Anthorn transmitter station

 military, LORAN, VLF transmitter station

The Anthorn Transmitting Station is located near Anthorn, Cumbria and is operated by Babcock International who took over the former contractor VT Communications. It has two transmitters: one VLF and one LF.

The characteristic triangular pattern of roads, clearly visible on the aerial photograph, is a remnant from the World War II military airfield which was operated by the Royal Navy Air Service as HMS Nuthatch.

VLF transmitter
The VLF transmitter is used primarily for transmitting orders to submarines on 19.6 kHz. Its callsign is GBZ.The antenna system consists of 13 masts, each 227 metres (745 ft) tall, which are arranged in two rings around the central mast. The VLF antenna consists of 4 rhombic antennas hung on large insulators on the masts, which are all grounded.
The LF antenna is a T-antenna spun between two masts.

It is a NATO facility, controlled from Northwood Headquarters along with three other VLF transmitters in Norway, Germany and Italy.

LF transmitter: 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, moving formally 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. The signals, transmitted at 60 kHz, also provide a national frequency standard. The effective radiated power is 15 kW.

LORAN
The General Lighthouse Authorities for Britain and Ireland have contracted VT Communications to develop eLORAN (enhanced LORAN) radio navigational aid for mariners. The transmitter is at Anthorn, transmitting the Yankee secondary signal on GRI 6731.

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