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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 signal technical data

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 maintenance 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 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 2024 maintenance periods are as follows:

13 March 2025 from 10:00 to 14:00 UTC

12 June 2025 from 11:00 to 15:00 BST (UTC + 1 hour)

11 September 2025 from 11:00 to 15:00 BST (UTC + 1 hour)

11 December 2025 from 10:00 to 14:00 UTC

In addition, the MSF signal will be off-air to allow the masts and antennas to be worked on safely during the period: 

Monday 21 July  to Friday 8 August 2025 including weekends, from 08:00 to 18:00 BST (UTC + 1 hour) each day.

The service will be restored overnight and at weekends whenever possible. If the weather is unsuitable for work to be carried out, then the service will not be turned off.

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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