[Elecraft] SSB RF problems on 20 Meters Only

[Ron Gruner]

I am getting RF interference when SSB on 20 meters on my Elecraft K3.  A 
warble in the audio (with either the speaker or headphones) starts at about 
5 watts which gets much worse as I increase power to the point the audio is 
just a screech.  It works fine on CW.  I have no problems on other bands 
both above and below, just 20 meters on SSB.  I still get the distortion on 
the sidetone with audio and RF gain turned to the minimums.

My antenna is an Ultimax DXpedition with a buried ground plane and a six 
foot ground rod attached to the start of the ground plane wiring.  I 
wrapped about 50 turns of #16 stranded around the feed coax close to the 
antenna junction box as a choke, and also attached a 17.3 foot wire off the 
ground plane to resonate at 14.15 MHz as a friend suggested.  Nothing 
helped.

I've only been licensed since July, so this is all new to me.  Thanks for 
any help.

Ron Gruner
K4RHG