I had a lot of helpful responses to my post below a couple of weeks ago. I
thought I'd let everybody know how I fixed the problem.
Added a Radio Works T-4G Line Isolator at the antenna base connecting
its ground strap to a dedicated 8 foot ground rod. Connected the
Elecraft K3 ground and the AC ground together at a terminal strip and then
led the grounding line (three 12 gauge wires in normal house wiring cable
from Home Depot) to a separate ground rod a yard away from the antenna
ground rod. Before getting all this to work, I tried a non-grounded line
isolator (Radio Works T-4-500) which did not help regardless of all the
grounding variations I tried. Also what did not work was connecting the
shack ground line to the same ground rod as the antenna choke's ground
strap. I guess the ground currents are pretty bad, and need to be shunted
off completely isolated.
The original problem was RFI getting into my transmissions out on 20 meter
SSB. SSB was fine on all other bands and CW worked fine on all bands.
I had a 30 minute 20 meter SSB QSO a couple of days ago and got a great
signal and audio report.
Thanks again for the suggestions.
73, Ron Gruner
K4RHG
----------------------------------------
From: "Ron Gruner" <r...@gruner.com>
Sent: Sunday, November 18, 2012 12:59 PM
To: elecraft@mailman.qth.net
Subject: SSB RF problems on 20 Meters Only
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
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