ISSUE NO. 85 August 1990
Scanned, OCR'ed, and proofed by Mike, N9BOR

FCC "Inundated" with Comments

If the unofficial tally is correct, the AM community’s response to the FCC petition was overwhelming. The informal count of comments as of August 2nd is as follows:

RM-7401, Petition to eliminate AM, 1 comment in favor, 333 against.

RH-7402, ARRL petition to permanently grandfather the 1 kW DC input standard for AM, 115 in favor, l against.

RH-7403, SPAM petition to increase AM power to l500 watts carrier output, 34 in favor, none against.

RM-7404, Dale Gagnon’s petition to redefine the AM power limit as 750 watts carrier output, 142 in favor, one against.

The total number of comments on the AM power issue was 29l in favor of historical AM power privileges and two against.

Only 83 comments were submitted for RM-3665, the Stankus petition to eliminate AM in 1980, This time around the FCC was inundated with comments, which strongly supports our claim that amateur interest in AM has increased substantially since the early 1980’s when the AM power limit first became an issue.

This encouraging response would not have been possible without the efforts of a few AM’ers who went to a lot of effort and expense to spread the news about the petitions and their RM-numbers to the AM community at large. In addition to the efforts by The AM Press/Exchange and Electric Radio, a number of individuals made up their own information bulletins, ran off dozens of copies, and sent them to their fellow amateurs who otherwise would not have become aware of the petitions until after the comment deadline had passed. To each one of these people, on behalf of the entire AM community, we say a big "Thank You."

Interestingly, RM-7401, the Prechtl petition to eliminate AM, drew more comments than the AM power issue. We had anticipated AM power becoming an issue in 1990 when the grand- father clause vas due to expire, but Prechtl’s petition was a surprise factor, appearing at the last minute, which somewhat diffused our response to the power limit petitions. Curiously, the FCC had received Prechtl’s petition last August, almost a year ago, and quietly sat on it until the power limit petitions came in, and then assigned it an RM-number along with the latter.

Although AM response was encouraging, with a total of over 600 comments, this still represents a fraction of the total number of active AM’ers. The total number of responses does not reflect the number of individuals filing comments because many persons submitted multiple comments on two or more of the petitions. Still, we responded overwhelmingly, considering that most rulemaking petitions initially draw at most a dozen or so comments. Once again, we did our homework!

We appear to have won another major "battle" but the "war" is far from over. The FCC is under no legal obligation to act on these petition and comments, favorably or otherwise. The FCC bureaucrats are not directly accountable to the public. They could simply take no further action at all, or they could claim to have access to "other data" than the comments and release a Notice of Proposed Rulemaking to further restrict or even eliminate AM, despite what a majority of the comments said. There is no deadline; the FCC could sit on this issue, possibly for years, before finally taking action.

Nor is our part of the struggle over. First, we sent letters to the ARRL Division Directors and convinced the League to support us and to submit a petition to the FCC requesting to keep historical AM power privileges. When the petitions were assigned RN-numbers, we responded with a large volume of comments. The next step of the process must come from the FCC in the form of NPRM (rulemaking docket). Then, once again, we will have to respond with yet another round of comments to the FCC. This final proceeding will determine the ultimate outcome of all our multiple efforts.

One thing we must keep in mind is that a NPRM (docket) will be more highly publicized to the amateur community at large than were the petitions. There will likely be a longer comment period. This will be a double-edged sword because the anti-AM element within the ham community will also have a better opportunity to organize and participate in the response, by presenting arguments AGAINST AM to the FCC.

Finally, there is no way to predict what form the NPRM will take, if any. The FCC has a history of twisting rulemaking petitions around in such a manner that the final docket proposal is vastly different from what the petition originally asked for. As a recent example, we have PR Docket 90-55, the pending no-code proposal. The ARRL petitioned the FCC to create a new code-free "Communicator" Class. Now that the FCC has released a NPRM, which includes proposals to eliminate the Novice and Technician, there are rumors that the League might come in opposition to the Docket that resulted from its own petition. On the AM issue, the FCC could propose to merely extend the grandfather clause a few more years, hoping that the current wave of interest in AM will have run its course by then. Or they could "compromise" by pro- posing to give us our old power limit back, until AM is phased out entirely after a certain period of time. As another possibility, they could limit a permanent grandfather clause to transmitters already in operation before a certain date such as June 2, 1990. We must be prepared to tell the FCC in a united voice that any "compromise" is unacceptable; we are insisting on the permanent, unconditional retention of our longstanding privilege to transmit AM at historic power levels on all amateur voice frequencies.

