I use a small capacitor on the audio in (mic hot) line that is supposed
to avoid DC on the audio input. I do this for other reasons, other
than RF in the shack, but it seems to do the job In any case.
Otherwise, a couple of ferrite beads may do the trick.
Sometimes, at least at a friend's house, we eliminated similar problems
by making a sort of RF choke by making a several turn loop of the audio
cable - kind of like coiling coaxial cable several times in a loop near
the feed point (sometimes called an "Ugly Balun"). Similar choke
coils and ferrite beads, Or combinations thereof, have eliminated such
problems on microphone lines, powered computer speakers, and other audio
lines running in the shack. particularly helpful when you have a
speaker that is not magnetically shielded.
Just my take.
Happy Trails.
==================== James / K8JHR ===================
On 1/30/2012 5:36 PM, PC Anderson wrote:
I am getting a little Rf into the mic circuit.
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