>> 2. The RX-output from the Control-Box in direction of the RX-input is not
>> directly connected to the loop,
>
> I'm not sure I understand.
>
> My radio is an IC-756PROII, driving an Alpha 76A amplifier (1500 watts
> out)
> and I did have feedback from the loop that distorted my transmit signal.
> I
> did modify my PROII so the receive antenna is disconnected during transmit
> and the problem went away.
>
> de Paul, W8AEF
---------
The preamp in the AYL-4 is basically a one watt power amplifier (a 2N3866 --
like a 2N5109 but higher voltage rating). It's more rugged than most RX
front ends, and with 17-18 dB gain it can deliver a pretty hefty signal to
the RX input if the loop picks up significant RF from the TX antenna.
As Paul found, receivers that disconnect the external antenna input during
TX are usually OK. In a few cases where the loop and TX antenna are quite
close, the AYL-4 itself needs protection. When in doubt, run tests with
gradually increasing power -- with preamp switched in and out.
73, Gary
K9AY
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