If and when the FCC does act on these petitions, our response as a community will be more critical than ever. It is not too early to begin making preparations. Let me suggest that every person who submitted comments on one or more of the AM petitions begin to work with hams of our acquaintance, with a goal in mind to get at least TWO MORE fellow amateurs to submit pro-AM comments on an eventual NPRM. Let’s inundate the FCC with a magnitude surpassing even the highly publicized issues such as no-code and Novice enhancement. It is extremely unlikely that the anti-AM element in amateur radio could muster a fraction of that response, and the FCC would find it hard to ignore.

Right now, our momentum is going stronger than ever. If we prevail in this matter, not only will we get our power privileges back, but AM will be firmly re-established as an integral part of mainstream amateur radio, hopefully allowing us to enjoy our hobby without having to continually expend so much time and energy defending our position.


Stolen 75A4

A 75A4 Collins receiver, with 6 kc. filter and matching speaker (serial number unknown) was stolen from a car in the Houston, TX area. Watch for someone, especially a non-ham, trying to sell it. Let’s nail this thief. Call Houston police and J.M. Wagner, W8AHB, 3890 Tubbs Road, Ann Arbor, MI 48103, (313)663-7031. Also, watch the radio stores and pawn shops. CU on 75.

-Jack, WSAHB




FCC: 10 M. Novice SSB Brings Widespread Cheating.

The FCC believes that 30% of those getting Novice tickets are cheating on the exam. At the FCC Forum at the 1990 ARRL National Convention in Kansas City on June 9th, FCC Special Services Division Chief Ralph Haller, W4RH, explained that the problem was pervasive, but that few cases have been prosecuted because the FCC has only one attorney dealing with all amateur enforcement.

John B. Johnson of the Personal Radio Branch elaborated further: "Me believed this (would happen), and the League anticipated this too when phone privileges were added which made (the Novice) a more desirable license. Back when you only had CW privileges there wasn’t a lot of incentive to had to know CW to use the privileges... For most people, actually getting on the air was a bigger challenge than passing the test. That changed when phone privileges were added and it made the incentive to cheat go up. And frankly (we are) turning up more cases than we can handle... We are going after them as much as we can... They (the volunteer examiners) said they thought this was just the tip of the iceberg..."

As part of PR Docket 90-55 (no-code), the FCC has proposed to abolish the Novice and Technician classes. Since Public Law PL-259 precludes the collection of fees by the volunteer examiners as reimbursement for expenses in administering Novice tests, the FCC has proposed to replace the Novice entirely by the Communicator, which would fall under the VEC testing system. Some of the volunteer examiners have suggested that they would be willing to administer Novice tests free of charge if the FCC would phase out the current Advanced class.

-TNX Westlink Report


Broadcast Industry Concerned About Pirate Radio.

The 1990 Society of Broadcast Engineers Convention and Broadcast Engineering conference will meet in St. Louis, MO October 4-7. Paid registrants will be able to attend special conference sessions covering many aspects of AM, FM and TV broadcasting. On Thursday, Oct. 4 at 1 p.m., Don Bishop of Mobile Radio Technology magazine will present a session titled "Avoiding Pirate Radio Interference: Pirates may capture listeners, but the FCC continually sinks the pirates," Registration fee for SBE members is $125, and for nonmembers is $185. For more information, call SBE at (317) 842-0394.


Attention Southeastern Hams!

Announcing the all new

Saturday Morning S.P.A.M. Net

9 A.M. around 3880 Kc.

Come Join The Fun!!

48 Evergreen Drive,

Hhitby, Ontario L1N 6N6,


19th July 1990.

