[Elecraft] RF feedback?

[Jim Brown]

On Tue, 14 Jul 2009 13:44:00 -0400, K2QI wrote:

>I am curious though; your previous email mentioned rectification of audio in
>the wattmeter, feedline or antenna. 

As noted, one or more good common mode chokes are in order. You mentioned the 
lack of a station ground. That is a lightning safety issue, but NOT a solution 
to RFI. 

You didn't mention what your antenna system is, or how far it is from the rig. 

The important question is, is this only RFI to the wattmeter, or is something 
else going on, like a spur or harmonic? Have a ham nearby listen for spurs (or 
take the antenna off another radio and listen for spurs).  

Is this an outboard wattmeter, or something built into the power amp?  If 
outboard, my first move would be to replace the fancy wattmeter with a Bird, 
and look for fluctuations indicating increased reflected power. If you don't 
see any, I would blame the meter. If you DO still see the fluctuations, I would 
look at the K3 and the power amp. The K3 does have some pin 1 issues. Ferrite 
chokes would help with that. 

http://audiosystemsgroup.com/RFI-Ham.pdf

73,

Jim Brown K9YC