Rotterdam device
Rotterdam device is the German name for an English radar device that was installed in a British aircraft that was shot down near Rotterdam during World War II . The Stirling bomber was shot down on the night of February 2nd to 3rd, 1943 during an attack on the Rotterdam refineries. This is a copy of the British H2S system , which had previously only been used once by the Royal Air Force in an attack on Hamburg on January 30, 1943 . During the rescue by German troops, parts of the device could be secured. Since the technical properties of the device were not clear to the German scientists, a committee called Arbeitsgemeinschaft Rotterdam (AGR) was founded. The protocols were published after the war by the German Society for Positioning and Navigation - at that time still under the name of the Committee for Radio Positioning .
technology
Although the viewing device in the form of a cathode ray tube had been destroyed, it was found that the device was a transmitter in the centimeter wave range of great power. An associated receiver and antenna could also be recovered. However, due to the lack of control elements and control devices, the intended use could not be determined at first, as the AGR employees assumed that radar beams could only be reflected by metal objects such as ships and aircraft; AGR did not know that built-up areas, rivers and fields reflect back different signatures. The Rotterdam device with the control unit was installed on one of the Berlin flak towers for tests in which a rough map of Berlin with its rivers and canals could be displayed. That was only possible after an intact control panel and tube had been recovered from another downed bomber. Together with the transmitter of the Rotterdam device, a complete device could be put together. It was now obvious that the system was a ground penetrating radar which was used as a bomb sighting device that was independent of the weather.
consequences
With the discovery of the magnetron , which was previously considered unsuitable for RADAR use in Germany , it was now possible to develop own radar devices for new, higher frequency ranges, such as “Berlin” or countermeasures such as “Naxos” . Previously, the highest frequency was 500 MHz, but frequencies of 3000 MHz could now be generated with the captured magnetron. Magnetrons are not very frequency stable. The magnetron could only be used for RADAR applications after the reception frequency was derived directly from the transmission frequency. Hans Erich Hollmann applied for a patent for the multi-chamber magnetron in 1935 .
literature
- Gaspare Galati: 100 Years of Radar , Springer Verlag, 1st edition 2016, ISBN 978-3319005836 .
- Bernard Lovell : Echoes of War. The Story of H2S Radar . 1991, ISBN 978-0852743171 .
- Albert Percival Rowe: One Story of Radar - Camb Univ Press - 1948, ISBN 978-1107494794 .
Individual evidence
- ↑ Gaspare Galati, p. 171, cf. [1]
- ↑ On the night of 30 January 1943, thirteen "Pathfinder" bombers, which dropped incendiaries or flares on a target to "mark" it for other bombers following in the bomber "stream", took off to give H2S its introduction to combat by marking the German city of Hamburg for a strike. Seven of the Pathfinders had to turn back, but six marked the target successfully, which was hit by a hundred Lancasters. […] Unfortunately, on February 2, 1943, a Pathfinder was shot down near Rotterdam, and the Germans noticed the unusual gear in its wreckage. The British had been clever with electronics, and the Germans were careful to look for anything out of the ordinary in RAF aircraft forced down in the Reich. Elements of the H2S set were recovered, and German engineers began to work on the "Rotterdam Geraet (Rotterdam Device)", as they called it. [2]
- ↑ cdvandt.org Minutes of the Rotterdam Working Group (accessed on July 15, 2016)
- ^ Bernard Lovell : Echoes of War. P. 232 ff.
- ↑ Patent US2123728 : Magnetron. Registered on November 27, 1935 , applicant: Telefunken GmbH, inventor: Hans Erich Hollmann.