The American Radio Relay League, Inc.,

225 Main Street,

Newington, Connecticut 06111,


Attention: Administrative Liaison, Advisory Committee

c/o Lisa Clark

Reference: Contest Advisory Committee

Dear Ms. Clark:

Please be advised that I heartily support and applaud the proposal, currently before the Contest Advisory Committee, calling for an A.R.R.L.-sponsored "Amplitude Nodulation Night" (as noted by Rich Assarabowski, K1CC, in his "CAC News" column of The National Contest Journal, for July/August 1990).

I envision the use of amplitude modulated phone as keeping wholly within the intended spirit of "Straight Key Night"; indeed, A.M. is the logical choice on New Year s Eve ---an alternative to hand-keyed c.w. contacts---for Amateurs who either can not (because of physical disabilities) or will not (because of a personal preference for radiotelephony) take part in the nostalgia and fun of this annual event.

A.M. operations during future "Straight Key/A.M. Nights" would create few, if any, interference problems to regular users of the Amateur Radio bands because of an existing---and gentlemanly---A.M. tradition of frequenting only selected "windows" of operation, away from the mainstream of activity (QST magazine could easily list these frequencies for the benefit of newcomers to A.M., on the occasion of future "S.K./A.N. Night" announcements).

Some very interesting QSOs take part in the amplitude modulated phone subbands, and I would invite any and all members of the Contest Advisory Committee, at his/her leisure, to eavesdrop on some of the activity. In doing so, one can not help but be immediately impressed with the high level of technical expertise displayed by the average A.M. aficionado; many of these operators have lovingly restored to "...better-than-new" operation every type of vintage Amateur, commercial, and military equipment that has been in existence for the past 50 years or more. Designing, modifying, and "homebrewing" are nothing new to the typical Amateur Radio operator interested in A.N. phone. What a tragedy it is that such inventiveness seems increasingly limited to just this small---but growing!---segment of the Amateur population.

We live in an age today wherein our ability to assemble an effective Ham Radio station seems to be dependent upon the extent of one's personal finances. What a refreshing change it is, then, to participate in an activity such as amplitude modulated phone, which---each and every day--- celebrates that noble Amateur hands-on tradition of "...tinkering and experimenting" which our forbearers established not so long ago.

Even if we simply sample but a taste of the magic that A.M. brings with it, just once every twelve months on the eve of a New Year, we will all be richer for the experience.


Fraternally yours,

Edward P. Swynar,


cc: Garry Hammond, VE3XN (C.R.R.L.)

John Kanode, N4MN (Board Liaison)

Billy Lunt, KR1R (Staff Liaison)

"Electric Radio" Magazine

"The AM Press/Exchange"



Latest Count: AM Petitions Draw 800 Comments

On Aug. 21, Bill Cross of the FCC was contacted concerning the AM petitions. He said the total number of comments received was "over 800." He then broke the figures down by petition as follows: RM-7401, 425; RM-7402, 149; RM-7403, 41; RM-7404, 185. This adds up to exactly 800 comments!


Use of TV Power Transformers for Modulator Service

The Timtron WA1HIR

There comes a time when the modulation transformer in your DX 100 Apache, B & W 5100 32V, Viking 1 or 2 Valiant or other 50 - 200 watt power class transmitter sources out. Maybe you are interested in building a low bucks transmitter or a modulator for your cw rig. The biggest stumbling block is getting a modulation transformer together. Well fear not, the TV power transformer has come to the rescue. There are a number of methods in using these beasts as shown below:

