Topband: Efficiently Matching Low-Impedance Antennas to 50ohms

[Herb Schoenbohm]

> I'd appreciate any advice that anyone can offer.
>
> Thanks and 73,
>
> Ron (W8RU).
>

Ron,

You can get close to what you want  (about 25 ohms) by tying two pieces of
50 ohm coax equal half wave lengths (in coax factoring the velocity factor)
in parallel  hooked shield to shield and center conductor to center
conductor...in series with the 50 ohm coax feed and the antenna.  This
should bring you in the ballpark and totally avoid any tuner losses. You can
either use the parallel coax cables as part of the run to the shack or you
can try coiling up the parallel cables.  IMHO the long run is probably
better if there are near field couplings issues to consider. This may turn
out better than either tune even though their is a 5 ohm differencial which
you can adjust by a small amount of length adjustment without sending the
reactance to high. I believe the coax parallel section should be equally
spaced or taped tight together for the distance of the trombone feed...or is
this a bazooka?

Hope this can help you.


73

Herb Schoenbohm, KV4FZ