jls wrote:
Also instrument needles go crazy.

Aircraft is a Lancair with antenna hidden in the horizontal stab. How
'bout directing us to some reading material about how to stop it.

Our local avionics guy says we may have to live with it, or install
external antennas, which will dirty up a Lancair in a hurry.

Jim Weir?

Thanks and happy holidays.

I'll take a completely different tack. Since your instrument needles
move when you key the mike, I suspect a ground loop. I would be
interested in knowing if you engine needles move when you turn on and
off other consumers like the strobes or nav lights.

I just finished working on a Lancair that had a similar problem. You
could turn the nav lights on and off and the CHT's would go up and
down. Keying the mic caused the trim indicators to change. We ended
up pulling out most of the wiring and redoing it for the plane's new
owner. Not cheap, but everything works now.

Rick Pellicciotti
Belle Aire Aviation