RAF Neatishead Type 84 radar modulator building and four radar plinths

Overview

Location

Reasons for Designation

Radar was one element of an elaborate air defence system that evolved during the Second World War, identifying the approach of hostile aircraft and accurately tracking their courses. This information was then filtered and disseminated, to co-ordinate the response of the fighter interceptor airfields and the ground based anti-aircraft gun and/or missile batteries. At the end of the Second World War over 200 radar stations defended the United Kingdom. By 1946, this was reduced to just 36 stations (of which only 26 were fully manned) sited between Flamborough Head and Portland Bill, in a strip known as the 'Defended Area'. By 1948, alterations to a number of wartime stations are evident, aimed at improving response times. These modifications were the precursor to a far more ambitious scheme in the early 1950s to refurbish the United Kingdom's radar defences, known as 'Rotor'. Rotor essentially made use of modified World War II radar technology but was accompanied by a massive infrastructure construction programme, principally directed at building large reinforced bunkers, many buried, to house radar operators and sector controllers. In areas considered to be at 'high risk', the bunkers were situated underground. Outside the bunker new plinths were constructed to house the turning mechanisms for the radar. Rotor period radar stations may be divided into five principal types: Centrimetric Early Warning (CEW), Chain Home (CH), Chain Home Extra Low (CHEL), Ground Control Intercept (GCI) and Sector Operations Centres (SOC). Each of these functions required different types of radar (except for the SOCs which had none) and supporting infrastructure, which produced a characteristic suite of components and layout for each of the station types, the reinforced operations room or bunker being the most distinctive feature. The Rotor system included fifty-four main radar stations spread across England (eight of which survive), with a concentration along the eastern and south eastern coasts, since the greatest threat was perceived to be from the east. However, subsequent improvements in radar technology, and in particular the introduction of the powerful Type-80 surveillance radar, quickly reduced the need for such a large system. The Rotor scheme was also reduced by evolving defence policy, which recognised the threat posed by intercontinental ballistic missiles. In 1957, a Defence White Paper argued that the defence of the UK would be best served by the deterrent effect of nuclear weapons and that guided weapons would be more effective than manned fighters for air defence. From this period on, the air defences were scaled down and directed at protecting the nuclear deterrent and to giving adequate warning of a hostile attack to allow the retaliatory strike to be launched, after which there would be little need for air defence. This was the so called 'Tripwire Response'. The scheme to reconfigure Britain's radar defences, both to respond to the new strategic demands and new technology was known as 'Linesman'. Major construction programmes associated with the Linesman programme were restricted to five sites, four of which are in England. The Master Control Centre was at West Drayton. The other three sites were at RAF Boulmer, RAF Neatishead and RAF Staxton Wold, all of which were located on existing radar stations close to the east coast reflecting the most probable line of attack by Soviet forces. A similar range of structures was built on each site, although the sites differ in plan form. The introduction of the Type-84 surveillance and control radar, as part of this project, may be seen as a continuation of a trend in radar development, where fewer, more powerful arrays were able to cover a far wider area. The introduction of new radar types is also, in part, a response to the increasing sophistication of the Warsaw Pact's electronics industry and its ability to manufacture equipment to jam NATO radars. For the first time radars were installed specifically to counter electronic jamming; these included a Type-85 and High Speed Aerials. But by the time the Linesman system was fully operational in the 1970s, NATO policy had moved to one of 'Flexible Response', whereby it was planned to strengthen its infrastructure to withstand a pre-emptive strike and to be able to launch a retaliatory attack using conventional weapons. The system designed to replace Linesman was known as the Improved United Kingdom Air Defence Ground Environment (IUKADGE). In place of fixed radar new mobile systems were developed which used sophisticated electronics for counter jamming in place of the massive power input required by the earlier system. These were supplemented by the use of inputs from air and seaborne radars. The operations centres were provided with refurbished hardened bunkers. Hold ups in the development and installation of the system resulted in its implementation being delayed until 1992, but nonetheless, it may be regarded as a Cold War system. IUKADGE represents the final development in Britain's Cold War air defences and the rapid evolution of radar technology from its practical invention 60 years previously. Archaeological remains dating from the Cold War period (1946-1989) are the physical manifestation of the global division between capitalism and communism that shaped the history of the second half of the 20th century. Radar sites exemplify many of the themes of the Cold War, including the rapid evolution of information technology and the obsolescence of sites which resulted. These sites are also a direct reflection of contemporary air defence strategy. Following a comprehensive documentary, air photograph and field survey of Cold War monuments in England, the location and condition of each Rotor, Linesman and IUKADGE period radar station is known. Sites are deemed to be of national importance where groups of contemporary structures remain in place providing a visual impression of the site and the location of it principal components. This will be enhanced if they are associated with other radar structures illustrating the evolution of radar technology and Britain's air defences. For Rotor period stations, the survival of the operations room/bunker, associated guard room and radar plinths is important; of particular significance are sites where internal fittings remain. Due to their overall rarity all Linesman period structures that retain their structural integrity and any internal fixtures are deemed to be of national importance. As only a small number of permanent structures and features were built to support IUKADGE, all are considered to be of national importance. RAF Neatishead opened in 1941, and through its fabric illustrates the evolution of radar technology over the last sixty years, with structures surviving from the Rotor, Linesman and IUKADGE periods. The site is unique in representing changes in Britain's air defence policy throughout the Cold War until the present day. It also has the distinction of being the longest continuously occupied radar station in Britain, and probably the world. The Type-84 at RAF Neatishead is the last surviving large Cold War radar still standing in England (36331/01). It is a local landmark and the dominant feature of the station, visible from all approaches. Technologically it represented a major step forward in radar technology based on the L band (23cm wavelength). It was in constant use from 1963 until 1993 and was responsible for detecting many hostile intrusions of Soviet aircraft over the North Sea. The preservation and public display of the R30 operations room which received its plots and survival of the contemporary R12 operations building (both recommended for listing) further enhance the significance of this outstanding Cold War era radar. The four radar plinths (36331/02-05) are good examples of Rotor period plinths, with sand filled sliding doors for increased protection. They are an integral part of the radar station and contemporary with the R3 bunker and guardroom (recommended for listing). They are also contemporary with chapel-like standby generator building and two wireless stations located outside the station.

