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Questions and answers

Why is my radio-controlled clock not showing the correct time?

What can you do to ensure you receive the correct time?

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.

Improving reception

Assuming that the signal is still on, the following suggestions, in order of increasing difficulty, may help to improve reception of the MSF radio signal:

  • Consult the manual for the clock before turning it on. There may be a set procedure which if not followed, will result in the radio controlled clock not working
  • If the clock uses both mains power and a battery, remember to switch on the mains power and allow the clock to set before inserting the battery. If this is not done, the clock may well run an hour fast or an hour slow (If the clock's manual indicates a different procedure to this, follow that instead)
  • Check that the power supply is in full working order. Change the current battery for a fresh one and reset your clock. It can take quite a few minutes for the clock to pick up the MSF radio signal, so be patient
  • Try rotating the clock. Most radio-controlled clocks have an internal antenna that picks up the signal most effectively when it is facing directly towards or away from Anthorn. Some clocks have a signal strength indication that helps in finding the best reception
  • Try moving your clock to a different location. Objects such as televisions, electric motors and fluorescent lights can interfere with the signal. A steel-framed or reinforced concrete building, or large metal objects such as metallic window frames, will reduce the signal inside. Externally, pylons, scaffolding or overhead power cables can also screen the signal

Information on the MSF time signal

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 radio signal is transmitted from Anthorn Radio Station in Cumbria by Babcock (formerly VT Communications), under contract to NPL.

The MSF radio signal 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, and in all areas of the UK radio-controlled clocks have been found to synchronise correctly to the signal.

Difficulties receiving the MSF radio signal are generally due to a combination of factors. These include attenuation of the signal due to location of the antenna inside a building or close to power lines or other large metal structures, and background interference which may be from a local source such as an electric motor, fluorescent tube, CRT monitor or TV.

If you have reception problems, first check whether the signal has been turned off for maintenance at our MSF Outages page.

NPL's work with time

As the UK's National Measurement Institute, we have a vital role to play in maintaining the UK's time scale. The current atomic clock system at NPL is the basis of all UK time, and cutting-edge research is being carried out to improve timekeeping accuracy even further.


Learn more about our research on time

Learn more about our time services

Learn more about the MSF radio signal

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