Fig. 1

Fig. 2 & 3

It will be noticed that there are two variations of a similar configuration. The original l15v primary is connected to one leg of the high voltage secondary (600-800v). The windings have to be in phase or else it won’t modulate worth a damn. A test voltage can be applied to the center tap and one end of the secondary. The test voltage can be from 6.3 -115 volts AC. The total voltage obtained from the combination of the primary winding and one half of the secondary should be greater than the test voltage used. If it is less than the test voltage, then the windings are out of phase. In this case just reverse the leads on the primary or tie to the other end of the H.V. winding. In tests conducted on an 800 V, center tapped unit with 1l5v primary, the impedance ratio was app. 2:l; perfect for the usual set up with common plate supply and typical 6146s modulated by 807s and other lash ups where plate voltage does not exceed 800 volts. The limiting factor is insulat1on break down rating of the transformer. Most are designed for 1500 - 2500 volts breakdown. In some designs the primary is the first winding on the core. In others, the primary may be wound 1n the m1ddle or on the outside. The types with the primary wound on the inside is more susceptible to crap-out. The transformer may also be mounted or insulated above ground in order to accommodate higher working voltages. You may ask yourself: How does a power transformer behave at audio frequencies? Amazingly enough most will have very good response characteristics. There are so many variables that it would he difficult to accurately predict what it will do. Power handling capabilit1es of the usual TV power transformer is in the order of 150 - 300 watts depending on the size of the core. It can generally be assumed that 1 lb. of core material wi11 handle 10 watts of aud1o for good, bass response, and 20 watts per pound with higher impedance, i.e.; PP 811 to 813 final 1250- 1500 volts.

In figure 1, the DC to the final flows through the transformer to the final. This causes an imbalance of current in the transformer, and core saturation to occur, therefore; the transformer must be modified. If you are observant you wil1 notice that typical modulation transformers, filter reactors and audio output transformers for single ended operation have "E" shaped laminations stacked together next to "I" shaped laminations. The "E" and "I" shaped stacks are separated by a heavy paper spacer. This enables the transformer to handle a certain amount of DC imbalance, but there are drawbacks. When this is done, the inductance of the transformer falls off rapidly as the spacing of the gap is increased. This causes a marked drop in the low frequency response of the transformer.

In the case of the power transformer; a gapped power transformer will work okay for frequencies of 70 - 5000 Hz. In order to modify the transformer, the whole unit must be disassembled. Remove the bolts holding the cover bells in place. With the careful use of a hammer and several sizes of screwdrivers, it is possible to do the job within an hour. It may be necessary to give the core stack a couple of well-placed whacks to loosen up the laminations. Some transformers come apart easily and others take much patience. Exercise extreme caution not to damage the windings. Once the unit is apart and the laminations are clean of foreign matter, group the "E" and "I" laminations into two separate piles. An educated guess wi11 have to be made for the thickness of the paper gap. For plate currents of 200 -300 mills try a piece of paperback book cover. For currents of 75 - 150 mA a sheet of paper from this magazine should do. Assemble the "E" laminations into the core of the windings. If you can’t get the last remaining pieces in don’t worry, it will have little affect on performance. Cut the gap spacer to the proper dimension and epoxy the spacer between the "E" and "I" group. Insert the bolts and compress the laminations with a large vice or heavy weight. This forces the epoxy to fi11 into all the crevices between the "E" and "I" laminations. The epoxy step must not be eliminated or else loud talk back will result causing acoustic feedback not to be believed. If the work has been done properly, you now have a modulation transformer.

In configuration #2, the DC to the final is handled by an inductor. The usual rule of thumb is 10hy to every 1000 ohms of class C load impedance. This can be made up by series-ing up several power supply chokes. Smoothing chokes must be used. You can get away with as little 5hy per 1000 ohms of impedance with some loss in bass response. Since there is no DC imbalance in the transformer, no modification is needed and is a better way to go than figure 1. Low-end frequency response is much better and time is not wasted in transformer modification. In addition to these benefits, separate supplies may be used for the modulator and the final. The coupling capacitor used is a 4 - 8 mfd oil capacitor. More capacity can be used if desired. Electrolytics can also be used, but two must be used in a back to back configuration. A non-polarized unit such as a motor-start or run capacitor can be used also. The voltage rating in the case of a common supply can be very low; say 10% of the DC potential used assuming that its capacitance is great enough not to allow very low frequency audio transients to develop across the capacitor that would crap it out. If a rectangular oil type of oil cap is used, it is advisable to float the case above ground.

In terms of impedance matching here is a table of computed values with most common voltages found:



1000 VCT


900 VCT


800 VCT


700 VCT


600 VCT


500 VCT



Table 1. Impedance ratio with typical power transformers. Values in Table 1. are AC ratings of secondaries with 115-volt primaries. Values given are full primary to secondary in modulation service.

