In article ,
Dave wrote:
Simply put, it is in the instruction books on flying, boating,
navigation, the manuals for the compasses, (marine & aviation),
placards on instrument panels, even some sunglasses....DO NOT, EVER,
FOR ANY REASON , place ANY object near the magnetic compass, in case
it MIGHT affect it.

None of my books make such a statement. I suspect that the deviation
cards in the aircraft most of us fly are not very accurate, unless you
have a compass swing done periodically. There are lots of things that
surround the magnetic compass that could affect it. A portable XM
receiver that can be easily removed if the compass is your last hope of
survival doesn't rate very highly on my list of concerns.


JKG