>No but I have a tube type, pull behind, GPS unit.

Heh. You joke, but back in '88 when I was in the Army, we got to field test
the AN/PSN-8, a 17lb backpack-monstrosity of a GPS receiver with a
tennis-ball-can sized antenna mounted on a flexible boom. (see PDF link
below, scroll to last page)
http://army-gps.robins.af.mil/pubs/pathFinder/path10-4.pdf

> >
> > having just gotten my fisher tube amp back from the shop i
> > went looking to see if anyone had tube amps for cars.

But back to the discussion at hand, the problem with tubes is that they're
not real "vibration-friendly". Mechanical stress really shortens the life
of vacuum tube devices, particularly when they're not designed for vehicle
applications. An acquaintance of mine was the guitarist in a band that
transported all their gear in the drummer's lowered mini-truck. The chopped
springs made it ride really rough and it kept breaking tubes on this guy's
amp, so he ended up pulling all the tubes and carrying them separate,
plugging them in on stage before the show. One-off anecdotes are
statistically meaningless, but it's still worth considering. It probably
wouldn't be a bad idea to mount it in a cushioned or flexible manner, as
opposed to solid brackets. Dunno. Just prattling, I am...

John Bange
'90 Vanagon "Geldsauger"