Sign-off (or closedown) 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. It is the opposite to a sign-on (or startup), which usually takes place at the start of the day.

Sign-off (or closedown) 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. It is the opposite to a sign-on (or startup), which usually takes place at the start of the day.