I have a 2003 Expedition and just installed the Z2. I've also installed the HD radio module. However, I've noticed that whether the car antenna is connected to the Z2 or the HD module, my radio reception (especially AM radio -- I listen to a couple news/traffic stations) has really suffered compared to the factory radio. The antenna is built into the rear right window glass and I was wondering if there is an antenna booster that I need to provide power to. Anybody know?