an amateur radiotelephone station Nhall not emit a carrier wave ort frequencies below 51 megahertz unless modulated for the purpose of communication. Biugte audiofre- quency tones may be transmitted for test purposes of short duration for the development and perfection of amateur radio telephone equipment. (Continued next month.) m m At Last . Repeater Sophistication Is HERE Now at a realistic price you can have "Touch-Tone" command functions, autopatch, and control. It's the Signal Systems Decoder. MODEL TTD-1 12/16 BUTTON DECODER Wired: Board $10.00 Kit: 12 button S77 .00 16 button S88.00 12 button $85.00 16 Button $98.00 THE IDENTIFIER TO END ALL IDENTIFIERS ROM 2 Repeater-Identifier (CW-RTTY) Board Kit Wired 8.00 Option I 25.00 $30.00 29.00 $35.00 Here is the greatest buy on an identifi- er you'll ever find. Look for product review write-ups on these and other exciting new products from . . . mnntftr charge BiiNhAM t 'f?h 'Sjb*, *,* , SIGNAL SYSTEMS 2650 Durango Dr. Colorado Springs, CO 80910 Phone toll free 800-525-5890 OCTOBER 1973 79 IF YOU REALLY WANT THE BEST, YOUU JUST HAVE TO ACCEPT THE FACT THAT ITS GOING TO COST YOU A LITTLE LESS It's the little things that make a GTX the value it is: • Operation over the entire 2-meter band (including MARS and CAP frequencies) without tuning • No automatic shutdown on SWR bridge. Operate with mismatched antenna with- out damage, due to balanced emitter out- put transistors • Lowest AM detection level of any com- parable unit (including many commercial rigs) • Power: the GTX-2 and GTX-200 boast 30 watts nom. output * . r Lightweight: manufactured to aviation industry standards High-sensitivity receiver pre-amp in- cluded as standard (GTX-2 and GTX- 200) l A " phone jack included as standard (GTX-2 and GTX-200) GTX-200 $269.95* (30 watts output power, nom., up to 100 channel combinations) GTX-2 $259. 95* (30 watts output power, nom., accommodates 10 channels) GTX-10 $209. 95 (10 watts output power, nom.. accommodates 10 channels) * Includes 146.94 MHz. Add'l. crystals $6.50 ea. Don't Let An Honest Price Scare You Away- See Your Amateur Dealer Today! General Aviation Electronics, Inc., 4141 Kingman Drive, Indianapolis, Indiana 46226 - Area 317 - 546-1 1 II 80 73 MAGAZINE SEW* $49.95 1 -2 WATTS I N 15 WATTS PLUS OUT SOLID STATE SWITCHING Wired and Tested • 12-14 VOLTS NEGATIVE GROUND • LESS THAN 1 DB LOSS ON RECEIVE PA-1501 H Only 2" x2%"x 6% r r Also available: $39.95 complete kit RX-50C 30-60 MHz receiver kit w/crystal filter $59.95 RX-144/220A 2/220 receiver kit 59.95 RX-144/220F 2/220 receiver kit w/ceramic filter 65.95 69.95 29.95 29.95 29.95 49.95 • RX-144/220C 2/220 receiver kit w/crystal filter • TX-144 1 watt exciter • TX-220 1 watt exciter • PA-144/220 15 watt amp less cabinet, connectors, and switching • PA-144/220 25 watt amp less cabinet, connectors, and switching • PA-8005H 90 watt amp 5 watts in wired/tested 159.95 • PA-8020H 90 watt amp 25 watts in wired'/tested 129.95 • PA-432 10 watt amp less cabinet, connectors, and switching .... 39.95 • PS-12 12 amp regulated 12-15 volt power supply kit 59.95 • PS-12W Wired/tested 69.95 • PS-24 24 amp same as PS-1 2 less case 69.95 • COR-1 COR with 3 second and 3 minute timers 19.95 Write for data sheets on any above units. Add postage. NY state residents add sales tax. HF ENGINEERING - DIV. of BROWNIAN ELECT. CORP. - 320 WATER ST. POB 1921 BINGHAMTON, NY 13902 607-723-9574 WORLD'S LARGEST SELECTION OF NEW & USED TV CAMERAS & ASSOC. EQUIPMENT iS2SS£25^ZB5SESS55S5SSS9 Broadcast & Closed Circuit TV Audio and Video Systems PRICE $1.00 INDEX PAGE 142 CATALOG # 973 S 1 $1,00 ppd USA— $2.00 Foreign, Free to requests on Company Letterhead. THE PENSON ELECTRONICS CORP. 9AM - 4PM Monday thru Friday; otherwise hy appointment OFFICE: Longview St. Tel. Area Code 203/875-5198 L: Post Office Box 85 ROCKVILLE, CONN. 06066 USA 82 73 MAGAZINE ANOTHER SELECTRONIC SPECIAL The R648/ARR41 Receiver Can be best described as a mini version of the R390A class of receivers, having most of the key features of the R39Qs. The unit covers from kc to 24.999 Me in 24 one megacycle bands. It does not include the band covering 1 Mc to 2 Mc As you might surmise, the rec. includes two Collins mechanical filters. Operation of the receiver is most pleasurable, especially when tuning sideband, fncidentafly, the crystal controlled calibrator delivers a tone every 100 kc and is of frequency meter accuracy. The receiver contains a dynamotor designed to operate from 27.5 volts DC at about 4 to 5 amps. Since most of the dynamotors are free of hash, retaining it and operating the set from 24 to 28 v, DC is not really a bad alternative. If you wish to power with A.C. supply requirements are 250 V @1GQ ma. and 28v for fiL These sets are in like new condition overhauled and checked out. Wt. 34 lbs. Price: $1 75.00 ea. Solid State 866A Direct Replacement Price: $5.95 ea. or 2/$10.00 R508 VHP Rec. 118-148 MHz Price: $14.95 ea MODERN ALUMINUM BENCH RACK CABINET 11Vi" H x 18" D x 19" W. 8" panel openings w/rubber feet and disappearing handle. LtBlue Price: $7.95 ea R.F, AMPLIFIERS TUNES 50 to 100 mhz - COMPACT ALL ALUM, CASE 12" x 15" x 6% ft WITH SK 600 EIMAC SOCKET. 1 LARGE AIR VARIABLE CAP. - 2 SMALL AIR VARIABLE TRIM- MERS - TEFLON MOUNTED ROTARY IN- DUCTOR - GOOD FOR LINEAR AMPLI- FIER - CAN USE EITHER 4 CX150A or 4 CX250- LESS TUBE, PRICE: . , > $14.95 ea. WITH 4 CX150A, PRICE: . . . . $19:95 ea. ADJUSTABLE PRINTED CARD BOX For R ack Mount 5" to 7%" — 16 slides and socke.s includes 30 double contact position edge connector type Price: $9.95 ea. Receiver type VHF-2RM 108-135 MHz crystal control Double Conversion AM with AVC noise limiter and squelch-tunable, 1 15 volts, 50-60 cycles. Price; $24.95. WINTRONIX MODEL 850 INDUCED WAVE FORM ANALYZER, This unit, in conjunction with your present oscilloscope, permits you to view wave forms in the range from audio thru MHz without any direct connection. The probe is simply placed over the tube in question and the wave form is displayed on the oscilloscope. It may also be used as a high gain amplifier to increase scope sensitivity. Excellent for TV, radio, amplifier, and transmitter repair and maintenance. Brand new, with probe. SHiPWT. 13 lbs. Price: $19.95 ea. MODULE TYPE POWER SUPPLY TRANSISTOR, REGULATED. 115V - 60 cycle in +12 -12 -6V @ 3 amp output. Front Panel adj + or -10%. On-off switch, Fuses. Barrier strip output. 6" x 5" x 7", Excellent Ccmd. Ship.Wt, 10# Pnce; $14.95 ea. DIGITAL READOUT SET Make your own counter, frequency meter, digitaJ voltmeter, readouts, etc. Kit includes 6 nixies with 6 sockets 1 transformer 1 P/S board w/socket PRICE: , . $12.95, 2/S20.00 B-7971 LARGE ALPHA NUMERIC READOUT With sockets & driver board. Can be hardwired to form unusual house address numbers. 2 tubes, 2 sockets, mounted on one driver board. Save $3.00 Price: 5/$ 5.00 COMPUTER TYPE CAPACITORS 40,000 @ 20V 32,500 @ 25V 55,000 @ 15V 1 00,000 @ 8V 50d each or 5 for $2.00 40,000 @ 10V 30,000 @ 10V PRICE: 3 for $1.00 Receiver R-36/GR 225-400 MHz. Crystal Control Double conversion FM with squelch and noise limiter, 600 ohms output, 1 15-230 Volts, 50-60 cps. Price; $24.95 Just arrived. PS for R648 fits into receivers. Price: $24.95 Coaxial relays, single pole UHF.BNC, Type N. Specify. double throw, available in Price :$4. 95 each. LAMBDA POWER SUPPLIES, LT 2095, 0*32 V 2 amp. rack mount. Like New. Pnce:$34.95 each. Adapters BNC to SO-239. Price: 2/$ 1.00. VACUUM VARIABLES, UCS 300, 300 mmF, 10,000 V. Price: $19.95 each. SPECIAL ONE OF A KIND Sorenson Power Supplies MA 28 30, 28 V, 30 A ERA 0-36 V, 50 A ERA 0-36 V p 20 A Price: $125,00 Price: $150.00 Price: $100.00 Transmitter, 110 W FM, 406-420 Mc. Rack mount, with power supply. Price: $150.00 ALL PRICES ARE F.O.B. OUR WAREHOUSE, PHILADELPHIA, PA. ALL MERCHANDISE DE- SCRIBED ACCURATELY TO THE BEST OF OUR KNOWLEDGE. YOUR PURCHASE MONEY RE- FUNDED IF NOT SATISFIED. TERMS ARE CASH, MIN. ORDER $5.00. ALL MERCHANDISE SUBJECT TO PRIOR SALE. RFE - REMOVED FROM EQUIPMENT. 1206 South Napa Street 215-468 7891 SEIECTBONICS Philadelphia, PA 19146 215-468-4645 OCTOBER 1973 S3 AKHBajl THE ULTIMATE POWER SUPPLIES • 60 A @ SLIGHTLY LESS THAN 12 Vdc • NOMINAL OUTPUT: 50 A at 12 Vdc • BUILT-IN VOLTAGE & CURRENT METERING • WILL RUN A MOBILE RIG& EVEN AN AMPLIFIER FROM 110 Vac WALLER ELECTRONICS TEST EQUIPMENT SALES P.O. Box 9913, Chevy Chase, Md. 2001 5 Telephone 301-652-0996 SHIPPED FREIGHT COLLECT 84 73 MAGAZINE EXCITING NEW PRODUCTS 2-METER PREAMP 20 dB Gain, 2.5 N.F., 12V j § dc, Size 1" x 1ft" x y a Diode protected MQSFBT, 90-day guarantee. Sh. wt, 4 oz, Major Components Separately Shield ad. Wired ; . . . .$12,50 TONE ENCODER Eight pre-adjusted tones. Duration and Output ad- justable, PLL circuitry for extreme stability, Choice of continuous or tone burst operation* Tone burst operation requires no batteries. Easy to install. Includes three special single or dual tones, TE8 KKit $31.95 Wired . . ., . .$39.95 TOUCH-TONE DIALER The electronic touch-tone dialer for home and car. It's safer and more accu- rate to use than a pad. Memory includes Access Code plus five phone num- bers. Numbers easily up- dated. Built-in monitor. Complete PTT operation with transmitter hold. TTD^4K WIRED .$59.00 Kit $49,00 • * ££ * <c ***K* Mi nutd'MrcH caamuE AUTO-PATCH CONSOLE This mobile or home con- sole includes all the fea- tures you need for com- plete auto -patch operation. A Touch-Tone Pad; an automatic dialer for send- ing one access code plus five Touch-Tone phone numbers; a single /dual tone burst encoder adjusted to your choice of frequency above 500 Hz, and a built- in motor. Complete PTT operation with one second transmit it* r hold* APC-4K Kit ....... $84.50 APC-4A Wired $98.50 TOUCH-TONE DECODER A highly reliable twelve digit decoder with input protection, and PLL cir- cuitry for extremely stable operation. Heavy duty out- put relays, small size, plug- in circuit board. All these major features at an UN- BEATABLE price. TTD-12KKU .,..$89.50 TTD-1 2 Wired . . . $129.50 OjiIA [■■mitlia* <M* 1 2 L :i [4 La] [e'l [a] Q * ' [0 [*» J TOUCH 1 OWE MO TOUCH TONE PAD In less than 15 minutes you can convert your por- table transceiver to Touch- Tone ©Deration* TTP Assembled . . . $44.50 TTP Kit $34.50 PAD-PULSER Now you can also obtain pulsed operation from your Touch Tone Pad, Convert Touch-Tone fre- quencies to decimal pulses at 2805 Hertz with just a flip of the switch. Option can be added to TTP-2/K, TTD-4/K and APC-4/K. PP 12K Kit $22.95 PP-12Wired $29.95 5— year guarantees. Send for Catalog VHF FREQUENCY STANDARD- FMS 5 Cal. receive and transmit crystals in 10 P 6, 2 and 1 \ meter FM bands. Markers for all FM channels. Check deviation. Precision 12 MHz crystal. No unwanted markers. Osc, and output buffered. Sh. wt, 2 lbs, ( Less Batteries) t . $44,50 Kit . ««.****... $37.50 REPEATER ID Highly stable oscillator for automatic timing, AC or DC operation. ROM pro vides for more than 25 characters, more than necessary for DC "any call" RPT. AUX is auto- matically added to ID if desired when main power is lost. Toneburst opera tion available. ID-101K Kit ..... $49.95 ID- 101 Wired/Tested $69.95 ID-101R assembled in Vti* rack cabinet ,...