Checking Radio Mast Antennas

Unplug antenna lead-in at back of radio and plug a test antenna into radio. Make sure test antenna base is grounded to the car 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. Tune to high and low ends of the dial on both AM and FM, checking weak and strong station reception. If reception is OK, the problem exists with antenna and/or its lead-in cable. If reception is still poor, service the radio.