Toyota Celica 2005 Repair Manual page 2266

Multipath
Fade Out
Noise occurs at a specific place.
Noise occurs when listening to
AM
faint broadcasting.
Noise occurs only at night.
Noise occurs at a specific place
FM
while driving.
2005 CELICA (RM1131U)
BODY ELECTRICAL − AUDIO SYSTEM
Multipath
S
One type of interference caused by bouncing of ra-
dio waves off obstructions is called "multipath". Mul-
tipath occurs when a signal from the broadcast
transmitter antenna bounces off buildings and
mountains and interferes with the signal that is re-
ceived directly.
BE2820
Fade Out
S
Because FM radio waves are higher frequencies
than AM radio waves, they bounce off buildings,
mountains, and other obstructions. For this reason,
FM signals often seem to gradually disappear or
fade away as the vehicle goes behind a building or
other obstructions. This is called "fade out".
BE2821
4. NOISE PROBLEMS
(a) Questionnaire for noise:
It is very important for noise troubleshooting to have good
understanding of the claims from the customers, so make
the best use of following questionnaire and diagnose the
problem accurately.
Strong possibility of foreign noise.
There is a case that the same program is broadcasted
from different local stations, and you are listening to different
station even if the program is the same.
Strong possibility of the beat from a distant broadcasting.
Strong possibility of multipath noise and fading noise
caused by the changes of FM waves.
HINT:
If the condition when the noise occurs does not meet any of the
above, find out the cause based on "Reception Problems". Re-
fer to the description about Multipath and Fading mentioned
previously.
2265
BE−91