Re: Microphone audio leaking into speaker

Adrian Chadd

I'm sure someone else mentioned but - that could just be RF leaking
back into the amplifier output path or speaker.

If you hook it up to a dummy load do you get the same effect? That'll
help identify if it's RF from the whole antenna system making it back
or something in the rig.

Normally one solves this with a combo of shielded cabling for
low-level signals, short cabling for everything, inductors on power
rails and bypass capacitors to ground. Eg, if it's coming into the
audio amplifier via the 12v line you could try a 100uH inductor in
series with the 12v line to see if it helps. And/or a 0.1uF cap to
ground on the amplifier side of the power input. You could also try a
bypass cap on the audio input into the amplifier if you think it's
coming in there.

It could also be where you route your speaker wires. Is your speaker
hooked up with shielded cable? Maybe try a 100nF cap across your
speaker terminal to see if that bypasses RF. Eg, there's a fun issue
with the Kenwood TS-440 where if you route your speaker cable
(shielded!) a certain way across the IF board it picks up SSB signals
from said IF board. So you have to route the cable around those parts.



On Tue, 4 Jun 2019 at 07:51, Jay - WS4JM <ws4jm@...> wrote:

First of all thank you all for your suggestions!

A little more information to clarify my issue. The microphone I am using has switched audio. The leakage occurs during transmission, similar to a monitor function, but the audio is distorted. I can reduce the gain to the point where this doesn't happen, but then the transmitted audio is inadequate.

I am planning on adding the N6DT pop fix. It switches the audio on and off during rx/tx maybe this will solve the problem. I'll post when this is complete. Any other ideas are welcome!

Thanks again to all who posted,
73 de WS4JM

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