For example, to modulate a DX 60 with these parameters: 700 volt @ 125 mA presenting a load of 5600 ohms. This will present a load of app. 10K to which are a pair of 807s 1n ABl configuration. With 600 volts this will deliver close to 45 watts of audio required to modulate fully. A 500 Vct transformer, and a 10 mfd oil is found in your junk box with several filter chokes having values of 10 hy, 150 mA, 8 hy, 200 mA, and 16 hy, 150 mA. Combined they make 144 hy which is sufficient for our purposes. Once assembled, it is found that your modulator is performing much better than you thought; and the most expensive component, the modulation transformer cost you nothing at all, and was put together from otherwise useless junk. In the case of replacement of the modulation transformer in a DX 100 or Apache, where space may be limited, you can solid state the power supplies and move around components to make room for additional chokes or insta11 a restructured unit with gap spacer. This was done to an Apache w1th good results recently. In the case of a Viking Valiant, converting the HV supply to solid state and moving the screen dropping resistor provides plenty of room for two typical 10 hy, 300mA chokes. An old power transformer can be squeezed in place of the original transformer.

You may be wondering what to do with the filament windings. They can be used for a variety of things. A 600 VCT unit with a 6.3 VAC filament winding used with 5K PP load impedance will present a load of .5 ohm at the filament winding. This makes an ideal pick off point for monitor headphones. The voltage step down ratio is such that enough level will be at the filament winding to drive headphones or a speaker without blowing your ears off. You can also use the filament winding for a loop of negative feedback to an earlier stage in order to improve response and, distortion characteristics, or for an audio take of for trapezoidal scope pattern. GOOD LUCK!

My special thanks to Sue KB2IRH for redrawing & retyping this work.


TEN-TEC Compares AM to Illegal CB Operation.

(submitted by Jay Mathisrud, WB0L)

I received some literature from TEN-TEC recently. Included with the new catalog and magazine reprints was a sheet answering the most frequently asked questions about TEN-TEC gear. Here is one of the questions and answers:

5. WHAT, NO AM MODE IN TRANSMIT?! Not now, not ever! The best thing we can say about the AM mode, as compared to SSB, is that it developed some good CW ops. Maybe part of our hang-up is that we remember when AM was King. The phone bands were a sea of heterodynes even with a ham population less than half of the present count. Unless you had high power and competitive antennas, you were well advised to polish your CW skills. As many will recall, the transition to SSB was frequently an emotional issue and took a number of years. Logic, demonstrated communications effectiveness and the need for spectrum conservation finally prevailed and the transition was made by all. To re-introduce the AM mode on modern amateur radio transceivers, to our way of thinking, is as irresponsible as adding mode compatibility for illegal CB operation.

... Our priorities may not receive universal acclaim but we hope that they do match yours.


1185 Dolly Parton Parkway

Sevierville, TN 37862

EDITOR’S NOTE: Many AM operators have long maintained a good opinion of TEN-TEC, the only major remaining U.S. amateur radio manufacturer, even though their equipment has never included the AM transmit mode. Most of us just assumed that they omitted AM because they believed there was not enough demand for AM capability to justify the extra expense of including it in their transceivers. Most of us who have ever dealt with the company have been impressed by their friendly, helpful attitude, especially in servicing what they sell.

The attitude displayed in this literature is most distressing to those of us who include AM phone among our major interests in amateur radio, and it will no doubt cause many of us to take a second look at the Japanese imports, which universally include AM capability along with the other legal modes. I suggest that all AM’ers who are upset with this display of anti-AM arrogance drop the company a line and let them know how you feel – especially if this has influenced your decision to buy from their competition. While you are at it, it wouldn’t hurt to drop Yaesu, Icom and Kenwood a line to remind them that there is indeed a market in amateur radio for AM capability, and express your appreciation to them for including in on their product – especially if this influenced your decision to buy from them.

