CHASSIS ELECTRICAL
-
Radio and Tape Player
54-167
A-8
Noise sometimes appears on FM during traveling.
No
Is the antenna completely extended?
Yes
t
Check the antenna itself.
(Refer to E-l, 2.)
+
Does the problem clear up when
re
1
No
Yes
i
Does the problem appear only in certain locations and only with yes
certain stations?
No
~
Due to electrical field conditions. (Multipath
noise*, fading noise*).
Are connectors property connected?
Yes
Check connector connections.
1
t
Does noise appear when the radio switch is turned on while the
vehicle is stopped
and
the radio is struck while tuned away from
a station?
Yes
No
*
Static electricity noise:
Sody
static electric from the shock absorber
rubber bushings used to prevent vibration, tires,
etc. occurs because of separation from the
ground, causing a buzzing noise.
Since no measures can be taken on the radio
side, steps should be taken to discharge the
static
electricitv
of the vehicle bodv.
Is the radio body correctly grounded?
No
(Is the mounting screw tightened securely?
)
Yes
-)
Tighten the screw securely.
I
Is the antenna correctly grounded? (If noise appears when the antenna
is moved, this means the ground is not securely connected.)
Yes
If rust is present on the antenna ground screw,
clean and tighten the ground securely.
*
1
Repair or replace radio.
1
About multipath noise and fading noise
Because the frequency of FM
waves
is extreme-
ly high, it is highly susceptible to effects from
geological formations and buildings. These ef-
fects disrupt the broadcast signal and obstruct
‘reception in several ways.
l Multipath noise
This describes the echo that occurs when the
broadcast signal is reflected by a large
obstruc-
tion and enters the receiver with a slight time
delay relative to the direct signal (repetitious
buzzing).
l Fading noise
This is a buzzing noise that occurs when the
broadcast beam is disrupted by obstructing ob-
jects and the signal strength fluctuates intricately
within a narrow range.
1
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