Pete,
> I would like to be the thousandth who asks the same old question -
> do, in
> your experience, small coax loops work?
Yes, they DO work. How well they work compared to other RX
antennas is another story. In my experience, a 5ft loop
is adequate.
>
> I must admit that I fail to see any
> real
> improvement in S/N compared to my TX antenna.....
> a) disconnecting the TX antenna (which is in proximity of the loop)
> does not
> determine any change in noise on the loop, and....
Your transmit antenna might be coupling noise into the loop.
Place the loop plane at a right angle to your transmit (vertical?)
antenna. You can finely adjust the placement of
the loop by connecting a very low power oscillator (at high noon!)
to your transmit vertical, then listen for a null in the signal
received by the loop as you (or a helper) rotate the loop.
> b) I do not use a preamp (I am almost certain that that would not
> improve
> the S/N...).
You should use a preamp, preferably with a BCB filter and/or some
tuning at its input. 15db gain is probably adequate.
73,
Charlie, N0TT
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160 meters is a serious band, it should be treated with respect. - TF4M
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