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Name:Radio Listening Station, Command Post, Rolphy Green, Ford End
SMR Number:20988
Type of record:Monument
Grid Reference:TL 672 156
Map Sheet:TL61NE


Radio Listening Station, Command Post

Full description

February 2006: Aerial photographs taken in October 1946 show the unusual configuration of five circular sites spaced out in a rough line about a mile long across the fields S of Ford End. <1> Each circle is perhaps 35 yards in diameter and a number of features are visible within each of them. S of the line, at Rolphy Green, two Nissen huts can be seen.

It is now thought, from local memory, that this was a radio listening and/or location station which was built around 1943 and continued long after WWII into the Cold War. <2> The circles were the sites of the aerials and the Nissen huts were the central command post which collected the data. This SMR covers the Nissen huts, which still survive; there are individual records SMR 20989 to 20993, for each of the aerial sites, none of which remain. It is believed, again from local memory, that the station was originally manned by personnel from the Royal Navy, perhaps to determine the positions of enemy shipping from radio transmissions. At a later date it is thought to have passed to the Ministry of Defence and then, still later, perhaps in the 1960’s or 1970’s to Marconi.

It is not known when the site ceased to be operational but it is recalled that it was fully functional in the 1950’s with five or six men manning the command post and one or two at each of the aerial sites. It may well have continued long after this but aerial photographs from 1980 show that nothing of the aerial sites remained by that date. All of the sites were connected to each other, electronically by cables and physically by concrete paths to allow the manning personnel to reach them. Some of these paths still remain around the field edges.

Nothing now remains of the aerial sites but the two Nissen huts which comprised the command post still remain intact although in a run-down condition. Each of them is of corrugated steel curved construction with brick end walls. They measure c. 70’ x 24’, with wooden-framed windows in the sides. These are of frosted steel-mesh glass.

The easternmost hut was primarily the garage; a Land Rover was kept here. Double doors in its E end lead into a large area which is now used for storage of farm implements. In here was the power generator and many of the electricity bases still remain on the central cross-wall. A couple of rooms at the W end were the workshops. The western Nissen hut contains around ten rooms off a central corridor, none other than a toilet/washroom functionally identifiable. It is recalled that these were the operational offices, not accommodation as the personnel were, apparently, lodged in separately-built houses locally. On the door of this hut is the faded notice “No Admittance”. <3>

With the undoubted secrecy which surrounded the site and the passage of time, it is not known how accurate the above historical information is. Nor can the exact purpose of the site be confirmed. No written documentary record has been discovered so far.

Twelve photos were taken of the Nissen huts. <4>

March 2011: Researched by Mr. S. Ames and included as a separate file in the HER, a wealth of information has come to light on this installation. Quoting from Mr. Ames' covering notes, this is summarised as follows; "The group of 5 wireless installations at Rolphy Green were “U” Adcock HF direction finding stations installed in the latter part of WW2 (1943/44) as part of a larger network with two other groups in mainland Britain and others planned in Iceland, Canada, Jamaica and West Africa. It is not certain if the non-British stations were built but two others have been identified in UK at Anstruther in Scotland and Goonhavern in Cornwall (traces of the latter are still visible in aerial images). The purpose of the groups of d/f stations was to obtain more accurate bearings on u-boats than could be obtained from a network of single d/f stations.

The stations were tested and commissioned by the Marconi company at Great Baddow and a report of their tests was found at the Bodleian Library, Oxford, a copy of which is attached.

Documents from Naval Intelligence in the files at National Archives show the projected cost of the scheme in 1944 was £100,000. The concept was based on the fact that the groups of d/f stations would take bearings on a target signal supplied by a network control centre by telephone to the local control room and thence to all of the 5 operators in the d/f stations in the surrounding fields. They would adjust their receivers and take bearings on the u-boat signal and pass them back to their local control room (in this case the nissen huts at Rolphy Green) who calculated the mean of the 5 bearings and passed the result back to the network control centre in London. From the information obtained from all the stations, the location of the u-boat would then be plotted. This initiative was influenced by the D Day invasion of Normandy and the threat from u-boats in the Channel was a particular problem.

At the end of WW2 the Ford End stations continued to operate as part of the Composite Signals Organisation in conjunction with GCHQ but still operated by naval staff. Their interests would have switched to Soviet targets.

The Naval Intelligence documents at National Archive show that the Ford End stations were the first to be installed and that two stations were already operating in the Chelmsford area and “all technical and scientific resources are readily available” (meaning the Marconi laboratories at Great Baddow).

The control rooms at the Anstruther group were identical to those at Ford end and are in current use as farm buildings." <5> <6>

<1> RAF, 1946, CPE-UK 1735-5020, Oct 1946 (AP). SEX65567.

<2> RAF, 1946, CPE-UK 1735-5021, Oct 1946 (AP). SEX65568.

<3> Freeman, Barry, 2006, Radio Listening Station, Command Post, Rolphy Green, Feb 2006 (PERSONAL OBSERVATION). SEX65569.

<4> Nash, Fred, 2006, Radio Listening Station, Command Post, Rolphy Green, 12 frames Feb 2006 (Photograph). SEX65570.

<5> Ames, Stan, 2010, Ford End (Rolphy Green) wireless station (DESC TEXT). SEX70037.

<6> Marconi company, 1944, Report on tests (DESC TEXT). SEX70038.

Monument Types

  • RADIO LISTENING STATION (WWII, Modern - 1939 AD to 1945 AD)
  • RADIO LISTENING STATION (Cold War, Modern - 1945 AD to 1980 AD)

Associated Events

  • Visit by Fred Nash - Feb 2006 (Ref: Nash CHL Feb 2006)

Protected Status

  • Historic Environment Character Area: Chelmsford 12
  • Historic Environment Character Zone: Chelmsford 12.1

Sources and further reading

<1>AP: RAF. 1946. CPE-UK 1735-5020. Oct 1946.
<2>AP: RAF. 1946. CPE-UK 1735-5021. Oct 1946.
<3>PERSONAL OBSERVATION: Freeman, Barry. 2006. Radio Listening Station, Command Post, Rolphy Green. Feb 2006.
<4>Photograph: Nash, Fred. 2006. Radio Listening Station, Command Post, Rolphy Green. print. 12 frames Feb 2006.
<5>DESC TEXT: Ames, Stan. 2010. Ford End (Rolphy Green) wireless station.
<6>DESC TEXT: Marconi company. 1944. Report on tests.

Related records

20990Related to: Radio Listening Station, Aerial Site (destroyed), N of Park Farm, Rolphy Green (Monument)
20991Related to: Radio Listening Station, Aerial Site (destroyed), NW of Park Farm, Rolphy Green (Monument)
20992Related to: Radio Listening Station, Aerial Site (destroyed), SW of Oldpark Farm, Rolphy Green (Monument)
20993Related to: Radio Listening Station, Aerial Site (destroyed), W of Oldpark Farm, Rolphy Green (Monument)
20989Related to: Radio Listening Station, Aerial Site (destroyed), W of Pleshey Road, Rolphy Green (Monument)