Most anywhere
comfordent - I don't have XM in my boat, but I do in my car, and know a lot of other people with XM. Although there is a debate about whether or not an XM antenna needs a metal "back-plane" to function correctly, similar to CB antennas, many people, myself included, have their car XM antennas on a non-metal dash or rear package shelf with no problems. On a boat, you should be able to place it most anywhere on the cabin top. I'd put it where it'll be out of the way, but not too close to the mast. It may be that the mast could block the signal on certain tacks. Good luck! Jack
