Hummer 2010 H3 - Manual (Page 163)

Infotainment System 7-9
Unknown: If this message is
received when tuned to channel 0,
there may be a receiver fault.
Consult with your dealer.
Chk XMRcvr: If this message does
not clear within a short period of
time, the receiver may have a fault.
Consult with your dealer.
Radio Reception
Frequency interference and static
can occur during normal radio
reception if items such as cell phone
chargers, vehicle convenience
accessories, and external electronic
devices are plugged into the
accessory power outlet. If there is
interference or static, unplug the
item from the accessory power
outlet.
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
16 to 65 km (10 to 40 mile). 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.
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.