[Maritime Q-Scout]

I picked up an XM Radio the other day with home kit. I've put the home antenna (and subsequently the car antenna) up on my roof. The home antenna is cutting in and out. It seems when the wind blows (and moves the tree branches) then it reacquires the signal and is fine until the next breeze.

Any ideas on what might be done to help solve this problem? If I put the antenna in the middle of my roof it works perfectly, however there's no where for me to secure the antenna down.

Just thought there might be a trick someone knows? I've read put the car antenna on a metallic surface and being omni directional as long as it sees the sky it's fine. If you think that would work, suggestions on what to use as a metallic surface I would attach to a non-singled part of the house?