It's what you get when you're listening to a station on a certain frequency, and you get two radio stations who both use that frequency at the same time. One signal is stronger than the other, then it changes so the other is stronger. This just keeps on happening and is called a 'frequency fight'.
"Dude, frequency fight imminent."
"Dude, change the station will you?"
if you happen to be an electronics student in high school and you can't stand the music they play on the bus, find a schematic for a tunable FM transmitter. then when you get on the bus, plug in your cd player and tune it to the frequency of the station the driver is playing! hopefully your signal will be strong enough to overcome the other one coming in. It great to see the looks on other peoples faces when all of the sudden a bill cosby comedy routine comes in over 50 cent hahaha