Perhaps Ten-Tec should be made aware of the response to the current AM petitions before the FCC, so that they would think twice about the market forces at work. A major reputable amateur radio manufacturer should strive to serve the entire amateur radio community, not to limit its clientele to the Robert Stankus and William Prechtl types within our hobby.


open forum

Editor, AM Press/Exchange:

Does Extra Class mean anything? The answer is no, by no means. It seems that lots of newcomers into the hobby are upgrading all at once to Extra. Yes, they have book smarts, but not radio smarts. No practical experience at all. Not just with radio, but with putting something together like an antenna, soldering or even knowing how the radio works. It’s sad but true. We’re just cranking out a bunch of radio-dumb people. Just listen on the air at night. Most QSO’s on SSB sound like CB or they only last 5-10 minutes. You have to hold most of the conversation. Very boring to me. I guess that’s why I like AM and CW. That’s where you have some of the best QSO’s nowadays. I’m not putting down SSB. It’s a great mode. I spent many years on it and still do it from time to time. My point is, the reason you have such good QSO’s on CW and AM is that first the people really care about their hobby and they have been around for a while. Second, passing a test and knowing all the answers to the questions doesn’t mean a darn thing. It’s what you learn from doing in the practical sense. I really think all of you who teach ham radio nowadays better sit down and start doing so. You just can’t teach rules and regulations and theory. Yes, even though Icom and Kenwood are out there, some young kids can’t afford them. So they’re stuck buying an older tube type rig. Nothing wrong with it. It makes for a great learning experience. You the teacher must take the time because it will make for a better ham operator. Not like the lids that are being cranked out today. Remember, you get out what you put into your product.

-Marty Drift, WB2FOU/5



Larry Szendret, NE1S is shown at the operating position of his yea-em mobile. TX is Elmac A-54H, RX is Gonset Super Six converter into original '63 Ford Falcon AMBC radio. TX power PE- 103 dynamotor. Antenna is Webster Bandspanner.


(Names Omitted - Past Copy)

FOR SALE: 1 KM CW-AM phone transmitter. Wood frame rack, pressed wood panels. 160-10 M. 6 ft. cabinet with blowers. $325. Pick up only.

WANTED: National HR05TA1 speaker and case (metal top, sides, bottom) and 7-14 MHz coil. Schematic needed for Johnson Valiant, owners manual (original) wanted for Collins 75A1.

WANTED: Socket for 304TH/TL triode. Also 6 to 10 A RF ammeter.

WANTED: Won’t give up till my AM P/X back issues are complete (and will gladly share with others when they are). Will pay quick and easy $1 per issue (plus postage) just to photocopy and return issues 1 through 50 (any or all).

TRADE: Will trade even a 4-1000A new for October, 1948 issue of Radio News, or a NC-270 or NC-155 receiver in good condition.

FOR SALE: Pick up only, TCK-4 transmitter with manual, $300. RBA-2 VLF receiver, built in AC power supply and manual, $100. RAO receiver (Navy NC-100AX modified) with schematic and NC-100 manual, $150. BC-348K receiver with built in AC power supply, $75 will ship. WANTED: RAX LF receiver, Gonset sM Comm. IV.

WANTED: Information on Air Associates, Inc. Aircraft Radio System type BR3T, clean unmodified NC-240D with speaker.

WANTED: Matching power supply for the Harvey-Wells TBS-50D in working condition.

WANTED: Disabled veteran desperately needs receiver. It can just be a one band radio (10 mtr. or 40 or even 2 mtrs) I also need a tape player for a 1983 VIC-20 computer or a 1540 disk drive. I am disabled and can’t work. I will pay postage. Won’t someone help?

FOR SALE: Johnson 275 watt Matchbox with built in SWR bridge $110. NC-300 $125. Bread slicer (new in box) Ca-dwell XE-240D $25. Dual Section 350, 1/8" spacing $25. I will ship.

WANTED: Modifications for the Globe King 500-C (especially modulation)

FOR SALE: Collection of old transmitting tubes, also transmitting variable condensers. WRL DSB 100 $70. WRL Globe Chief 90 watt CW rig $60. Apache $100. Collins 75S3 $300. Globe King 175 812A in final $200.

FOR SALE OR TRADE: Globe King 5OO with 755 VFO, also Air System socket and chimney for a 4-1000.

WANTED: Eico 730 modulator, 722 VFO, Heathkit Mohawk, Mohican receivers - work or repairable. FOR SALE OR TRADE: New Fox/Tango 6 kc AM filter for FT-901, 902, 101ZD, 107, 707.

