H Johnson wrote in message . ..
If that does not work, and since Radio Shack stuff is normally
readilly available, they sell a Ground LP Isolator (270-0054) that
should do the trick or you can roll your own using their isolation
transformer (273-1374) which is $4.

The problem isn't ground-loop related; the problem is horrible with even
battery-powered receivers plugged into the sound card. Interference goes from
minor before I plug it in, to S9 hash all over the SW bands after I plug
it in.

I already tried isolation transformers. The capacitive coupling through
the isolation transformer (measured to be about 100pF) lets way too much
noise through... the net effect of the isolation transformer is a very
minor improvement. Better grounding on the receiver side would probably
help here, I'm going to drive a rod down just for the receiver soon.

Perhaps a grounded receiver + an isolation transformer will do the trick.

If that doesn't do it, it looks like fiber optics will be the solution.

Tim.