R12 Radar Equipment Building

R12 Radar Equipment Building

RAF Neatishead opened in 1941 and holds the distinction of being the longest continuously occupied radar station in Britain, and probably the world. The R12 radar equipment building was constructed in the early 1960s as part of the Linesman scheme to modernise Britain's radar defences. The Type-85 radar became operational in 1967. RAF Neatishead was one of only four stations where major rebuilding work took place as part of this scheme, and the R12 is one of only three such structures built for this purpose.

The building is a massive rectangular box measuring 58 metres by 47 metres, comprising two storeys and a basement. It is constructed on a reinforced concrete frame carried on 48 square columns, a structure necessitated by the large span rooms required. The principal exterior feature is a square-plan pressure vessel that carried the Type-85 radar array, which rises the full height of the structure against the north axis. The building has no windows except for narrow openings in the former workshop occupying the north-east corner. Air intake openings, service ducts and air extract ducts are located in annexes on the south side. A wooden guardrail runs around the edge of the flat roof. The radar array was removed in the early 1990s following decommissioning.

The main entrance is in the north-west corner and leads into a decontamination room. The interior is divided into two large halls. The northern half contained the transmitter apparatus hall, which originally held banks of electronic data-handling and processing equipment on a false floor above the basement, with cabling and ducting running below. The southern half houses the massive air conditioning plant and associated switchgear, with generators located towards the west end. The enormous space devoted to air conditioning and cooling reflects the tremendous heat generated by the processing equipment; the forced air ducts below the floor and under the ceiling were originally attached to equipment racks and consoles by flexible metal hoses. Stores and loading bays are located along the east side.

On the first floor is the main Type-85 radar receiver and passive tracking apparatus hall, a vast central space extending the full width of the building and broken only by rows of free-standing columns. Equipment was originally fixed to parquet flooring supported on steel frames raised on low brick carriers, an arrangement that permitted installation of cable-runs and forced-air cooling supply ducts. The three-sided south wall of the pressure vessel projects into the halls at ground and first-floor levels. A narrow bay along the west side housed the control room, restrooms and kitchen, while stores, office space and workshop were along the east side.

Other surviving structures on the site include the R30 operations room, Type-84 radar and modulator building, R3 underground operations block and guardroom, and four radar plinths. Together these reflect the evolution of radar technology over the last 60 years, making RAF Neatishead unique in its ability to represent the changes to Britain's air defence policy throughout the Cold War.