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

[Don Wilhelm]

Yes, that condition *does* sound like RF-in-the-Shack - on only some 
bands and only at higher powers is the clue to that conclusion.
Refer to the RFI document by K9YC 
(http://audiosystemsgroup.com/RFI-Ham.pdf) and construct the common mode 
current chokes that he details.  One should be at the antenna feedpoint, 
and possibly another may be required at the shack entry point (on all 
feedlines).

You may get by putting clamp-on ferrites on your mic cable, but the best 
solution is to keep the RF out of the shack with the addition of 
effective common mode chokes in your antenna system.

73,
Don W3FPR

On 3/11/2014 4:39 PM, tomb18 at videotron.ca wrote:
> 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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