Reception conditions will constantly
change because of vehicle movement.
Buildings, terrain, signal distance and inter-
ference from other vehicles can work
against ideal reception. Described below
are some of the factors that can affect your
radio reception.
Some cellular phones or other devices may
cause interference or a buzzing noise to
come from the audio system speakers.
Storing the device in a different location
may reduce or eliminate the noise.
FM RADIO RECEPTION
Range: FM range is normally limited to 25 –
30 mi (40 – 48 km), with monaural (single
channel) FM having slightly more range
than stereo FM. External influences may
sometimes interfere with FM station re-
ception even if the FM station is within 25
mi (40 km). The strength of the FM signal is
directly related to the distance between
the transmitter and receiver. FM signals fol-
low a line-of-sight path, exhibiting many of
the same characteristics as light. For ex-
ample, they will reflect off objects.
Fade and drif t: As your vehicle moves away
from a station transmitter, the signals will
tend to fade and/or drif t.Static and flutter: During signal interfer-
ence from buildings, large hills or due to
antenna position (usually in conjunction
with increased distance from the station
transmitter), static or flutter can be heard.
This can be reduced by adjusting the treble
control to reduce treble response.
Multipath reception: Because of the reflec-
tive characteristics of FM signals, direct and
reflected signals reach the receiver at the
same time. The signals may cancel each
other, resulting in momentary flutter or loss
of sound.AM RADIO RECEPTION
AM signals, because of their low frequency,
can bend around objects and skip along
the ground. In addition, the signals can be
bounced off the ionosphere and bent back
to earth. Because of these characteristics,
AM signals are also subject to interference
as they travel from transmitter to receiver.
Fading: Occurs while the vehicle is passing
through freeway underpasses or in areas
with many tall buildings. It can also occur
for several seconds during ionospheric tur-
bulence even in areas where no obstacles
exist.
Static: Caused by thunderstorms, electrical
power lines, electric signs and even traffic
lights.
AUDIO OPERATION PRECAUTIONS
MP3 or WMA terms
∙ MP3 — MP3 is short for Moving Pictures
Experts Group Audio Layer 3. MP3 is the
most well-known compressed digital
audio file format. This format allows for
near “CD quality” sound, but at a fraction
of the size of normal audio files. MP3
conversion of an audio track from CD-
ROM can reduce the file size by approxi-
mately a 10:1 ratio with virtually no per-
ceptible loss in quality. MP3
compression removes the redundant
and irrelevant parts of a sound signal
that the human ear doesn’t hear.
∙ WMA — Windows Media Audio (WMA)* is a compressed audio format created by
Microsof t as an alternative to MP3. The
WMA codec offers greater file compres-
sion than the MP3 codec, enabling stor-
age of more digital audio tracks in the
same amount of space when com-
pared to MP3s at the same level of qual-
ity.
4-32Monitor, climate, audio, phone and voice recognition systems
