Chevrolet SUBURBAN - 2011 Owner's Manual page 234

The AM-FM antenna is located in
the passenger rear side windows.
Make sure the inside surfaces of the
rear side windows are not scratched
and that the lines on the glass are
not damaged. If the inside surfaces
are damaged, they could interfere
with radio reception.
If a cellular telephone antenna
needs to be attached to the glass,
make sure that the grid lines for the
AM-FM antenna are not damaged.
There is enough space between the
grid lines to attach a cellular
telephone antenna without
interfering with radio reception.
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
(if equipped) may be affected if the
sunroof is open.