Flensburg Radar Detector (FuG 227)

The Flensburg, or FuG 227, was a World War II passive radar detector developed by Siemens AG and used by the Luftwaffe from Spring 1944. The FuG 227 used wing-mounted dipole antennae and was sensitive to frequencies of 170-220 MHz. It allowed Luftwaffe nightfighters to home in on the Monica tail warning radar fitted to RAF bombers. On July 13, 1944, a Junkers Ju 88G-1 nightfighter equipped with a Flensburg radar detector mistakenly landed at RAF Woodbridge. After examining the Flensburg, the RAF ordered Monica to be withdrawn from all RAF Bomber Command aircraft. Subsequently, further variants of Flensburg (Flensburg II to Flensburg VI) were developed for detecting Allied radar jammers. Only Flensburg II and III were used operationally.