KENWOOD TS-940s Low transmit AM Modulation

Discussion in 'General Technical Questions and Answers' started by KC1KWX, Oct 15, 2020.

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  1. KM3F

    KM3F Ham Member QRZ Page

    Problem with AM from my point of view is the long time established stations run commercial or old Ham equipment out of some loyalty from being broadcast engineers, audio engineers and the like.
    Some is home brewed.built. That capability is all but gone now, to the new commer..
    It's not the real issue until you hear how they converse. Not bad, but not inclusive.
    Plenty of others listen in but feel quite out of place with the established conversations.
    I don't have either or that type equipment but have about as good audio as all the rest, leaving room for some who would not agree.
    I continue most often to hear very early critique of a new comers station performance before they even get to know each other with a few transmissions, to get to that point.
    You hear 'piss weak', modulation is low, how much carrier and on and on.
    Many of these people don't even know what's being asked or the relationships of them.
    These station who try AM are not at all amused with those early notations that can't wait a while to see how much interest there is to help improve the new comer's effort..
    They very often don't come back and it's wondered why AM does not grow..
    Then there is the scrapping about SSB and AM both ways.
    These die hard AM users who use the old wide band receivers in order to hear better fidelity complain about slop buckets.
    Wonder why that is?.
    Now, the east coast complains about the midwest at night using the 75 meter 'slot'.
    AM will never grow under these circumstances, add in FT8, DMR and all the other digital modes plus all the attitudes that prevail.
    I was exposed to AM before there was SSB back in the late 40s.
    Today I use a Kenwood TS2000 unmodified , outboard speech processing and drive an AL80B amplifier on both AM, SSB. On FM I put out 180 watt signal using a different amplifier. All these from the same radio.
    Do I know what i'm doing? A lot think I do to get the performance I do from plug and play equipment.
    After being in the business a long time I think I have the act together pretty well and don't have a habit of extolling it unless asked or see the need to do so.
    AM will not grow until the attitudes change which I doubt very much will ever happen.
    Look at the political state this country is in now let alone improve ham radio.
     
    KC1KWX likes this.
  2. KC1KWX

    KC1KWX Ham Member QRZ Page

    IMHO, to me AM is the new frontier. New radios nowadays are point and shoot which intrigued me enough to buy a shiny new FTDX 101MP. I have many other rigs which require thought to operate and I would much rather run them as I feel like I am operating rather than talking (on ssb). For my uncertainty on AM, the point and shoot could be helpful until I become better versed in it.

    In my world making a DX contact is much more satisfying than talking about what type of antenna I have with someone a few states away. Because I grew up during the CB rage I thought AM was simple but have learned relatively recently that it is not. I wish I had the time to dedicate to learning more about AM theory and how to put it into practice. I too listen in on AM stations for background noise when I am working near the shack. I have picked up a lot of information just by piecing together parts of technical conversations. There are a couple of great groups in NY that seem friendly enough but I have also heard other groups that are pretty clicky.

    I have heard everythong from some running modulator setups that require high voltage isolation transformers and I have heard guys running modern pro audio equipment into tube transmitters. I hear of these things and am intrigued even more and look at my 101 as a stepping stone. Sure, I can run my 101 on AM and push it into my alpha 87a. However, even with the 101s point and shoot ease of operation I am not sure enough of what I am doing so I worry about splattering onto a neighbors car radio or onto a non ham band. I wish there were an Elmer nearby that was into old school AM but no. I have been a ham for a little over a year and a half so I still have a lot to learn. Again too, I am trying to master CW and am intrigued by it. All in due time, I guess. Even in this thread I have learned a lot and appreciate nearly everyones comments and suggestions. I cannot learn from books but practical information and others knowledge I can often readily grasp. Hopefully soon I will have the time to give AM a go.
     
    Last edited: Oct 19, 2020 at 9:56 AM
  3. W2VW

    W2VW XML Subscriber QRZ Page

    AM isn't for everybody. The current thing is people trying to get their old AM rigs to work as well as a Flex or Anan.

    It is important to have some way of quality controlling the transmitted signal.

    Asking others is sort of OK but that gets old.
     
  4. WB2WIK

    WB2WIK Platinum Subscriber Platinum Subscriber QRZ Page

    I never answer that question with anything other than, "I hear you.":p

    Shortcuts a lot of potential babble.:)
     
  5. KC1KWX

    KC1KWX Ham Member QRZ Page

    But Dave, you're one that I've listened in on... Now I'll never ask any questions on tbe air.... Well sort of. :) Maybe I'm wrong but don't the guys in your group usually talk about how their equipment sounds and what you're doing to improve it? :)
     
  6. KA0GKT

    KA0GKT Ham Member QRZ Page

    AM radio stations make modulation percentages with asymetrical modulation. While positive modulation may indeed exceed 100%, negative modulation NEVER exceeds 100%. Exceeding 100% NEGATIVE modulation causes splatter causing interference on adjacent frequencies (ALA many CBers with their power mics). It should also be pointed out that in parts of the world where the rules are made and enforced by the Federal Communications Commission AM broadcast stations are licensed at Carrier power levels, not Peak Envelope Power so there is an advantage in asymetric modulation, questionable though it may be.

    If you wish to reduce your carrier and employ asymetric modulation using a commercial modulation processor to increase your PEP to Carrier power ratio without exceeding the F.C.C, imposed P.E.P. limit, go for it. Your signal will sound louder than the reduced carrier would otherwise provide, but if you properly modulate your carrier to reach the F.C.C. peak envelope power limit your audio quality will sound better when listening on an older AM receiver with an envelope detector.

    So, If you have the where-with-all to buy one of Bob Orban's magic AM modulation processors, a beautiful old Harris MW-1A, or McMartin AMM-1, or any of the many 1 KW AM broadcast transmitters which will convert to 160 meters, go for it, otherwise, don't overdrive your rig designed for SSB and enjoy full carrier AM at thePEP limit of your transmitter / Linear Amplifier combination.
     
    KE0NSK likes this.
  7. KE0NSK

    KE0NSK Ham Member QRZ Page

    Very well written, and I think I agree with all of it. On the other end of the spectrum, international short wave will run as low as 85% modulation. A giant class c carrier is a lot easier on finals than the ab mod tubes that get worked really hard. I wonder how much modulation they would run if tube life wasn't an issue? Probably a lot more is my guess.
     
  8. WB2WIK

    WB2WIK Platinum Subscriber Platinum Subscriber QRZ Page

    Back in the vacuum tube era, AM-BC and SW-BC transmitters typically ran at as much power as the tubes were rated to provide, not less.

    Now, most have switched or will be switching to solid state amps where removing the heat fast enough is the issue, but the big broadcast transmitters are made of many lower power modular amp decks combined to produce the final output power and those modules are replaceable in operation.
     
  9. KE0NSK

    KE0NSK Ham Member QRZ Page

    What do you mean by this exactly?
     
  10. N3HGB

    N3HGB Ham Member QRZ Page

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