I installed an American International XM micro antenna on the metal plate underneath the rear parcel shelf. That works most of the time, but I'm getting consistent dropouts when I drive on streets with tall trees.

Do people with antennas mounted in other locations also notice problems with trees and dropouts?

Another question: is there any way to tell signal strength using the stock HU and XM tuner? Posts on XMFan imply that Delphi units appear to be able to display their signal strength.

 

Following up with more information: I had a loaner G35 with XM (roof-mounted antenna) today, so I tried driving through the same areas that gave me dropout problems. The roof-mounted installation had some minor dropouts but not nearly as much as with my antenna mounted under the rear parcel shelf.

On the other hand, it looked like a big black wart on the roof.

So the antenna mounted under the rear parcel shelf does seem to result in more dropouts. I may try putting the antenna on top of the parcel shelf to see if that makes a difference.