Measurement for our planet
Measurement for our planet

Following COP26, discover how NPL plays a key role in enabling climate action through the delivery of accurate, reliable data that supports decision making and enables low carbon innovation.

Time and frequency

MSF radio time signal

Accurate and reliable time

The MSF radio signal is a dedicated standard-frequency and time broadcast that provides an accurate and reliable source of UK civil time. It is available 24 hours a day across the whole of the UK and beyond. The signal operates on a frequency of 60 kHz and carries a time and date code that can be received and decoded by a wide range of readily-available radio-controlled clocks.

The MSF signal is transmitted from Anthorn Radio Station in Cumbria by Babcock International, under contract to NPL. The signal covers the whole of the UK, and can also be received throughout most of northern and western Europe. It is monitored against the national time scale UTC(NPL) and corrected when necessary, ensuring that the transmitted time is always correct.

Technical information

Find out more detailed technical information about the MSF time code, signal strength and carrier frequency accuracy.

MSF Reception Difficulties

The main causes of reception problems are local interference from electrical equipment and a reduced local signal due to screening by nearby metalwork, for example in a steel-framed building. If your radio-controlled clock is having difficulty receiving the MSF signal, please first read through the information in the 'Common clock problems' document.

Common MSF signal reception problems


MSF Signal Outages and Scheduled Periods

The signal is occasionally taken off-air to allow maintenance work on the masts and antennas at Anthorn Radio Station to be carried out in safety. A radio-controlled clock will not be able to pick up the MSF signal during these periods, so may drift off from the correct time.

The shutdowns will take place between 10:00 and 14:00 BST in June and September, and between 10:00 and 14:00 UTC in December. The duration of each outage period will be kept to a minimum, and the signal may be back on-air prior to the times given above.

In addition to these dates, the signal is likely to be taken off-air for a two-week period during summer each year, though the transmission will be restored overnight whenever possible. The dates of this longer outage will be announced on this page and by emailed notices to registered users as soon as they are known.

The dates and times of the 2021-2022 maintenance periods are as follows:

09 September 2021 from 10:00 to 14:00 BST

09 December 2021 from 10:00 to 14:00 UTC

10 March 2022 10:00 to 14:00 UTC

09 June 2022 10:00 to 14:00 BST

08 September 2022 10:00 to 14:00 BST

08 December 2022 10:00 to 14:00 UTC

Stay informed

Scheduled maintenance notifications
Keep informed about planned outages to the MSF service via an email prior to any scheduled maintenance.
If you wish to be kept informed about planned outages, please complete and submit the form below.>

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