WANTED: Manuals or copies for the following Clegg equipment: Clegg 99er, Thor 6, 22er and interceptor. Need schematics and alignment info.

WANTED: Military transmitter BC-191 or BC-375. I need the bottom plate with shock mounts also the plate that covers the tubes, and cables for same, and manual for BC-191.

FOR SALE: 2 Collins F25O A67 series 12V2 filters, offers. Hallicrafters SX101A, very good, $150, or best offer. Hammarlund HQ-180 XE with spkr, very good, $225 o.b.o. Hardline connectors: Phelps Dodge 7/8" X "N", $50 for 4 ppd. H.P. 608D test oscillator (10-420 MHz) $125. TEK RM45A scope, $75. G.R. 1862B megohmeter, mint $65. Lambda 5v./18a. regulated supply $20. TEK plug-ins CA, IL5 (Spectrumanal.), M (four trace), others. H.P. 520B. test oscillator (7-11 ghz), $495 ppd, or best offer.

FOR SALE: Johnson 500 $600* Valiant $200* Johnson 6 & 2 $45. 6 & 2 VFO $25. Johnson Invader 2000 $600* Hallicrafters HT-37 $125* Heath Marauder $100* Johnson Pacemaker $150* Collins 51J/R388 $150. Atlas 210X $350. Atlas 215X $350. Central Electronics MM-2 RF Analyzer $35. HP 2008, 200C audio generators $25 each. All equipment has been checked out, retubed and is ready to go. (*) will not ship: pick-up only. Call after 2000 EDST.

FOR SALE: Heath power meter 2 kw model HM 102 $35. Apache AM xmtr $100 mint. SSB adapter $50. Panaramic receiver adapter $45. 813 tubes with sockets $20. 805 $20. Heath Cantenna dummy load $20. new. HRO 60 rcvr with all coils $100. Modulation transformers LS-56 UTC $25 ea. 100-watt modulation transformer $20. 50 watt modulator 6L6 pushpull rack mounted $40 nice. Viking Valiant II with matching VFO $85. Limited supply of 4-1000A near new $75 each. 2 KW isolation transformer 115 to 115 volts $50. Several variacs $45 each.

FOR SALE: Class B driver and modulation transformers from KW AM rig; mod xfmr by Coto Mfg. Co. (maker of the "Coto Coils") $100. KW plus power transformer, mfg by Inca Div. of Phelps-Dodge, 7800 vct, rated 1.5 KVA CCS with pair of 872-A’s, fil transformer, $250. Both items pick-up only. Also many modulation, interstage, driver and filament transformers. 4 ea. HK-254 triodes, new in box, $50/pair or $80 for 4. Pair 813’s, $50. Pair 304TH’s $100. Pair 805’s $20. 100TH, $20. Other tubes, TM’s, SASE for list.

FOR TRADE: One Johnson 500 transmitter, new Peter Dahl low voltage transformer, very nice, will trade for Globe King 500 or T-368 or homebrew KW.

WANTED: Vintage 6 meter AM equipment.

FOR SALE: Collins 312B4/RE $130. National NC100ASD (WW2 general coverage rcvr) $80. NC200 Silver Anniversary with matching speaker (see 1940 QST) 8120. 7 coil seta for HRO with 175 kc if, $65. Two Central Electronics 20A transmitters $35 ea. 100V $90.QST mag. collection, missing 1 issue from mid 1920’s to Dec. 1975, 6 issues prior to 1920. Recently bought complete set. Sell my incomplete set for $950.


This is the AM PRESS - An amateur radio publication dedicated to Amplitude Modulation.

This is the AM EXCHANGE - offering FREE ADVERTISING to enhance the availability of AM equipment and parts.

SUBSCRIPTIONS $10 per year (12 issues) in North America. Classified ads (AM related) free of charge to subscribers and non-subscribers. Display advertising and foreign subscription rates upon request.

Edited and published by Donald Chester K4KYV

NOTICE: The purpose of this publication is the advancement of amplitude modulation in the Amateur Radio Service, and there is no pecuniary interest. Therefore, permission is hereby expressed for the use of material contained herein without permission of the publisher, with the exception of specifically copyrighted articles, provided that The AM Press/Exchange is properly credited.

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