Radio Poor Reception

RADIO POOR RECEPTION

IMPORTANT: Review the system operation in order to familiarize yourself with the system functions.

Refer to Radio/Audio System Description and Operation.

Using a Test Antenna
Use a test mast antenna to quickly check for poor vehicle antenna operation. Unplug antenna lead-in connector from radio receiver and plug a test antenna into radio. Make sure the test antenna base is grounded to the vehicle chassis and keep hands off the mast. Check radio reception in an area away from electrical interferences. Tune to several weak and strong AM and FM stations. If the radio reception improved, the problem exists with the vehicle antenna and/or lead-in cable. If the reception is still poor, refer to Audio System Troubleshooting Hints. Troubleshooting Hints - Audio System

Antenna Ground Test

IMPORTANT: Always zero out the DMM before taking a resistance measurement in order to ensure an accurate reading.

1. Disconnect the negative battery cable.
2. Disconnect the antenna lead-in connector from the radio receiver.
3. Measure the resistance from the negative battery cable to the coaxial cable, outer conductor, connector.
4. The resistance measured should be 0.20 ohms or less.
5. Test the following when the resistance is greater than 0.20 ohms.
- Base of the antenna for a poor connection to body ground.
- The coaxial cable interconnects for a poor connection or corrosion.
- Test for an open or high resistance from the battery negative cable to the body.
6. After finding and correcting the condition, operate the system in order to verify the repair.

Antenna Coaxial Cable Testing

Mast Antenna System:

Use the appropriate chart and diagram to test the antenna coaxial cable resistances for the antenna system on the vehicle. Refer to the table when testing the antenna and/or lead-in cable.

IMPORTANT: Always zero out the DMM before taking a resistance measurement in order to ensure an accurate reading.

1. Measure the resistance from the coax center conductor to antenna mast, ohmmeter probes at points 2 and 7.
2. Total resistance from end to end of center conductor-ohmmeter probes at points 2 and 5:
- RG-58/RG-59 type cable - less than 0.20 ohms per foot
- RG-62/RG-62M type cable - less than 3.5 ohms per foot
3. When checking the resistance, cautiously wiggle the lead-in tip and cable.
4. Replace the antenna and/or lead-in cable when the above readings are not obtained.