Details

The monument includes the above ground remains of the Type 84 radar and modulator building and four radar plinths, in five separate areas of protection. These are some of the key surviving elements of RAF Neatishead radar station which opened in 1941 and has the distinction of being the longest continuously occupied radar station in Britain, and probably the world. Other structures on the station have been recommended separately for designation by listing. The station opened in June 1941 as a Ground Control Intercept (GCI) Station and its development was typical of many stations of this type. GCI stations were developed from late 1940 to assist in the tracking and interception of hostile aircraft after they crossed the coast, particularly at night. The original Chain Home radar system was strung out along the coast and the tracks of enemy aircraft were lost as they headed inland. GCI stations were designed to counter this problem by tracking hostile aircraft as they passed inland and directing the local fighter squadrons to attack the intruders. Typical of a first phase GCI radar station, RAF Neatishead comprised mobile caravans and wooden guard house all surrounded by a perimeter fence; accommodation huts were added later. The second phase of building activity began in January 1942, when a timber operations hut (which survives in modified form, in use until recently as a dental and medical centre), a timber 'goalpost' gantry (to support a Type-8 radar) and other ancillary structures were built. This phase is known as an 'Intermediate GCI Station'. This was quickly followed by construction work for the last wartime phase, the Fixed or 'Final' GCI Station. Neatishead was one of 21 Final GCI Stations, and one of only 12 to be fully equipped with searchlight and fighter control. The main feature of this phase was the double storey, protected Operations Room or 'Happidrome', which was completed on 15 July 1942 (later refurbished as the R30). Adjacent to it was a standby generator building. The station became operational in its final wartime form in January 1943 with a Type-7 surveillance radar giving it cover to 90 miles (149km) and up to 70,000ft (21,336m), linked to it were Type-13 radars which provided information on target heights. Neatishead was retained after the end of the war and as a result of the Cherry Report (an examination of Britain's post-war air defence requirements), it was recommended that the Sector Operations Centres should be combined with a number of GCI stations. Alterations to accommodate this, including the extension of the wartime 'Happidrome', began at Neatishead in December 1948 and were completed by October 1950. In the early 1950s Neatishead was equipped with the following radar: Type-7 Mark II surveillance radar, Type-11 Mark II, two Type-14 centrimetric search radars, and five Type-13 height finding radars. In the early 1950s, as part of the Rotor scheme to refurbish Britain's radar defences, an R3 double level sunken bunker, which was entered through a 'bungalow' guardroom, was built. And on the surface new protected radar plinths were constructed (36331/02-05). Some distance away from the site, in Neatishead village, a standby generator building, designed to resemble a church, was built. By the late 1950s, as a result of a change in defence policy, the emphasis was moved to the nuclear deterrent to ensure Britain's security. The air defences were scaled down under a project to protect the nuclear deterrent bases and to give adequate warning of a hostile attack to allow the retaliatory strike to be launched, after which there would be little need for air defence, the so called 'Tripwire Response'. The scheme to reconfigure Britain's radar defences, both to respond to the new strategic demands and new technology was known as 'Linesman'. Neatishead was just one of four stations where major rebuilding working took place as part of this scheme. Structures built in the early 1960s include the Type-84 and R17 modulator building (36331/01), the Type-85 radar and R12 bunker to house its processing equipment, High Speed Aerials, HF 200 height finders and a new generator building. A major set back occurred in 1966 when the refurbished R3 bunker was gutted by fire, with some loss of life. The radars, however, continued in use sending their data to remote sites. Neatishead regained its operational role again in 1972 when the Standby Early Warning and Control (SLEWC) centre was established in the wartime Happidrome, now restyled the R30. But by the time the Linesman system was fully operational in the 1970s, NATO policy had moved to one of 'Flexible Response', whereby the reaction to any Soviet aggression would not immediately be met with massive nuclear retaliation, but might begin with a conventional phase to allow time for negotiation. The infrastructure of Linesman with its few static sites was clearly very vulnerable to destruction in a pre-emptive strike. The system designed to replace Linesman was known as Improved United Kingdom Ground Defence Environment (IUKADGE). In place of fixed radar new mobile systems were developed which used sophisticated electronics to counter jamming in place of the massive power input required by the earlier system. These were supplemented by the use of inputs from air and seaborne radars and the operations centres were provided with refurbished hardened bunkers, exemplified in the R3 bunker at Neatishead. This system finally became fully operational in 1992. Subsequent to the end of the Cold