Denmark Hill Y Station

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Historical map (1888) of the London borough of Dulwich with Denmark Hill in the far north and the location of the listening point (green circle)
The HRO of the National Radio Company was the most widely used wireless receiver in the British Y stations .
A typical undulator tape (approx. 12 mm wide and many meters long), as it was used to record the German radio teletype traffic.

Denmark Hill Y Station (more precisely: Metropolitan Police Wireless Station at Denmark Hill ) was a radio eavesdropping station of the British secret service . It was located within the then police station of the Metropolitan Police on Denmark Hill , a district directly south of central London in the borough of Southwark and immediately north of Herne Hill , at 113 Grove Park . Denmark Hill was an important radio station during the Second World War ( Y station ) of the British Government Code and Cypher School (GC & CS) ( German about "Staatliche Code- und Chiffrenschule").

history

The radio listening post was set up in the police station on Denmark Hill in May 1936 and initially headed by Commander (equivalent to frigate captain ) Harold Charles Kenworthy (1892-1987), who later, in June 1942, took over the management of the newly founded Government Communications Wireless Station (GCWS) Ivy Farm in Knockholt (25 km southeast of London) took over. Between 1934 and 1937, the focus was on intercepting secret Soviet radio broadcasts with the British Communist Party .

From 1939, after the beginning of the Second World War , the station housed one of the British War Office Y Groups (WOYG) (radio eavesdropping groups of the War Department), whose task it was to intercept and record enemy radio traffic. The Denmark Hill listening post specialized in intercepting and recording German high-speed radio transmissions. Here, in the second half of 1940, the British succeeded for the first time in intercepting the brand-new German radio telex , which clearly differed from the usual sound of the Morse code . They first gave him the nicknames new music ("new music") and NoMo for No Morse ("no Morse"). A little later, radio broadcasts of this kind were grouped under the code name Fish ( "fish" ). Due to a lack of capacity and resources, these messages were initially only tracked with low priority and could not be deciphered . The cryptanalytic break- in then succeeded in the second half of 1941 (see also: Cryptanalysis of the Lorenz Machine ) by the British Codebreakers in Bletchley Park . After the successful deciphering and intelligence service evaluation of the intercepted German radio telex, the British summarized the information, which was often important for the war effort, under the code name Ultra and used it for their own planning.

Immediately after the war, the radio station on Denmark Hill was given up.

literature

Web links

  • Photo of a voice frequency device at the Denmark Hill Police Station (1936). Retrieved March 22, 2017.
  • GCWS Ivy Farm, Knockholt Pound. Report on the Metropolitan Police Sigint Station from Denmark Hill . Retrieved March 22, 2017.

Individual evidence

  1. ↑ James A. Reeds, Whitfield Diffie, JV Field: Breaking Teleprinter Ciphers at Bletchley Park. An edition of I. J. Good, D. Michie and G. Timms. General Report on Tunny with Emphasis on Statistical Methods (1945). Wiley-IEEE Press, 2015, p. 515 (English). ISBN 978-0-470-46589-9 .
  2. ^ Nigel West: Historical Dictionary of British Intelligence. Scarecrow Press, 2014, p. 254, ISBN 0-8108-7897-6 .
  3. ↑ Friends of the Metropolitan Police Historical Collection , accessed February 25, 2019.
  4. ^ Nigel West: Historical Dictionary of Signals Intelligence. Scarecrow Press, 2012, p. 75, ISBN 978-0-8108-7187-8 .
  5. ^ Francis Harry Hinsley, Alan Stripp: Codebreakers - The inside story of Bletchley Park. Oxford University Press, Reading, Berkshire 1993, p. 101. ISBN 0-19-280132-5 .

Coordinates: 51 ° 28 ′ 6 "  N , 0 ° 4 ′ 55"  W.