54-126
SYSTEM
Troubleshooting
Noise appears at certain places when traveling (FM).
Yes
OK
l
Extend antenna completely.
On radios with an FM stereo switch, is noise still present when
switched to monaural?
No
OK
Yes
If there is more noise than other radios, find out the noise conditions and the
name and frequency of the
stations from the user, and consult with
the service center.
NOTE
About FM waves:
FM waves have the same properties as light, and
can be deflected and blocked. Wave reception is not
possible in the shadow of obstructions such as
buildings or mountains.
The signal becomes weak as the distance from
the station’s transmission antenna increases.
Although this may vary according to the signal
strength of the transmitting station and inter-
vening geographical formations or buildings, the
area of good reception is approx.
k m
6 miles) for stereo reception, and
km (19-25 miles) for monaural reception.
2. The signal becomes weak when an area of
shadow from the transmitting antenna (places
where there are obstructions such as mountains
or buildings between the antenna and the car),
and noise will appear. <This is called first fading,
and gives a steady buzzing noise.>
3. If a direct signal hits the antenna at the same
time as a signal reflected by obstructions such
as mountains or buildings, interference of the
two signals will generate noise. During traveling,
noise will appear each time the vehicle’s anten-
na passes through this kind of obstructed area.
The strength and interval of the noise varies
according to the signal strength and the condi-
tions of deflection. <This is called multipath
noise, and is a repetitious buzzing.>
4.
Since FM stereo transmission and reception has
a weaker field than monaural, it is often accom-
panied by a hissing noise.
FM Broadcast Good Reception Areas
FM Signal Characteristics and
Signal Interference
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