Again AM power , A new view

Discussion in 'Amplitude Modulation' started by WA1HLR, Mar 20, 2018.

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  1. K5UJ

    K5UJ Ham Member QRZ Page

    I wasn't a ham when PHL was doing his thing but I don't think I would have been a fan. Wiseguys and juveniles who exploit loop holes and abide by the letter of the law while clearly and egregiously violating its intent, almost always wreck everything for the rest of us eventually. That's because the loop hole will get closed, and in a way that almost always imposes a burden and inconvenience for the rest of us. Thanks Fred (you lid in my opinion). He could have run 2 or 3 KW audio with his carrier and been plenty good copy, sort of like driving 80 in a 70 mph zone, but no. Fourteen KW? Lamborghini red lined on Lake Shore Drive.

    I wonder what that sounded like in an envelope detector. My guess was not good.
     
  2. AC0OB

    AC0OB Platinum Subscriber Platinum Subscriber QRZ Page

    The FCC should have awarded him with a plaque that said: "Innovator of the Decade." :D


    Pheel

     
  3. AC0OB

    AC0OB Platinum Subscriber Platinum Subscriber QRZ Page

    From the article:

    The harshness of his audio and sideband content made it difficult on adjacent frequencies. A result, many complaints filed from the SSB community.

    So were the SSBer's trying to communicate with him using the SSB mode? Sounds like sour grapes from the Slopbucket community.


    When cited, he told them about his methods of modulation they couldn’t measure nor have knowledge of its workings.

    Sounds similar to the same lame excuse the FCC used in not subjecting their investigators to high voltage as an excuse in the attempt to denigrate AM.


    Pheel
     
  4. AC0OB

    AC0OB Platinum Subscriber Platinum Subscriber QRZ Page


    I guess I would have to see a schematic of the PHL system to understand his system.

    So was his input power to the modulator 14kW? What was the efficiency of the modulator system in order to achieve DSBRC?

    Something just doesn't add up here.


    Pheel
     
  5. N2EY

    N2EY Premium Subscriber QRZ Page

    I was a ham then, though I didn't know him. I heard about his.....exploits......third-hand.

    Exactly. FCC finally got tired of his antics (and some others) and changed the rules.

    In those days, FCC had an office in Philadelphia, so it was a quick drive up the Schuylkill Expressway to his location.

    I don't know, never heard it.

    73 de Jim, N2EY
     
  6. N2EY

    N2EY Premium Subscriber QRZ Page


    He ran a pair of really big tubes (3CX3000s) as a balanced modulator, same as used in SSB.

    The best I can offer is that he reportedly had some articles in CQ during the 1960s/70s describing his "Advanced Modulation" system.

    73 de Jim, N2EY
     
    Last edited: Nov 28, 2018
  7. N2DTS

    N2DTS Ham Member QRZ Page

    I think some rigs had the ability to control the amount of carrier power separate from the audio power.
    I thought the ft101 and other older rigs could do that.
    Just run it into a big amplifier and turn the carrier power down.

    I think it would sound nasty no matter how you received it.
    Anything over 120% is bound to sound bad in most receivers.

    I guess there have never been any shortage of rude selfish hams on the air.


     
  8. N2EY

    N2EY Premium Subscriber QRZ Page

    Maybe. Point is, FCC clearly got tired of Fred's shenanigans and went the PEP route as a way to shut down ALL such game-playing.

    There's an old saying I recently learned:

    "Mom (or Dad) doesn't want fair. Mom (Dad) wants quiet."

    My 1971 License Manual shows that as 97.73. My 1962, 1954, 1951 and 1948 LMs show it as 12.133. Wording is the same...but Fred's counter would be that what he was doing wasn't "A3 emission". Right.

    He pulled the tiger's tail once too often - and we all got bitten.

    73 de Jim, N2EY
     
  9. K4KYV

    K4KYV Subscriber QRZ Page

    I'm not sure he ran 14 KW of audio. That may be an urban legend, probably more like 5 kw. I recall he ran 600 watts DC input to the final with several kilowatts of audio. I visited him one weekend back around 1971 or 72 and he showed me the rig. He had already dismantled the big "upside-down tube" DSB transmitter, but still had the modulator components on hand. The modulation transformer was a custom made UTC unit that looked very similar to the LS-691 I have, which is rated at only 1 kw of audio. Fred's may have been capable of 3 to 5 KW of audio, but I doubt it would have handled 14 KW. I recall that his modulator tubes were some kind of external anode triodes, but I didn't remember the type. When I visited, he had converted the rig to a linear amplifier and was transmitting SSB; his wattmeter showed up to 5 kw on voice syllables. I think that meter read average power, not pee-e-pee. He used the big rig primarily to talk to a group of friends in Australia early mornings on 7295 kc. I think the primary purpose of the upside-down tube circuit was not to run a super-modulated AM signal, but to circumvent the FCC power limit by running a "legal" 5 kw-plus on DSB, far more power in each sideband than one could achieve with SSB at 1 KW DC input. I suspect that after the FCC cited him for his high-level DSB signal, he just said hell with the loopholes and legalities, and ran several kilowatts of SSB. His 40m antenna was a cubicle quad on a 120' tower with a 4-sided footprint that had a built-in stairway for climbing. With all that power and the antenna, working VK/ZL was like talking to locals.

    It was some time around 1957 that the FCC cited him for spurious sideband products outside the ham band. Even though his signal was clean and well within the standards of good engineering practice, the letter of the rules at the time stated that any detectable sideband products outside the ham band were to be considered illegal out-of-band operation. Normally they wouldn't have bothered anyone over a few weak products from a signal that clean, but they were determined to zap him any way possible, and used the presence of detectable out-of-band sideband products as justification for the citation. His penalty was a 6-month licence suspension. It was a few years after the suspension that he abandoned super-modulated DSB and converted the rig to over-power SSB.

    With an envelope detector, I remember his signal sounded very distorted. It would have been perfectly clear with a synchronous detector, but most hams copied him in SSB mode using a narrow filter that received only one sideband. The only advantage of the DSB might have been a sort of diversity reception, where one could switch sidebands at the receiver in case of QRM. For a while he was active on 3810, at the bottom of the 75m phone band at the time and that's where I used to work him. His 75m signal always drew a great many SSB hecklers.
     
  10. N2EY

    N2EY Premium Subscriber QRZ Page

    The number is from the article I linked to.

    The article says 3CX3000s

    According to the article, his tower was actually scaffolding made for the military. With proper guying, he was all set.

    1960, actually:


    upload_2018-11-27_22-11-33.png
    upload_2018-11-27_22-12-50.png

    I think the real "advantage" was that, in his mind, his system was legal. An SSB amplifier running that much power would not be.

    Which is understandable....

    His being able to work VKs and ZLs on 40 almost at will was, IMHO, due as much to his location and antenna as it was to the power level.

    It is quite interesting to me that the FCC remembered his shenanigans more than 20 years later, when they changed the power level.

    73 de Jim, N2EY
     

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