USA National Anthem (1960s TV Station Sign-Off)

A sign-on (or start-up in Commonwealth countries) is the beginning of operations for a radio or television station, generally at the start of each day. It is the opposite of a sign-off (or closedown in Commonwealth countries), which is the sequence of operations involved when a radio or television station shuts down its transmitters and goes off the air for a predetermined period; generally, this occurs during the overnight hours although a broadcaster's digital specialty or sub-channels may start up and closedown at significantly different times as its main channels.

Like other television programming, sign-on and sign-off sequences can be initiated by a broadcast automation system, and automatic transmission systems can turn the carrier signal and transmitter on/off by remote control.

Sign-on and sign-off sequences have become less common due to the increasing prevalence of twenty-four-hour-a-day, seven-day-a-week broadcasting. However, some national broadcasters continue the practice; particularly those in countries with limited broadcast coverage. Stations may also sometimes close for transmitter maintenance, or to allow another station to broadcast on the same channel space.