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 characterisation service for frequency standards, oscillators and GPS timing receivers, and a GPS common-view service that can monitor continuously a frequency standard at the customer's site.

Time products & 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.
  • Includes computer time and characterisation services, subscription to time bulletins and GPS-common view services.
  • 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.