Anthorn VLF transmitter

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Map sources for Anthorn VLF transmitter at grid reference NY179581

The Anthorn VLF transmitter is a very low frequency (VLF) transmitter near Anthorn, Cumbria, used primarily for transmitting orders to submarines on 19.6 kHz. Its callsign is GBZ.

The transmitter is a NATO facility, controlled from Northwood Headquarters along with three other VLF transmitters in Norway, Germany, and Italy.^[1]

The characteristic triangular pattern of roads clearly visible on the aerial photograph indicates that this was a World War II military airfield, in this case operated by the Royal Navy Air Service as HMS Nuthatch. The transmitter is now operated by VT Communications.

1 National Physical Laboratory time signal
2 Further reading
3 References
4 External links

[edit] National Physical Laboratory time signal

The National Physical Laboratory (NPL) has installed three atomic clocks at Anthorn and on 27 February 2007 Britain’s national time signal transmissions, retaining their original call sign of MSF, were transferred there on a trial basis, pending the formal changeover on 1 April 2007. Monitoring and logging of the clocks and control of the transmissions is by internet link from the NPL offices at Teddington, using comparison with GPS signals at both locations. Signal monitoring is by radio. To ensure accuracy, dynamic adjustment of the aerial according to local conditions (such as wind distortion) is controlled from computers on site.^[2] The signals, transmitted at 60 kHz, also provide a national frequency standard. The effective radiated power is 15 kW.

[edit] Further reading

Hall, L.L. (1965). Anthorn Very-Low-Frequency Radio Station. Post Office Electrical Engineers' Journal, Vol. 58 (July 1965), p.114.

[edit] References

^ John Ainslie (October 2005). The Future of the British Bomb. Clydeside Press.
^ MSF the time from NPL. National Physical Laboratory. Retrieved on March 20, 2007.