Corolla Sedan 4-Door L4-1587cc 1.6L DOHC MFI (1997)
One type of interference caused by the bouncing of radio waves off obstructions is called "multipath". Multipath occurs when a signal from the broadcast
transmitter antenna bounces off buildings and mountains and interferes with the signal that is received directly.
Fade Out
Because FM radio waves are of higher frequencies than AM radio waves, they bounce off buildings, mountains, and other obstructions. For this reason.
FM signals often seem to gradually disappear or fade away as the vehicle goes behind a building or other obstruction. This is called "fade out".