The AM Press/Exchange

ISSUE NUMBER 77                                      NOVEMBER, 1989

On A Roll

Following the FCC's 220 mhz decision by a matter of months, maybe the AM power issue couldn't have come at a better time. The 220 mhz matter shocked many members of the amateur radio community out of their apathy into widespread concern that the FCC is trying to "do in" amateur radio for the benefit of commercial interests and because the Commission perceives amateur radio as a pain in the neck to administer. Suddenly, any action by the FCC that is seen as taking away existing frequencies or operating privileges is treated as a matter of serious concern. The ARRL has asserted that it will oppose the loss of any existing amateur privilege. The amateur community has put the FCC on the defensive, and it looks like the 220 mhz issue is headed to the federal courts. The AM power issue is made-for-order to become an integral part of this larger issue.

The FCC, acting on no widespread consensus on the part of the amateur community, arbitrarily decided to reduce a privilege enjoyed by amateurs in the U.S. for over 60 years: the privilege to run a fully modulated DSB AM signal with approximately 750 watts of carrier power to the antenna. This is a loss not only to a handful of AM'ers, but to every amateur radio licensee in the U.S. Following the FCC's logic that peak envelope power is a relevant standard for all modes of emission, then every licensed ham in the U.S. will by definition lose 3 dB of power privilege in June 2, 1990.

A few AM'ers have taken the trouble to contact their ARRL Division Directors, and the response has so far been positive. There has not yet been any news of opposition among the Directors to somehow permanently extending the grandfather clause. A couple of the Directors have mentioned bringing the matter up at the Executive Committee meeting. It will be interesting to see what is reported when the minutes appear in QST.

The most critical need now is for each and every Director to receive enough input from the membership to convince them that this is indeed an issue of significant concern. A momentum presently exists within the amateur community to re-examine recent decisions by the FCC. All we have to do to join this bandwagon is to let ourselves be heard in a firm, but positive, responsible manner. To those AM'ers who don't want to bother to get involved because they "know" the ARRL and FCC "won't pay any attention," would you have believed just a month ago that there would now be holes in the Berlin Wall? The citizens of East Germany have just shown the world what a potent weapon "people power" can be. The events over Veterans' Day weekend were like an overdue breath of fresh air at a time when the news has so long been monotonously negative and depressing. To extend the analogy, the 1990 AM power reduction is not yet carved in stone. The division of Berlin was, and now those stones are crumbling. Has the Director in ARRL Division received any mail over the AM power issue?


Flash! AM Power Issue Discussed at ARRL Executive Committee Meeting

According to the minutes of Meeting Number 435 held in St. Louis, MO on October 21, "The Executive Committee discussed, without taking formal action, the status of the special exemption for AM transmitters in Section 97.313(b) of the Commission's rules." (see Minute no. 2.6.3, page 54, December 1989 QST)

The good news is that we at least have a foot in the door. The issue was discussed at the EC meeting, even though the minutes did not say exactly how the issue was treated in this discussion. We are now undoubtedly in a very critical period. All AM'ers who are League members are urgently requested to immediately write to your Division Directors, or better yet, call them on the phone, to express your concern over this impending loss of amateur privileges. All Directors' names, addresses and phone numbers are listed on page 8 of any recent issue of QST. If you have already contacted your Director, a follow up communication wouldn't hurt. Now that the momentum is going, we must not let this matter lose steam and die. Remember, the AM issue must compete with other current amateur radio matters such as no-code, the 220 mhz situation, upcoming WARC conference preparations, etc. Directors who have not yet been contacted must now hear from the AM community. Those who already have heard from us must be reminded to keep this issue on the Board's agenda.

Now that the matter has been mentioned in QST, there is another reason why we must make an extra effort to keep in touch with the Division Directors. Not all members of the amateur community share our enthusiasm for AM on the ham bands, and the Directors are now
likely to begin receiving mail from some members opposing extension of the grandfather clause, and possibly urging the elimination of AM altogether. Our chances for success will be greatly enhanced if any anti-AM mail is overwhelmed by the volume of mail in support of AM. Since AM'ers are in a minority, especially among ARRL members, we have to be much more actively involved in our lobbying efforts than the anti-AM elements within the amateur community.