$109.00 TONE DECODER Versatile single/dual ton*. decoder. PLL circuitry for extreme stability. 1 amp output relay can be reset automatically or manually. Monitor position. Adjus Table sensitivity. Internal strap selects single or dual tone operation. TD-2K Kit $31.95 TD-2 Wired $39.95 -OF r master charge ■ ■ i H ' ■ -i h * * * * ►■■ Data EngiriEErin g , inc. $554 portRoyai Road V Ravensworth Industrial Park, Springfield VA 22151 Phone: 703-321-7171 OCTOBER 1973 85 < \P\UTOK YSSORTMENTS ANTENNAS INTIGRATI.I) CIKCUITS RESISTORS v. s 3 * i /- s 2 O 2 HAVE COPY OF OUR NEW CATALOG YET ? > n t to * m ^ en O 3 2 IF NOT, WRITE OR CIRCLE READER SERVICE CARD FOR YOUR COPY NOW! ffJ > 53 as O B u < § P.O. BOX 773 3 v. oub siatti $y%im% a mt ~ ^ COLUMBIA, MISSOURI 65201 % (CALL TOLL FREE) 800-325 -2981 sAV'idsiu uai • sx.\:'jkiuossv hoxsis;ih • sunn nNiiNnw) acivaaa iysmi yinti 86 73 MAGAZINE ipi -:-:-:-:•:■ WWW: : ivx': #:S;¥&W «wss :£&: '■"■ J , .".'. , V.".', J . :■:■; SC 250 8 DIGIT COUNTER SEMI-KIT with built in prescaler, and p.s. good up to approximately 250 MHz. Fully assembled and tested board. Send for data . . , $1 65 ST-5A BOARDS ONLY (same size as those in the ST-6) $ 5.25 ST-5A KIT OF ELECTRONIC PARTS , $ 54.00 ST-6 BOARDS ONLY {these are the 8 original by W6FFC) $ 18.00 ST-6 KIT OF ELECTRONIC PARTS $128.50 MOD. KIT FOR UPDATING THE ST-5 TO THE ST5A ..........$ 9.00 AK-1 BOARD ONLY (same size as those in the ST-6) , . - $ 3.25 AK-1 KIT OF ELECTRONIC PARTS ( Same size as *hose in the ST-6) $ 20.00 PEMCO MODEL 50A FREQUENCY COUNTER Sfcivn-KIT . $125.00 This is a fully assembled and tested board with built-in power supply, cabinet, etc. Write for details. You must supply the cabinet, A.C. cord, meter, switches, etc. on all kits except where noted otherwise. (All prices are postage paid - we pay shipping.) If you have been putting off building because of circuit board layout, you have no problems . . . . just send a schematic to PEMCO and we will design and build your circuit board to ytur specs using high quality G10-FR4 2 oz. copper and tin plated for long resistance to oxidation. . .:■;■: •'£ fig ;■■■" :>j;. yy.'Vwi ;-X'V.v." ■:■ W-j-y/.-y.-i' I m ¥8 :■:■:■:■:■:-■*:■- . .v.(i. .-.•.■.- PEMCO ■ ELECTRONICS nc. MANUFACTURING » 422 18th St., N.E., Salem, Ore. 97301, (503) 585-1641 mm ■zy*±w&-]r:$fti& !.> j v.:jwv.;v:v:v,:.viv,',;, :■:>:»:■ xc-Ux^t-. :■:■: :■:-:-. . . : •: o>1o:o - - ■■:-:■ :-x.v.%:-»7*7':o ■ . '.■-■.' .■.'.■' ', .,... : . : .;. : .;. r : ; ;^>j.r.:.v.:-:.:''. ^>^>^5^5SSSS ^>:-:::'x^«i$:SJ: ^S:¥;S:";¥: : :c-x: : ' • ' :£:W*K£: ; ; ; - : ; . .' OCTOBER 1973 87 Modal THIDXX HYGAIH A TRULY SUPER BEAM SUPER THUNDERBIRD TRIBANDER. Ulti- mate in tribander performance. 6 elements. For 10, IS and 20 meters. Gain 8.7 dB. F/B ratio, 25 dB. Input, 1 kw am, 2 fcw PEP. Longest element, 31.1'; boom 24'; turning radius 20'. Requires CDR HAM-M rotator* (See p. 12). Modal THIDXX. 66 lbs "_ —™ 171*15 TH3MK3. improved super 3-element beam, 10-15*20 meters, U lbs, 14445 TH3JR. 600 watts PEP, 3 el. beam, 10-15-20 meters. Turn radius 14.3\ 21 lbs, ... 9J.95 TH2MK3. Improved 2 -element beam. 10-15-20 meters, Turn radius, 14,3\ 22 lbs, .._ if JS HY- QUAD VHF QUAD and VHF BEAMS 3-BAND, 2-ELEMENT HY-QUAO. Complete, nothing else to buy! Extra strong. For ID, 15, 20 meters- fain, 8.5 dB. F/B ratio, 25-35 dB 52 ohms. Spreader length, 25^5", boom dta., 2"; turning radius, 13'6". Medil HY-QUAO. 42 lbs, ,..* 1«-W 3 ELEMENT, i-METER BEAM. Maximum perform- ance, rugged. Gain, 10 dB, F/B ratio, 20*25 dB. Input, 1 kW. 52 ohms. Longest element, ^10"; boom, W\ turning radius. &. Medal 6 3 EL 7 lbs DISCONTINUED {-ELEMENT, S-METER BEAM. Gain, 12.7 dB; F/B ratio. 20-25 dB. Input 1 fcW. 52 ohms. Longest eL, 9*11"; boom, 12'; turn, radius, 1'. Model MB io lbs _™™™," _.. 2i.se 1-ELEMENT, 2 METER BEAM. Gain, 9 dB. F/B ratio, 20 dB. Input, 1 kW. 52 ohms. Longest element. y6*; boom 3'; turn, radius, *', Model 23* 4 lbs. _ _"_ M9 8-ELEMENT, 2-METER BEAM. Gain, 14.5 dB. F/B ratio, 25-30 dB. Input 1 kW. 52 ohms. Longest el.. 3'6"r boom, 14'; turn, radius, 7'6*. MOSLEY Clastic Baa mi Trap Master CLASSIC t-ELEMENT BEAM. For 10, 15, 20 meters. Extremely rugged and lightweight, Rust and corrosion proof! Maximum gain with increased bandwidth. Rated 1 kW AM/CW, 2 kW PEP on SSB, 52 ohms. Longest element, 2^3"; boom, 24 r ; turning radius 19'3", ' Model CL-36. (Needs HAM-M rotator), 72 lbs 188 . 10 Medal CL*33. As above, but 3-elements, Longest element, 27'; boom, 16'; turning radius 16'. S dB gain. 47 153.75 TRAP-MASTER SERIES. Provides outstanding performance on 10, 15, 20 meters. Exclusive Mosley trap design offers resonant frequency stability under all weather conditions. Traps are weather and dirt-proof, TA-31. elements, 1 kW AM/CW, 2 kW PEP on SSB. Longest el., 2^; boom, 24'; turning radius, 19'3". 73 lbs 18 5 . 10 TA-33, 3-etements, 1 kW AM/CW, 2 kW PEP on SSB. Longest el., 28'; boom, 14'; turning radius, 15'6". 41 lbs 143.40 rA*33Jfl. 300 watt version of above. Longest element 26 / 8"; boom, 12'; turning radius, 14'9". 28 lbs. -- 100.00 TA-32. 2-elements t rated 1 kW. Longest element, 28'; boom, 7'j turning radius, 14'G". 29 lbs, 103.00- TA-32JR. 300 watt version of above. Longest element 26'8"; boom, 6'; turning radius, 13'. 20 lbs. 73 . 15 A50-5 144-11 CUSH-CRAFT 6 METER BEAMS, Proven performance, rugged. Engineered for best pattern, high forward gain, good F/B ratio and broad frequency response. Brackets are heavy gauge alumi- num. Horizontal or vertical mount. 52 ohms. Model A50-5. 5*elements, longest element, 117"; boom, 12'; turning radius, 7'6". 12 lbs 29.50 Model A5D-3. 3-elaments. longest element, 117"; boom, 6'; turning radius, 6'. 8 lbs 18.50 2 METER BEAMS. High performance VHF beams. Light- weight, rugged and easy to install. Horizontal or vertical mount. Features 1 kW Reddi Match for 52 ohm feed with PL-259 fitting. All elements are spaced at .2 wavelength and tapered for improved bandwidth. Model A144-7, 7-elements, boom length, 98". Fwd. gain, 11 dB; F/B ratio, 26 dB, 4 lbs . '[3 * 95 Model A144-11. 11-elements, boom length, 144". Fwd. gain, 13 dB; F/B ratio, 2d dB. 5 lbs. 17 ,95 ZIPPER PORTABLE BEAM. For 6 and 2 meters. Full size performance and sturdy, swing-out portability. Ideal for emergency stations, camping, vacationing, etc. Complete package folded is 4 x 4 x 50" and weighs only 4 lbs. Tuned Reddi Match for 52 ohms. Longest elements, 117"t boom, 66"* Ready -to- use. Model A2MP. Shpg. wt, 5 lbs. " " 17.95 NEW MOSLEY TR1-BAND QUAD Designed for top OX efficiency. For 10, 15, 20 meters. Aluminum spreaders are well insulated for greater strength, P re-drilled for easy assembly. Maximum forward giin, F/B ratio, 20 dB, Rated 1 kW on AM. 52 ohms. Spreader length, 12'6"; element length, 17'; boom, 8'; turning radius, &'. Modal MCQ-3B. 40 lbs. ."" 111.50 CUSH-CRAFT HALF WAVE SQUALQ Full half- wave, horizontal I y-po la r- ized, omnidirectional 6-meter an- tenna. Use it on car top, on mast, or out the window, Direct 52 ohm Reddi Match feed. Only 30" square. Complete with rubber suc- tion cups and mast support. Model ASM. 5 lbs " 15J5 Model A3Q 2. For 2 meters. 10" square. 3 lbs. _ _ 11 J5 Elect r onix Sales 23044 CRENSHAW BLVD.. TORRANCE, CALIF. 90505 Phone (213) 5344456 or 5344402 ALSO AMERICAN EXPRESS CLOSED SUNDAYS & MONDAYS 88 73 MAGAZINE CHARGE IT ON master charge THE INTEHBANK CARD CALL TRADE CHARGE IT ON BankAmericard we$mte^e&& CALL TRADE NEW CALL Bill Du Bord, W0KF USED (9 A.M.— 5 P.M. Central, daily except Sunday) FOR A SQUARE DEAL ON DRAKE TEMPO/ONE HALLICRAFTERS CLEGG STANDARD YAESU SWAN COLLINS KENWOOD REGENCY We carry all major brands and a large stock of used reconditioned equipment Write for used list HAM RADIO CENTER INC. 8342 OLIVE BL. ST. LOUIS, MO 63132 OCTOBER 1973 89 uiuvpuu Numttron 5V 7-Segment Siimline or Regular $2.50 ea. ZM 1000 Neon $1-75 GE Y4075 25V Miniature $1 75 GE Y 1938 24V Standard $1/75 RAY CK 1905 Standard $1,75 MAN-3 1.7V Miniature $3,50 m. 10/$30 GIANT ALPHA NUMERIC OIL CAPS 16 MFD 5000 VOLT Rare find. $9.00 each 3 $25.00 B7971 $1.00 NOISE ACTUATED SWITCH $1.35 Solid stale notse actuated switch fully wired, includes mike pick-up, amplifier, SCR switch Actuates by noise or whistle. Useful for burglar alarms, lamp lighter, etc, 15 ft range, LIGHT EMITTING DIODES 3/S1.00 Ruby red, gold plated leads. With mercury celt for instant testing. H.H, SCOTT MULTIPLEX Solid state brand new multiplex module w/ schematic. Possibility of conversion of various mono seis to stereo. $3.00 each 1 for $25 00 Alpha-numenc keyboards. Excellent to new in condition. Styles may vary shghtly from picture. Two models available, one with ASCI I encoder in base $55.00 postpaid in the U.S. Keyboard with no encoder in base $35.00 postpaid in U.S. KEY BOARDS $35.00 & $55.00 RCA MEMORY STACK 32x32x9 3rd generation, ultra compact. Measures 1x4 1/4x7. Brand new. $50.00 3 for $125.00 CORE STACK Late model memory stacks, unused, I <\. A -J ************* *• * f « *J} O^ O -. \J \J 2Kx9 50.00 8K 4 bit Y plane . 40,00 16K 4 bit Y-plane 60.00 147K stack . . , . . 100,00 HflMI AM-FIVI RADIO $20.00 Fully built chassis by Delmonico with front panel, solid state- Also has stereo tape and stereo turntable inputs, 115 VAC power. Brand new with schematics. $20,0(1 Made for console installation. Cost over $1 00.00. URC-11 WALKYTALKY 243 MC 2 way radio, hand held, measures 3x4 inches. Used for survival in downed aircraft. May be converted for other frequen- cies. URC-11 $15 each or 3 for . $40.00 12 VDC 3 AMP POWER KIT $5.00 Just right for powering car tape deck, CB sets, car radio, etc. from regular house current. We furnish parts — transformer, silicon bridge, filtering caps, directions. Ail new parts, order #KT-3 at $5.00 ea or 6 for $25.00. ■i ^rfesA^ 7 SEGMENT LED Hobby craft due to being factory rejects. Most have a segment or decimal inoperative. Still a great "buy" for the experimenter. What an unusual tie clip you can make with pocket battery . , , demo displays, etc. In many appli- cations you don't need full 7 segments, $1.00 each or $10 the dozen. 0.333 inches high character. GIANT 7 SEGMENT As above only this one is the giant display 13/16 inches hgt of character. First time offered and as far as we know, offered nowhere else. This one is quite an attention getter. Also available in this giant display numeral "one" with "plus" and "minus" sign. Again, these are rejects. Giant display $1.50 each 12 for $15.00 ostage extra on above. MESHN A PO Bx 62 E. Lynn Mass, COMPUTER KEYBOARD W/EN CODER %35 Another shipment just received, Alpha-numerics keyboard excellent condition. Once again we expect an early sellout. Price of $35 includes prepaid shipment in the US and shipment made within 24 hours of receipt of order. POWER TRANSFORMER 1 15ac/12V@3 amps . . . $2.50 POWER AMP TRANSFORMER Brand new compact, regular 115 V 60 cycle input Output of 40 VCT at 4 amps plus another winding 6V at 2.5 amps. Fine business for Power Amps, Logic or Op Amp supply, $5-50 each or 5 for $25.00 12VCT2AXFMR$t50 Regular 115 volt 60 cycle input. 12 volt transformers are always in demand, these are brand new. $1.50 each or 10 for $12,00 iC SPECIAL - ONE MONTH ONLY Our regular S1 5 IC board with appro*. 