Operation Manual

112 Saab 9-3 Audio System
Sources of FM interference
Interference to FM reception can be caused
by the electrical systems in other vehicles,
particularly if the signal from the transmitter
is weak. Car phones can also produce inter-
ference.
To maintain good radio reception do not tint
the rear windshield, particularly with film
containing small metal flakes.
Cross-modulation
When the radio is tuned to a weak transmit-
ter in the vicinity of a stronger one, the car’s
antennas will receive signals from both.
Such interference is apparent when the
unwanted broadcast can be heard faintly in
the background.
Radio waves, FM/AM
FM radio waves radiate in straight lines from
the transmitter. Because such waves do not
follow the curvature of the Earth, their
strength becomes weaker the further they
travel. That is why a large number of trans-
mitters are needed to provide good recep-
tion.
AM waves, on the other hand, are reflected
off the ionosphere, thus greatly extending
their range.
IB980
IB388
AMFM
IB979