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

[Tom Blahovici]

Hi,

It was some time ago I read that article.  I bought about 40 of the big ferrites and I have made one of the chokes near the antenna feed point.  I guess another is needed in the shack entry.  I used to have them ine th shack just before the equipment but I guess a better place is right outside.  It was too much of a pain in the shack.
Will try this out tomorrow.
73’s
On Mar 12, 2014, at 12:09 AM, Don Wilhelm <w3fpr at embarqmail.com> wrote:

> 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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