Antenna: Testing and Inspection

Antenna System Check:

CHECKING RADIO ANTENNA MAST
Unplug antenna lead-in at back of radio and plug a test antenna into radio. Make sure test antenna base is grounded to the vehicle chassis. Do not touch the mast. Check radio reception in an area away from tall buildings, metal structures, power lines, fluorescent lighting and power tools. Then to high and low ends of the dial on both AM and FM, checking weak and strong station reception. Refer to "System Performance Check". If reception is Ok, the problem exists with antenna and/or its lead-in cable. If reception is still poor with test antenna, check for aftermarket equipment that may be causing complaint.

CHECKING LEAD-IN CABLES
In case of continued reception or noise complaints, always check the lead-in with a digital multimeter (refer to the following illustration and chart). If long jumper leads are not available, check center conductor continuity by jumping the antenna mast to ground and checking for continuity from the center conductor at radio to ground. The type of coaxial cable used is RG-59/U.

When checking resistance, cautiously wiggle the lead-in tip and cable. Consistent readings from table should always be obtained. If not, some portion of the lead-in is intermittent and lead-in should he replaced. Also try:
a. Running a braided ground strap to the antenna lead-in.
b. Changing the antenna lead-in.
c. Disconnecting the lead-in to check resistance.
d. Check in-line connection for corrosion or poor connection.