Antenna elements not touching but got 1.2 SWR - Buddipole

Discussion in 'Antennas, Feedlines, Towers & Rotors' started by N2NGO, Mar 4, 2020.

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  1. N2NGO

    N2NGO Ham Member QRZ Page

    Hi everyone, I have what I find a strange question. I have been using an expandable carbon fiber rod for a while as a field antenna. Usually I attach a wire from the rod to my Buddipole versatee to make a physical/electrical connection. In short, is it possible to bypass this cable if the rod sits right on the versatee? Testing on 6M and 10M so far.

    The longer story. The versatee has little arms where I can just position the rod and extend from there, like a telescopic antenna. I just received an antenna analyzer (sark60s) and for the first time I am testing the antennas and playing with the analyzer. So I set the antenna, I am ready to connect the cable and I see that the analyzer says 1.2SWR. Oh wow, there is continuity between the rod and the versatee, but when I get a multimeter and test for continuity there is none.

    The versatee has a little metal arm connected to it where the rod sits, so is it possible that without an actual electrical connection between these 2 parts, an antenna would work? Am I missing something here?

    [​IMG]

    Thanks,
    Carlos
     
    Last edited: Mar 4, 2020
  2. W6MK

    W6MK Ham Member QRZ Page

    Has your carbon fiber rod worked successfully as an antenna? QSOs? Reverse beacon network spots?

    Whatever the analyzer says is irrelevant if there is no real antenna connected. On what frequency do you get your SWR reading?
    If you scan a frequency range do you see an indication of a typical SWR curve?

    You may be loading up the "versatee." Although in some cases almost anything will work as an antenna, anything is
    unlikely to be a good antenna.

    If there is no continuity at DC (multimeter) then there is no RF continuity.

    What you are missing is that there is no magic happening.
     
  3. N2NGO

    N2NGO Ham Member QRZ Page

    I have used the rod on the field many times, all from 10M to 20M and 40M when extending with a wire. If I extend the antenna the SWR changes, if I take the antenna off the versatee it also changes. Its behaving like any antenna I have ever used on that system but without a connection. I can receive well, but until I know better I don't want to try and Tx.
    I did not check the curve as I did not have it attached.
     
  4. W6MK

    W6MK Ham Member QRZ Page

    Sorry, but it's very difficult for me to understand what you are saying.

    As you suggest, if an antenna seems to work adequately for receiving, this says little about how it might work for
    transmitting.

    It seems that the carbon fiber pole you are using is at least somewhat conductive. Thus it may work for receiving.
    You can measure the DC resistance of the fiber pole using your multimeter. Unless the resistance is very low, it
    won't work well for transmitting--you ohmic loss will be high and efficiency very low.

    You mentioned an SWR measured by your antenna analyzer. No reading on an antenna analyzer can be meaningful
    if the analyzer is not connected to the antenna in question.
     
  5. WE4E

    WE4E Premium Subscriber QRZ Page

    But it certainly be misleading.

    I recently did some seasonal maintenance work on a 160m horizontal loop I have up. When I finished, I checked it with the radio and although it had changed, the tuner would tune it on 160m. No joy on any other band which was out of character. Turns out the center conductor in the dipole center had opened, and I was "tuning" the ~130 ft of RG6 I was using as a matching section.
     
  6. W6MK

    W6MK Ham Member QRZ Page

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