In
broadcasting,
rotation is the repeated airing of a limited
playlist of
songs on a
radio station or
satellite radio channel, or
music videos on a
TV network. They are usually in a different order each time. However, they are not completely
shuffled, so as to avoid varying the time between any two consecutive plays of a given song by either too much or too little. Stations playing new music typically have a short rotation of around four hours, while stations playing "
classics" may go as long as eight hours.
College radio and
indie radio stations sometimes have no particular rotation, only the
music director's suggested lists for the
disc jockeys, or are totally
freeform radio.
Broadcast automation systems handle a limited rotation quite well, in turn making
voice tracking easy. Even if a live person is present, the automation system at commercial stations usually picks the music ahead of time out of the current rotation, thus the DJ becomes only an
announcer.