Greenwich Time Signal

[1] The broadcast pips replaced an electrical time coordination system based on the railway telegraph network, which itself was an extension of the mechanical time balls in Portsmouth (1829) and later Greenwich (1833), which enabled navigators aboard ships moored in those places to set their chronometers for the determination of longitude on voyages.

A rare quarter-hour Greenwich Time Signal was heard at 05:15 weekdays on Wally Webb's programme on local radio in the east of England until it ended in March 2020, as part of his "synchronised cup of tea" feature.

In 1999, pip-like sounds were incorporated into the themes written by composer David Lowe to introduce BBC Television News programmes.

The pips are timed so that they are accurately received on long wave as far as 160 kilometres (100 mi) from the Droitwich AM transmitter, which is the distance to Central London.

Newer digital broadcasting methods have introduced even greater problems for the accuracy of use of the pips.

On digital platforms such as DVB, DAB, satellite and the Internet, the pips — although generated accurately — are not heard by the listener exactly on the hour.

The pips have been broadcast daily since 5 February 1924,[9] and were the idea of the Astronomer Royal, Sir Frank Watson Dyson, and the head of the BBC, John Reith who commissioned Marconi / Siemens in Charlton, close to Greenwich, to create the signal.

The pips were originally controlled by two mechanical clocks located in the Royal Greenwich Observatory that had electrical contacts attached to their pendula.

[9] The Royal Greenwich Observatory moved to Herstmonceux Castle in 1957 and the GTS equipment followed a few years later in the form of an electronic clock.

This was most often referred to on Terry Wogan's Radio 2 Breakfast show, although usually only in jest since the actual event happened rarely.

As a contribution to Comic Relief's 2005 Red Nose Day, the BBC developed a "pips" ringtone which could be downloaded.

During her final broadcast as presenter on BBC Radio 4's The Today Programme – following 11 years sharing the post – Mishal Husain asked for forgiveness having previously "crashed the pips."

Husain remarked that "in the tradition of [her] faith, when people used to go on pilgrimage in generations past, they would not only take leave of their associates, but they would ask for their forgiveness because in those days many would not return from the arduous journey.

[15] Part of Humphrys' surprise was probably because of his deliberate avoidance of crashing the pips with the help of an accurate clock in the studio.

A sudden total failure in the generation of the audio pulses that constitute the pips was experienced on 31 May 2011 and silence was unexpectedly broadcast in place of the 17:00 signal.

[18] Many radio broadcasters around the world use the Greenwich Time Signal, or a variant thereof, as a means to mark the start of the hour.