Fixed Mast Antenna; Xm™ Satellite Radio Antenna System - Hummer H2 2009 Owner's Manual

AM
The range for most AM stations is greater than for FM,
especially at night. The longer range can cause station
frequencies to interfere with each other. For better radio
reception, most AM radio stations boost the power levels
during the day, and then reduce these levels during the
night. Static can also occur when things like storms and
power lines interfere with radio reception. When this
happens, try reducing the treble on the radio.
FM Stereo
FM signals only reach about 10 to 40 miles
(16 to 65 km). Although the radio has a built-in electronic
circuit that automatically works to reduce interference,
some static can occur, especially around tall buildings
or hills, causing the sound to fade in and out.
XM™ Satellite Radio Service
XM Satellite Radio Service gives digital radio reception
from coast-to-coast in the 48 contiguous United States,
and in Canada. Just as with FM, tall buildings or hills can
interfere with satellite radio signals, causing the sound to
fade in and out. In addition, traveling or standing under
heavy foliage, bridges, garages, or tunnels may cause
loss of the XM signal for a period of time.
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Cellular Phone Usage
Cellular phone usage may cause interference with the
vehicle's radio. This interference may occur when making
or receiving phone calls, charging the phone's battery,
or simply having the phone on. This interference causes
an increased level of static while listening to the radio.
If static is received while listening to the radio, unplug
the cellular phone and turn it off.

Fixed Mast Antenna

The fixed mast antenna can withstand most car washes
without being damaged as long as it is securely attached
to the base. If the mast becomes slightly bent, straighten
it out by hand. If the mast is badly bent, replace it.
Occasionally check to make sure the antenna is
tightened to its base. If tightening is required, tighten
by hand until fully seated plus one quarter turn.
XM™ Satellite Radio Antenna
System
The XM Satellite Radio antenna is located on the roof of
the vehicle. Keep the antenna clear of obstructions for
clear radio reception.
If the vehicle has a sunroof, the performance of the XM
system may be affected if the sunroof is open.