140 DIP ICs on them p with fdent sheet. For one month only we are pricing them at $6.50 per board to reduce our inventory. ^1C-S $6.50 Or 5 for $25 COPPER CIRCUIT BOARD Brand new GE 2-sided glass epoxy G-10, the standard of the industry, bright and shiny new. 6x12, Si. 00. 12 x 12, $1.50. AM-FM RADIO $5.50 Due to the West Coast ship strike they came in too late for the customer. Now it's your bargain. Use it as is or build it into your own cabinet, desk, wail, etc. All built, ready to use, with AC supply. To make it portable all you do is power it with a couple of "D" cells. Fully assembled solid state chassis with AC power supply, less speakers. Covers full AM as weJI as FM broadcast. The price. . .an astounding meager $5.50 PISTON CAPS 1-8 mmF 3 for $1.00 Unused Military surplus. For hi freq. work. List price over $3.00 each. We have 1 size only, 1-8jUF. No hardware. ^73-18 3 for $1.00 60-SECOND TIMER A bonanza for the photo lab or any require- ment for a precision spring-wound timer, May be set at any interval 0—60 seconds. Contacts rated at 15 amps. Contacts close while running and open at end of time interval. Brand new. $1,50 each, 10 for $12 455 KC IF ASSEMBLY Complete miniature 455kc I F. amp assembly. 1.5 inches long, little over X A inch square. Ready to use w/schem. Sim to Miller 8902 2,50 RF VACUUM SWITCH Made for the ART 13 good for 100 watts RF, no doubt handles mufch more due to being urv denated for the mili- tary . . 1 #71-17 3/2.00 ■ -»' ' " k I 7400 SERIES IC GRAB BAG Mix of 7400 series DIP, unmarked untested. Some schematics provided 10 for 1,00 100 for 8.00 1000 for 60.00 I BATTERY ELIMINATOR- CHARGER Plugs into 115 volt 60 cycle and puts out approx. 12 volts DC 100 mils. Sufficient to power most any small transistor radio and also useful for charging small dry cells and small ni-cad cells, Fully built, ready to use. SI 00 each, 6 for $5.00 GIANT LED83«I Price break at last on these giant LED with 1,000,000 hours of life. Measure full 1/4 by 1/4 inch. First time offered. RED S1.00 GREEN 1.25 SUPER BRIGHT coJiimated RED with para- bolic reflector, measures 3/16 diameter. A real hi-intensrty red visible over 100 ft, SUPER RED $1.25 Postage extra on above. WIESHNA PO Bx 62 E. Lynn Mass. 01904 OCTOBER 1973 $ COMPUTER KEYBOARDS MANV NEW 50 postpaid Just arrived, a superb batch of brand new keyboards still in original manufacturers cartons. Beautifully finished in pastel colors with contrasting colored keytops. Made for table operation with fully enclosed metal cabinet. Two encoder boards mounted inside the cabinet with connections terminat- ing on Spectra flat cable with plug. Key operation with bounceless magnet reed switch action. These computer keyboards were dumped as surplus by one of America's largest electronic companies and we were lucky enough to be on the receiving end. The price of $50 includes prepaid insured shipment in the US and shipment same day as order received. Orders out of the US require an extra $2.00. LOGIC POWER SUPPLY 10 $ With 400 of these power supplies on hand, we figure we'd better sell them cheap and get them off the floor or all will collapse with a great crashing roar and land in a heap in the cellar. These are from computer power supplies, used, good condition. Operate from standard house current. 4 output voltages .... MINUS 30 Vdc at 1 Amp, PLUS30Vdcat 1 / 2 Amp, PLUS 10 Vdc at 1 Amp, MINUS 10 Vdc at 1 / 2 Amp. Solid state construction with harmonic regulation on the transformer and transistor regulation on the 10 volt outputs. This is one helluva bargain and worth buying just to scrap for parts (if you're crazy enough to tear it apart). You've got 2 transistorized zener regulated plug-in boards with sockets and by changing the zener you can regulate from zero to 25 volts, 2 husky filter caps (18,000 (if at 35 volts), power transistors on heat sinks, a nice transformer, and misc. other parts. Ship. wgt. 37 lbs (you pay shipping) $10.00 each or 3/$25.00 Postage extra on above. MESHNA P0 Bx 62 E. Lynn Mass. 01904 92 73 MAGAZINE PAY TV ASSEMBLY $15.00 A "Super Value" for the gadgeteer. A complete Pay TV installation made for ZENITH and all in original packing (3 cartons — wgt 36 lbs) and all unused. Operates on regular 115 volt 60 cycle power. A wealth of parts, easily removed due to long leads on components, most over one inch long. The 3 units consist of Translator, Adapter, Decoder. Transistors, tubes, solid state bridge power supply, geared clock motor, 35mm geared transport, time recorder, solenoid, relays, hundreds of small parts such as resistors, caps, etc. Our estimate as to cost to Zenith, approx $1,000 per set. Schematics with each purchase. One set of 3 units $15.00 wgt of 36 lbs. Special . , . 3 sets S35 wgt of 106 lbs. All unused, original boxed. COOLING FAN L BARRAGE $12.00 For the photo enthusiast, electronic industry, people cooler; etc. Brand new assembly made by HOWARD Industries, 3 fans per panel, 1 15 volt 60 cycle. Each fan good for 100 cfm and have blade guards both sides of each fan. To reverse flow of air, mount panel backwards. All brand new, ready to use. Silver gray panel finish. Standard 19 inch panel, 5 1/4 inches high. Si 2 per panel of 3 fans or 2 panels of 6 fans for only S20. Ship wgt 7 lbs per panel. AM-FM STEREO RADIO $18.00 AS IS THESE ARE FACTORY REJECTS TAKEN OFF THE LINE FOR REWORKING BUT THEN THE FACTORY CLOSED. We have UNUSED Solid State AM-FM radios with built in AC supply, extra outlets for tape, mike, or turntable. We furnish the schematic. These units made for console installation. Each with minor defects but we can furnish most any part found defective. Postage extra on above MESHNA P0 Bx 62 E. Lynn Mass. 01904 yffesfm^ OCTOBER 1973 Semiconductor Supermart • MOTOROLA • RCA • FAIRCHILD • NATIONAL • HEP • PLESSEY POPULAR IC*s MC1550 Motorola RF amp SI. 80 CA302O RCA Y, W audio $3.07 CA3020A RCA 1 audio S3.92 CA3028A RCA RF amp $1.77 UAJUU1 nUA, ■*■•••«**.*■ IjiO.OO MC1306P Motorola f /? W audio $1,10 MC1350P High gain RF amp/1 F amp _$1.15 MC1357P FM IF amp Quadrature del . $2.25 MC1496 Hard to find Bai. Mod. ..... $3.25 MFC9020 Motorola 2 -Watt audio . $2.50 MFC4010 Multi-purpose wide band amp $1.25 MFC8040 Low noise preamp ..«....« $1.50 MC1303P Dual Stereo preamp $2.75 MC1304P FM multiplexer stereo demod$4.95 FETs MPF102 JFET , ., $.60 MPF105/2N5459 JFET $.96 MPF107/2N5486 JFET VHF/UHF. . $1.26 MPF121 Lowcost dual gate VHF RF , . $.85 MFE3007 Dual-gate $1.98 40673 Dual-gate .- . $1.75 3N140 Dual-gate $1.95 3N141 Dual-gate . . . , , , $1.85 NEW FAIRCHILD ECL HIGH SPEED DIGITAL IC'S 9258 Dual J D" FF toggles beyond 160 MHZ ....._... . . . . . $4.65 9582 Mufti-function gate & amplifier . . . $3.15 95H30 300 MHz decade counter ..... $16,00 A 95 H 90 & 9582 makes an excellent prescaler to extend tow frequency counters to VHF — or use two 9528s for a 1 60 MHz prescaler* SIGNETiCS PHASE LOCK LOOP NE561B Phase Lock Loop «$4,75 IME562B Phase Lock Loop >.«.,♦,*..♦. $4.75 N5111A FM/IF Demodulator $1.50 NE566V Function Generator .$4.75 NE567V Tone Decoder . , , .$4.75 TTL BARGAINS 7400 . . . . . $.28 7404 * * * $.30 r " 1 *J ■ i • ■ • • ■ ■ • ■ - ■ • ■ <■*■■ ■■• . •* i» ■-••■■*P.vU f*Tj£.\J . »>•■•.•** + « »•**•»«■ ► ■ « . - .,.■». *J),0 U 7446/7447 - $1.50 f*4-/0 »*«•*« ....... **■.**« ''■'■''■'■ V I .UU 7490 $1.00 74192 $2.00 NATIONAL CLOCK CHIP $12.50 Set of circuit boards to build a digital clock $5.00 CORES AND BEADS KW Balun kit only . T68 2 3 cores . T50-2 3 cores . T50-6 3 cores , T50-10 3 cores T 44-10 Scores . , i . • # » . ■ . . $2.00 . . $3.50 $1.00 .$1.00 .$1.00 $1.00 .$1.00 BEAD SPECIAL Ferrite Beads 1 doz. $1.00 INTRODUCING \p^DEVICES NEW LOW PRICES LA301 8 {Replaces CA3018 $1.60 L A3046 ( Replaces CA3046) 1 .60 LS370 (Replaces LM370) 4.00 LS1 496 (Improved MC1496) 2.00 LS3028A (Replaces CA3028) 1 .60 LP1000 (A new fun-type device to make LED flashers, audio osc, timer etc.) 1 ,60 LP2000 Microtransmitter 16.00 THINKING R-4C DRAKE TR-4C T-4XC Check us out TR-22 1 NOW OPEN FOR LOCAL SHOPPING STOP BY AND CHEW THE RAG 1110 N. Scottsdale Road Hayden Plaza East Please add 35tf for shipping Circuit Specialists Box 3047, Scottsdale, AZ 85257 FACTORY AUTHORIZED DISTRIBUTOR FOR Motorola HEP - Circuit-Stick - Plessey All devices are first quality and are fully guaranteed. 94 73 MAGAZINE GAM has what your repeater needs 8.2 dB GAIN OVER ISOTROPIC Vertical Radiation Pattern TG5-S — — — Dipole • **• Isotropic Horizontal Radiation Pattern — TG5-S ———Dipole -•••Isotropic (ON FILE WITH FCC) MODEL TG5-S LIST PRICE $104 50 Weight 3*4 lbs- Offset Side Mount Radiation Pattern Reference: Dipole Electronics 191 VARNEY STREET MANCHESTER NH 03102 TEL. (603) 627 1010 OCTOBER 1973 $70 BOX 2673, OAKLAND AIRPORT, CA 94614 555 Timers $1.10 ea Rfifi Rm 7 QR pa LED 7 seg. readout, .3 char size sim to MAN I 2.95/10 @2.50 Power Supply, 5V 2.5 A & 28 V 1 A RO Type 602-28B 19.50 BRAND NEW Flat Packs in carriers T! 7300/7400. Excellent assortment includes gates, flipflops 14.50 per 100. Digital Flat Packs U-Test-M Factory refect 4.95 per 100 Small Memory Core Planes 3 types for experimental use . . .10.00 for 3 Small ROTRON SPRITE (muffin) fan 30 CFM 5.95 Red LEDs, excellent assortment 2.95 for 12 Zener Diodes U-Test-M assorted 2.95 for 100 1000 Assorted Resistors, Capacitors, Diodes including over 100 TTL DTL & Linear ICs on PC boards 10.00 5V Digital Logic Supply Parts Kit with schematic easy to hook up! Includes line filter, transformer rectifiers filter & bypass caps 3 terminal regulator 5.50 12V 8A REGULATED power supply parts kit. Ideal for powering FM rigs. Everything except the chassis 12.95 ICs, most TTL & LINEAR in stock - Send Stamp for FREE Catalog CMOS 74C00 74C02 74C04 74C10 74C20 74C73 74C74 74C76 74C107 74C151 74C160 74C161 74C162 74C163 74C195 DIGITAL .70 .70 .95 .70 .70 1.65 1.50 1.65 1.65 3.00 3.25 3.25 3.25 3.25 3.50 CD4001 CD4002 CD4009 CD4010 CD4011 CD4012 CD4013 CD4016 CD4019 CD4023 CD4025 CD4035 .70 .70 1.00 1.00 .70 .70 1.50 1.50 1.40 .70 .70 3.00 LINEAR LM370 LM371 LM372 LM374 LM380 741T CA 3028 CA3065 CA 3086 1.25 1.25 Replaces HEP 590 1.25 2.00 1.75 .45 .75 .75 .45 Buy 10 ICs - 10% discount Buy 100 ICs - 20% discount All ICs tested and guaranteed LINEAR VOLTAGE REGS LM 309K 5V 1 A REG 2.00 LM 320K NEG Reg available in 5V 12V & 15V 2.25 LM 340K POS Reg available in 6V 12V & 15V 2.25 LM 723 Adjustable precision reg 1 .00 TRANSISTOR GRAB BAG mixed NPN PNP 1 00 for 2.95 ALL ITEMS IN STOCK and will be shipped within 24 hours of receipt of order! Include 504 postage and handling on orders under $10.00, all others postpaid. Sorry, NO C. O.D. 's. CA LIFORNIA RESIDENTS ADD 6% sales tax. 96 73 MAGAZINE V 4 -$ FM27B $479.00 £ i 1 I * * 'Jh. ' ■I ~ ^ ''. " ■ 1 _ | Att>B 1 f X j W( ■' *-jj^g Wfe sfoc/r Hy-Gain, Antenna Specialists, Hustler, -* CushCraft and Shakespeare. 4// 2 meter xtals in stock . . . Bo mar 3.95 L r* :jirv.J ' ■■<*' -iff '* FM-21 220 MC $299.00 ^*^ &> *? We also stock VHF and UHF amplifiers TPL, Dy-Comm, Standard ,: £ £$ with each Regency rig you purchase. . . you receive 4 FREE CRYSTALS of your choice! ^o" * 7 t HR 2B NEW 1 2 ch xmt-rcv 1 5W min $229.00 HR-220 NEW 1 2 ch 20W 220 MC $239.00 [i % $ AR-2 80W 2 meter amp. $100.00 EC 175 175 MC counter $400.00 HR-6 6 meter 25W $239.00 HR-212 1 2 ch 20 watt $259.00 s. FN *.