Surviving components of the Ventnor Radar Station, 1938-9, comprising an Rx receiver building, three receiver tower bases, one modified with the addition of a VEB (Variable Elevation Beam) radar building in late 1941-2. Also remnants of the site perimeter defence including a pillbox, small arms locker and two associated cable pillars.
Reason for Listing
The receiver site to the former Ventnor Chain Home radar station (built 1938-9) comprising the Rx receiver building, bases to three receiver towers and a Variable Elevation Beam (VEB) radar building of late 1941-2; also remnants of the radar station’s defensive cordon, are listed at Grade II for the following principal reasons: * Architectural interest and degree of survival: a largely intact example of a receiver site with its surviving principal building, three tower bases and a rarer VEB building; also remnants of the station’s defensive scheme including a pillbox distinct in form to radar stations; * Historic interest (history of radar): a physical manifestation of pre-war tensions and fears, anticipating the need for a national defence system which resulted in a chain of radar stations to protect Britain’s coast; * Historic interest (Ventnor’s WW2 role): given its southerly position, Ventnor was a key station during the Battle of Britain in intercepting enemy aircraft and thus was in the front-line of the country's defence. It also played an important role during Operation Overlord in support of the D-Day landings and in tracking V1 flying bombs or ‘doodlebugs’; * Early date: one of the original twenty Chain Home radar stations built nationally, just prior to the Second World War.
The site on St Boniface Down was chosen for the establishment of a radar station in 1937 and the following year a temporary station, one of the original twenty Chain Home Stations in England, was erected. By the end of January 1939 the site was operational with its huts fitted out, timber receiver towers and steel transmitter towers rigged and the site calibrated.The radar station was to play an important role during the Battle of Britain, its strategic southerly position providing essential early warning of enemy aircraft approaching the south coast. It was attacked twice by the Luftwaffe in August 1940 resulting in severe damage with most of the service buildings destroyed but fortunately only one individual sustaining any injuries. Later the same year an underground operations room was constructed. This was followed in late 1941-42 by the addition of a VEB (Variable Elevation Bean) radar to the receiver site (a prototype of this new system) and in 1942 by the construction of a buried reserve. By July 1942 the site was modified for Chain Home Extra Low with Type 271 radar and an experimental set (centrimetric layout) also in use. By December CD No. 1 Mk IV and CD No. 1 Ml VI radar were in use (Dobinson, 137). During Operation Overlord, the codename for D-Day, Ventnor played a key role monitoring both ship and aircraft movements involved in the landings. From June 1944 onwards the radar station was active in detecting incoming V1 flying bombs or ‘doodlebugs’. By the end of the war Types 16, 24, 52 and 53 radar had also been added.After the war the station was kept on a care and maintenance basis until 1947 when it was designated a Chain Home Low station. At some time between 1949 and 1953 the road which ran to the north of the site was moved northwards and large amounts of new build took place such that in the early 1950s the site was re-activated as part of Phase 1 of the Rotor programme. Rotor essentially made use of modified wartime radar technology. It was accompanied by a massive infrastructure construction programme, the most distinctive feature of which was the construction of large reinforced-concrete control room bunkers, many buried, to house the radar operators and sector controllers. At Ventnor an R1 (single level) operations room bunker was built in 1950 and operational from 1951; also a guardhouse bungalow was erected as were new plinths to house the turning mechanisms for the radar. Rotor period radar stations were 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 requiring different types of radar and associated infrastructure. Ventnor was operated by the No. 23 Signals Unit under the control of the GCI station RAF Sopley (Hampshire, which was in turn administered by Box Sector Operations Centre, south-east of Bath). In circa 1952 it was remodelled as a Centimetric Early Warning (CEW) station, one of only seven (the others being at Portland (Dorset), Beachy Head (East Sussex), St Margaret’s (Kent), Trimingham (Norfolk), Inverbervie (Aberdeenshire) and Cold Hesledon (Co. Durham). By December 1953 the station was codenamed ‘OJC’ and was classified as a Chain Home (East) and CEW station with Types 13 and 14 radar. By the end of 1956 Type 80 Mk 1 radar had been added and the site remained operational until at least 1957 when most of the original Chain Home towers are known to have still been present (only two of the three receiver towers survived as one had had to be demolished following an aircraft strike in 1947). In 1961 the site was decommissioned by the RAF and was then used, from 1962, by the Civil Aviation Authority (CAA) as a communications station. In the early 1960s the Linesman radar programme was established with Linesman/Mediator a proposal to combine military and civil air control. The refurbishment of the United Kingdom’s radar defences at this date reflects the development of radar technology and contemporary defence strategy which saw the nuclear deterrent as the most effective way of ensuring the security of the country; many Linesman related sites continuing in use until the 1990s. Over this period sites were regularly involved in the detection and interception of intruding Warsaw Pact aircraft. Ventnor was also used as a test location for other tracking systems. Marconi Type 264A radar and secondary surveillance radar were in use. In 1962 the CAA building was erected. The operations bunker was not used by the CAA so it was refurbished as the Isle of Wight Council’s Control Centre: it remained operational until 1991 as the Isle of Wight Emergency Command Centre for command of the island during a nuclear attack. In 1991 the guardroom bungalow was demolished. At some time between 1998 and 2004 the Transmitter block was demolished. In 2004 the bunker was sealed shut following unauthorised access. The Type 80 Modulator Building and CAA Secondary Surveillance Radar buildings were still extant at the time but have since been demolished. In October 2005 the Receiver site, which had been purchased by the GPO in 1962 and then owned by its successor BT, was sold at auction, and in 2006 horizontal windows were inserted in the Rx building and the gravel trap removed from the roof. The central compound remains (2014) in use by NATS for air traffic control with telecoms masts owned by other companies also on site. The land surrounding the NATS and Receiver compounds is in the care of the National Trust.
