[Elecraft] K3: Very distorted audio on transmit but only on 20m and only with the KPA500 on

[Donehrlich at q.com]

Almost certainly RF getting into the mic circuit.  Try a different mic 
.. or use the rear panel mic connector as a check.  You probably have 
high SWR into the antenna feedline (or coax) after the tuner on 20 
meters and that is why you only see problem on 20M.  High SWR on the 
feedline (Note: your rig can be seeing low swr .. it is AFTER the tuner 
where you have high SWR) results in high current or high voltage that 
then couples into other shack wiring.  Of course, the higher power from 
the KPA500 pushes those voltages/currents to levels that are more likely 
to cause problems.  Been there, done that .. many times.

Don K7FJ


> Ok,
>
> So my audio is quite distorted as I can hear in my headphones with the monitor. But this only happens on 20m and only with the KPA500 in operate.
> Sound like RF? or is something else going on?
>
>
> Thanks
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