UNST - RAF Saxa Vord radar station

In February 1940 instructions were issued by the Director of Signals Development at the Admiralty for construction to began on Admiralty Experimental Station (AES) No. 4 on the island of Unst in the Shetland Islands. The site selected was on top of Saxa Vord, at 950 feet the highest point on the island. Due to delays caused by the weather and RAF requirements for equipment, the station did not become operational until September 1940. Saxa Vord (the Navy appear to have referred to it as a single word, the RAF as two) was equipped with CDU (Coast Defence U-Boat) radar, the Naval version of CHL, and was tasked with tracking submarines and shipping attempting to break out into the Atlantic. It was also able to plot aircraft and was to play a major part in the destruction of several German aircraft in the area. Saxa Vord closed down in July 1945, having been manned by the RN throughout its operational life.

In 1956 construction of a new radar station, on the same site as that which had been used by the Navy, was begun by the RAF.

The final stage of the ROTOR Programme (Rotor 3) was to provide radar cover for the north and west of the British Isles which were still exposed to attack and to give low and surface level cover over the Atlantic, the absence of which prevented effective action against low flying enemy aircraft. Three new Centimetric Early Warning (CEW) stations were to be built at Saxa Vord, Aird Uig and Faraid Head equipped with Type 80 Mk 2 and Type 13 radars . The new CEW operations buildings were to be above ground and designated R10, similar in internal layout to the underground R1 bunker.

http://www.subbrit.org.uk/rsg/sites/s/saxa_vord/index.html