National Physical Laboratory

MSF Bulletins

Latest Monthly Bulletin (PDF File PDF)

Bulletin Archive

MSF Signal

Since 1 April 2007 the MSF standard-frequency and time signal - the Time from NPL - has been broadcast by Babcock (formerly VT Communications) from Anthorn radio station in Cumbria. Information about the MSF service can be found here.

The MSF Monitoring Service

The NPL MSF monitoring service is based on two independent MSF receivers which phase-lock their internal oscillators to the received 60 kHz carrier frequency. The output of each receiver is measured against a reference signal derived from the UK national time scale, UTC(NPL). The phase difference between the reference and the received 60 kHz signal is logged continuously.

MSF Bulletin Data

The MSF bulletin reports the value of the phase time difference between UTC(NPL) and the MSF 60 kHz carrier recorded at 12:00 UTC each day. The values are expressed in terms of a time interval, with a resolution of 0.1 ms. Note that the bulletins attempt to avoid discontinuities associated with cycle ambiguities, hence the readings can be used to calculate the frequency offset of the MSF carrier but not to calculate the absolute propagation delay between Anthorn and Teddington. Discontinuities in either the received signal or the phase are indicated in the bulletin by the letters (a) or (b) respectively.

Last Updated: 27 Aug 2014
Created: 11 Jan 2011


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