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Portland CEW R1 ROTOR Radar Station ('NIB'): 815 Signals Unit

Portland Centimetric Early Warning (CEW) Radar Station


Constructed 1950-51 by Robert McAlpine.
GPO installations began 1st December 1951
Operational availability by 20th February 1953
The R1 was transferred to the RAF under the command of Squadron Leader NOYES, AFC.
Portland ROTOR consisted of a single storey R1 operation block accessed from a nonstandard design guardhouse/bungalow built of local Portland stone.

At 70 feet below ground level it was the deepest ROTOR underground facility and instead of the usual steps at the rear of the guardhouse and a long sloping tunnel into the bunker, Portland was equipped with a lift and an iron staircase winding round it. The emergency exit consisted of a standard emergency stairway in two sections joined by a length of solid floor.


1950-51= Constructed
1st December 1951 = GPO installations
20th February 1953 = Operational
1953 = Equipped with a 'stop gap' American AN/FPS Type 3 radar (and its associated TPS/10), installed 1953, operational in November 1953
May-Aug 1954 = Type 10 IFF replaced Type III IFF, entered full fighter interceptor trials in September 1954
April 1956 = AN/FPS Type 3 was removed (probably to Ventnor) and the station diminished in importance
June 1956 = T14 and 3 T13's radar's dismantled
17th June 1956 = Portland station declared non-operational.
September 1956 = station officially run down' and at CHEL 'readiness' only.
1958 = station is placed under care and maintenance, within the control of 11 Group, finally becoming 'non-operational'.

The site was taken over by the US Air Force who built a microwave relay station (forming part of the Troposcatter cross-channel relay link at the old Ringstead CH site) within the fenced enclosure. 

1969 = USAF did not use the underground bunker, damaged by fire in 1969 while the USAF were still present on the site

More recently the site has been used by the MOD as a dog training centre.

October 2001 = MOD offered the site for sale by auction and shortly before two public open days they stripped out the lift and surrounding stairs, the emergency stairs and all the wooden flooring. They also filled in any open cableways in the main corridor and installed a 70' caged vertical ladder for access. Six radar plinths still survive on the surface together with the emergency exit blockhouse, a communications mast, gatehouse, kennels, the old USAF compound and a reservoir built in the 1980's to serve the dockyard.

Command Structure

 RAF Portland’s CFP reported to the Box sector (SOC) for identification along with Hope Cove, Treleaver, Comberton (Later deleted) and Beachy Head.

Original Equipment

  • 1 x T14 Mk 9 250 prf ‘G’ IFF Low Angle
  • 1 x T14 Mk 8 500 prf ‘G’ IFF High Angle
  • 2 x T13 Mk 6 250 prf ‘A’ IFF
  • 1 x T13 Mk 7 250 prf - Note: original plans show this as Mk 6.
  • 1 x T54 Mk3 No IFF on 200 ft Tower
  • 9 x 60A Moving Coil PPI ‘G’ IFF
  • 3 x 61 – HRI – Displays T13 signals (Elevation Scans)
  • 1 x 61A – ‘A Scope’ (Range Signals)
  • 3 x Video Marker Units (Detailed in AP 2527R) - T14 Units supplied in Sept / Oct 1955
  • 2 x M.R Units – ‘Plug-in’ units for Mobile Reserve
  • 1 x UHF R.T Recorder
  • 1 x Timing Unit  
  • Resources

    Subbrit record: http://www.subbrit.org.uk/rsg/sites/p/portland/ (last updated 2001)
    Bunker tours: http://www.bunkertours.co.uk/portland_rotor.htm (last updated 2001)


    The Verne


    Portland ROTOR