: This leads me to suspect one of the *NAV* radios. Can you physically
: remove them from your plane, one at a time, and leave them in your car?

: Not a problem. Can this really be caused by a radio which is *powered
: off*? Because I did try switching the navs to different frequencies
: and also turning them off, along with all the electrical power in the
: plane.

Yes, it can be caused by a radio switched off. With those ACK elt units that
cause problems, they are off when their problems occur!

: I'm perfectly happy to take it off and slap some 50 mph duct tape over
: the resulting hole, providing it's not going to hurt the MB receiver
: to be attached to dangling coax.

It won't.

: If I were doing this, I'd probably
: terminate the RF input to the radio, as well.

: IIRC this would be a PITA -- the coax goes to the antenna with a
: standard BNC connector, but is soldered on to the radio tray.
:

It would be OK to terminate the coax where the antenna was connected.
As someone else pointed out, you can short out the antenna at its
BNC connector to electrically remove it from the plane. You could
probably make a BNC shorting plug from parts found at Radio Shack.

--
Aaron Coolidge (N9376J)