Car radio reception
151n
AM, LW and SW broadcast signals
have substantially longer reception
ranges than FM transmissions. This is
because the broadcast signals propa-
gated at ground level in the form of
surface waves are also reflected from
the ionosphere as atmospheric waves.
Frequency modulation (FM) provides
substantially better sound quality than
the other frequency bands. However,
because FM transmissions rely on line-
of-sight broadcast waves, their effec-
tive reception range is limited.
The limitations inherent to radio recep-
tion in a moving vehicle have been
minimized by a number of innovative
system designs.
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