Questions about AM mode

Discussion in 'Amplitude Modulation' started by KI5OMM, Jul 2, 2021.

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  1. N1BCG

    N1BCG Ham Member QRZ Page

    In the Part 97 world, sure, but I doubt you'll see one at a hamfest.

    Exactly.
     
  2. KC2ZFA

    KC2ZFA Ham Member QRZ Page

    nobody ever made an image like this for a Nautel :)
     

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  3. K5UJ

    K5UJ Ham Member QRZ Page

    The intrigue is there, but only if a fellow is interested in MOSFETs and A to D conversion and chips with firmware that switch the FETs on and off according to coded firmware logic. Each 50 KW rig is made to order and it's taking over six months now. I don't know how long Nautel supports their rigs with parts and board inventories. I always heard Harris wasn't so good. If anyone is still running a DX50, I think they're on their own. I also heard that even if you have a 3DX, if you call Harris (or is it GatesAir now) you get a guy who reads the manual to you over the phone. And of course, any solid state rig is more vulnerable to lightning damage than the tube rigs were, but they're so much cheaper to operate. Broadcasting has been going the way of ham radio with plastic radios. Nowadays everything between the microphone and the ATU is either beyond me, or of no interest.
     
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  4. W2NBC

    W2NBC Ham Member QRZ Page

    Just as an experiment, I used the external ALC “mod” (negative voltage applied to the ALC loop) with a slop bucket Icom IC-751A (circa 1988 or so). Audio was fed via the back bypassing the mic preamp:

     
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  5. W2VW

    W2VW Ham Member QRZ Page

    With a voice like that you can't lose.
     
    K5UJ likes this.
  6. W7TFO

    W7TFO Premium Subscriber QRZ Page

    Sterile is a good descriptor for that Nautel 50.

    It doesn't even have any meters or adjustments showing.

    You get a touch screen for everything.

    That would be hard on an engineer missing any fingers.

    Maybe they could lick it...

    73DG
     
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  7. W3SLK

    W3SLK Ham Member QRZ Page

    I remember a fellow on 75M years ago who ran his audio through the 600 ohm rear input (used for phone patching), of a Kenwood TS-440. He had excellent audio to the point I thought he was using a tube rig. He said by doing this he was able to bypass all the speech processing and ALC that was at the MIC input of the rig.
     
  8. K5UJ

    K5UJ Ham Member QRZ Page

    The problem with many plastic radios is that the RF carrier driving a leenyar, is usually unstable. Set the exciter cxr at 20 watts and over the next several minutes it will drift down. You have to keep bringing it back up. Then on the next xmission, boom your drive is twice what it should be. Having to constantly futz with that makes running a plastic radio suck even more than usual. Not all do it, but I'm told Kenwoods and Yaesus do.
     
  9. K4KYV

    K4KYV Premium Subscriber Volunteer Moderator QRZ Page

    That's exactly how I run (ran) my Eico 730 modulator used with the Eico 720 that I use(d) on 10m. Even though the "phone patch" input to the 730 is unbalanced through an RCA jack, I fed the 500/600 balanced line output from the audio rack directly to it, simply grounding one side. That works excellently with full fidelity.
     
    W3SLK likes this.
  10. N2DTS

    N2DTS Ham Member QRZ Page

    The ts440 and the Icom 735 had that problem, the power would go up as things warmed up.
    I think someone had a fix for that, but I never did it.
    The new radios are very stable in output.

     

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