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K30/President JohnQ issue

Discussion in 'General CB Services Discussion' started by ColdTurkey, Aug 9, 2012.

  1. ColdTurkey

    ColdTurkey
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    Hello,
    Anyone know if its possible to tune an antenna lacking a vswr?
    Im using a President John Q mobile 40 with a K30 mag on my GMC Sierra
    roof. When I tx on ch 1 it does a 4 watt rf swing, but on ch 40 it
    drops ALL the way down to 1 watt tx, according to the meter onboard
    anyway. Ive already seated the aerial all the way into the socket.
    Any thoughts? thanx in advance...CT


     

  2. 9C1Driver

    9C1Driver
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    If you have another radio sitting around use it to set the SWR. Remember, the antenna is set to the vehicle, not the radio. Once done as long as you don't move the antenna you should be able to switch radio's and not have to re-tune the SWR. Sounds like your radio needs a little alignment work.
     
  3. Robb

    Robb
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    A couple of things:

    If you have a radio that transmits; then having a SWR meter is an imperative. Can't operate a car w/o a gas gauge. A SWR meter is a 'must have' and not a 'I want' item. They are not expensive; even a cheap $20/used one from eBay will suffice.

    Your antenna. These antennas are known for having an incomplete operating range for the entire CB band. Chances are, that the antenna might be OK for 30 of the 40 channels your radio has. But it will either be lacking on one end of it or the the other - having a 2:1 SWR at some point.

    I don't blame your radio for having the readings that you are seeing. I believe the K-30 antenna is the fault; not the radio. You would find this out as soon as you get an SWR meter and test out your antenna. Well-known failing of this antenna - BTW. In addition, this antenna could serve to do damage the radio you have. As transistor transceivers can be damaged with an SWR above 2:1.

    You will probably be better served by getting a better antenna and a SWR meter.

    Just two cents worth . . .
     
    #3 Robb, Aug 9, 2012
    Last edited: Aug 9, 2012
  4. psycho

    psycho
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    Whoever tuned that radio definately fumbled the ball, the wattage output on 1 and 40 should be close to the same. A K30 is a line of sight antenna only, get a Wilson 1000 and the range will definately increase.
    I gotta admit, that is the first time I ever heard a CB antenna refered to as an Aerial.
     
  5. 9C1Driver

    9C1Driver
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    LOL, I guess I assumed he Was using an external SWR meter. I had a K30 years ago as a back-up, I could slap the thing about anywhere on the car and get a 1.8 or better.
     
  6. ColdTurkey

    ColdTurkey
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    JohnQ issue followup

    Just an update,thanx 4 replies by the way, appreciated.
    I picked up an archer vswr meter and followed protocol
    for tuning eventually had to trim rod (1/8" increments at a time)
    ended up getting swr down to 1.4:1 mid ch(20) and approx
    2.1:1 on either end(1/40) best I can do any shorter and low channels
    (1) start climbing even though high channels(40) continue to drop a bit.
    Also now the rf tx on meter shows improvement as follows:
    ch 1 thru 30 = approx 4 watts, and 31-40 decays to approx 3 watts.
    Im thinking the damn antenna was designed for 23 ch rigs and I
    should leave well enough alone????
     
  7. trucker

    trucker
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    Yep, leave well enough alone or rethink your antenna and installation.
    Given the frequency coverage between channel 1 and 23 (26.965 to
    27.255) and then add 24 to 40 (27.235 to 27.405) I doubt that at those
    frequencies, and range ( 440Khz total bandwidth for all 40 CB channels) that
    the antenna you have is the problem. Unless, it was originally trimmed (tuned)
    for someone using it with an old 23 channel CB. If so, then it would be tough
    to impossible to re-tune without replacing the stinger (top portion above the coil)
    and starting over and re-tuning it from there.
    A lot depends on where on your vehicle you have the antenna mounted and how
    it is mounted. Having the whip close to metal, (along side the bed of a pickup or
    behind the cab mounted low) for example, will cause tuning problems. You need to
    have as much metal UNDER the antenna as possible. And a solid connection to the
    body. (for the ground) The body of your vehicle is the other half of your antenna.
    If it is not well bonded between sections,(body to frame, hood to body, etc. with
    flat metal straps) then you will have problems. But, the main thing at CB frequencies
    is to get the antenna up high as possible. And, again, well connected to the body.
    Once that is done you will find improved performance.
    trucker
     

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