Site Name: RAF Ventnor ('OJC') R1 CEW ROTOR Radar Station
St. Boniface Down
Sub Brit site visit 1st October 2004
[Source: Nick Catford]
RAF Ventnor was one of the 20 original Chain
Home radar stations authorised in 1937 and the station first became
operational in temporary hutting in late 1938. While many Chain
Home radar stations around the country closed at the end of the
war, RAF Ventnor remained in use and in November 1947 it was one of
only 26 operational radar stations in the UK. The Type 24 long range
microwave height finder and Types
52 and 53 radars were still in use while the Type 1 Chain
Home radar remained on care and maintenance.
Photo:Cutaway drawing of a typical R1 ROTOR bunker
Drawn by Jason Blackiston
The entire station eventually went into care and maintenance. By 1950,
the threat of the Atomic bomb had caused a serious rethink in the organisation
of air defence and a plan, codenamed ROTOR,
was instituted to replace many of the existing stations with new protected
underground operations rooms. RAF Ventnor was chosen to participate
as part of the first stage of the ROTOR
Programme which was itself divided into four phases. Phase 1 was the
re-establishment of 28 WW2 Chain
Home radar stations. 13 were brought up to a fully operational state
while the remaining 15 were brought up to a 'readiness' state. These
stations would have required some notice before they were fully operational.
Phase 2 was the construction and installation of 14 new underground Centimetric Early Warning (CEW) and Chain Home Extra Low (CHEL) stations. Phase 3 was the construction and installation of 11 new underground Ground Control Intercept (GCI) stations Phase 4 was the construction of 14 new semi-submerged or above ground GCI stations.
Photo:Aerial view of the ROTOR site in the 1970's. The large building towards the bottom of the picture is the CAA building. Just to the left of it is the ROTOR guardhouse. (Click here for enlargement of the guardhouse). Towards the centre of the picture is the WW2 Chain Home transmitter block and to the left of it the Type 80 modulator building
Photo from NATS
A CEW station was designed to provide the first contact with any attacking force. Its big advantage over Chain Home was its ability to fairly accurately assess height, range and size of an attacking force. The Centimetric Early Warning system needed to be situated at least a 100 feet above sea level and sited relatively close to the coast. The high position of the stations enabled the radars to have an uninterrupted sweep of the coastal approaches of which they protected. Ventnor was therefore an ideal location.
Ventnor (code OJC) was to be one of seven underground
CEW radar stations (the others being Portland,
Beachy Head, St.
Inverbervie & Cold
Hesledon). Each of these stations was provided with a heavily
protected underground operations room designated R1. Although protected,
underground technical buildings were never intended to survive a direct
hit from a nuclear weapon but were designed to withstand a near miss
from Russian pattern bombing with 2,200lb armour piercing high explosive
bombs (BRAB) dropped from 35,000 feet.
Photo:The Type 80 modulator building still standing in 2004 but due for demolition
Photo by Nick Catford
The domestic camp and married quarters were located below St. Boniface
Down and in order to provide communication between the controllers in
the R1 bunker and intercepting aircraft; two VHF/UHF multi-channel radio
transmitter and receiver blocks were built across the valley. The receiver
was on Stenbury Down and the transmitter, quarter of a mile north on
Appuldurcombe Down. These were remotely sited to avoid interference
from the radars.
Photo:Type 80 Radar
RAF Ventnor was manned by No. 23 Signals Unit and came under the control of the GCI station, RAF Sopley which, in turn, was administered by the Sector Operations Centre at Box. RAF Ventnor remained operational until at least 1957 but eventually closed and was placed into care and maintenance. The '1958 Plan' states that the station may be required for a different purpose.
Further information and pictures of RAF Ventnor click here
[Source: Nick Catford]
Last updated 11th December 2004
© 2004 Subterranea Britannica