■ >*1 Standard Communications 146A 2 meter walkie $289.00 SR815TH 25W 1 2 ch $589.00 ' *V*i£ sr*: at |SB SB 450 12 ch 10W 450 MC $399.00 SB-144 12ch 10 W $259.00 9 ^ * ^J 826MA SCARPT-1A 12 ch 10 watts 2 meter RPT $398.00 $690.00 SRC14 24 ch 10 watt base unit $598.00 SEND FOR OUR CATALOG WITH SPECIAL PRICES ► ■TV to la i ■ i U 491 Riverside, Medford, Mass. 02155 (617-396-5550) OCTOB£R 1973 97 ?& E CALCULATOR kmSS*o Attractively designed! 1 ! Excellent craftsmanship Case and keyboard (designed as one unitl Cabinet is made oT high- impact plastic beige color with black bezel and amber window. Keyboard consists of a J position slide switch and 25 keys, 5 of which are used for memory function. 20 keys gray, 5 keys orange* All keys mounted on one printed circuit board.....*. 11" wide X 10. S M X 2. 9" high This nodular unit Is well suited for our calculator chips . Ideal for the CT5QQ5 Case and keyboard complete only S29.95 3 CHIP CALCULATOR This calculator set provides all of the electronics for an eight digit, floating point calculator with left hand entry*. Keyboard, display .clock generator, and display driver is all that need be added to make a calcu- that will add, subtract, multiply, and divide. Overflow and negative signals are also provided. Complete instructions to build a calculator included , . . Chips and data — — — S7«95 Data only --1,00 (refundable) ICT5005 CALCULATOR This calculator chip has a full four function memory, which is controlled by four keys, +M (adds entry into me- mory) , -M {subtract entry from memo- ry) , CM (clear memory- -without clear- ing rest of registers) t RM (read rae- ory or use as entry) , 12 digit display and calc . fixed decimal at 0,1,2,3,4, or 5 leading zero suppression seven segment multiplexed output true credit sign display single 29 pin chip Chip and data >---- $14-95 Data only {refundable) — — — 1.00 5001 CALCULATOR 40 pin calculator chip will add, sub* tract, multiply* and divide. 12 digit! display and calculate. Chain calcula- tions* True credit balance sign out- put* Automatic overflow indication. Fixed decimal point at 0, 2, 3, or 4 Leading zero suppression. Complete data supplied with chip. Chip and data, only S9.95 Data only (refundable) 51, 00 All 1C " s are new and Fully tested leads are plated with gold or solder Orders for $5 or more will be ship- ped prepaid. Add 35C for handling and postage for smaller orders, residents in California add sales tax. IC or- ders are shipped within two workdays of receipt of order-kits are shipped withen ten days of receipt of order. $10.00 minimum on C.0.D;*s (phone in) , f916) 96G21 Zip~95606 P.O. Box J Carmichael Cal i forma GUARANTEE Oti ALL GOODS. . * r keyboard General Telephone Ten push buttons (0-9 touch-tone^ encoding, programming devices* Easy for panel mount- ing. Size : 5X2WJ rciEIHQRV SALE!! 256x1 BIT Random Access Memory Fully decoded TTL Compatible fnpot and output. No clock or refresh required. INTEL 1101 MOS 16 pin DlP-full data a cc U per BIT— each *£,OD 10 for$22«56 7400 series DIP! 7400 S .35 74H53 *50 74HO0 .50 74S4 .36 7401 . 35 74L54 .50 74H01 ,50 74L5S .50 7403 ,33 74*0 .35 7404 .35 74L71 .30 74L04 ,50 7472 ,50 74H04 ,50 74L72 ,60 7405 .35 7473 .65 74H05 .50 74L7 3 ,90 74H0B .50 7474 ,65 7410 .35 74L74 .90 74L10 .50 74K74 .go 74H11 .60 7476 .70 7413 1.75 74L7A 1. 00 74 20 .35 7490 ,6S 74L20 ,50 7463 1*30 74H2Q .50 74B6 ♦ 80 74H22 •BO 7430 .35 74L30 ,50 7491 1*15 7440 -35 7492 1,15 74H40 .SO 7493 1.15 7441 1.60 7495 1.25 7442 1.30 74L95 2*00 7446 1*75 74107 *70 7447 1.75 74121 1.60 7448 1.15 74123 2,00 7450 .35 74154 2*50 74H50 .50 7451 .35 74192 2,50 74L51 .50 74193 1.50 74HS1 ■50 7419S 1 .10 7453 .35 . RECTIFIERS flil Varo Bridg H III/ VS447 2A 400V $ .90 J*** VS647 2A 35A Stud 6oov - iao 400V "* 1.10 / M&810 50V 1A .10 / 1N4997 50V 1A .10 1 1N4001 1A .10 9 1N4002 1A .11 / 1N4003 1A .12 / 1N4004 1A .13 f 1S4DQ7 1A .17 £|j£CF Vs MB IR122 100V8AKP -50 Fj IR122 /// 1R122 iJJ IR122 200V BAHP ,60 300V 8AHP .80 400V SANPl'OO LED's MV-50 red emitting lO-40ma^2V 5 for ft— MV5054^ red LED l5-l30mag2V S .30 10 for 2.50 $ .25 1*00 $ .30 MV-109 visible red 5-70ma 2V 10 for 2.50 GIANT "NIXIE" Comes complete with Socket and DD700 202 Numeric Driver. Readability 1n high am- bient light... 200 footlanrberts bright- ness! I All DC operation. Long life with no loss of brightness. Compatible with conventional solid state circuitry. Only S2*25 These were used in the New York Stock Ex- change HCfl £010 MUMJTRQN Popular digital display tube. This incandescent five volt, seven segment device provides a -6" high numeral which can be seen from a distance of 30 feet* The tube has a standard nine pin base (solderable) and a left hand decimal point.... $5.00 each 54.00 each for 5 or more til III Seven Segment #0-9 plus letters* Snaps in 14-pin DIP socket or He lex. Operates with XC voltage requirements ■ Long operating life $4.25 each MAN l* Seven segment*Q-9 plus letters* j Right hand decimal point. Snaps* in 14-pin DIP socket or Molex.^/^ IC voltage requirements* ideal ; ™" ■ for desk or pocket calculators!* < Each ...**.... s 3 * 00 Ten or more. . $25*00 red lens NAM a 0*9 plus letters. Right hand decimal point. flat-Pack type case. Long operating life. IC voltage requirements. Ideal for pocket calculators 1 1 1 1 1 c*a en ......*.«^ * . u u Ten or more.. $20. 00 red lens LINEARS HK531 op amp TO-5 $2.00 NES60 phase lock loop DIP J. 25 NE561 phase lock loop DIP 3.25 WE565 phase lock loop TO-5 3.25 SE566 function generator TO-5 4.00 KE567 tone decoder TO-5 4.00 HE5556 op amp DIP l.oo 709 popular op amp DIP .45 710 voltage comparator DIP .50 711 dual comparator DIP .40 723 precision voltage regulator DIP 1.00 747 dual 741 op asp DIP 1.00 743 op amp TQ-5 1.00 LH100 positive DC regulator TO-5 1.00 LM302 op amp voltage follower TO-5 1.25 LK1595 4 quadrant multiplier 52.00 mill comparator TO— 5 1.75 LK380 2W audio amp DIP 1.75 LN703 RF-IF amp epoxy TO-5 1.00 U4309H 5V-200ma power supply TO- 5 1*00 LM309K 5V-1A power supply module TO-3 2.00 FREQUENCY SYNTHESIZERS *-v£ YOU'LL NEVER HAVE TO BUY CRYSTALS AGAIN! * >■ MODEL rST-1 40 Price: $129.95 ppd. Tested, guaranteed and complete with mobile mounting bracket , tilt stand and transmitter matching kit. NOTE: NY State residents add sales tax, CHECK THE ADVANTAGES OF A VANGUARD SYNTHESIZER OVER OTHER BRANDS... (excluding transmitter * No microphonic*. Can be uied mobile over bumpy roads. • Reference frequency and spurious output down 70 dB harmonics of output frequency which are used in the anyvwy) * All output frequencies are generated directly from the VCO without the use of multipliers and are therefore free of sub-harmomcs. • Now available witn outputs in the 6. 8, 1? end 18 MHz bands (corresponding to 144 MM?, dial reading) for direct substitution of transmitting crystals. More output frequencies are being made available Gall us if you don't see what you need. * Entire frequency appears inline in clear digits. No guesswork or mental addition*. Thumbwheel switches provide fast, accurate selection of 1000 channels in 10 KHz. steps from 140 00 to 149 99 MHz • 50 ohm output and impedance transformer kit allows use at any distance from transmitter. Maintains an accuracy of 0005% (5 parts per mi ll ion I over the entire <ange of 10" to +60 C with a precision temperature compensated crystal that requires no oven. Operates at & MHz, for easy checking with WWV end includes a zero trimmer for correcting long term aging drift Fast response time of only 3 milliseconds for a TO KHz. step chance in frequency and a remote control, gated output amplifier for push to talk operation. No hunting or fabe locks as with some other synthesizers Operates from 10 to 15 VDC, 3 precision regulators eliminate input voltage fluctuations. Can also be used on 110 volts AC with a vnaii 12 vglt J>7 amp pernor supply. Smallest sue of any commercial synthesizer Only 1 3/B J ' high. 3-5/8" wide, 8" long. All IC'S are mounted rn high quality insulated sockets and aJI parts *re marked. Manufactured by VANGUARD LABS renowned lor qua lity s ince ! 9S?. NOTE: Our 45 MHz receive synthesizers are now in production. Call us for details. IMPORTANT: When ordering be sure to state the output frequency you want. PRE-AMPS CONVERTERS VHF FM RECEIVER VA NGUAKD HIGH GAIN • LOW NOISE 35 dB power gain, 2.5—3.0 dB N F. at 150 MHz, 2 stage, R.F. protected, dual-gate MOS- FETS. Manual gain control and provision for AGC. 4-3:8" x 1-7/8" x 1*3/8" aluminum case with BNC receptacles and power switch. Available fac- tory tuned to the frequency of your choice from 5 MHz to 350 MHz with approximately 3% bandwidth, Up to 10% B W. available on special or- der. Model 201 price: 5—200 MHz $24.95 201—350 MHz $28.95 HOW TO ORDER: AM the items o*> this pac^ are available only from Vanguard Labs, For receivers and converters, $tat£ model input arid output frequencies and band- width were applicable. Remit En full, including sales tax if vou reside in New York State, direct to Vanguard Labs, Prices include postage by regular parcel post. For air mail or specie' delivery include extra amount; excess will be refunded. Send money order or certified check for faster shipment. 40 dB GAIN 2.6-3.0 N,F. 9 160 MH* 2 RF sugei with transient protected du*)-f*te MOSFETS give thU convener the high i*in and Low notw you need fo* receiving very weak lUnal* The mixer stage ts alio a dual-gate MOSFET u it greatly reduces spurious mixing products — some by as much as lOO dB over that obtained with bipolar mixers A bipolar osc ilia tor using 3rd or 5th overtone plug-in crystals is followed by a har- monic bandpass filter, and where neces- sary an additional amplifier is used to assure the correct amount of drive to the mixer. Available in your choice of input frequencies from 5—350 MH/. and with any output you choose within this range. The usable bandwidth is appro* > 3% of the input frequency with a maximum of 4 MH*, Wider band widths are available on special order. Although any frequen- cy combination is possible (including converting up) best results are ob tamed if you choose an output frequency not more than W3 or less than 1/20 of the input frequency. Enclosed in a 4-3/8" x 3" x 1-1/4" aluminum case with BNC receptacles, power and antenna transfer switch. Thousands of our converters are now in use by satisfied customers, many of whom are government agencies and universities. Model 407 price: &— 200 MHz $49.95 201—350 MHz i .:.->.., * $54.95 Prices include 005% crystal. Additional crystals £5.95 each. 1 1 CHANNELS • 1 35-250 MHz • 11 crystal-controlled chan- nels # Available in your choice of frequencies from 135 — 250 MHz in any one segment from 1—4 MHz wide* I. F. band* width (channel selectivity) available in your choice of ±7.5 kHz or ±15 kHz. • 8-pole quartz filter and a 4-pole cera- mic filter gives more than 80 dB rejection at 2X channel bandwidth • Frequency trim* mers for each crystal # . 2 to .3 jJLvolt for 20 dB quieting • Dual- gate MOSFETS and integrat- ed circuits # Self-contained speaker and external speaker jack # Mobile mount and tilt stand # Anodized aluminum case. 6"x 7" x l-3/8'\ Model FMR-250-11 price: 135—180 MHz $119.95 181—250 MHz $129.95 Price includes one .001% crystal. Additional crystals $6.95 each* VANGUARD LABS Call 21 2 468-2720 for fast C.O.D. shipment. 