War, more concern has been given to the working environment on the station; a new combined mess was constructed in the early 1990s and in 1999 the redundant standby generator building was demolished. In common with other radar stations ornamental tree planting enhances its surroundings. Neatishead is home to the RAF's Air Defence Radar Museum, which is housed in the wartime Happidrome (R30) and is open to the public. The Type 84 radar and R17 modulator building (36331/01) is located on the north side of the R3 bunker towards the north-west corner of the station. A Type-80 radar was originally mounted over the R17 modulator building, but this had been replaced by the Type-84 by 1963. The radar comprises a pair of back to back 75ft (18.28m) x 25ft (6.23m) parabolic reflector dishes mounted on a horizontal girder. At either end of the girder are steel frameworks for mounting eight L-band hornfeeds that transmitted and received the radar beams. Only one stack of hornfeeds was installed and this remains in position. An Identification Friend or Foe (IFF) aerial is placed above the reflector dishes. IFF was an electronics system which elicited coded reply signals from suitably equipped aircraft. The cabin immediately below the horizontal beam housed the turning gear. The radar array is supported on a steel gantry which sits over the single storey flat roofed modulator building. The modulator building measures approximately 29m east-west by 10m north-south at its greatest extent and is constructed in reinforced concrete. The part of the building immediately beneath the radar housed the DC supply rectifiers to convert alternating electrical current to direct current and the switch and control room. Apparatus to ensure that the radar emitted a wave of constant frequency was located in an annexe to the west. There is also a small annex off the south wall which served as a store. A short corridor connects the modulator building to a second block, single-story except for the square-plan fan and filter room at the east end. This block housed separate rooms for generators and switchgear. All of the equipment was removed when the radar ceased to operate in 1993. The Type-84 was a high power medium to long range surveillance radar introduced on three stations as part of the Linesman project in response to advancements in Soviet electronic technology. At Neatishead the Type-84 replaced the Type-80, utilising the same modulator building. With increased range of detection and peak power output of 4 megawatts (drawn from on-site generators big enough to provide electricity for a small town) the Type-84 was able to burn through the latest Soviet jamming technology. To establish height, the radar worked with two or three HF200 height-finding radar mounted on distinctive segmental conical towers. These have been removed with the exception of some footings. The importance of the Type-84 radar is enhanced by the survival of the contemporary R30 operations room and R12 bunker. Together these structures represent the Linesman scheme to update Britain's radar defences. The R30 operations room and R12 bunker are not included in the scheduling but are subject to separate recommendations for designation by listing. Dispersed across the station, to the east of the R3 bunker and to the north of the R30 operations block, are four radar plinths, built under the Rotor scheme to house the turning mechanisms for the radar (36331/2-5). The radar plinth is a small single storey building measuring approximately 3.5 x 3.5m square, constructed of reinforced concrete with a concrete slab roof. There are no windows and ventilation is provided through three grills, one in each wall except for on the front face, which is taken up by a single doorway protected from blast damage by a substantial sliding steel door filled with sand. The sliding door is set into a concrete plinth which slopes down to the grass. The design of these doors is identical to that of the late 1930s RAF hangar doors. Access to the radar was via a ladder step to the right of the door which has been removed on all but one of the plinth buildings (36331/03). Three of the plinths (36331/03-05) housed the turning and control mechanisms for the Type-13 Mark 6 height finding radars, which have since been removed. The fourth plinth (36331/02) housed a Type-14 Mark 9 radar used to fix the plan position of targets. The radar plinths are contemporary with the R3 bunker as constructed in the 1950s under the Rotor scheme. The bunker is not included in the scheduling but is recommended separately for designation by listing. The modern surfacing of the access road to the north of the R17 modulator building is excluded from the area of scheduling, although the ground beneath is included.

MAP EXTRACT The site of the monument is shown on the attached map extract.

Legacy

The contents of this record have been generated from a legacy data system.

Legacy System number:

36331

Legacy System:

RSM

Sources

Books and journals
Cocroft, W D, Thomas, R J C, Cold War - Building for Nuclear Confrontation 1946-1989, (2003)
Cocroft, W D, Cold War Monuments: An Assessment by the Monuments Protection Programme, (2001)
Other
Air Defence Radar Museum, Layout of the R30 operations room, (2005)

Legal

This monument is scheduled under the Ancient Monuments and Archaeological Areas Act 1979 as amended as it appears to the Secretary of State to be of national importance. This entry is a copy, the original is held by the Department for Digital, Culture, Media and Sport.