S.P.A.M. Drafts Petition For Rulemaking on AM Power Issue

AM P/X has received a copy of the first draft of a petition for rulemaking requesting the FCC to reconsider the AM power reduction, from Norm Scott, WB6TRQ, S.P.A.M. President. A copy was also forwarded to Fried Heyn, WA6WZO, Southwest Division Director and S.P.A.M. member, requesting his help in getting this issue on the January, 1990 Board of Directors meeting.

We must emphasize that no petition has actually been submitted to the FCC as of yet. This is a first draft, a working paper that is being circulated; S.P.A.M. is seeking input from the AM community on this issue. Norm suggests that we should wait until after the ARRL Board of Directors meeting to see if we can get League support. If not, the final draft petition should be on its way to the FCC by the end of January, 1990.

The petition is lengthy (12 double spaced typewritten pages), so we will not attempt to reproduce it in full this issue, but we are providing a summary. In some instances the wording has been slightly revised for the sake of conciseness, but we have made every attempt to accurately report all the main ideas.


The petition will set forth new facts and analyses to show that the use of the p.e.p. measurement standard to indicate the interference potential of an AM signal is erroneous. It will demonstrate to the FCC that the 3 dB power loss will have a greater impact today because of renewed interest in AM and how many 1 KW AM transmitters will be affected. It will provide evidence that p.e.p. meters have errors of 3 dB when measuring AM DSB emission. The petition will suggest changes to standardize the amateur service with all the other services which use power output limitation to control interference.


The power output standard should be equal to the amount of recovered audio regardless of the emission used. The interference potential of an AM signal is 6 dB lower and not equal to that of the SSB signal with the same output. In fact it is the AM carrier that has the most potential for harmful interference. The most useful purpose of p.e.p. is to measure the capabilities of a linear amplifier, which is why the standard was developed in the first place. The greatest interference potential from an AM signal is not the apparent power in the sidebands. Other services which employ AM control interference by limiting carrier power output. Probably no other service is as tightly regulated as AM broadcasting in terms of interference control. The FCC amended the AM broadcast regulations a few years ago to allow stations to run 125% positive peak modulation. In terms of p.e.p. this is a significant power increase, yet stations running extended positive peak modulation were not required to reduce their carrier power.

Adverse Impact

From about 1960, operation of AM in amateur radio was on the decline. At that rate, by 1990 amateurs would have stopped using AM. S.P.A.M. members have worked very hard to turn this situation around. In 1983 S.P.A.M. had 362 members; today there are over 1000 members and S.P.A.M. is still growing. It is estimated that there are 423 commercially built one kilowatt AM transmitters and over 1000 homemade units in operation in the U.S. today (the source of these statistics is not documented. -Ed.). With an average cost of $1000 per transmitter, the value of this equipment is $1,420,000 not including the thousands of hours amateurs have spent building or restoring this equipment.

Standardize Output Measurement

The amateur service is the only service to try to use a p.e.p. standard to control the interference potential for all 14 authorized emissions. In (14 C.F.R. 2.985) Measurements Requirements, are listed the methods for measuring the power output for all type-accepted radio equipment. For transmitters which have emissions with carrier, the power output is measured by carrier output. For transmitters which have suppressed or controlled carrier, the output is measured by the p.e.p. standard. Of 14 authorized emissions in the amateur radio service, all but two contain carrier. For emissions with carrier, the carrier power output standard is the recommended standard in the C.C.I.R. (international telecommunications) guidelines.


The following amendment is proposed for the amateur radio power limit:

97.313 (b) No station may transmit with a transmitter carrier power exceeding 1.5 KW. Emissions with suppressed carrier are limited to a maximum of 1.5 KW PEP.