136-23 JAMAICA AVE. H0LLIS, N.Y. 11423 OCTOBER 1973 For the most powerful antennas under the sun the 2 Meter Fixed Station 268 Designed for the man who demands professional standards in 2 meter equipment. REPEATER LINE fixed station antennas are the 2 meter HAM's dream come true. With everything you need for top fixed station performance... toughness, efficiency and the gain to gain access to distant repeaters with ease. Work many stations, fixed or mobile, without access to a repeater. The right antennas for the new FM transceivers... or any 2 meter fixed station. REPEATER LINE Fixed Station Antennas Tough, high efficiency antennas with a long, low radiation. For the top signal and reception you want... and the top perfor- mance your transceiver's ready to deliver. 267 231 15 element high performance beam. 17.8 db gain. Coaxial balun. Beta Match. Unidirectional. Boom length 28'. VSWR 1.5:1 52 ohm feedpoint. Extra -strength heavy wall commercial aluminum tubing. 267 Standard 1/4 wave ground plane. May be precision tuned to any discrete frequency between 108 and 450 MHz. Takes maximum legal power. Accepts PL-259. Con- structed of heavy gauge seamless aluminum tubing. 268 For repeater use. Special stacked 4 dipole configuration. 9.5 db offset gain. 6.1 db omnidirectional gain. Heavy wall commercial type construction. 144 thru 174 MHz. 1.5:1 VSWR over 15 MHz bandwidth eliminates field tuning. Extreme band- width great for repeater use. Center fed for best low angle radiation. DC ground. Complete with plated steel mounting clamps. 100 73 MAGAZINE from hygal 341 Antennas with real PUNCH! 340 3 element high perfor- mance beam. 9 db gain. Co- axial balun. Special VHF Beta Match configuration. Unidirectional pattern. VSWR 1 .5:1 . 52 ohm imped- ance. Heavy gauge alumi- num tubing and tough alumi- num rod construction. i j 349 341 8 element high perror- mance beam. 14.5 db gain. Coaxial balun. VHF Beta Match. Unidirectional. Boom length 14'. VSWR 1.5:1. 52 ohm feedpoint. Heavy gauge commercial type aluminum construction. 338 Colinear ground plane. 3.4 db gain omnidirectionally. Vertically polarized. 52 ohm match. Radiator of seamless aluminum tubing; radials of solid alumi- num rod. VSWR less than 1.5:1. All steel parts iridite treated. Accepts PL-259. 362 SJ2S4 high performance all-driven stacked array. 4 vertically polarized di- poles. 6.2 omnidirectional gain. 52 ohm. May be mounted on mast or roof saddle. Unique phasing and matching harness for perfect parallel phase relationship. Center fed. Broad band response. DC ground. WRITE FOR DETAILS For top fixed station performance on 2 meters THE REPEATER LINE From HY-GAIN ELECTRONICS CORPORATION 362 338 Dept. CK, 8601 Northeast Highway Six 402/434-91 51 Lincoln, NE 68507 Telex 48-6424 OCTOBER 1973 101 S & R Enterprises 1344 E. Indian School Rd.-Phoenix, AZ 85014 (602) 277-2712 This Month's Specials ^&rt^ MJE 340 MJE3Q55 MJE1093 MJEUOO 3U4913 2N4910 2N4912 2N4399 2N377I 2N4B01 2N37H 2N3055 3N1545 2N3238 2N1358A 2N«05 2SB473 Motorola RF Transistors Sale (Unmarked) QlT Type 2673 2N3866 3/1. 90 384 2N5589 3/6,00 12$ 2N559Q 3/9- 50 48 2N5591 3/20. 00 227 2N6Q80 3/6,00 2S0 2N60S1 3/9. SO 174 2M8082 3/16.00 174 2N8083 3/24. 00 260 2N6084 3/40. 00 50 2N6166 3/50. 00 Please do not mix ! ^ — ^ . Motorola RF Transistors Stole (Marked) Qty Type 3 2N1692 3 2NL693 1 2N2857 2 2N28S7 9 2N2947 419 2N3925 13 2N39S0 1963 2N4072 2 2N4Q73 1361 2N5I09 1 2N5I77 1754 2NS179 I 2N5583 33 2N5590 16 2N5643 4 2 N 58 49 MM 1622 U 2N5862 U 2N5942 42 2N5591 30 2N6Q64 330 MMieaa/ 2N6084 U 2N6097 IS. 00 1 2N6135 5.00 40 2N6166 30, 00 2 2N6266 40, 00 % MM1500 2.00 990 MM1607/ 2.00 2N5842 3 MM1620 1 MM1661 23 MM1669 1000 MM8006 1 MRF207 4 MRF209 17 MRF304 30 2S6081 24 2N60S2 25 2N6083 Motorola ICs, RTL, DTL, ECL, Some in limited quantity. in 816 827 830 832 833 836 637 839 844 845 846 848 849 851 853 855 862 880 889 930 944 945 946 BID K)14 HU5 1020 1023 1096 1125 1213 1223 1302 1511 1802 1806 1610 1811 2363 3002 3081 4000 4006 6160 8603 9709 9718 9719 9720 14010 LOO LOO 2.00 2.00 3.00 3.00 3,00 3.00 2.00 3.00 2-00 3,00 2.00 7.00 2.00 2.00 LOO 2,00 LOO 4.00 4.00 6.00 4.00 L00 2.00 2.00 LOO L50 2.00 5,00 3.00 2,00 LOO 8.00 .50 -50 .50 .50 5.00 LOO 3.00 2.00 2.00 W.00 3.00 LOO LOO LOO LOO 2.00 linear ICs 723 Power Transistors FETs LOO 2N3O70 LOO 2N3438 L 00 2N3821 2.00 2N4343 LOO 2N4391 . 85 2N4352 LOO 2N4166 LOO 2N5460 LOO 2NS465 LOO 2N5556 LOO 3N140 L 25 3N141 LOO MFE10000 2.00 MFE2O01 2.00 MPF102 L25 MPF120 L25 SCRs 2N4443 2N5061 T140A2 a> « p* « t* *2 ^ ^ in iA u> tr> Q u> H q Oi f- in ij Uj aj -* . . . . *™ , ! —* pa ■«• « cq -J v — i ui to r- c o o o r- fv to OT W to o+ n &, a, a* Pi U r; (^ [ti cj [xj X X S K X X ICC- 2 ICC-3 ICC- 50 1CC-5I 1CC-52 ICC-53 ICC-54 ICC-55 ICC- 56 jCC-57 ICC- 134 ICC- 151 ICC-154 ICC- 156 ICC-157 ICC- 158 ICC-162 ICC- 170 SI SI 51 SI SI RF RF RF V s$ & SI 81 SI 31 SI GE RF Transistor - PNP-7GG MK2-300 MW GE RF Transistor - PNP- 250 MHz-300 MW SI RF Transistor - NPN-250 MHz -400 MW Transistor - PNP-150 MHz-GOO MW Transistor - PNP-300 MHz-40G MW Transistor - NPN-200 MHz- 60 MW RF Transistor - NPN-30 MHz-310 MW RF Transistor - NPN-3O0 MHz- 310 MW SI UHF Oscillator - NPN-750 MHa-3iO MW SI RF Transistor - PNF-200 MHz-310 MW GE Diode (1N34A, 1N60, LN541, IN295, IN64) Substitute SI Power Rectifier-Stud- 50 PIV-15 Amps SI Rectifier- Axial Lead-50 PIV-1 Amp Rectifier- Axial Lead-200 PIV-1 Amp Rectifier- Axial Lead- 400 PIV-l Amp Rectifier- Axial Lead -600 PIV-1 Amp Rectifier- Axial Lead- 300 PIV-3 Amps Rectifier- Axial Uad-XXH) PIV-2. 5 Amps ICC t30 GE Power Transistor-PNP-to-3-5 Amps - 90 Watts 1CC-231 GE Power Transistor- PNP -to -3 6- 15 Amps - 150 Watts 1CC-292 GE Power TransLstor-PNP-to-3-7 Amps - 90 Watts ICC-238 GE General Purpose PWR Transistor - PNP-60V-3 A. ICC- 240 SI Power Transistor - NPN-300V-50O MA - 10 Watts ICC- 241 SI High Power Transistor - NPN-160 V 5 Amps-40 W, ICC- 242 SI Med, Power Translator- PNP-60V-3 Amps-6 Watts ICC- 243 SI Med. Power Transistor- NPN-80V-3 Amps-6 Watts ICC-245 SI Med. Power Transistor- NPN-60V-3 Amps-30 Watts ICC- 246 SI Med. Power Transistor- PNP-60V-3 Amps-30 Watts ICC-250 GE General Purpose Transistor -PNP- Med. Gain-200 MW ICC-251 GE General Purpose T ran Blstor- PHP- Med. Gain-200MW ICC-253 GE General Purpose Transistor- PNP -Med Galn-225MW ICC-254 GE General Purpose Transistor -PNP- Med Galn-225MW ICC-310 SI Unijunction Transistor - 300 MW ICC-631 GE General Purpose Audio Amplifier - PNP ICC-632 GE General Purpose Audio Amplifier - PNP ICC-633 GE General Purpose Audio Amplifier - PNP ICC-637 GE General Purpose RF-PNP GE General Purpose Drift- Held - PNP GE General Purpose Drift Field - PNP GE General Purpose Drift Flekt - PNP GE General Purpose RF and Audio Amplifier - NPN SI General Purpose Audio Power Amplifier - NPN General Purpose Audio Power Amplifier - NPN General Purpose Audio l\»wer Amplifier - NPN UHF Oscillator, Mixer, RF Amplifier - NPN Low Frequency Oscillator, mixer, RF Amplifier - NPN Hi Voltage Audio Amplifier - NPN General Purpose Low Frequency HP and Audio Amp - PNP SI General Purpose Med. Current Amplifier and Switch- PNP SI VHF/tJHF Oscillator, Mixer, RF Amplifier - NPN SI General Purpose Audio AmpUHer - NPN ICC-724 SI General Purpose Audio Amplifier - NPN ICC-7 SI General Purpose Audio Amplifier - NPN SI General Purpose Audio Amplifier - NPN SI General Purpose Audio AmpllJler - NPN Field Effect Transistor Audio - N Channel Field Effect Transistor - RF-N Channel ICC-639 1CC-640 ICC-641 ICC- 703 ICC-704 ICC- 706 1CC-T09 ICC-7I2 ICC-714 ICC-715 ICC-716 ICC-71B ICC-721 ICC-729 ICC- 736 ICC-801 ICC- 80 2 51 SI SI SI St 28A8S6B/ 81 General Purpose Power Amplifier- PNP 90V 7A 90W Microwave RF Transistors Communications Corp* i P/N Wattage Frequency Dl-28 1 D10-28 10 El-28 1 L38 1.68 L40 L42 L35 L20 L90 L30 2.40 L40 .45 L68 .55 .55 .58 .55 L67 • 4b 1.20 2. 55 2.15 4.90 2.35 2,15 L75 2.10 2.10 2.55 L10 L28 L65 L85 1.8$ L10 2. JO LU L40 L85 L65 L65 L55 2.15 3.90 4.00 L9S 4.00 2.95 1.20 L30 2.00 L65 140 L35 1.40 L42 2,15 L85 6.10 400-1200 MHz 400-1200 MHz 1-2 GHz Microwave Semiconductors Corp. M5C200I I 2 GHz MSC3001 1 3 GHz MSC4001 1 4 GHz MSC4003 2. 5 4 GHz Voltage 38V 28V 28V 28V 2SV 23V 28V Seven Segment Display Price DI^TOT Utronix COO 1.75 MOR1DA Motorola 3.00 19,00 MAN 1 Mansanto 3.00 30.00 Bird Slugs Fbr 43 Qtf. 35.00 4 ' 2, 5W 105-120MC 20,00 ea 60.00 1 25W 50-L25MC 20.00 ea 87.50 3 25W 200- 500MC 23.00 ea 125.00 I 25O0W 2-30MC 25.00 ea Microwave Diodes Varian VAS21 VAS31 VABB00 VAB801 VA8812 Motorola MV1S05C MVlfiOS Motorola Bridges Step Recovery Step Recovery Standard Bimode Standard Bimode Standard Bimode Power Varactor Power Varactor MV1862D Microwave Tuning MV1B63B Microwave Tuning MV1B64B Microwave Tuning MV1868D Microwave Tuning 15.00 15.00 15.00 15.00 15,00 10.00 10,00 3.00 3.00 3.00 3.00 MMM3r4 MDAl 591-5 MDA962-1 MDAS60-3 MDAB20-4 300V 400V 50 V 200 V 200 V 10 Amps 8 Amps 10 Amps 2,9 Amps 1 Amp Diodes 1. 5A K100PIV L 5A 800PIV IN 9 14 1N4148 1NU&0 IN270 3000 firv 750MA A W/L50 10 A 00 10/LOO PHce 3,60 3.75 2.45 2.25 L40 Kss 4 iJ &, 0, b CO TTL ICs 7400 Series 7400, 7410 t 7430, 7440, 7450, 7453, 7460 .25 7474, 74HOO, 74H04, 74H10, 74H30, 74H40, 74H53 7483, 7495 t 7496 10/L00 gg§SS 10/L00 SS222 10/L00 LOO 2XSX W 45 55 & MC1355P .75 MC1SI9C LOO 102 73 MAGAZINE Check these bargains and compare our deal with others... DRESS UP YOUR RIG and keep the XYL happy with these modern control heads. These are made by RCA but will work with any rig if you do a little soldering. Contains a DPST switch, and two 20K pots for volume and squelch, all on concentric shafts, and an Amphenol mike connector. The multiple frequency version contains the above plus a four position, two pole rotary switch, and lots of room left inside for extra boards for scanners and toneburst generators. / ^ \ Single frequency control head only. $4.00 postpaid Multiple frequency control head only $5.50 postpaid ^m^ ADD MORE TALK POWER with these like new handsets and mikes. Both have a transistor preamp built in and come with coil cord and Amphenol connector. landsets in very ood condition ..$6.00 postpaid Handset hangers with built-in multiple pole switch, only $1 .50 postpaid Mikes only $4.50 postpaid TERMS: All items sold as is. Illinois residents add 5% sales tax. Send your check or money order today to DuPage FM Inc. P.O. Box 1 Lombard, III, 60148 If you have any questions or are looking for something special give us a call. Just ask for Bill Lester. Our easy to remember (for us) Telephone is 312-627-3540. SPECIAL NOTE TO CATALOG HUNTERS and those who like having price data handy for future needs: LOOKING FOR A UNIT? No matter what your needs are send us a postcard with your name, address, phone number, and a description of the unit you need — We'll do the rest — m VID TAP RECORDER ;;:. *$ < BELL & HOWELL MODEL 2965 This is a portable system and comes with recorder, camera and charger, A TV monitor is built into the recorder. Camera includes built-in Microphone and Zoom lens. Recording time is 20 minutes on 5" tape. Recording is both video and audio. SPECIFICATIONS RECORDER AGC Aud*o& Video RESOLUTION 535 l-nc*. HOP" RESOLUTION; 3001-nei AUDfO RESPONSE 80-10.000 Hz. POWER REQUIREMENTS 12V DC, 10 watts BATTERIES ? 