XM Reception
WARNING: This page is about a different car, the 2008 Cadillac DTS. However, it is still accessible from the selected car via links, so may be relevant.
XM satellite radio provides digital radio reception. The XM signal is broadcast from 2 satellites and, where necessary, terrestrial repeaters. The high power satellites allow the antenna to receive the XM signal even when foliage and other partial obstructions block the antennas view of the satellite. Terrestrial repeaters are used in dense urban areas. These repeaters will receive the satellite signal and re-broadcast them at much higher power levels in order to ensure reception in areas with densely packed tall buildings.