100 years ago today (05/02/2024), the iconic Greenwich Time Signal (GTS) ‘pips’ were broadcast by the BBC for the first time. A series of six short tones broadcast at one-second intervals by numerous BBC Radio stations, the pips mark the precise start of each hour and are typically used before news bulletins or news programmes.
Broadcast daily since the 5 February 1924, the pips were the idea of Sir Frank Watson Dyson and the then head of the BBC, John Reith. The BBC had previously broadcast the chimes of Big Ben for the first time during the countdown to the New Year in 1924. This led Dyson, a leading astronomer whose previous work had helped to prove Albert Einstein’s theory of relativity, to suggest that reliable time signals could be broadcast more regularly by the BBC. Reith approved the idea and enlisted the help of the Royal Observatory at Greenwich to create an effective time-keeping system.
The pips were originally controlled by two mechanical clocks located in the Royal Observatory that had electrical contacts attached to their pendula. The electrical signals were sent each second to the BBC’s headquarters at Broadcasting House. These were converted to an audible tone by an oscillator. In 1957 the Royal Observatory was moved to Herstmonceux Castle in East Sussex. This was due to the increasing levels of light pollution emanating from London. The GTS equipment followed a few years later, in the form of an electronic clock. The original clocks (fittingly designed by the watchmaking company, Dent, which also constructed the famous turret clock of Big Ben) can still be seen today at the Royal Observatory Museum in Greenwich.
Since 1990, the BBC has created its own pips based on signals from the GPS satellite network as well as a radio transmitter located in Cumbria. The BBC’s pips are generated from an atomic clock that sits in the basement of Broadcasting House. Although now largely inaccurate due to the inherent delay in the encoding, transmission, and decoding of digital radio broadcasts, the iconic pips are still a part of most BBC radio programming and are a much-loved British institution. In 1999, the famous tones were even incorporated into the BBC News theme by composer David Lowe. Thus, they continue to ring out to this day. Indeed, many radio broadcasters around the world have since adopted the famous GTS, or some variant of it, using the classic pips in commercial and public broadcasting.