The methods and standards proposed in this petition are not new, but have been around for years, used each day to control interference in other services. FCC enforcement personnel are already familiar with the test procedures and would not need additional training or equipment.


The technical evidence shows that the interference potential of a 100% modulated AM signal is not equal to four times the carrier power. The appropriate power standard is based on the class of emission, and most services follow the C.C.I.R. guidelines. The use of both carrier power and p.e.p. standards are justifiable because of the number of authorized emissions in amateur radio which are subject to the power limit.

At issue is not the fact that only one percent of amateurs happen to engage in AM operations. An inappropriate standard is still inappropriate no matter how many amateurs it affects. The FCC committed itself to a review of the power limit before June, 1990, if it appears to be justified. We have used the time during the grandfather period to gather the facts and explore other remedies. If this matter cannot be resolved before June 2, 1990, we request an extension of the input power standard for AM DSB emission until the Commission can consider our petition.

Editor's Note:

S.P.A.M. is seeking input from the AM community on this issue. Please address all comments to S.P.A.M. (Address removed, article is from 1989) You are welcome to forward a copy of your comments and opinion to AM P/X for possible publication.

10 Metres: Gateway to AM

The most effective way to preserve AM on the amateur bands is to attract the interests of more hams. We have an excellent opportunity to do this now that 10 metres is open during the high part of the current sunspot cycle. Most HF transceivers on the market today have the capability of transmitting high quality, true double sideband AM albeit low power, and many of these rigs have excellent AM receivers.

Until recently, use of the AM mode on these transceivers was frustrating for the average uninitiated amateur. 10 was dead, and the 25 to 40 watts output on AM was ineffective on the crowded 75, 40 and 20 metre phone bands where the big guns hang out. Linear amplifiers are tricky to tune up on AM, especially for the technically inexperienced, so the AM position on the mode switches of most of these transceivers have remained unused. But now that 10 is open, low power operation is possible with excellent results. Using a simple but effective antenna such as a dipole or ground plane, the low power AM signal from a transceiver can work coast to coast and round the world, with strong, high quality, pleasant-to-listen-to signals, and the QRM is usually minimal, and bandwidth is not so much a concern.

Let's take advantage of this excellent opportunity to get more amateurs interested in AM. Talk up 10 mtr. AM at local ham club meetings and hamfests. If you operate 10 m. SSB, why not invite your contacts to QSY up to 29.0-29.2 and try out their rigs on AM. It may take some patience to talk some of your contacts through the procedure of getting their rigs properly adjusted on AM transmit (the instruction manuals are woefully inadequate in explaining the principles of AM transmitter adjustment), but the results will be worthwhile if more hams are bitten by the AM bug. The relaxed, QRM-free, hi-fi QSO's possible on ten are bound to attract newcomers to AM, if they can only be persuaded to try it the first time.

Once the 10 m. AM'ers are hooked, they can be guided through the lower bands and introduced to higher power rigs available today, including government surplus, old broadcast transmitters, vintage equipment, homebrew, and AM linear operation.

While the band is open for the next few years, let's maintain our highest profile on 10 metres. AM newcomers can later be guided to the lower frequencies via 160, where the QRM is also minimal, especially above 1840 khz. With their fledgling operation on AM a pleasant success, these hams will eventually gain the experience necessary to tackle the greater challenge of 75, 40 and 20-metre AM operation. The very survival of AM on the lower frequency ham bands may depend on whether the AM community today takes advantage of this golden opportunity!

W1AW Shuns Amateur Radio "Appliances"

An interesting commentary on "state-of-the-art" amateur transceivers appears in December, 1989 QST. In a feature article displaying the renovations at W1AW, the reasons are given why the League chose to equip its bulletin station with transceivers made by Harris Corporation for commercial service, instead of the more familiar equipment manufactured for ham use.

Since the station is on the air 10 hours a day, 362 days a year, at a thousand watts out, the transmitters had to be rated for punishing duty no ham rig will encounter. The possibility of using regular amateur transceivers and amplifiers was explored with several manufacturers, but that idea was soon abandoned. If ham rigs were designed for this kind of service, few amateurs would be able to afford them.

