Area broadcast shift

In telecommunication, an area broadcast shift or radio watch shift is the changing from listening to radio transmissions intended for one broadcast area to listening to transmissions intended for another broadcast area.

An area broadcast shift may occur when a ship or aircraft crosses the boundary between listening areas.

Shift times, on the date a ship or aircraft is expected to pass into another area, must be strictly observed or the ship or aircraft will miss messages intended for it.

Source: from Federal Standard 1037C