This is a wrap-up post to the discussion about RFI feedback into the
audio of my K3.
First, I want to thank everyone who offered suggestions, most of which I
tried to follow up.
After numerous failures, I managed to lure a local guru--a ham who makes
his living getting RF and audio things to work. After ten minutes of BS
in my ham shack, he said to start disconnecting each wire from the back
of the K3, one-by-one. Some of you may have told me to do the same
thing, and I remember approximating that, but somehow I must have messed
up. At any rate, as soon as we disconnected the line from my outboard
USB sound card to the rear input of K3, used for digital work, the audio
RFI went away. My friend says he thinks that an isolated line would be
better, but the fact that I have a stereo output going directly to the
mono input is probably the real culprit. At the moment, only hours
since his discovery, I have successfully worked on 80 and 40 meters with
the amplifier, but I have not yet fixed up an isolated digital line.
My thanks to the entire K3 community who attacked this problem.
I am now using the original vertical, fed with patched lengths of
hardline, with a hardline, wound choke at both ends. Each choke is
40-50 feet long.
I also discovered that my RF ground point in the shack (back of the
Ten-Tec KW tuner), shows 30-50 ohms resistance vis-a-vis the electrical
ground terminals in the shack. Another rod as part of my RF ground
system may be forthcoming.
73,
Jan, KX2A
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