The number one problem with amateur radio equipment is what engineers call Mean Time Between Failure. If you take the cover off any 1980s ham transceiver, you will encounter another major problem: serviceability. Commercially built ham rigs are not easy to work on. Individual hams can afford down time but W1AW cannot. Finally, it is explained, there was concern over the constant changing of commercially built ham gear. W1AW was looking for many years of service from this equipment. They could have ended up stuck with radios no longer in production, and as many hams already know, repair parts would eventually become difficult to obtain.

In the past, the ARRL's lab engineers built custom rigs, and it was originally recommended to go the homebrew route. But it was decided that the lab engineers would be taken away from their regular duties such as testing equipment for QST product reviews and building and testing projects for the Handbook. Otherwise, outside help would have to be hired and construction facilities set up for a one-time project. The League decided that commercial service gear was cost competitive when all the intangibles of homebrewing were figured in.

- QST, December 1989, pp. 14-17

"AM'er" Accused of Jamming Earthquake Relief Efforts

The following item appeared in the October 27 issue of Westlink Report:

Organized malicious interference to HF nets--and the apparent unwillingness of the FCC to solve the problem--was the single greatest handicap to amateur radio relief efforts following the devastating 6.9 magnitude earthquake that hit northern California on October 17, according to Frank Collins, N6TAF, who runs the Veterans Administration Hospital amateur radio station in Los Angeles. Collins, who brought the VA station on line immediately following the quake, says that he cannot believe fellow radio amateurs----even its lunatic fringe-could possibly act this way in light of the massive devastation: "We got on 20 meters, and we have a guy singing on AM-he is in the AM mode-and he is singing 'The Star Spangled Banner' and 'Glory Glory Hallelujah.' And we have these others who get on there and tune up their radios and make comments like, 'You can't help nobody in the disaster area!' Well, why don't they watch a little television and see some of these kids that are being pulled out of crushed cars. I mean, even the hope that you give people by trying to help them is a lot better then saying, 'No, we can't do anything because we have a jammer on frequency.' This is the lunatic fringe [of amateur radio] and maybe in the future we ought to have psychiatric testing to get an amateur radio license!"

The jamming definitely seems organized. Collins noted that three or four interfering stations would band together to harass a net that is in operation and then move onto the next one. And no band seemed to be safe. Collins noted that the malicious interference seems to follow the flow of disaster communications: "We had three Veterans Administration hospitals on line on 14.287 MHz and it was intentionally jammed between the Long Beach VA and the West Los Angeles VA. And we were also on 40 meters and had a station come on there and say 'you can't help those people up in San Francisco, and good riddance, we won't have to worry about the AIDS epidemic.' That's one of the comments that was made."

Collins said that his people were unable to contact the Cerritos, California FCC office to request assistance in keeping the QRM clear of net operations: "The number is busy all of the time." He says that he spoke with the FCC in Washington, but they were unwilling to act, referring him back to the Cerritos office which could not be reached.

In view of our efforts to gain support for the AM cause in the impending AM power issue, this is the kind of publicity we don't need. Nothing in the story suggests that the offenders were regular operators of AM or members of the AM community as we know it. With widespread availability of AM equipment in the form of multi-mode transceivers, there are thousands of lids with instant AM capability. Any one of them could decide to jam emergency traffic with his appliance in the AM mode. Nevertheless, any news report connecting AM with such activity is likely to give us a black eye in the mind of the greater amateur community, and this can be especially damaging in light of the tenuous position of AM in amateur radio at the present time.

open forum

Editor, the AM Press/Exchange:

I was greatly saddened to learn that W2VJZ was cited by the FCC for "Broadcasting." Up until 1-1/2 years ago, when I was located on the east coast, I used to work W2VJZ almost every day. I never considered Irb's actions and comments made to me during our QSOs a violation of the rule against broadcasting. Of course his comments were many times critical of the establishment. He was fighting "City Hall" for many years. This we should try to understand. Is freedom of speech an illusion? I thought it was guaranteed by the U.S. Constitution. (So did Irb.)

