[hharney]

GPS antennas have to go on top. Comm antennas normally are on the roof too away from the GPS antenna. I have seen a couple Skymasters with the Comm antenna on the wing just in front of the boom. The mounting out on the booms would stay away from the pressurized hull. I really thought of doing it to my plane when I had it all torn down last winter but I just had way too many other things happening.

Attached photos are comm antennas on the wings and I have two GPS antennas on the roof, in line (front to back)(the clecos in the picture are patches from my old comm antennas when they moved them for the GPS antennas. I had holes there that were never really covered correctly) and my 2 comm antennas are in front of the rear engine air intake scoop. The comm antennas are not exactly staged out parallel but that's life.