3G * 3 U Rechvge^fe I net vWranreed) CHARGER MooV( 105905 -Built-in 2:1 EIA Sync grn#rat*r CAMERA: RESOLUTION 5?5 line* VERT fREQ ©OHilEIA* HOR FREQ 15,750 Hz 1EIA1 VIDEO OUTPUT 1 p -p., 75 ohm. unbalanced WIN! ILLUMINATION: 30 Ui*. VIEWFINDER l\" M"CRT wfrnarjrufor) LENS 5:1 zoomF2-72 SHIPPING WT 3Btb LIST: $1595 0(7/? Pfl/CE (NEW) $550-00 BELL & HOWELL Model 2966 - SHIBADEN SU700VC (Assemble, Edit and Stop Motion) This video recorder will record directly from a standard TV set or a TV camera. It will play back over your home TV set Audio may be dubbed onto the tape, A 7" reel (2400') will record 1 hr. No home VTR unit under $1000 can match the quality and capabilities of this unit. SPECIFICATIONS RESOLUTION 525 Unci. Standard TV or CCTV tKonJing VIDEO- Input uttd output I OV p-p, 75 onrm, unbalanced GrealL'i than 3,5 MHz ffeoj, response 300 linti plut Hot. resolution. AUDIO Mi lit- ot Sine inputs. 60-10,000 Hz freq, rangr POWER REQUIREMENTS 1 10V AC. 95 wafti DfMENSEONS; ia3/8"Wx 10 3/16" H * 15 11/16" D AGC or Mimupl Audio & Video gain POWER REQUIREMENTS 11 DV AC, 95 walls WEIGHT 65 lbs. MAI NTAI NANCE MANUAL $5.00 LIST PRICE (1972) $995.00 OUR PRICE (NEW) $450.00 (USED) $250.00 Experimenter's Special $125.00 104 73 MAGAZINE Please rush ORDER BLANK Bell & Howell model/s 2966 Bell & Howell model/s 2965 Rolls, Video Tape, Batteries ,Color Adapters Price to: Name Shipping Total State ZIP RECHARGEABLE BATTERIES - New, for Porta Pak I $36. 00 a set. COLOR ADAPTERS — limited number available, will work in almost any Black and White VTR to convert to color, record-playback $275.00 ea. prepaid. NEW NAME BRAND VIDEO TAPES - 2400 ft. (1 hr.) any quantity available, shipping wt. 2 lbs. $25.00 each. CONDITIONS OF SALE: NEW EQUIPMENT — sold new, but as Is. Guaranteed to be new and in good working order. Replaced or repaired by us if found defective upon arrival. USED EQUIPMENT — sold as Is in good working order. NO warranty. All units checked prior to shipment. EXPERIMENTER'S DELIGHT - used as is repairable. Physically intact not beat to hell, but requiring some work. Problems and probable causes listed with each machine. PARTS — available at near giveaway prices, through us. SERVICE — units can be serviced by any competent video technician, as well as through Bell & Howell AV Service and Shibaden in Melrose Park, Illinois. QUANTITY DISCOUNT — on orders of more than 10 machines. DEALER INQUIRIES — are invited for sale of new equipment. New machines have standard Japan EIA 8P connector to mate with alt popular VTR monitors. Used machines have all coax and cannon xl connectors as shown in the ad sheet. Used machines do not have AGC or edit ability but are otherwise identical and interchangeable. All sales are final. Cash with order. Shipped best way. Add $20.00 per VTR and $1 2.00 per Porta Pak for shipping — excess refunded. COMMUNICATIONS UNLIMITED 9519 MAIN STREET P.O. BOX 463 WHITMORE LAKE, MICHIGAN 48189 (313) 449-4367 *v&° ic©' V ij^e a»* <a &\o OCTOBER 1973 105 NEW and SURPLUS ELECTRONICS FOR THE HAM and EXPERIMENTER SI£E: 3.55" X 6,20" X 2.12" 5 VDC 3/*a AMP POWER SUPPLY KIT 12,35 USES THE LATEST STATE-OF-THE-ART THREE TERMINAL REGULATOR CIRCUITRY. HAS INTERNAL CURRENT LIMIT, THERMAL SHLTTD OWN , AND - SAFE -AREA COMPENSATION. $ iq95 WAHL Greatest advance in soldering since electricity . . . COMPLETELY PORTABLE HEATS IK 5 SECONDS SOLDERS UP TO 150 JOINTS OH MORE PER CHARGE RECHARGES AUTOMATICALLY IN tTS OWN STAND NO AC LEAKAGE OH INDUCED CURRENT TO DAMAGE DELICATE ELECTRONIC COMPONENTS. COMPLETE WITH RECHARGING ST AMD r TINE TIF AND INSTRUCTION BOOKLET ALPHA -NUMERIC KEYBOARD SSOSS MICRO SWITCH MODEL 5W-10639 contains 61 #JSWU Solid-State switches including key tops, ROM encoded Into EBCDIC. MODEL RW-Q1I35 contains 56 #7A1MS Reed switches including key tops, diode encoded into EBCDIC, DIP CUP 11 \C TEST CLIP 1 V FE POMONA ELECTRONICS MODEL 3916 FOR 14 OR IS DUAL-IN-LINE PACKAGES The ''Dip Clip" sn specially dtsixnad ia hJIow 14ii attachment at iesl probes to 14 or 16 lead CHPS. The- unique dei»gn srtmH^ re- duces the po-sfirbslity af accidents aho-rtine while teilirig hw& clrv CuiLi, Nimirirous t«! pfuUcS may tic quickly connected fur hand* rr<m1r-?tin K MOS DIGITAL CLOCK CHIP CKE POWER STRIPS WTTH: FUSE, SWITCH, AND LAMP Four digit electronic clock LSI circuit In 40 pin DIP. Designed lor direct output to liquid Crystal Display. Internal options include: Alarm, Snooze, Seconds Display, Reset t and 24 hour operation. $g3D KJJ5EL ]l Other Models Available •Mmii if N B alpha-numeric display bezels Ev ! ' A L ■ 1 C . ■ 1 . |i Oft! L UNO B DIKEN5IG* [ PRICE HOD&I *A ■ *B* ■c ■D* 1-24 25-99 100- UP 90^-3 a $ J UJ7 \LV< '? 1.74. (2.2? 2.07 1.91 9 1 0-3 Ut & 3 2.00 U*l f 2 2*37 2.30 2.12 t*95 915-3 ex M 3 3.00 1.1; '2 3.37 2.40 2.2 1 2.04 920-3 ur. ,& 3 £t,0Q 1 .1' '2 it, 37 2.45 Z.25 2,06 930-3 oc 1.3J 3 5-00 1*7; tt 5-37 2.75 2.53 2-33 940-3 tx .a 3 5,53 i-.iti r£ 5,9? 2.65 2.43 2.25 950-3 tx i.3 3 6.50 1,7! ?0 6.B7 3. t5 2, B9 2.67 mm BGJXS Deluxe Electronic Equipment Enclosures WHEN ORDERING REPLACE XX WITH FILTER COLOR G0©H: HEUTRAL * 1 5, REE * 60i AMBER * 70, GREEN = 90 sxamplflj 9^0*60 {Hodel 9J0 with RED FiltaiO UIMCNS1DNS 6cf**n fttSAlE MOaEL W N. DEPTH Vanwd N£T "A" 65* * t l A * 3 h& 3-7B ■ r £" B"Jf, * 3^ * 3£ rto 4.9$ ■f 7% k 3*; * 5 yfrfl 6.96 "[}■' B K IW * 6 Imgblli mlg j^ll I yea »,7B "1" a^ 1 z% * 7J& fM B.l* "F" 7 ! > > 4'i i 10 10k,. * a\ * 8 r« 8^9 "(j- m 8-95 ,r H -. AH x SW* 4 no a,9i "D1 " Mrq. bracket aei 1or "□" .35 "HI" "H" Panel with maunlfld Wide Vu 1 mi &C * 2 Rocker nrfctof b malar, 3Ji" fH.95 "HA" 5 1/8x5 1/2 x 4 [fliar*k Pjittl] 6.95 "y. 5n] 1/3 x 5 3/4 I Sloping Parcel} 7.45 "K" 4 3/4 * 7 3/B * t L W/Handle IJ.50 "l_" 11 1/fl H6 1/B x LP 3/4 SO-^fl ,l M" 11 i^a « <5 i/Bx t&a/vi 21.Ji<iJ OTHER DISTRIBUTOR LINES^ K 5 S E J\r y^-i - ■■■r 1 lr pi-^t-i J.W.MILLER Co, pfD)ectS WAHL unlimited HUNTER TOOLS 1 i'liiiiiiii d> ritnhil l^iiaii'Pi i^IAICq \ BUD RADIO, INC. .°>*ih ::i :» WJisn 'AfiHNLH MCflOClfllMS iir»«iuiN iiEUidflT uiftflnEfl coflPOBflnon KA ELECTRONIC SALES 131£ SLOCUM STR&eT DALLAS, TEXAS 752Q7 iSl-ai 747-333D 7d7-1BB2 WRITE FOR FREE CATALOG. VISIT OUR STORE SATURDAY FROM 10AM to 4 PM. LOCATED OFF STEM- M0NS FREEWAY NEAR OAKLAWN. 106 73 MAGAZINE Buy Af«y 3— Take 10*7* lUfltl ^1 -5 jNTEGRATEDl CIRCUIT SOCKETS * □ 14-Pi"> DIP r=i iji Pin. Wirt 14-Pin 3 14*P»« 15-Plh Wrap S.4S .59 Side DIP □ 16P1», Wjr*^ Mount 1 OO . .so .29 Wrap ,□ TO-S" » orlOj^i *HAM' UHF 400MC HIGH POWER TRANSISTORS By RCA or equal 2N3632. NPN. 2li watts. ft am; TO-tiO ease, with Mud mtR. \TEV max *■-"». $1.49 *^ HIGH POWER TRANSISTOR 3 for 53 WITH HEAT SINK Removed fn«m nevi i«jn:i»- mi-ril! Inrhnlr^ pitptllar jN t 7 1 'rfrHjrkntth 1 Tim TU '. , / ' t mjin j 1 1 in t i'MV I fiO \v;iii^, VCtHI MtV, I "i Amp**, til hfi j . Knr i Kta » 1 1 • »J1 « InisJi powei 1 ft«\ r M'ilLlHt + *f "tl .» ^nik "i \ 2 l I 1 -AEROSPACE" BABCOCK & LEACH CRYSTAL CAN RELAYS 12 for $3.50 iJcrYM -v.V i i **- All hi j rmi»T jrnlly . ;tU-iL Khihmim, l/i>. half. iitnl fulJ cr>%stJiJ ran type* in <*-12-^4V in jLKst contact* up to ll'IH". 1 .imp up 1 1) ,il!|[lN. Siiih t>|H ,L Hit Hi. J I . 10, II, 10, Li I. t§U\ Surry, n't HiofiHing VfjRnjreri ur type*, huni factory mix- ture* *.*<*' yi*u! (Irifjci usst, if > o .<ri' i' - minded, ill U»w jirues. Gl "GLASS AMP II" SPACE AGE FEATURE j&Seela critical JAN upecti, A ft 1 4191 'bait "t sili i it fl sirengili" tliat metrtJi JAN s\>- hmli reJmhilHy, wtili- si.iiHi- KValancf pttwer >Lirgl*N t*i IK WIlltlL, ON'fS ;irnp raliims Willi 2 iimp rafuslnJille Axial lead T M .r PTV Sal** 1N4245 200 £.14 1N4246 400 2 2 1N4247 600 .39 IN4248 SOO .49 1N4249 1000 59 ^siucofTrijiES □ 5B4 866 1149 3,9$ 7.95 8 TRACK CAR RADIO STEREO TAPE TRANSPORT 1'iTtt.nns cnmplete >-track stereo recording /p\ UY hark unit you find in expensive car tape lierks, Excellent direct replacement unit if your "wn does tiol fraction property. Priced to toss away old, and replace with new, Less amplifier. Design your own lu*(i stereo system* around it. Uses Standard fi-tracli cartridge. With hi-fi sttrecj tape and nil its mechanical parts tliiit eti with it. Operate* uff I2VDC, Automatic track Locating and rhuiigmj? plus truck Indicator output. a 4 8 ips speed. WOW and KLrTTKK less than CI Ml' metM shield riwrtoi reduces motor nnf, I'.ses .separate 73D pn-anip noise tn an inaudible and is ready In Size r> x . Low**! Pricei ^^ " ' ' -N^ — _ S»«t Selection TTL ICV Bra Type D SN740O D SN7401 D SN7402 D 5N7403 n SW7404 Q 5N7405 □ SN740S ] 5N7407 ; SN7408 SN7409 SN7410 5N7411 I SN7413 ; SN7415 I SN74I6 I SN7417 5N7420 SN7421 . SN7422 _ SN7425 SW7426 Sale SO. 30 .30 .3D .30 -5S -55 .35 .35 .30 .95 .55 .55 55 .30 .35 .35 .30 .37 Factory Marked DIP" Pichjff LI SN7430 Q SW7432 LJ SN7437 Q SN7438 SN7440 l_ v SW7441 . SN7442 DSN7443 : SN7444 D SN7 44S Q 5N744G Li 5N7447 LJ SN7 440 ._ SN7^50 SN7451 -_ SN7453 G 5N7454 Q SM7460 ■ J SN7461 ._ 5N7 462 G SN7464 Li SN746S •■ Ordei b> sumfaerl .sn,, mbmmti 30j.. SN7470 30 .60 GO .30 1.40 1.25 1.35 1-35 1.35 165 I 50 ISO .35 ,50 -35 .35 .50 SO U5N7472 SN747 3 SN7474 C SN74 75 SN7476 SN7477 SN747S (J SN74S0 U SN74S1 U SN7482 SN7483 U 5H74SS Q 5N7486 I SH7489 5N749Q SN7491 U SM7492 . SN7 4 93 . SH7494 _ SN7 49S . . : SN7496 A4an«y Bach Guarantee .45 .35 ,52 .95 .55 130 .95 .75 1,15 .95 115 1.41 .55 4.25 1.30 l.SO 1,10 1.10 1-iO 1.10 1 io D SM7 4104 D SN74105 5N74106 ., SN74107 ^_i 5H74108 i . 5W741I2 SN74113 I SN74H4 BSW74121 5N74I22 [ SN74123 SN74139 SW74140 SN74 145 SN74148 SH74151 5N74153 SN74154 SN74156 SN741ST D SN74158 D SH741SO u LJ »»n reftneat .55 ,55 1.25 .60 1.25 1.25 1.25 1.25 .70 .75 1.20 1.50 .50 1.40 4.50 1.25 1 60 1.95 1.42 1.55 1.55 1.95 o\LY SN74161 ! SW74162 J SN74163 5N74164 Cl SM74165 } SN7 4166 1 5N7 4174 SN7417S C SN74176 : SN74177 ; SW74179 1 SN741SO SN741B1 SN74182 SN74192 SN74193 SN74194 SM74195 SN74196 SN74197 SN74199 1,65 1.95 1,95 3.50 3.50 2.05 2.10 2.10 2.10 2.10 2.10 1.20 4. SO 1,20 1.95 1,95 1.95 1.35 1-50 2.10 2.65 KRONOSSi|7 # - Buy lOQ _ Take 20% Buy 3 Take 10% Cabinet: All "MAN" Type sei vinKlc* National MQ5 "clock chip" 12 or 24 Hour operation readouts 7 segment type* I **■ - ij^tinl i'. ,r s« nfHifu lii eajfineeTM ii- tin- mi ,ul..iin*"1 difiiinl timing de\je*' in llie « >»n^tjrnet limt^ MeJd, h irt Mt i' 1 iTiiU K,KONl>S KKJmi Snir.H, in tu*- ni'Vk >ii^-k tdl^purpitae w*almii-und-hUu*k nirjdern de- ttitrti i.ilnni'1, enhanei - any iiI(mi<, ht*me k den. etc. It h< ■ u "\ i-sible-iitt mri n*nver?iiition pie**< where vi STAN 5ARI3 TlT ' i''-* r, "d. tUi.s nidiJt'rn L>l \atinnal c lut-k C'lup, .irnl • patfe broithuf^ L'hwfc full wiiU picit>nat> and r,^y-i'»- CHRONOMFTFR Jlu> ' ' >m '> ^H-p4i>->Up ni»tnn tmn^. Tint* Kit i> t'U.M- c Vi/ c> r ?h """iM-TKlt SlMl*tlKIKU raaktnjt do-it-youra«lf *?w*y! Utini ** li.ULir*^ iiltlufic ,i * I 1 inn itfntniLs, i lunir \n\ iceoiul, i ntiiiutr per ><■< ond, atid hold huttori, Ka«y-to -change from I J in 2 1 a our*, i I (^ li di^M.s. ," f ii to \\\\ h% utieru- Any Type Clock TIME readouts LED 101 MAN-3 102 MAN-1 103 MAN-4 104 Nixie 105 707* 106 704** 107 SLA-1* 108 Same as KR by Monsanto Char. Siilo .12 547. .27 47. ,19 47. .45 47. .33 47. .33 47. .33 47. -107 except add 512, for green digits* *Litronlcs or Opcoa equals to MAN-1 char **Lltron4cs equal to MAN-4 characteristics COMING SOON: Scientific Devices low-cost Crystal Standard, watch for it TWO CLOCKS IN ONE! LINEAR • FACTOWV QUAHAMTfCO Op flmps |r*CTO»y TESTEtfl FACTOeV hahkip NATIONAL 'OP' AMPS 10% Type L. LM LM LM LM LM 300 301 302 304 305 QLM-307 LM30S j LM-309H BLM.309K LM-311 ] LM 320 ; LM 320 ' LM 320 : LM 350 D LM-37© ] LM 37 1 ' LM373 D LM-374 a LM-380 Q LM-3070 LM 3071 ♦TO-3 ca BUY ANV 3 TAKE Description Sale Super 723 V. reg. ,-,.