I also listened to K1MAN playing broadcaster on 75, (My letter to him objecting to his actions went unanswered.) I feel sure that Irb's actions were brought on by the lengthy un-checked useless broadcasts of K1MAN. These were a considerable thorn in the side of east coast AMers on 75 since they always began on top of QSO in progress.

Why was not K1MAN not cited by the FCC for "Broadcasting?"

Byron H. Kretzman, W2JTP/7

Editor, AM Press-Exchange:

Many of us have dedicated hundreds of hours of our personal time of late in the collecting of petitions, writing of letters, presentations to League officials, and presentations to ham clubs in the promoting of the positive side of AM in the attempt to keep our present power limit- in fact, to even just keep AM operation legal in the face of strong opposition from many amateurs. And along comes W2VJZ who by his childish on the air tantrums designed to deliberately get the goat of the FCC and amateur community in general has probably undone much of the goodwill generated by our sweat and financial commitment to the AM cause.

If W2VJZ wishes to exercise his constitutional rights of free speech in such a manner in the future, I recommend doing so on SSB rather than on AM. Better yet, I recommend that he turn in his ham license entirely and continue to operate with a "handle" as the CB operators do. Hell, since the Constitution guarantees us free speech and freedom of assembly, no radio license should even be required in the first place, by golly, and Irb could really make a statement by doing so.

Thanks, Irb. I sincerely appreciate your help. Hopefully you can continue to look like a self centered idiot as well on SSB after they cut our power back and finally outlaw AM operation thanks to your confirming the League's and FCC's worst feelings about AM operators being a bunch of selfish, band hogging Neanderthals.

Bill, KD0HG


Jim Taylor W4PNM

There comes a time during the normal course of human events when we all must evaluate our existence (AM) and make a determination as to whether or not we want to take a hard stand for our right to operate AM.

First, my topic of course is the Preservation of AM for those of us who enjoy the old fashioned mode. Also, to introduce this old outmoded style of modulation to the newcomers. Have you noticed the SSB rigs on AM, those signals emitting from SSB rigs with amplifiers are coming for the most part from SSB oriented hams who happen to tune across the AM signal, and liked what they heard.

Have you ever considered the newer ham licensed since the 60's has not had any choice but to buy an SSB rig. My son is a prime example. He just recently got back active on the air with his Drake Twins, and he finally got around to asking me what all this talk is he hears about AM. His next statement was, "I don't know anything about AM, it looks too complicated". I had MY chance to let him it on the nostalgic kick I have been on for going on 7 years, now. Believe it or not with his father ( me ) and his grandfather W8DFV Chick, both old AM operators, he has never been exposed to AM operation. How you like them apples?

Well, I have given him a few choice words, and directed him to get on AM if he wants to talk to us! But, unfortunately it is not that easy when it comes to the other non-AMers. So, the way I see it we must do something special to attract more interest.

Lets start with setting an example! Our operation on the band should be beyond question. Our signals should be the best we know how, and our operating procedures should be the best also. Let us welcome anyone who sounds like they would enjoy AM. Let us encourage them to get or help them build a AM high level plate modulated transmitter. All this is very mindful of the days when some of us progressive guys promoted SSB with a fever! Starting in 1955 while in the employ of Collins Radio, I was one of many who traveled around the country promoting SSB. We went to all the radio clubs we could get to, and talked about the features of SSB. Slowly but surely we sold the world on that mode. Now, I hate to admit that I played a very important part of that switch over. On behalf of Collins, I tried to give a KWS-1 and 75A-4 to W1AW, and they refused! Now, we should be trying to get W1AW back on AM!

