Common Radio Reception Conditions - Ford 1996 Escort Manual

Common Radio Reception Conditions

Several conditions prevent FM reception from
being completely clear and noise-free, such as
the following:
1. Distance/Strength
The strength of the FM signal is directly related
to the distance the signal must travel. The
listenable range of an average FM signal is
approximately 25 miles (40 kilometers). Beyond
this distance, the radio is operating in a fringe
area and the signal becomes weaker.
2. Terrain
The terrain (hilly, mountainous, tall buildings) of
the area over which the signal travels may
prevent the FM signal from being noise-free.
If there is a building or large structure between
the antenna and station, some of the signal
"bends" around the building, but certain spots
receive almost no signal. Moving out of the
"shadow" of the structure will allow the station
to return to normal.
When the radio waves are reflected off objects or
structures, the reflected signal cancels the normal
signal, causing the antenna to pick up noise and
distortion. Cancellation effects are most
prominent in metropolitan areas, but also can
become quite severe in hilly terrain and
depressed roadways.
To minimize these conditions, a stereo/mono
blend circuit has been incorporated into this
system. This feature automatically switches a
weak stereo signal to a clearer monaural signal,
which improves the quality of reception.
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