Inspection Procedure 10: Noise Sometimes Appears on FM during Travelling.


DIAGNOSIS PROCEDURE


STEP 1. Check the state of the antenna.


Q. Is the mast antenna assembled?

Go to Step 2.

Assemble the mast antenna. Check that there is no noise.

STEP 2. The check after adjusting the radio.


Q. Readjust the radio. Is the noise eliminated?

Check that there is no noise.

Go to Step 3.

STEP 3. Check with several broadcasting stations.


note Multipath noise and fading noise: Because of the frequency of FM waves in extremely high, it is highly susceptible to effects from geological formations and buildings. These effects disrupt the broadcast signal and obstruct reception in several ways.
Multipath noise
  • This describes the echo that occurs when the broadcast signal is reflected by a large obstruction and enters the receiver with a slight time delay relative to the direct signal (repetitious buzzing).
Fading noise
  • This is a buzzing noise that occurs when the broadcast beam is disrupted by obstructing objects and the signal strength fluctuates intricately within a narrow range.

Q. Is the abnormality in reception generated only within a certain range?

The effect of an electrical field condition (multipath noise, fading noise) could be the cause. Check that there is not noise.

Go to Step 4.

STEP 4. Check that noise appears when the radio switch is turned on while the vehicle is stopped.


note Static electricity noise: Body static electric from the shock absorber rubber bushings used to prevent vibration, tires, etc. occurs because of separation from the earth, causing a buzzing noise. There is no measures to discharge the static electricity of the vehicle body. Check that there is no noise.

Q. Does noise appear when the radio switch is turned on while the vehicle is stopped and the radio is tapped while tuned away from a station?

Go to Step 5.

It may be static electricity noise.

STEP 5. Check that the radio is correctly earthed.


The radio is connected to the earth with an assembling screw.

Q. Is the radio correctly earthed?

Go to Step 6.

Tighten the screw securely. Check that there is no noise.

STEP 6. Check by replacing the radio and tape player or CD player.


Q. Are operations normal when using another radio and tape player or CD player?

Either repair or replace the radio and tape player or CD player. Check that there is no noise.

Either repair or replace the antenna assembly. Check that there is no noise.