All of us should go to as many hamfests as possible, in groups and organized if that's possible. We all I should make a strong effort to promote AM as a high quality mode of transmission. Some time ago I read Don Chester's remarks regarding bandwidth usage. The SSBers make no bone about our wide bandwidths, and chastise us for using too much. If that be the case, as Don says, how can they defend SSB when CW would take much less than they use. The answer to this, of course, is our licenses give us the privilege of operating any mode we wish. Sure, we use more bandwidth, but we sound much better. I guess that's a trade off to some degree.

Let's take a look at our so-called AM windows. The most familiar to me is 3885. There are many nights I hear no AM activity on there at all. When that occurs, the SSB signals move in, then when we get on we are the culprits. What's the answer to that dilemma? The way I see it, it is the need for more AM activity in the AM window. I hasten to mention, that as long as there is activity the SSBers will stay clear, that steady heterodyne drives them crazy. There have been many times, while listening I hear SSBers from the south, and AMers come on up north, and the SSB operators pitch a fit. About that time I must admit I take advantage of the situation and turn on my rig and start talking to those big AM signals from the north. When I do that, you should hear them. I am not talking about a deliberate plot to QRM, but rather a slightly off frequency maybe a couple Kc away. They don't like it and often I'm challenged. My standard answer to them is, I don't own the frequency and they don't either! I advise them they have chosen to operate in the middle of the AM window, and more AMers than not are crystal controlled. If they won't operate in the AM Window I promise not to operate in the SSB part of the band. Most of the guys will accept my kind dissertation, there are a few that want to dispute it, but my opinion is, if there was constant activity on there, they wouldn't have to inclination to get on the frequency in the first place.

For those of you who were not present at the Atlanta hamfest last year, you missed me running around with my special shirt that says, AM Kilowatts Forever"! A little corny I suppose, but very effective! Because a multitude of hams asked me what it was all about. The AMers who wish they were still on AM came out of the woodwork and identified themselves. I would like to think I encouraged some of them to get back on.

The thought in this article is to promote AM, but do it in a leadership way. Encourage those bored to death SSBers to get back ( or get on ) a mode where intelligent conversations can be had. The mode where hams are really hams, and know something about radio, and are willing to help their fellow ham with a problem instead of complain. Let's all be hams in the true sense of the word. Be leaders, and the rest will follow, when they hear those nice big beautiful signals, and the voices behind the signal have something to share!

Old Pushbutton Light Switches Wanted

AM P/X readers came to the rescue when I was looking for the brown glazed ceramic tube sockets and Sangamo mica condensers. Now, I am asking for your help again for my personal collection of old radio and electrical devices to be used in a restoration project.

I am looking for old style push button 110-volt a.c. light switches, as shown in the illustrations below. Every day, old buildings are electrically rewired or torn down, and this sort of old electrical hardware is tossed out. Few antique collectors or nostalgia buffs seem to be interested in this sort of thing, so not only are these switches and cover plates unavailable new, but practically no antique/collectables dealers bother to keep them.

Check your junk pile, and if you have any of these lying around, in any condition, I am interested in begging, buying or trading for them. I am also interested in cover plates, especially solid brass or bakelite. I will gladly pay a reasonable price plus shipping costs.


Donald Chester, K4KYV
Editor and Publisher, AM P/X

Final Amplifier Tube Modification for Viking I
by Ronald G. Reu WB0LXV

I recently obtained a Johnson Viking I transmitter in fairly good condition. And as with all my transmitters I try to obtain a few extra tubes to serve as spares. As many of you know, the 4D32, which is used in the Viking I and some Collins transmitters, is very hard to obtain. Fortunately though, I was able to obtain the original assembly manual with the transmitter.

I was quite surprised to find in the back of the manual a description of changes required to use an 829B as final amplifier. I had never considered the 829B as a substitution for the 4D32 because the 829B is a dual tetrode where the 4D32 is a single tetrode. However, the tube tables in my 1949 Handbook lists for interelectrode capacitances for each section of the 829B to be 1/2 that of the 4D32. That means when both sections are placed in parallel, the interelectrode capacitance closely equals that of the 4D32. There are a few other changes in the description to take into account different screen voltage requirements and different pin connections. The tube socket required for the 829B is the same as the 4D32 socket, so that doesn't have to be changed.

