24 January 2017 | 3 °C

Monday Miscellanea

Dave Haste
By Dave Haste Last edited 119 months ago
Monday Miscellanea
Greenwich Time Signal pips

This Day In London’s History

1924: The Greenwich Time Signal pips are broadcast on BBC Radio for the first time.

This one is quite pleasingly geeky.

Shortly after the formation of the BBC in 1922, it was suggested that it might be a nice idea to broadcast a time signal “under direct control of the Greenwich Observatory”. No-one did much about the idea for a couple of years, until John Reith (general manager of the BBC) and Frank Dyson (the Astronomer Royal) paid the Royal Greenwich Observatory £40 to modify two of their clocks to provide a time signal to the BBC every 30 minutes. And so, at five seconds before 9:30pm on 5th February 1924, a 1kHz oscillator at the Observatory sent six short pips down a GPO line to the BBC, and the BBC broadcast them to the public for the first time.

Some more things you need to know about the Greenwich Time Signal pips:

  • Each of the six pips was originally a tenth of a second long, but the final pip was lengthened to half a second at the beginning of 1972, because...
  • ... small variations in the earth’s rotation introduced the need for ‘leap seconds’ to occasionally be introduced into Greenwich Mean Time, resulting in the odd minute containing 61 seconds. On these rare occasions, seven pips are broadcast at the end of the hour (instead of the normal six), and so the final pip was lengthened so that listeners would always know which pip was the last one in the sequence.
  • The pips are actually transmitted a fraction of a second early, to compensate for the time it takes the radio signal to reach a consumer’s receiver. However this is largely pointless, as the transmission delays will vary depending on where in the country you’re listening from (or whether you’re listening on digital or analogue).
  • In the early 1990s there were complaints from musicians that the pips’ 1kHz tone had dropped in pitch. This was thought to be due to the aging of the oscillator equipment.

Capital Connections

Generation of the pips did not stay in Greenwich for very long, moving to Abinger in Surrey in 1939 then Herstmonceux in East Sussex in 1957. However the pips eventually returned to London on their 66th birthday (5th February 1990) when the BBC started generating them with their own equipment in Broadcasting House.

Much more information on the Greenwich Time Signal can be found on Mike Todd’s website.

Londoner Of The Week

Think you know who ‘Diddy’ is? Think again. As far as the UK music market is concerned, the name ‘Diddy’ applies only to the London-based dance-music producer Richard Dearlove. Or at least that has been the official legal position since last September. Unfortunately, the other pretender to this name, global hip-hop superstar Sean Combs a.k.a. ‘P. Diddy’ (remember the ‘P’, kids, it’s now legally important) is in hot water for allegedly breaching this agreement.

Londonist’s renowned impartiality prevents us from taking sides on the matter, although we have fond (but blurry) memories of nascent clubbing experiences jumping up and down to (the London) Diddy’s early-nineties dance classic ‘Give Me Love’, almost eight years before Puffy had thought to change his name to ‘P. Diddy’…

One Thing You Must Do In London This Week

For the next month or so, a new collection of private photographs taken by Hunter S. Thompson (yes, the original ‘gonzo’ journalist) will be shown in an exhibition at the Michael Hoppen Gallery in SW3. This is the first showing of these photographs in Europe, and critics seem fairly impressed on the whole. We reckon it’s worth a look if you’re in the area. The exhibition is open from Tuesdays to Saturdays until 10th March – see the gallery’s website for full details.

Last Updated 05 February 2007