Keep in mind that you will need a "zero ground plane" antenna, if you mount it on a mirror, or anywhere that's not in the middle of a large grounded metal plate. (like a roof, for instance)
Not hard to get, just be sure you pick the right one. "Firestik" have some (they call them NGP, "no ground plane"), and they're readily available.
ZGP antennae mounted on, say, a mirror, can be a pain to tune, and will have a weirdly-distorted radiation pattern, so allow yourself plenty of time and patience. :-)
IanP, the man from Scotland
Jay Feather 19XUD, pushing a Jeep Grand Cherokee