Old 4D32 circuit

New 829B circuit

In case you are not familiar with the 829B, the tube was quite common on the surplus markets from just after WWII up to about 15 years ago. One can still obtain them for very reasonable prices at flea markets if one shops around. Fair Radio sales used to have a bunch of them. I don't know if they have any more or not. The 829B can be tested on the military TV-7A/U tube tester provided you have proper adaptor that was usually supplied with the tester.

One note of caution in handling the 829B, the glass envelope surrounding the plate pins is extremely fragile and any attempt to put strain on the plate pins will cause the envelope to break. I found this out the hard way several years ago when I was building a transmitter for 10 and 6 metres.

I have enclosed a copy of the instructions as found in my manual for the conversion. I suppose the Collins transmitters could be converted in a similar manner.

Of course if you have a supply of 4D32's tubes, conversion would be meaningless to you. I intended this article for the person whose transmitter is off the air because of a blown 4D32. I am in the process of converting my rig to use the 829B and I don't foresee any problems with it. If I have any problems or suggestions I will send it in to the AM/PX. Good luck.


Changes required for use of 829B final amplifier.

1. Turn coupling capacitor C31 down towards chassis to keep the plate leads short.

2. Connect another parasitic choke (L11) to C31 by means of a solder terminal.

3. Connect a plate terminal (Johnson 119-848) to each of the parasitic chokes L11.

4. Leave pins 4 and 5 of socket X7 grounded to the chassis, but remove the ground lead from pin 7.

5. Remove filament wire from pin 7 and connect filament lead to chassis by means of a solder terminal under a convenient screw.

6. Connect pins 1 and 7 together with #20 wire.

7. Remove the ground lead of the filament bypass capacitor C40 and re-connect to ground on the socket mounting screw near pin 1.

8. Remove C28 lead together with the grey screen grid lead from pin 2 and connect to pin 3.

9. Either change screen dropping resistor R28 to 12,500 ohms 20 watts, or connect a 3,000 ohm 10 watt resistor in series with R28.

10. Remove capacitor C25 and choke L6 from pin 6.

11. Connect a jumper of #14 wire between pins 2 and 6 allowing it to bow upwards 1/2".

12. Re-connect C25 and L6 to the center of the jumper to provide balanced drive to the grids.

Adjustment: With the final amplifier loaded to approximately 230 ma., the voltage divider tap should be adjusted so that screen voltage is approximately 225 volts. This screen voltage setting should provide about 80 ma. no audio signal cathode current in the 807 modulators on the "phone" position.

Typical operation using 829B final within ICAS tube ratings.
CW operation with 115 V 60 cycle ac input:

Phone operation with 115 V 60 cycle ac input:


SCREEN GRID VOLTAGE 225 volts (loaded)

SCREEN GRID VOLTAGE * 225 volts (loaded)
P.A. PLATE VOLTAGE 660 volts (loaded)

P.A. PLATE VOLTAGE 620 volts (loaded)

P.A. GRID BIAS -97 volts

P.A. BIAS VOLTAGE -97 volts



* - 13,000 ohm screen dropping resistor used.


W2IQ station

May 1989 Rochester, NY hamfest

Do radio listeners want HIGH FIDELITY?

Reprinted from Electronics February, 1934

In all of the talk about improving the broadcast system, one question remains unanswered, and points to a very fundamental problem. Do radio listeners want wide-range tone transmission and reception?

Transmission engineers believe that broadcast stations should handle equally well all frequencies out to 7000 or 8000 cycles. Many of them feel a reallocation of broadcast channels should be made on this basis.

Some receiver engineers claim the average listener does not want such wide-range transmission. They point to the fact that tone controls on modern sets are nearly always turned as far as they will go toward the bass, and away from high notes.

