Editing Greenwich Time Signal (section)

{{Short description|Series of six pips broadcast by the BBC}}
{{Use dmy dates|date=February 2023}}
[[File:Greenwich Time Signal pips.png|thumb|350px|Graph of the six pips]]

The '''Greenwich Time Signal''' ('''GTS'''), popularly known as '''the pips''', is a series of six short tones (or "pips") broadcast at one-second intervals by many [[BBC Radio]] [[List of BBC radio stations|stations]] to mark the precise start of each hour. The pips were introduced in 1924, generated by the Royal Observatory, Greenwich, and from 1990 were generated by the BBC in London.<ref>{{cite journal |first=Jim |last=McIlroy |title=Network Radio: New Time and Frequency distribution system |url=http://bbceng.info/Eng_Inf/eng-inf-files/EngInf40.pdf#page=5 |format=pdf |journal=Eng Inf |publisher=[[Wood Norton Hall#BBC Academy|BBC ETD]] |date=Spring 1990 |issue=40 |access-date=2024-02-12 |archive-url=https://web.archive.org/web/20240212173449/http://bbceng.info/Eng_Inf/eng-inf-files/EngInf40.pdf#page=5 |archive-date=2024-02-12 |url-status=live}}</ref> The broadcast pips replaced an electrical time coordination system based on the railway telegraph network, which itself was an extension of the mechanical [[time ball]]s in Portsmouth (1829) and later Greenwich (1833), which enabled navigators aboard ships moored in those places to set their [[Marine chronometer|chronometers]] for the determination of longitude on voyages.<ref>{{Cite web |title=The Greenwich Time Service |url=http://www.royalobservatorygreenwich.org/articles.php?article=1084 |access-date=2024-02-07 |website=www.royalobservatorygreenwich.org}}</ref>