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A Kenwood HF rig's "real" frequency in CW

Discussion in 'Electronic Design' started by billcalley, Apr 22, 2007.

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  1. billcalley

    billcalley Guest

    Hi All,

    This may sound like a very silly question, but what is the "true"
    frequency of, lets say, a Kenwood TS-530S? What I mean is, when it is
    said that a particular CW calling frequency is exactly "7.040MHz",
    then should I set the TS-530S' frequency display to 7.040MHz (in
    receive mode), or to 7.0392MHz (for a display of 7.040MHz during
    transmit) to be spot-on a designated Calling Frequency? I obviously
    would like to make 100% sure that I'm exactly on frequency, and not
    off by 800Hz, when monitoring for any CQs!

    Thanks for any clarification,

    -Bill
     
  2. Wimpie

    Wimpie Guest

    Hi Bill,

    It sounds silly, but it isn't.

    I don't know the answer with high confidence, but maybe I can help you
    to get it.

    I "believe" that when you tune in to a station with 800 Hz beat, you
    will transmit on exactly the same frequency as the station that you
    are listening to. Make sure the RIT is in the middle or off.

    You can check it yourself.
    Do you have a separate frequency counter (or other receiver)? If so,
    try to tune to a source with a known frequency (with the TS530S, for
    example a broadcast station or). Now you can compare the actual
    frequency with the reading on the TS530S and you know the difference
    in reading and actual transmitting frequency of other station.

    Now the transmitting case
    Press the key (check frequency in use or use dummy load) and read the
    frequency from the counter, or tune with the other receiver to find
    out the difference in the transmitting frequency of the other station
    and your frequency.

    I hope this will help you a bit.

    I had several problems with adjusting old equipment to make sure that
    SSB receive and transmit (carrier) frequencies are the same.

    Best Regards,

    Wim
    PA3DJS
     
  3. billcalley

    billcalley Guest


    Thanks for the info Wim. The TS-530S's actually show you only the
    RX frequency on the digital display dial while you tune around or sit
    on a frequency waiting for a CQ, and then -- but only when you
    transmit -- they shift the dial display (and I assume the TX frequency
    too) 800Hz higher. Frankly, I had thought most other radios did
    *exactly* the opposite (I.E.: Their BFO's shifted the RX frequency by
    800Hz or so, while their TX frequencies where as displayed on the dial
    -- but I must be incorrect about that!). But I'm still hoping to
    understand if it is correct to set a Kenwood to "7.040MHz" on the
    digital display when listening to the 7.040 MHz Calling Frequency (but
    it then shifts 800Hz higher on TX...), or set it to 7.0392MHz (for a
    display of 7.040MHz during transmit with its 800Hz TX offset)? With
    all the Kenwood rig's out there, you'd think that someone would have
    the answer -- but maybe no-one has really thought about this? (Hard
    to believe!!).

    -Bill
     
  4. Dee Flint

    Dee Flint Guest

    Did you read my answer??? You have an older Kenwood radio. It displays the
    transmit frequency only when you transmit. It displays the receive
    frequency the rest of the time. So set your receive at 7.0392 in receive
    mode. When you transmit it will then be transmitting at 7.040 as shown by
    the readout.

    NEW radios (including new Kenwoods) display the transmit freq. at all times
    whether receiving or transmitting.

    Dee, N8UZE
     
  5. billcalley

    billcalley Guest

    Cool Dee -- thanks for clarifying that! It was confusing the death
    out of me (I've been on the wrong darn frequency all this time too!).

    I didn't see your original post on my Google newsreader under
    'sci.electronics.design' because, for whatever weird Google reason,
    your response didn't cross-post).

    Thanks again!

    -Bill
     
  6. John Siegel

    John Siegel Guest

    Another consideration, particularly for VHF operators, is what happens
    when you switch from SSB to CW. For example, the TS2000 says that it
    always displays the carrier frequency regardless of mode. If you are on
    SSB and need to switch to CW becaue you have a weak signal look at what
    happens. If the displayed frequency is the carrier and does not change
    when you change mode you are now transmitting zero beat with the
    receiving station and he won't hear you. You actually have to tune off
    a bit (by the sidetone amount) so the receiving station can hear you.
    The TS2000 actually has a menu choice to allow the frequency to
    automatically make this correction if you wish.
    John
     
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