Features of your vehicle
102
4
How car audio works
AM (MW) 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 speakers.
When a strong radio signal has reached
your vehicle the precise engineering of
your audio system ensures the best pos-
sible audio reproduction. However in
some cases the signal coming to your
vehicle may not be strong an 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) broadcasts can be received at
greater distances then FM broadcasts.
This is because AM (MW) radio waves
are transmitted at low frequencies. These
long low radio frequency waves can fol-
low the curvature of the earth rather then
travelling straight out into the atmos-
phere. In addition they curve around
obstructions so that they can provide bet-
ter signal coverage.
FM broadcasts are transmitted at high
frequencies and do not bent to follow the
earth’s surface. Because of this FM
broadcasts begin to fade at short dis-
tances from the station. Also FM signal
are easily affected by buildings, moun-
tains or other obstructions. These can
result in certain listening conditions
which might lead you to believe a prob-
lem exists with your radio. The following
conditions are normal and do not indicate
radio trouble.
JBM002
AM(MW) reception
JBM003
FM radio station
Mountains
Unobstructed
area
Iron bridges
Buildings
JBM001
FM reception
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