2008 Subaru Impreza Owner's Manual - Page 181
2008 Subaru Impreza Manual
Page 181 highlights
Audio 5-3 You may experience problems in receiving XMTM satellite radio signals in the following situations. . If you are driving northward in a coastal area You will notice that the XMTM satellite radio antenna is fixed to the upper right hand corner of your windshield. The signal comes from the south and may not be able to reach the antenna in some circumstances when you are driving north. . If you are driving in a tunnel or a covered parking area . If you are driving beneath the top level of a multi-level freeway . If you drive under a bridge . If you are driving next to a tall vehicle (such as a truck or a bus) that blocks the signal . If you are driving in a valley where the surrounding hills or peaks block the signal from the south . If you are driving on a mountain road where the southern direction is blocked by mountains . If you are driving in an area with tall trees that block the signal (33 ft (10 m) or more), for example on a road that goes through a dense forest . The signal can become weak in some areas that are not covered by the repeater station network. Please note that these may be other unforeseen circumstances when there are problems with the reception of XMTM satellite radio signals.