Off-the-air
In telecommunication, the term
off-air or
off-the-air has the following meanings: ▪ In radio communications systems, pertaining to a radio station or television station that is completely shut down,
i.e. that is not transmitting any signal, not even an un-modulated carrier wave. Other terms in this context include "dark" or "silent", though those terms were typically used for a station that has left the air for an extended period of time, or permanently; while "off-the-air" is generally used for a brief period of time, or for a station that has recently stopped broadcasting. ▪ In a radio station, pertaining to a particular source of modulation, such as a specific microphone, that is disconnected,
i.e. is no longer capable of modulating the carrier.
Note: The carrier wave may continue unmodulated or it may be modulated by another signal source, such as a subcarrier. Also, off-the-air may be synonymous with over-the-air or from-the-air, as in picking up a terrestrial broadcast TV station off-the-air instead of from cable TV.