Dave,
Ten Tec has a nice Counterpoise Tuner kit. Very simple to build, has a
tuned circuit of a switched set of caps in series with a toroid coil having
a "wiper" to tap off various amounts of inductance. It also includes an RF
current detector. You tune for maximum current in the counterpoise.
The counterpoise ground tuner kit can be easily modified to an L network, as
an antenna matching device. I did a paper on the conversion for a ham
convention. Basically, inspection of the schematic and the mechanical
layout makes it obvious where you can replace a binding post by an isolated
BNC.
With a shorting plug, the circuit is a tuner; with the cap off the BNC jack,
you can hook up a BNC to binding post to tune a counterpoise.
The conversion to dual use also requires you relocate one wire or so of
where the RF current detector is hooked up, so that it is in the circuit for
both applications.
Stuart
K5KVH
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