-,-, -$1.49 Hi -performance amp , . , .49 Voltage follower ... 1.49 Neg T V. reg 1.49 Pos. V. reg, ,..,..... 1.49 Super 741 . . ..,,--- .59 Hi-Q Fet Type Op Amp . 1.50 5V 200 mil V. reR 1.50 SV l-amp V, reg.* - - 2.25 Comparator . , , . 1,50 Minus 5V lamp V.R.* . 1.95 Minus 12V lamp V.R.* 1.9$ Minus 15V 1 -amp V.R.* 1.95 Dual peripheral driver . , .59 AGC squelch op amp . . . 1.49 R-F, l-F* op amp 59 AM-FM, SSB, I.A.D, 3.75 AM-FM. S5B, IVAD 3.7 5 2- watt audio amplifier - 1.95 Chrome regenerator . , 1.50 TV chroma IF amp . l.SO e, — other* TO*5 i 2 ir.-.{*2^ Terms: "i«M ptiMuffe Rated: tii-i :tfl Phone i if *i»*r> Wakefield, Mios. < i> t \ a-i »-*sffj£ttj Retail: I H- I N l*td Carmine St., WakrlteJrL Mil*-, lull Water Strt-t-t > < n.K> MAY |€|-: 1'ilOXKH " iHIGH VDLT UMP | PIV SALE 2000 s 1,00 ! 1 I l ■ I D a a n □ ! J ! I I 3 a a a a p a p a n n n a □ n i □ 531 Hk slew rate op -amp (TO-5) . . 532 Micro power 741 'TO-5) . ... 533 Micro power 709 (TO-5) 536 FET Input op amp (TO-5> , . . . 537 Precision 741 fTO-5) 540 70W pwr driver amp (TO-5) . . 550 Precision 723 voltage reg, (DIP) 556 5 Times fatter than 741C 558 Dual 741 (mini DIP) 5S0 Phate loefc loops (DIP I 561 Phaitt loch loops (DIP) 562 Phas* lock loops (DIP) 565 Phase lock loops { £ i 566 Function generator (A) 56 7 Ton* generator (A) - 595 Four quadrant multiplier . - . . , 702C HI grain. DC amp (TO-5) . . 703C RF.IF, amp, 14 ckts (TO-5) 704 TV sound IF system 709C Operational amp (A) ...,,,.. 709CV Op amp (mini DIP) ......... 7 IOC Differential amp (A) ........ 71 1C Dual dlff, comp (A) 723C Voltage regulator (A) 7 33 Diff, Video Amp 74 1C Frequency compensator 709 (A) 741CV Fr*q. comp 709 (Mini DIP) . 747C Dual 74 1 C (A) 74 8C Freq. adj. 74 1C (A) 7 4BCV Freq, *d|. 74 1C (mini 7 53 Cain Block 709-709 Dual 709C (DIP) .... 739-739 Dual stereo preamp . . . 741-741 Dual 74 1C (A) 751 SO Dual peripheral driver . . 75154 Dual peripheral driver . . 745512 Dual line driver ... PA265 5 Watt voltage regulator ULN23O0M Op amp with SCR CA3065 VttiaG Audio system - • . iAi TO-fi or DIP dual in line pak DIPj $2.50 2.50 2. SO 3.95 2.50 2.50 1.17 210 1.00 3.25 3.25 3.25 3 25 3- 25 325 3.10 -49 1 00 1,50 .49 .49 ,49 .49 .95 1.75 .49 .49 1.25 .49 .49 1.75 too 1.98 1.0O .88 .88 1,95 1.50 1.50 ISC CATALOG on fiber Optics, 'Its'. Semis I POLY P.O. BOX 942A LYNNF ELD. MASS. 0194c r 3000 D 4000 1.65 5000 225 6000 2.96 8000 3.50 10000 3.95 i HI Fl 1 SQUARE MINI METERS ■ Plaitic case $1.49 • Red ni-itllf Indicators Bttlnm inis t tereo, tape, amps. VI", niile miff, plu> ;l minttA 2tt dh, n v l"» fruni Hiig, ptiiH ;i mlniw Ju 4b, '!=* e»i r -i • -' i (or S3.75 OCTOBER 1973 107 F2* Southern x Hospitality For hundreds of years, the South has been famous for its hospitality and friendliness. Rex Johnson offers you the finest in new and used gear, along with service and follow thru in the true tradition of the South. fir)(i : ) • • Write us for our Free Used Equipment List and trade-in quote on all Major lines. Remember, the Southern tradition of friendliness and hospitality is alive and well at Johnson Electronic Sales. P.O. BOX 332 GRIFFIN, GEORGIA 30223 (404) 228-3831 JOHNSON J ELECTRONIC S/UES " LITRONICS-MONSANTO-OPCOA LED Readouts MAN 5 MAN 8 SLA- 1 SLA2 1 5LA-3 All tit 14-fiifi 1* r,v 1 n to 2n rmK o.t« i nt-rat*. n\un letter* hV ijt-cimaL With M't" *hei ' * M n unto KijiijlI. MAN- 1 ■■ 'MAN- I Kpel f,,Tn-l)tno!e Array, MONSANTO "ALL LED M T *P* MAN MAN-3 SLA-3H Size: MONSANTO MAN-l* 27 MONSANTO MAN-2* 32 1 Red MONSANTO MAN-3* .IIS Red MONSANTO MAN-3* 1 15 MONSANTO MAN-4* MONSANTO MAN-4- MONSANTO MAN 5* 27 MONSANTO MAN 8* Color . Display Decimal Red Red .190 Red 190 Red •Gfeert .27 Yellow Ye* SN7447 4. SO 3 for 512 Ye* Y«i SN7448 ! 2,25 3 for 56 No No Ye* Ye* Driver Each 2513 6 SO 3 for $ 18 SN7448 1.49 3 lor S3 Yes 5N7 448 2.95 3 for $B. SN7448 5N7447 G.50 3 for SIS. SN7447 6. SO 3 for SIS spccui OAK FEATHER I ibi r - _ •— — -— REFLECTIVE LITE BAR" (SEGMENT} LEO READOUTS! • * # ' Decimal n^lil ur left LITRONIX 707** f MAN 1) 33 LITRONIX 704**+ JMAN-4) .33 J OPCOA SLA 1** (MAN 1 t ,33 OPCOA SLA-1** < MAN 1 I .33 OPCOA SLA-3H Giant Ditit 70 Red Red Red Red Red OPCOA SLA. 2 Plus/MJnu*/l .33 Red OPCOA SLA- 11C I MAN 5| 33 Green OPCOA SLA. 12 P|us/Minu*/1 .33 Green SN7447 4.95 3 for 512 Yes | t Yea Yes No N, • * * SN744B 3.50 3 for 59 5N7447 3. SO 3 for 59. 5N7447 1.95 3 for 55. Yes SN7447 8 60 3 for 524 SN7447 3.50 3 for $9. 5N7^47 4 95 3 for 513 RRV m RANGE t « P 3 for 515, TWIN DIGIT ARRAY Tyg* SP3&2, each ilicit is mciiv nluaU)' mm ml ted. op- erates off isovm\ infl ua. 200 tnw. Color: 0KANU&. 7-digil , class protection uvi-r digits * harac fcer height: D*t(3. P.C r mount - i UK, .Hi/c: ' t ■" K ' \" , D*pfna npr digit. Driver: SNT447, RTTY nted To •Pri For Unique Panel Jrcuiti TOUCH SWITCHES c - Sal* Switches j, 49 No. G 0* 1.79 3 for SS- *"*• ^P "AK Uf um KTTY, too* & nuu- " U 3* board n 4* •wily 4.4 V * to S 7 * Printed circuit. n a * jviiiif top. hia^k uamhei, 9 ** 1 "ft or ir .,"," , wtteh "a _y 'Of keybo ard 57.50 D 4 = r 3 xt B LED GaAs INDICATORS y 2-MVl*. Ambe-r, viaiblir jumhn ftpuKy Jen* upright, ... * 1-MV2*, TO-1 B, Dome, .green, visible . . . | l-MV-2*, pret-n small dome, green cliff, tit* Q l-MV-2*, clear *mall plastic dome, green ill It. lite . . 1MV-3V micTQ-mii|l pin head' dome, T<)h, j*reen |i t«- u 3-MV3*, uMblf. "Vu-iv pin pafc" . tr-ri, mi nr dome lep- P 1-MV4*, mod, Ingh power, red, 2-uL'utt* ..*.... Q 1.MV4H 1 , stud, high power, hi-dame, red. 2-wntts 3 MviOB, rhtih!*, rt-«i, clear, dome len- r TO- 18 2 3-MVlDC \ -bit-. ri-iL diffused, dump tens, TO- I ** . tl 3-MV5G*. ttxlitl Lt-.id»» micro- mini dome, clear, red , . 3 3-MVSQl2* ( n si bit-. rer|« small d+irm- tem 3MV5022*, jum.hu red dome, TO* 18, visible I 3-MVS020*, jumbo cl^ur dome, TO- 18, visible, red . - , IH 1-MV5040*, i-LED red array, with 5-tea(i puk - , ] 3-MV50S4*. visible. per4, fumbri dome lins, upright . . , ] 2-MV5080** TOrt.H« mifrn-rm ni, clear dome, red . 4-MV50B2. visible, ristl. I* tear flat l*n«i, To- 1 h . ; 1-MV5222*, fSTcvrt tu MlfLsiii dome, ■! Hi. ed cretin llti i 1-MVS222** dear hi dome, ditf. tfn ■» li hi< 3 1-MV5222*. jumbo dome, green, oanel snaD-in .,,*.. r] 1-MV5322*. jumbo dnrnr, Ga.Asp. panel Ktiap-in Vellow l-MV9000* t nuirifllfr |ian*-t iamo, s*^i|ci(. r*d* < le.tr lens 2-MT-2*. i*!n»to Tt.iii- Iiplil -i-n-«»r. TO- i ^ □ 2 -ME-l-. mfra-red. pA r&n "l |C lei**, pin type .... "3-ME-4*. infra-red. ^aible". TO- 18, ,liff. dome Z3-ME60* t infra-red. "invisible ", axial, rrncro-mini MUX'D DIGITAL CLOCK PC BOARD Your choice 4 r $1.00 1.00 1 00 i-oo 1-00 1.00 3.95 3.95 1.00 3 for 527 9.95 O 1,00 1.00 1.00 1,00 1 .00 1.49 l.OO 1,00 l.OO l.OO 1.00 1.49 1.98 1.49 1.00 l.OO l.OO l.OO h h-j.irii property uiljIti- p!r\fd fur tl rtinits, tn ti« *] i E MAN-'lV. MAN-.r« ( MAN- i > t Lftrimict; T 07 i M AN. I \ rind TO I iMAN-ii, and llpi . . ; i. - RLA- t '\1A\-! I Jh.:iid fi m " |i»BfE with *pl*C !'■• I $2.50 I MAN-l pUtronlcs 707 IMAN-1*) MAN-3 I ! Litronics 704 (MAN-4*; ! ' MAN 4 I I Opcoa SLA 1 (MAN-l* \ D e-MAN-3A"» for abov* board. 59-50. G Etched calculator burnl CA LCU LA X OR with hole«. as above, leas mM^m^Mw^***. M w^m*> switches $2 50 Board §j FY KflflH } Properly etched, drilled 4 "MULTIPLBXEO/* with proper di . Heady \>» no! Lsed with i^gr own CAL TKril'* ifOOl chip £iHvertm«Mt at $ if equ^l to Oil Tech *tt Mmhifh. chip. Keyboard use* the new manufar lured by OAK* prmted-circuit low-profile FEATHER TOITH >witt-hi-s. f>-tti-9 in white with black letters. l>eciPial white with black dot. t*K, CL und the 4 function n witches ure in blue with whin ir&cterti. DeMjcned bv tup maker. Si?:e: fiVa * ** ! 'n >* ' '". All etched rnn- rii<f h t]iiiis link tn take a 12-pin t?djte ronnectnr. D Cal Tech 5001 l ^-tlifCil calculator ^w-pia DIP for 9.95 II Keyboard, 50OI -i-hip"\ and 1^ MAN-iKs, specs 35.00 1 Twelve MAN-3's fur iibuve 17. SO ] Twelve MAN-4"* f<ir above . 32. OO _J Twelve MAN-Ts fur .iliove ,. + ....... . 42,00 9.95 3 for 527, KJer i - har. >ume OJi Monsan!-- devices MAN-l or t Hi \tnHT MAN-l MAN-4 707* 704** SLA-1* •Vour choice of 5 red LCD readouts! Only Buy 3 9.99 t ii.ir. Maker .27 h. Monsanto .19 h. Monsanto .33 h. LftronJct .33 h, Litronics .33 h. Opcoa Scteniitit" ||evici 'Ihcttal < .ntmi: M«m1uIi ltp«r- forrii any other IH_'M *m the market today' More fea- titre* ih.in • i before' Not u tj*. not tncanileM-i-nis, -^ nut nixie bm the mv»dern LKI». * - from such fatuous LED manufacturer* a* Mon^anhi's MAN-L* M.W-l. Litn>nics f^\# TOT and Til 1. 0pcaa*4 SLA-1 i Lhi- last 1 having i ha rut- r i-r rtefohtM "f iK'd'A at no extra ctiarftel. Each kl1 in- ■t-l'jdi ■-. £Mi" p t o board with (inner* for ii FREE ciise connectorg side-rnuuittlnif dil* nocket, LEU readout ^f (T\0 rUI ,r choice, rc-^itn.^, 'A M ' ^. and Mnles conneclor-s a-Fl^nn [%hi9 ELLMINATES iLUEJtl-NC Yni \i If and booklet. INCLUDES P-C, EDGE CONNECTOR — FREE! " Pin-for-pilt MAN-l. ■ * Pin-for-pJT) M \N-I ele< . . i'lut. -arne «- CALCULATOR ON A CHIP| D| GIT q CT5001 Chtp D Similar in Mo*tel< I rforrom T ditt rAfSlHOi. A i»-pin t»lP. Add*, multiptie*. >uhtr.iitr, .iful divides. Ise wiih 7-segrnent readout*, ,\t\ifs, and L£D"«, We jpriude BChe- », iiifitrortiofu t<» huild calculator CT50O2 9 Volt version of above 59,95 CTSOOS-Same as above with MEMORY $14.95 " RATIONAL EQUAL "DIGITAL CLOCK on a CHIP" Any "Chip" SI 2.88 * Money Back Guarantee! DIGIT l5 v C*tU06 ,nf^ f0otlCS parts Terms: ,mI*1I fp«»-^iic:*- Rated: m-t JO Pboae Orders: Wakefield, M BITi 245-1829 Retail: 1 i.- 1 N l»el Carmine St, . Wakefield, Mnu. loff WuUr Street i f,i>.l>. > MAY BE PHONED POLY PAKS P.O.BOX 942A LYNNFIELD.MASS 01940 }5311 26-pin, ceramic, any readout, G-digitS: A-B D __5312 24-pin, ceramic, ^t%y readout, 4-diKit*: C-f> OS313 28-pm, ceramic, any readout, 6 diRits: AC a 5314 24-pin, plastic, LED and incand^escent readouts, 6-dlKits; A-B oflVG I Code. A^ — Hold Count. C — I PPS Output. B — Output Strobe. D — HCD $12.88 *Wi*J1 512.88 Spec 512.88 Sheet ! 512.88 STUD 'TRIACS' POTTER BRUMFIELD Your chai " MINI CAP RELAYS $2*49 3 for 56 Q 115 VAC a M VDC Mi [inures only ' i x 1 v 1 J ^". Plastic eaaed. Uke KNP tvpe. For pr huard nr kt-t, 1-1 itlfl 1*H/ - fttud too! llolh IFDT, All amie construction^ 'i aftijt>, rontart»> For r-f ant, >witchinir, \\ t. 1 -i*?.. U her- ever space <s prime, yoti neeil a "mini cap*' relay, OCTOBER 1973 109 SUPER-QUAD FIBERGLASS ANTENNAS COMPLETE KITS INCLUDE HARDWARE. WtRE, ALL MOUNTS, BOOM, STRONGER AND LIGHTER THAN ALUMINUM MAXIMUM GAIN AVAILABLE IN A COMPLETE RANGE OF KITS Special fnstunjtion Munuul un Kirks "Super Quads" $200 • 2 3 4 ELEMENT TRi BAND 10 IS 20 METER . . A MATE UP NET F ROM $129 95 - ? 