It sounds like you have a bad antenna or bad antenna cable. Both are easy to replace. However, your car is probably still under warranty, so I would hand that one off to the dealer.

__________________
SOLD
2000 E38 750iL Highline Edition, Upgraded with the lastest 2006 X5 Electronics
MKIV Navigation, 16:9 Display, Bluetooth, TV/Video with Backup Camera, Sirius, and Aux Input