National Physical Laboratory

Time

As the UK's home of precise time and frequency measurement, NPL offers a range of services that provide access to a reliable and trusted source of time: the Time from NPL.

The MSF radio time signal covers the whole of the UK and is widely used to set radio-controlled clocks to the correct time. Computers can synchronise their internal clocks to the correct time by using NPL's two computer time services, based on either dial-up or internet connection to time servers located at NPL.

Companies that need to know the precise frequency of off-air signals or use the signals to obtain traceability back to UTC can make use of the NPL monthly Time & Frequency Bulletins. For those users that require the highest accuracy, NPL offers a GPS Common-View Time and Frequency Transfer Service that provides its customers with greater accuracy and data integrity than other commercially available time and frequency traceability routes.

Time products and services

  • The MSF signal transmitted from Anthorn (in Cumbria) provides a signal strength in excess of 100 microvolts per metre at a distance of 1000 km. This level should be sufficient to allow the time and date code to be received without difficulty.
  • NPL operates a time and frequency transfer service that provides its customers with greater accuracy and data integrity than other commercially available time and frequency traceability routes.
  • The MSF 60 kHz standard-frequency and time signal, broadcast by Babcock on behalf of NPL, is occasionally taken off-air to allow maintenance work on the masts and antennas at Anthorn Radio Station to be carried out in safety.
  • The MSF radio signal is a dedicated time broadcast that provides an accurate and reliable source of UK civil time, based on the NPL time scale UTC(NPL). It is available 24 hours a day across the whole of the UK and beyond.
  • The NPL Monthly Bulletins for time & frequency cover the three standard-frequency and time radio signals that are most widely used in the UK: the MSF 60 kHz standard-frequency and time signal, the 198 kHz long-wave transmission from Droitwich radio station and the GPS navigation satellite signals.
  • If the computer is to tell the time accurately it must set its internal clock regularly against a trusted external source of time, which must be both accurate and reliable. NPL offers two services that provide access to just such a source.

Changes to the Telephone Time Service (TTS)

From 16 August 2015, the previous method of accessing NPL TTS using a UK premium-rate telephone number, 0906 851 6333, will be replaced by a direct-dial number, 020 8943 6333. Calls to the service will then be charged at the standard network rate, and there will be no additional costs for using the service.

Find out more about NPL TTS

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