Surviving components of the Ventnor Radar Station, 1938-9, located on St Boniface Down above Ventnor, Isle of Wight at SZ 566 784, comprising the receiver site with Rx receiver building, three receiver tower bases, one modified with the addition of a VEB (Variable Elevation Beam) radar building in late 1941-2. Also remnants of the site perimeter defence including a pillbox, small arms locker and two associated cable pillars.PLAN The former radar station site is polygonal in shape and oriented broadly W-E. In the north of the site a roadway runs W-E before turning N-E and then continuing in a N-E then S-E direction. This now largely forms the northern boundary of the site with the exception of four small brick structures, including a pillbox, located in pairs to its north (see below).
In the western part of the site is the Receiver (Rx) compound. Here is a rectangular Rx building oriented south-west to north-east and three tower bases, each with four concrete feet to its north, west and south, one of which also has a VEB radar building (see below).
RX BLOCK (SZ 5664 7846)
EXTERIOR This receiver building is a protected ‘A’ type receiver block from the first phase of the development of the radar station in the late 1930s. It is rectangular receiver station, oriented south-west to north-east. Receiver buildings usually had a surrounding earth traverse for blast protection. This survives here, revetted internally by a high concrete wall, creating a covered way around the building. There are two protected entrances through the traverse in the south-east and north-east elevation. Both have reinforced concrete wing/blast walls. The building is single-storey with a flat reinforced concrete roof with a raised parapet. This roof space, in common with other receiver buildings, would have been filled with shingle (now removed) to a depth of circa 1.7m to disperse any blast, with drainage holes through the parapet wall. The western parapet wall has also been dismantled. The building itself is of red brick Flemish bond. There are airbricks in the walls and new (post-its sale in October 2005) irregularly placed horizontal window openings with concrete lintels inserted and a new door affixed.
INTERIOR The interior is divided into a number of rooms and as the layout of early receiver buildings followed a standardised form (built to Air Ministry drawing 4238/38) we would expect a lobby, office, WC, receiver room, calculator room, plant room, switch gear room and transformer cubicle, with the interior divided broadly into three - two larger rooms flanked by an entrance lobby and smaller rooms in the centre. Here, the main entrance, leading into the lobby, is to the north. The secondary entrance is in the north-east elevation.
Elements of the original colour scheme survive with a dark green-painted simple wooden architraves and skirtings, also one room where the wall is painted dark green up to a black-painted dado band. Two rooms at the western end, one of which is entered externally from the covered way, are white-tiled to dado height. There is a wide cable pit, which housed the cables from the receiver towers, running through the centre of the building. There appears to be no surviving plant. All original doors, both external and internal, have been removed.
WEST AND SOUTH RX TOWER BASES These are Second World War receiver tower bases of a standard form, located at approximately SZ 5658 7844 and SZ 5665 7843. Each comprises four concrete block ‘feet’ which are square in plan and slightly tapering in elevation. They would have supported wooden received towers (long since demolished).
EAST RX TOWER BASE & VEB BUILDING The east tower base, located at approximately SZ 5664 7850, is non-standard in that it comprises four similar concrete ‘feet’ (which would also have supported a now demolished wooden receiver tower) between which is a small subterranean building. This is a Second World War VEB (Variable Elevation Beam) radar building (erected late 1941-2), which is a type of height-finding radar. The building has a main room (the receiving room) with evidence in cable trenches on the floor that there were two receiving units housed here (one would have been a back-up system), also at least one ancillary room leading off. As is typical of VEB buildings, the entrance is protected by concrete blast walls and the double entrance doors are wooden so as not to interfere with the receiving equipment.
To the north of the road are four brick structures which are all contemporary with the Second World War radar station. At approximately SZ 5653 7853 is a pillbox and a cable pillar. The PILLBOX is essentially triangular in plan, a form specific to Chain Home radar stations, and is built of red brick Flettons in English bond with a flat reinforced concrete roof. The elevations are punctured by a series of loop holes with concrete embrasures; also air bricks. The entrance faces south-east, towards the radar station, where the footings of a protective brick blast wall survive. On the roof above the entrance is the concrete base for a Light Anti-aircraft gun: there are also some metal fixtures on the roof presumed to be for the fixing of camouflage. Within the pillbox is a black stencilled graffito of a family in silhouette; two adults, one with a babe in arms, and two children (a boy and a girl). This is understood to be of 1980s date and stencilled by a women’s peace movement activist.
To its south is a CABLE PILLAR which is also in red brick Flettons in English bond with a reinforced concrete roof and a blast wall to the east and its entrance to the south. Within the structure is a recess in the floor for cabling.
At approximately SZ 5666 7854 are two small brick structures. To the west is a second CABLE PILLAR of the same form as Cable Pillar 1 but on a different orientation with the blast wall to the south, and its entrance to the west. Within the structure is a 75cm drop in the floor for cabling with a pipe visible in the north wall.
Approximately 10m to the east is a SMALL ARMS LOCKER which is a small rectangular structure of red brick Flettons in random bond with a reinforced concrete roof. The entrance faces south towards the radar station and is too low to walk into upright. On the wall opposite the entrance is a white stencilled graffito of the same family group as in the pillbox and of the same date and origin.
Listed building text is © Crown Copyright. Reproduced under licence.