1 4 ELEMENT DUAL BAWD 10 15 OR 10 6 METER AMATEUR NET FROM ( S77-95 • 2 ELEMENT 40 METER AMATEUR NET • UHF 4 ELEMENT 2 OR 6 METER AMATEUR NET FROM $54.95 S389 95 ANTENNA MOUNT KITS COMPLETE PACKAGED KITS INCLUDING SPIDERS OR V SUPPORTS • BOOM TO MAST MOUNT ■ ALL NECESSARY ASSEMBLY HARDWARE • INSTRUCTION MANUAL HEAVY DUTY CAST ALUMINUM DL-1 DL 2 DL3 (2) (1! ft) in (2) ID DELTA LOOP MOUNT KIT IVj" Hub V -Supports 1 '4" Boom 1o iVi" Mast T-Mouni 2" Hub V Supports 2" Boom to V/" Mast T Mount ; ; QM-1 QM-2 QM-3 QM-4 OM-5 (2) (13 (21 (II 12) ni (2) (11 (2) (1) 3 Hub V Supports 3? Boom to 2" Mast T Mount QUAD MOUNT KIT 1V." Hub Spiders (Small Spfder tor VHFl 1%" 8oom to Va" Mast T -Mount 1%" Hub Spiders (Heavy Spider tor 6M St 10M) V// Boom to \ l A " Mast T Mount . , . . . Wt" Hub Spiders \-&" Boom to VA n Mast T Mount 2" Hub Spiders 2" Boom lo 1%" Mast T- Mount 3" Hub Spiders 3" Boom to % Mast T- Mount . . . . . Net $10.85 Net $13.75 Met SI 4.65 Net $22.45 Net S3G.95 KIRK'S BRAND NEW ALL- FIBERGLASS HELICOI DAL BEAMS AVAILABLE IN: 2 &3 ELEMENT - 40 METER 2 § 3, 4 & 5 ELEMENT * 10-15-20 METER CHECK THESE OUTSTANDING ®» ALL FIBERGLASS ELEMENTS & BOOM ELEMENT LENGTHS 25% 1 ' ^ TO 35% SHORTER THAN METALLIC AftflAYS PRECISION CONSTRUCTION, MINIMUM ASSEMBLY TIME. NO TUNING MO ADJUSTING I AND EXCLUSIVE FEATURES: COPPER TAPE. SPIRALLY WOUND ELEMENTS COATED WITH DURATHANE VSWR LESS THAN 1.5 AT UPPER A LOWER BAND LIMITS GREAT STRENGTH AND VERY LTGHT Example: i Element 40 M - 4£ Uj*. I525.00 3 Element 5?0 M~ !7 L&*. *21&,9i 3 Element li M 9 L13S. tl6<5-9b ■; L lement tl> M ft L-bi. $!*'>. 9i <© MO** WJM§ WORLD'S FINEST BROAD BAND Kirk Broad Sand Baluns are designed for match- ing 'an unbalanced line, such as coaxial cable, to a balanced antenna to produce a symmetrical wave form of &qual intensity from the current cycle. BALUNS 1:1 Or 1:4 RATIO Kirk Batons provide the greatest breakdown insurance by use of mylar insulation between the tough poly thermaleze winding and the Fernte Core and a final dip coating of low dielectric impregnation Handle peak power of 2000 watts provided ratio error is low. Unique in design. Kirk Etaluns are produced in two distinc- tive models: One for Djpoles. and one for Beam Antennas. NET PRICE «12» s vm Application frequency Coverage & Power Rat- ings For I lie Various Hade Is Shown Below MODEL APPLICATION F/HC. POWER 5075-S 5075 -LF Dipore 3.4-S2 mns 2K PEP Beam 3-4 52 mts 2K PEP Dipole 1,7-10 mes 2K PEP MODELS 507 5-0 & 5075 -IF Far DiDtfle Aricrinas Ntl Wt. 7 Df. MODEL 5075. B For Beam An tennis Net Wl. 7 Oi. WRITE FOR FULL INFORMATION. PRICES DO NOT INCLUDE POSTAGE. PRICES ARE SUBJECT TO CHANGE KIRK ELECTRONICS DIVISION ELECTROTEC CORP. Dept. K 73 Ferry Road Chester CT 06412 • Telephone: (203) 873-8643 110 73 MAGAZINE know this sign To most people this is a symbol from Greek mythology. But to hundreds of thousands of active amateurs, Pegasus is the symbol of the Radio Amateur CALL- BOOK the single most useful operating reference for active amateur stations. The U.S. Edition lists over 285 r 000 Calls, Names and Addresses in the 50 States and U.S. possessions while nearly 200,000 amateur stations in the rest of the World are listed in the DX edition. Both editions contain much other invalu- able data such as World Maps, Great Circle Maps, QSL Managers around the World, ARRL Countries list and Amateur Prefixes around the World, Time informa- tion, Postal Information and much, much more. You can't contest efficiently, you can't DX efficiently, you can't even oper- ate efficiently without an up to date CALLBOOK. To make the CALLBOOK even more val- uable, three supplements are issued each year which bring your copy completely up to date every three months. These are available at a modest extra cost. Full de- tails in every CALLBOOK. Get your copies of the big new 1973 CALLBOOKS today. US CALLBOOK (less service editions) Just $8.95 US CALLBOOK (with service editions) $14.95 Mail orders add 50 r l DX CALLBOOK (less service editions) Just $6.95 DX CALLBOOK (with service editions) $11.45 per CALLBOOK postage and handling. See your favorite dealer or send today to: RADIO AMATEUR ca lib oo k INC. Deot b 925 Sherwood Drive Lake Bluff, III. 60044 MINIATURE METER 0-100 v A {approxj - 14" dia. 1 ¥ ¥ F ..,$1.00 MINIATURE POWER SUPPLY Output 6Vdc- 100 Mils _, . m $1,00 5 Volt ZEN EH and Electrolytic for 5 Volt supply furnished for $1.00 additional. REED RELAYS 6Vdc-SPST-%x 1" $1.26 12 Vdc - SPST - 1% x %" . . . , $1.50 FULL WAVE SILICON BRIDGE RECTIFIER 200 PRV (line) 25 Amps - V'sq $2.50 OIL CAPACITORS 4MFD-3KVdcG + E i 23F44 4x5x4-7 lbs. ea. ,,,,.«, . ,2 foe $10.00 100 MFD 1 500 Vdc - Sprague F1 537 Use 2 in series for 50 MFD 3KV 13 x 6 x 5 25 lbs. ea , 2 for $25,00 POWER SUPPLY Input 1 15V/ 1/60 Output 28 Vdc 50 Amps filtered Silicon studs — Cased transformer and choke 21 x 1 2 x 7 — 1 50 lbs $90.00 .\Jlfr OMNIBUS Elechonic Ondu&biie& $ Uric 3W CANAL ST., NEW YORK N, Y. 10013 12121 226-36931 In this issue, do you think there is a need for more Simple construction projects Complex construction projects General interest articles Humor articles Specialized columns Operating news Comments Yes No □ □ D □ D □ □ □ d □ □ □ OCTOBER 1973 111 READER SERVICE Please either tear out this list of advertisers and send it in to 73 with as many boxes checked off as you would like to see brochures, data sheets or catalogs -, . . or else make a copy and send that in. Include your zip code, please. Send money directly to advertisers. ADVERTISER INDEX D Amateur Wholesale 75 □ International Elec. 72 □ Antenna King 15 D Jan 59 □ Antenna Mart 63 D Janel 32 D Ascom Cover 1 1 □ Jeff-tronics 53 • ATV 58 □ Jensen 53 a Autek Research 12 □ Johnson 108 a A&W 97 a KA Sales 106 a Babylon 98 D Kirk 110 D Callbook 111 a LA Elec. Sales 88 a Circuit Specialists 94 a Larsen 18 a Clegg 30, 38 □ Linear Systems 41 a Com, Unlimited 1 1 04, 10B □ Meshna 90, 91, 92, D ComSpec 12 a MFJ 58 a Cornell 52 a Milliwatt 63 a CushCraft 46 a Morgain 12 D Data Engineering 85 D M-Tron 52 a Demon 82 a Newtronics 48 a DuPage 103 a Omnibus 111 p Dynamic Elec. 5E I a Palomar 32 a ECM 53 □ Pemco 87 □ Electronic Distr. 12 a Polypaks 107, 109 1 1 Erickson 50 i j Q-Tronics 71 a Fair 52 a Regency 42 ! 1 Freck 63 • RP 58 D GAM 95 □ Savoy Cover 1 1 1 a Gateway 78 a Selectronics 83 a Genave 80 D Sentry 9 □ GLB 52 D Signal Systems 79 a Godbftut 96 D Solid State 86 a Goldstein 76 □ S&R 102 D Goodheart 62 D Stahler 63 a Gregory 66 a Standard 3 D HAL 71 a Tri-Tek Cover 1 1 a Ham Radio Center 89 a Vanguard 99 a Hatry 71 D Venus Scientific 24, D Henry 36, 56 a VHF Engineering 81 □ H&H Engineering 52 D Waller 84 n Hobby Industries 28 a Wolf 63 a Hy-Gain 100, 101 D World QSL 53 a ICOM 64, 65 a Yaesu 16 73 Stuff FM Atlas 59 How to Use FM 59 Subs 73 Books > 74 Coupon expires in 60 days 93 25 not solicited. Correspond OCTOBER 1973 * Reader service inquiries directly to company. Mail to; Reader's Service 73 Inc., Peterborough NH 03458 Please Print or Type Name Call Address City _ State Zip PROPAGATION CHART J.H. Nelson Good (Open) Fair ( □ ) Poor October 1973 (O) SUN MON TUES WED THUR FRI SAT 12 3 4 5 7 8 {9} 10 11 12 13 13 (15) £2 11 18 19 20 H Hi Possible aurora 24, 25, 26, 27. EASTERN UNITED STATES TO: GMT: 00 02 04 06 OS ID 12 14 16 IB 20 22 ALASKA 14 7 7 7 3 3 3 7 If 14 14. 14 ARGENTINA 14 7 7 7 7 7 14 21 21 21 21 21 AUSTRALIA 14 7B 7B 7B 7B 7B 7B 14 14 T4 14 T4A CANAL 2QNE 14 7 7 7 7 7 14 14 14A 21 21 14A ENGLAND 7 7 7 3A 7 7 14 14A 14A 14 7A 7 HAINAN 14 7B 7 7 7 7 7 7 7A 1 4 14A 14A INDIA 7 7 ?B n\ 7B 7B 14 14 146 7B 7 7 JAPAN 14 7H 7B IB 7 3A 7 7 7 7 7B 14 MEXICO 14 7 7 7 7 7 1 14 14 14 A 14A "A PHILIPPINES 14 7B 7S 7B 7B 7B 7 7 7 f 7B 7 A PUERTO RICO 7 7 7 7 7 7 7A M 14 14 T4 14 SOUTH AFRJCA 7 ? 7 7 7B 14 14A 21 21 14A 14 14 U, S. S. R. 7 3A 3A ? 7 7B 14 ij 14 7A 7R 7 WEST COAST 14 7 7 7 7 7 7 14 14 14 14A 14A CENTRAL UNITED STATES TO: ALASKA 14 7A 7 7 3 3 3 7 7 14 14 14 ARGENTINA 14A 7 7 7 ; / 7 T4 21 21 21 21 AUSTRALIA 2| 14 7B 7B 7B 7B 7a 7 14 14 14 14A CANAL Z ONE 14 7 7 / 7 7 7 14 14A 21 21 14A ENGLAND 7 7 3A 3A 7 3A 7B 14 14 14 7 7 HAWAII 14 14 1 f 7 ■' 7 7 7A 14 14A 14A INDIA 7 7B 7B 7B 78 3a 3B 7 7A 7 7 7 JAPAN 14 7A 7B 7B 7 7 3A 7 7 7 7B 1 4 MEXICO H 7 7 7 7 7 7 14 14 14 14 14 PHILIPPINES 1 4 7A 7B 7B 7B 7B 3A 7 7 7 7B 14 PUERTO RICO 14 7 7 7 7 7 7A 14 14A 1<1 A 14A 14 SOUTH AFRICA 14 7 7 7 7B 7B 14 14A 21 14A 14 14 U.S.S. R 7 3A 3 A 7 7 3A 7B. 14 14 7A 7H 7B WESTERN UNITED STATES TO: A - Next nigher frequency may be useful also. B = Difficult circuit this period. 112 73 MAGAZINE MODEL DGA-2M SAVOY -f+^^^hwb Postpaid in U.S.A. TYPE 900 A TYPE 901 HIGH ACCURACY CRYSTALS FOR OVER 30 YEARS 2-6-10-15-20 40-75 Identical size, post, and appearance Either type for amateur VMF in Regency, Swan, Standard, Drake, Van* tronics, Tempo, Yaesu, Galaxy, Trio, Sonar. Clegg, SBE, Genave. Quotes on request for amateur or commercial crystals for use in all other equipments. Specify crystal type, frequency, make of equipment and whether transmit or receive when ordering. FULLY ADJUSTABLE TO FREQUENCY IN FIELD BASSETT VACUUM BALUN $ 5 ■--'-.* ■"im - t< Polished chrome brass standard 3 /s-24 thread High gain collinear on 2 meters BASSETT VACUUM TRAP ANTENNA SYSTEM Complete packaged multi band antenna sys- tems employing the famous Bassett Sealed Resonators and Balun from which air has been removed and replaced with pure helium at one atmosphere. Operating bands are indicated by model designation. MODEL DGA 4075 $59 SO MODEL PGA-204075 $79.50 MODEL DGA 2040 $59.50 MODEL DGA-T52040 $79.50 The famous sealed helium filled Balun . . . employed with the DGA Series Antenna Systems, Solderless center insulator and easily handles more than full legal power while reducing unwanted coax radiation, Equipped with a special SO 239 type coax connector and available either 1:1 or 4:1. MODEL DGA 2000-B $12.95 Postpaid in U.S.A. CONTACT VOUR DISTRIBUTOR OR WRITE FOR DATA - Fart Lauderdale, Florida - 33310 Tel: 3Q5-56B-8416 or 305-947-1191 _ 73 Pine St. Peterborough, NH 03458 USA \^* O tf fm f two colors QSO info book 10W PRICfg Just when you're used to being abused by ever skyrocketing prices, 73 comes along with yet another way for Hams to save money! We have figured out a way for you to get High Quality QSL cards foraslowasaPENNY-A-PIECEpostpaid! These cards are printed on High Quality Glossy Card Stock and are as good, or better than cards sold elsewhere for two or three times the price. By ganging up QSL printing between other jobs in our own print shop, we are able to offer you this fantastic low price. At this price, do you really have an excuse for not getting in a supply of these nice QSLs? Don't be one to give U.S. amateurs a bad name by not sending a card when requested. (£^ e fl S STYUS to choose from! f ORDER 7J ftme Street Prfn-bcfDugh. NH UJWtf 250 . . 500 . . 1000 . 2000 . • » - AND PAYy . . $6 (2.5dea) . . .$10 (2i ea) . $15 <1.5dea) . . .$20 ( M ea) iS^ Ve -a W 1MSDI I • Wtynt Grurtl 73 hrn?Sl'*»! P*i*rti»n>iHar.,NH 0345 B &SW sXvvv. ORDER BLANK Name (First and last name is most friendly) Call .■:*: m Address (as brief as possible and still get through the mail) Style 1 □ 2 □ 3 D :-;;:v: City. State ZIP County. (a must) tif desired on the card) Awards to be listed on card m. □ 250 □ 500 □ 1000 □ 2000 cards Amount enclosed $ Mail order to: 73 Magazine Peterborough, NH 03458