On 8/15/2013 7:39 AM, Tom W8JI wrote:
Depending on any networks or transmission lines between the detuning
switch and the element, the optimum termination at the switch might be
almost anything.
If the antenna is close to a quarter wave, one rather easy termination
is t make the feedline either a shorted quarter-wave or an open
half-wave of transmission line. A halfwave of RG8/RG213 for 160M won't
have much loss, and a simple antenna relay box (like W2VJN's 2X1 Top Ten
box, which runs on 12VDC) would make it quite easy to rig. So simply add
enough coax to reach either of those lengths and add the relay and
control line that provides the short or open in RX mode.
The downside of this, of course, is that you can't listen on the TX
antenna for diversity. .
73, Jim K9YC
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Topband Reflector
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