Site Records

Site Name: RAF Ventnor ('OJC') R1 CEW ROTOR Radar Station

St. Boniface Down
Isle of Wight
OS Grid Ref: SZ568785

Sub Brit site visit 1st October 2004

[Source: Nick Catford]

In the Cold-War context, contrary to what might be expected, there was no living accommodation down this 'Hole'. Small rooms were provided for relaxation purposes and I believe that there was a small kitchen. I am curious about the water supply: St.Boniface is the highest point on the Island so special pumping would have been required to provide a mains supply. Undoubtedly there must have been an adjacent reservoir somewhere, but there was no above-ground water tower. Drainage would also have been a problem. The underground lavatories were akin to those used by submariners. Equipment to deal with these vital services must have existed in the Plant Room, but this would have been dealt with by civilian contractors, known within the Service as 'Works & Bricks'.

However, I found it all very claustrophobic and was heartily glad that I was to be employed above ground and so was relieved when he led the way back up to fresh air and across the two hundred yards of gorse to the unsleeping monster that was generally known as 'The Eighty'.

While I absorbed the unanticipated noises of the machinery, a muffled roar from the alternator room, a whine from the turning-motors and above all a hiss from the seventy foot reflector.

Photo:CAA Secondary Surveillance Radar at Ventnor (late pattern IFF)
Photo from NATS

After a brief inspection of the modulator, the purpose of which was to produce very short pulses of very high voltage, I was shown the Signal Office Diary, the Meters Records book and the Standing Orders. Then we went out, clambered up the iron stairs to the gantry and on to the running board of the rotating transmitter cabin. A grey cabinet contained the true heart of all this equipment, the water-cooled magnetron which, fed on the diet provided by the modulator below, produced enormous 2 megawatt microwave pulses for 2 microseconds, 270 times a second for every second of every hour. These colossal bursts of energy were directed by means of highly scientific piping known as 'waveguide' to the focus of the giant reflector and thence bounced into the atmosphere. When the pulse ceased, the waveguide from the aerial became joined electronically to the receiver kit and any re-radiated energy from a distant target returning to the reflector would be passed on to the underground consoles.

We could see reliably targets 250 miles away and sometimes much more. This was state-of-the-art Early Warning, incredibly better than anything used in the war years. However the Type13 height finders could not match this range as they did date from the war."

For a more detailed report on Don Adams's time at RAF Ventnor see his RAF Ventnor web site.


For RAF Ventnor Domestic Camp click here
For RAF Ventnor VHF transmitter and receiver sites click here
For RAF Ventnor Chain Home Radar Station click here
For RAF St. Lawrence (Remote reserve site for RAF Ventnor) click here


Type 80
Modulator Buiilding

Type 80
Modulator Buiilding

Type 80
Modulator Buiilding

Site of
the Guardhouse


CAA Secondary
Surveillance Radar

CAA Building


Click on thumbnail to enlarge

[Source: Nick Catford]

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Last updated 12th December 2004

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