Dead air

This article is about the technical phenomenon, for the Iain Banks novel see Dead Air.

Dead air is a phenomenon whereby a broadcast which normally carries audio or video unintentionally becomes silent or blank (also known as unmodulated carrier). The term is most often used in cases where programmed material comes to an unexpected halt, either through operator error or for technical reasons, although it is also used in cases where a broadcaster has 'dried up'. It is the duty of all concerned to rectify the problem as quickly as possible; in many parts of the world dead air is considered to be one of the worst crimes a broadcaster can commit.

This is different from being off-the-air. When a station is off the air, the transmitter is not active and there is no signal at all. Dead air is where a carrier signal is being transmitted, but there is no modulation of that signal.

In the United Kingdom, any radio station which transmits dead air for more than ten minutes without rectifying the situation, broadcasting an announcement, or otherwise warning its listeners, can be penalised and may be fined up to £25,000 per minute by the independent regulator and competition authority for UK communications industries, Ofcom.

Dead air can also apply to television broadcasting, generally when a television channel has an interruption to its output, resulting in a blank screen or in the case of digital television, a frozen image, until output is restored or an apology message is broadcast.

Having dead air during commercials or sponsorship announcements can cost networks considerable advertising revenue.

Examples

An example of dead air was a Chris Evans radio transmission for the British Virgin Radio station. As a promotional stunt, Evans did not arrive for work, and his show went to air carrying nothing for about twenty five minutes.

Another case was BBC Radio 4's failure to broadcast Big Ben's midnight chimes on New Year's Day 2003; after announcing the chimes, a technical error caused the station to fall silent for a minute. This was caused by the correct feed not being faded up. Ironically, the chimes were supposed to be coming via a new link which the BBC had just installed to Westminster just to avoid cases of dead air.

On September 11, 1987, Dan Rather walked off the set of the CBS Evening News when a late running U.S. Open tennis match threatened to delay the start of his news broadcast. The match then ended sooner than expected but Rather was gone. The network broadcast six minutes of dead air before Rather was found and returned to the studio. There was considerable criticism of Rather for the incident.