This difference of opinion is of vital importance. The cost of broadcast-station equipment, cost of receivers, cost of telephone lines, cost of preparing programs, the number of stations that can be put into the broadcast spectrum, the musical appreciation of millions of youths growing up in radio homes--all these matters are vitally concerned with the proper settlement of this difference of opinion regarding high-quality broadcasting.

If people do not like notes higher than 3000-4000 cycles, all the past musical experience is wrong. To judge by the best of present day "high-quality" receivers there is little use in transmitting much beyond 3500 cycles. But it is extremely difficult to believe this to be the fact. Certainly the experience in sound pictures does not bear this out. Higher fidelity has resulted in keener appreciation by the lay audience, and no one would go back to the poor-quality reproduction of the early days.

If people like high notes in the original music but do not like them from their radio, something must be wrong with the radio system. If the trouble is static, higher power is the answer. If the trouble is distortion products originating in transmitter or receiver and appearing in the higher portions of the audible range, the answer is clear. If inter-station racket or over-modulation is the trouble, the solution is evident.

But before going much further in the discussion of improving the broadcast system, it seems imperative that a clear-cut answer be found to the questions raised by proposing to widen the tone range. Do the listeners want the high frequencies that make for high fidelity?

West Coast AM Report

AM is going well on 75 metres. There is activity almost every night 9 to 10:30 PM. The center of gravity of AM activity has moved northwards. More stations showing up in Oregon, Washington and Northern California. Southern California has kind of slowed down. N7JW has a Johnson Desk going from Las Vegas, Nevada. N6UR, Bakersfield, CA, has a KW-1 on. Various Viking Rangers have appeared up and down the coast. 160-metre AM is almost nil; the band is not in good shape and amateur activity in any mode is very light. 40 metre AM activity is just Sunday S.P.A.M. sked and weekend nights.

-Fred Huntley W6RNC

(Contact information removed; this issue is from 1989)

WANTED: 833A tube for display. W6RNC

WANTED: Diagram and instructions for alignment of a "Knight" 10-tube communications receiver. Also wanted a 60-watt modulator.
FOR SALE: T-368 assemblies - modulator exciter $15. RF exciter deck with 6000 tube $25. 11 Hy 500 MA choke $15. Large rotary inductor, 14 uH, #8 silver wire, $35. Tube testers, Heath IT-17 with roll chart and manual, $35; Hickock "CardMatic", $50. Will horse trade - I need tubes 8008, 304TL. Bill, KD0HG

WANTED: VFO for Harvey Wells TBS-50 transmitter. Working or non-working. Pat, WB9GKZ

WANTED: UTC audio transformers LS-18 and LS-49. K4KYV

FOR SALE: Both excellent, DX-100 $100, National NC-184D receiver $100. You pick up. I can't see dials. W2TGK, Ralph Heerkens

FOR SALE: Viking Ranger, good condition, works, with manual $120. Bill Drager, K3UMV

WANTED: Stancor ST-203A 10 meter mobile xmtr. Rich Smith, KF6EA

FOR SALE: 810 tubes (6 ea.), look like new, but probably used. $60 plus shipping. 4-400A broadcast pullouts, full output, 3 ea. $100 plus shipping. John Basilotto, KC2EH

WANTED: UTC S-62 filament transformer. James T. Schliestett, W4IMQ

FOR SALE: Viking II with VFO excellent $150. Viking II fair $75. WRL Globe linear $100. WRL Globemaster SR. $100. PE103 Dynamotor $35. Small prop pitch $100.
WANTED: Schematics on BC110 and REL # 206 early transmitters. Parker, W1YG

WANTED: Collins 75A1 receiver in good working condition and good appearance with manual. WX4C, Don Landes

FOR SALE: Dow Coaxial relays 110 volts, $20 each. Variacs 115 volt @ 15 amps $45 each. Two 19" rack enclosures black $40 each. Tubes, 807 $3 ea. 1625 $2 ea. Inquire on others. Levy

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

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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.