Hello Harry and all topbanders, from down under, with a big hole in the ozone
(ionoshere) layer.
The only way to make sure the loop does not interact with the beverage and
therefore degrade its performance is to use relay switching to detune the loop
while listening on the beverage.
That is to switch the loop to another tuner, that is tuned to for example to 80
mtrs while listening to 160 on your beverage.
Another answer is to adjust your feeder length so that when the loop is open,
circuit while listening on your beverage, the loop is detuned by the inductive
loading of the feeders and the loop will have a new reasonant frequency out of
band (this also require relay switching to acheive this).
Do not just short out the loop as this will introduce a similar effect as
having a "shorted turn" in an electromagnetic circuit and further reduce the
performance of the beverage.
The above is true for any antenna 1 and antenna 2 situation, where both
antennas are tuned to 160, but when your listening on one antenna, the other
one, if it is close by will interact (by close by I mean within one wavelength
seperation).
I use open wire feeders and have no trouble using simple 24 volt DC coil, 240
volt 15 amp contact AC motor control relays to do the feeder changeover (even
up to 10 metre band). Of course we are only allowed 400Wpep down here.
good luck Ron vk3io vk3io@iinet.net.au
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