Experiment on Tuned Counterpoise

Discussion in 'Ham Radio Discussions' started by BU2EQ, Nov 5, 2018.

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  1. BU2EQ

    BU2EQ Ham Member QRZ Page

    After trying to build a spiral counterpoise with cooper foil tape, my quest of portable multi-band counterpoise goes on. This time is to make a foldable tuned counterpoise.

    I use a piece of 30x30 inches aluminum foil mattress I bought in a local camping gear store:

    I attached a thick wire to the mattress and the wire then goes to the "antenna" socket of my MFJ 16010 tuner, which is connected, via its "transceiver" socket to coaxial shield at the feedpoint of the antenna.

    The 16010 is a random wire tuner that utilizing L Network Matching, just like most commercial and homebrew "ground tuner" (aka artificial ground).

    My tuning steps for this experiment:
    1. Disconnect the counterpoise and adjust the loading coil of the antenna for maximum noise level.
    2. Hook up the 16010 and the mattress, adjust the knobs on 16010 for lowest SWR.
    3. If necessary, activate ATU for the final fine tune.
    The first test was on 15 meters, I was able to bring down the SWR from 2.2 (without any counterpoise at all) to 1.5 (with tuned mattress):

    Then I go for 40 meters, even better, SWR was brought down from >10 to 1.0:

    In addition to good reading on the analyzer, I also did some "real life" test by QRV, within an hour I was able to work two Russian and three Japanese stations (from Taiwan.)

    Before going home for dinner I very briefly tried to send some FT8 signals, went all the way to US west coat with 10W:

    I think I will bring this setupito my upcoming SOTAs.
    WF7A, KL7KN, G3ZPF and 1 other person like this.
  2. K0RGR

    K0RGR Premium Subscriber QRZ Page

    In order to determine the comparative performance of any antenna, you need something to compare it to.

    I would try comparing the metal blanket to a real 1/4 wave radial, and see how your signals compare. WSPR would be an ideal mode for this.
    K4AGO, WZ7U and BU2EQ like this.
  3. VE3IPS

    VE3IPS Ham Member QRZ Page

    this is an awesome and creative idea that I am implementing today
  4. KL7KN

    KL7KN Ham Member QRZ Page

    Much better set up than my old manpack radio set...

    weighed a ton, but hey, it was a Collins radio!
    BU2EQ likes this.

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