The FuG 227 ''Flensburg'' was a German passive radar receiver developed by
Siemens & Halske
Siemens & Halske AG (or Siemens-Halske) was a German electrical engineering company that later became part of Siemens.
It was founded on 12 October 1847 as ''Telegraphen-Bauanstalt von Siemens & Halske'' by Werner von Siemens and Johann Geo ...
and introduced into service in early 1944. It used wing and tail-mounted
dipole antenna
In radio and telecommunications a dipole antenna or doublet is the simplest and most widely used class of antenna. The dipole is any one of a class of antennas producing a radiation pattern approximating that of an elementary electric dipole w ...
e and was sensitive to the mid-
VHF
Very high frequency (VHF) is the ITU designation for the range of radio frequency electromagnetic waves (radio waves) from 30 to 300 megahertz (MHz), with corresponding wavelengths of ten meters to one meter.
Frequencies immediately below VHF ...
band frequencies of 170–220
MHz
The hertz (symbol: Hz) is the unit of frequency in the International System of Units (SI), equivalent to one event (or cycle) per second. The hertz is an SI derived unit whose expression in terms of SI base units is s−1, meaning that one he ...
, subharmonics of the Monica radar's 300 MHz transmissions. It allowed
Luftwaffe
The ''Luftwaffe'' () was the aerial-warfare branch of the German ''Wehrmacht'' before and during World War II. Germany's military air arms during World War I, the ''Luftstreitkräfte'' of the Imperial Army and the '' Marine-Fliegerabtei ...
nightfighter
A night fighter (also known as all-weather fighter or all-weather interceptor for a period of time after the Second World War) is a fighter aircraft adapted for use at night or in other times of bad visibility. Night fighters began to be used i ...
s to home in on the
Monica tail warning radar
Monica was a range-only tail warning radar for bombers, introduced by the RAF in June 1942. Officially known as ARI 5664, it operated at frequencies of around 300 MHz (on the boundary between VHF and UHF). The system was also used by the US ...
fitted to
RAF
The Royal Air Force (RAF) is the United Kingdom's air and space force. It was formed towards the end of the First World War on 1 April 1918, becoming the first independent air force in the world, by regrouping the Royal Flying Corps (RFC) and ...
bombers.
An RAF bomber with Monica radar crashed in German-occupied territory in February 1943 allowing for the development of Flensburg. The British set was captured just seven days into its operational life in February 1943. On the morning of 13 July 1944, a
Junkers Ju 88G-1 night fighter of 7.''Staffel''/
NJG 2
''Nachtjagdgeschwader'' 2 (NJG 2) was a German Luftwaffe night fighter and night intruder wing during World War II.
Background
Night fighter operations did form part of Wehrmacht war games during 1935 and 1936. Luftwaffe Service Regulation No. 1 ...
equipped with Flensburg landed at
RAF Woodbridge
Royal Air Force Woodbridge or RAF Woodbridge, is a former Royal Air Force station located east of Woodbridge in the county of Suffolk, England.
Constructed in 1943 as a Royal Air Force (RAF) military airfield during the Second World War to ass ...
by mistake and was captured. When British military scientists examined the Flensburg equipment, they quickly realised its purpose and informed the RAF, who ordered Monica to be withdrawn from all
RAF Bomber Command
RAF Bomber Command controlled the Royal Air Force's bomber forces from 1936 to 1968. Along with the United States Army Air Forces, it played the central role in the strategic bombing of Germany in World War II. From 1942 onward, the British bo ...
aircraft.
Subsequently, further variants of Flensburg (Flensburg II to Flensburg VI) were developed for detecting Allied
radar jammer
Radar jamming and deception is a form of electronic countermeasures that intentionally sends out radio frequency signals to interfere with the operation of radar by saturating its receiver with noise or false information. Concepts that blanket the ...
s. Only Flensburg II and III were used operationally.
References
Further reading
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External links
Analysis report on the Ju 88 at Woodbridge(PDF format; 44 kB)
World War II German radars
Avionics
Radar warning receivers
Military equipment introduced from 1940 to 1944
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