Yep, grounding is strange. I'd try ungrounding stuff and see if that
helps. I was trying one of those clear speech speakers a friend had here
once and when I hooked it up to my main power supply, I almost blew the
thing off of the desk when I hit the ptt. I grabbed a little 12v wall
wart and used that instead for the speaker, and was clear as a bell. You
just have to try stuff.
One trick I saw a ham use years ago, and yes, it does work, for a long
ground run take a piece of coax using the center conductor for your ground
wire. Bypass each end to the braid with a .01 cap. I don't know why, but
keeps the ground from radiating as an antenna.
73s
Butch Bussen
wa0vjr