Mitsubishi Montero (2004+). Manual - part 551
RADIO WITH TAPE PLAYER AND CD PLAYER
TSB Revision
CHASSIS ELECTRICAL
54A-173
1. The signal becomes weak as the distance from
the station's transmission antenna increases. The
signal strength received depends on the signal
strength of the transmitting station and intervening
obstructions such as buildings and hills. Generally
speaking, the area of good reception is
approximately 20
− 25 km (12 − 16 miles) for
stereo reception, and 30
− 40 km (19 − 25 miles)
for monaural reception.
2. The signal will becomes weak when an area of
shadow from the transmitting antenna (places
where there are obstructions such as mountains
or buildings between the station transmitter and
the vehicle), 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. When moving, noise
will appear each time the vehicle's antenna
passes through this kind of obstructed area. The
strength and interval of the noise varies according
to the signal strength and the conditions of
deflection. <This is called multipath noise, and is a
repetitive buzzing.>
4. Since FM stereo transmission and reception has a
weaker field than monaural, it is often
accompanied by a hissing noise.
After taking measures to prevent the noise, check
that no noise occurs.
5. Change to a different station with a stronger wave
to boost resistance to interference.
6. Suppress high tones to reduce noise.
7. Extend antenna completely.
If there is noise, the following causes can be consid-
ered.
8. If due to vehicle noise: It may not be possible to
prevent noise if the signal is weak.
9. If due to external noise: In almost all cases,
prevention on the receiver side is not possible.
Weak signals especially are susceptible to
interference.
If there is more noise than on radios in other vehi-
cles, find out the noise condition and the name and
frequency of the receiving stations from the owner,
and consult with the radio manufacturer's service
center.
INSPECTION PROCEDURE 7: Sound mixed with Noise, Only at Night (AM).
The following can be considered as possible causes
of noise appearing only at night.
1. It is significantly easier to receive long-distance
signals at night. This means that even stations
that are received without a problem during the day
may experience important to remember that the
weaker station is more susceptible to interference.
The appearance of a beat sound may occur in the
evening. A beat sound is created when two
signals close in frequency interfere with each
other. A common sign of this type of interference
is a repetitious high-pitched sound that may over
power the desired radio station. This sound is
generated not only by sound signals but electrical
waves as well.
2. The changing system may also be a source of
noise. When diagnosing radio noise, do not over
look the possibility of a problem with the vehicles
generator.
DIAGNOSIS
STEP 1. Check the vehicles lighting system.
Q: Does the noise disappear when the vehicles
headlights are turned "OFF"?
YES :
Go to Step 2.
NO :
Go to Step 3.
STEP 2. Check that the following actions
disappear the noise.
Tune to a station with a stronger wave.
Q: Is there more noise than on radio in other
vehicles?
YES :
Consult the radio manufacturer's service
center.
NO :
Check that there is no noise.