Crossmodulation

This is the most common form of interference on the FM band, and is caused by signal reflection. This means that the receiver in the car is picking up two or more signals - one from the source and one from the reflective surface. The result is that the received signal appears warped or shifted. This form of interference occurs most often in built-up areas, but can also occur in rugged country areas.

This problem usually occurs when one or more strong signals coincide and produce a false signal. This leads to fuzz, or too many channels on the reception band. This often happens when the car passes one or more transmitters, or when the car is very close to the transmitter.