Adjustable Gamma match for mobile antennas

Discussion in 'CB Radio Forum' started by rabbiporkchop, Jun 27, 2016.

  1. rabbiporkchop

    rabbiporkchop Road Train Member

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    Does anybody know if such a thing exists in Pre manufactured form?
    Shunt matching coils are pretty cool things too[​IMG]
     
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  3. breadtrk

    breadtrk Heavy Load Member

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    I have used the gamma match from an ice trashed moonraker 6 bolted to the bumper of a Dodge van, tuned with the old mfj and worked Cali skip from downtown Nashville TN.
     
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  4. rabbiporkchop

    rabbiporkchop Road Train Member

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    Do you have any pictures?
     
  5. breadtrk

    breadtrk Heavy Load Member

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    Dude, cell phones was dick Tracy stuff back then. We had a Polaroid camera but sure want gonna waste a $2.00 picture on booze induced fun. :)
     
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  6. breadtrk

    breadtrk Heavy Load Member

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    We had a time with that Van. 2 leece nevell 200 amp alternators, 8 18v tow motor batteries, Pluto swinging into a Texas Star 500 driving a 32 pill box built by black John in Memphis, copper coil copper antenna dead center of the top with a1/4" steel plate supporting it.

    Take it to Manchester every year for the Good Times gang shootout. Hold a steady 4 grand on the 318 and key down baby.
     
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  7. Ridgeline

    Ridgeline Road Train Member

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    Wondering if it is the same Black John I knew of. All he built was hacked linears.

    IIRC, he got a Bluegill Special to copy from that.

    What a harmonic boxes they were.

    Anywho ...

    I saw an interesting antenna the other day, a circular dipole. It was a vertical setup and the owner claimed it worked well on 11 meters, just a 1/4 copper tube in a circular pattern with a gap/resister at the top and a little matching network attached to the feed point. the resister is a 75 ohm (I think that's what he said) terminating the two halves. I heard him about 26 miles from where I met up with him the other day.

    No pics, I didn't have my phone with me at the time. I think he is a TTR member, I mentioned I was one and we talked about odd antennas.
     
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  8. kc0iv

    kc0iv Light Load Member

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    I think you are talking about a "DDRR Antenna." There is also a square made the same way.

    leon
    kc0iv
     
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  9. Gadfly

    Gadfly Medium Load Member

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    Curious. What are you trying to 'match'? Is this on 11M? If you are trying to match impedance, that's not usually necessary on that band. When you get below about.....oh, maybe 20 Meters, you start running into this. But I'm looking at it from the back side. so I don't know what kind of antenna it is. For matching MOBILE antennas, this simple coil shown often gets the match right, depending on # of turns, diameter of coil and wire size. Is that a "switch" to cut it in and out? There are a few commercial matchers made--often made for matching screwdriver-style antennas, but its just as easy to wind your own.;) If you are working the HF band, usually there's no need to switch anything; it'll accept it and match on all bands!
     
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  10. Ridgeline

    Ridgeline Road Train Member

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    But gadfly I have to point out that his picture isn't a gamma match circuit.
     
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  11. rabbiporkchop

    rabbiporkchop Road Train Member

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    Just trying to hit the elusive 50 ohm mark on a single frequency.
     
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