[Elecraft] RFI in audio chain

[Bill]

1. I have printed out Joe's directions and placed them in the K3 file - 
for future reference.
2. Is you K3's chassis connector OK - loose ground?
3. Have a proper ground from the K3 to your station ground?
4. You are using the same feedline to test the K3 as used to test the 
730? If not - do so. Everything needs to be eliminated.

You have now eliminated the problem from causes in  your station layout 
and the antenna/feedline to the K3 - as the complete same using the 730 
works fine. True? Then the problem is with the K3 or something attached 
to it.

5. Disconnect everything from it except power, antenna, and mic. Test 
it. All clear - the RF is coming in on something other than the mic 
(plugged into the K3). Problem still there?
6. At this point, try an alternate mic and see if it works. If it works 
good - the problem is the mic/mic wire/connector. If it does not and you 
still have RFI - walk away for a while and cool down.

Just a few simple steps that would apply to any radio in a similar 
situation.

Bill W2BLC K-Line