Features of your vehicle
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4
How car audio works
AM (MW, LW) and FM radio signals are
broadcast from transmitter towers locat-
ed around your city. They are intercepted
by the radio antenna on your car. This
signal is then received by the radio and
sent to your car speakers.
When a strong radio signal has reached
your vehicle, the precise engineering of
your audio system ensures the best pos-
sible quality reproduction. However, in
some cases the signal coming to your
vehicle may not be strong and clear. This
can be due to factors such as the dis-
tance from the radio station, closeness of
other strong radio stations or the pres-
ence of buildings, bridges or other large
obstructions in the area.
AM (MW, LW) broadcasts can be
received at greater distances than FM
broadcasts. This is because AM (MW,
LW) radio waves are transmitted at low
frequencies. These long, low frequency
radio waves can follow the curvature of
the earth rather than travelling straight
out into the atmosphere. In addition, they
curve around obstructions so that they
can provide better signal coverage.
FM broadcasts are transmitted at high
frequencies and do not bend to follow the
earth's surface. Because of this, FM
broadcasts generally begin to fade at
short distances from the station. Also,
FM signals are easily affected by build-
ings, mountains, or other obstructions.
These can result in certain listening con-
ditions which might lead you to believe a
problem exists with your radio. The fol-
lowing conditions are normal and do not
indicate radio trouble:
JBM001
JBM002
FM reception
AM (MW, LW) reception
JBM003
FM radio station
EL ENG 4B AUDIO.QXP 8/11/2010 10:55 AM Page 120
