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| Version 3 | Version 4 |
|---|---|
| Time change marks end of an era | Time change marks end of an era |
| (2 days later) | |
| British timekeeping has marked the end of an era with the switch to summer time in the early hours of Sunday. | British timekeeping has marked the end of an era with the switch to summer time in the early hours of Sunday. |
| The change at 0100 GMT was the last one to be signalled from Rugby, in Warwickshire, which has been the source of the time signal since 1927. | The change at 0100 GMT was the last one to be signalled from Rugby, in Warwickshire, which has been the source of the time signal since 1927. |
| From 31 March, the long-wave signal, which helps keep the "pips" heard on BBC radio services accurate, will start to be broadcast from Anthorn, Cumbria. | From 31 March, the long-wave signal, which helps keep the "pips" heard on BBC radio services accurate, will start to be broadcast from Anthorn, Cumbria. |
| The contract to transmit the signal is switching from BT to VT Communications. | The contract to transmit the signal is switching from BT to VT Communications. |
| Users of the signal, such as emergency services, banks and mobile phone networks, should not notice any change. | Users of the signal, such as emergency services, banks and mobile phone networks, should not notice any change. |
| "The signal is already up and running and they are swapping between the two," said Fiona Auty of the National Physical Laboratory (NPL), which has responsibility for the time signal. | "The signal is already up and running and they are swapping between the two," said Fiona Auty of the National Physical Laboratory (NPL), which has responsibility for the time signal. |
| "So there are times when people are picking up the signal from Cumbria without even knowing it." | "So there are times when people are picking up the signal from Cumbria without even knowing it." |
| World clock | World clock |
| The national time signal is accurate to within 1,000th of a second of Co-ordinated Universal Time. | The national time signal is accurate to within 1,000th of a second of Co-ordinated Universal Time. |
| It is controlled by two caesium atomic clocks housed at the antenna in Rugby. | It is controlled by two caesium atomic clocks housed at the antenna in Rugby. |
| Peter Whibberley uses atomic clocks to keep British time accurate | Peter Whibberley uses atomic clocks to keep British time accurate |
| "They are typically accurate to tens of nanoseconds, or billionths of a second, over a day," said NPL's Dr Peter Whibberley. | "They are typically accurate to tens of nanoseconds, or billionths of a second, over a day," said NPL's Dr Peter Whibberley. |
| These are kept in line by comparing them to GPS signals and a suite of reference clocks at NPL in Middlesex. | These are kept in line by comparing them to GPS signals and a suite of reference clocks at NPL in Middlesex. |
| "That allows us to get a good measure of whether those clocks are changing - we can then apply an adjustment if necessary," said Dr Whibberley. | "That allows us to get a good measure of whether those clocks are changing - we can then apply an adjustment if necessary," said Dr Whibberley. |
| The master clocks at NPL are in turn kept in check by comparing them with measurements from atomic clocks around the world, a task co-ordinated by the Bureau International des Poids et Mesures (BIPM), near Paris. | The master clocks at NPL are in turn kept in check by comparing them with measurements from atomic clocks around the world, a task co-ordinated by the Bureau International des Poids et Mesures (BIPM), near Paris. |
| Changing hands | Changing hands |
| The national time signal underpins many aspects of society. | The national time signal underpins many aspects of society. |
| "It's used incredibly heavily by police, the ambulance service, the fire brigade, in speed cameras on the road and clocks in train stations," said Miss Auty. | "It's used incredibly heavily by police, the ambulance service, the fire brigade, in speed cameras on the road and clocks in train stations," said Miss Auty. |
| In addition, many home users have the relatively inexpensive receivers in clocks and some radios. | |
| All receive the MSF 60 kHz signal, as it is known, currently transmitted from the Rugby Radio Station by BT under contract from NPL. | All receive the MSF 60 kHz signal, as it is known, currently transmitted from the Rugby Radio Station by BT under contract from NPL. |
| But the telecom company's contract has now expired, and responsibility for broadcasting the signal has changed hands to VT Communications. | But the telecom company's contract has now expired, and responsibility for broadcasting the signal has changed hands to VT Communications. |
| Their mast, located on a Ministry of Defence site in Anthorn, on the west coast of Cumbria, will be easier to maintain than the older antenna in Rugby. | Their mast, located on a Ministry of Defence site in Anthorn, on the west coast of Cumbria, will be easier to maintain than the older antenna in Rugby. |
| It will start broadcasting the national time signal around the clock from midnight on 31 March, one week after the switch to British Summer Time. | It will start broadcasting the national time signal around the clock from midnight on 31 March, one week after the switch to British Summer Time. |