1996 Lincoln Continental Owner's Manual - Page 179

If the sound skips: Badly scratched discs or extremely rough roads will cause the sound to skip. Skipping will not damage the disc player or scratch the discs. Terrain The terrain (hilly, mountainous, tall buildings) of the area over which the signal travels may prevent the FM signal from being noise-free. Repeated pops and hisses which are heard during an otherwise clear broadcast can occur near the station because of the "line of sight" characteristic of FM radio waves. If there is a building or large structure between the antenna and station, some of the signal "bends" around the building, but certain spots receive almost no signal. Moving out of the "shadow" of the structure will allow the station to return to normal. When the radio waves are reflected off objects or structures, the reflected signal cancels the normal signal, causing the antenna to pick up noise and distortion. Cancellation effects are most prominent in metropolitan areas, but also can become quite severe in hilly terrain and depressed roadways. Common Radio Reception Conditions Several conditions prevent FM reception from being completely clear and noise-free, such as the following: Distance/Strength The strength of the FM signal is directly related to the distance the signal must travel. The listenable range of an average FM signal is approximately 24 miles (40 km). Beyond this distance, the radio is operating in a "fringe" area and the signal becomes weaker. Also, "Signal Modulation" is used by some stations to increase their "loudness" relative to other stations. The difference in loudness can be a result of signal modulation as well as signal strength. 176