last examples of which left service in 1993. In 1950 a further requirement for more accurate conventional bombing was raised, demanding accuracy from an aircraft flying at and . This led to the early consideration of a version operating in the Q-band at 8 mm wavelength. An experimental version was constructed in 1951, but in practice the Mk. IX proved useful enough on its own and development was dropped. Versions From Lovell: Mark I – prototype versions fit to Pathfinder Force (TR3159) Mark II – main production version with standard scanner (TR3191) Mark IIA – replaced the scanner's dipole antenna with a horn and waveguide Mark IIB – IIA with Fishpond displays Mark IIC – IIB with Type 184 scan-corrected display, roll stabilized scanner, and improved antenna reflector that eliminated the metal fillet Mark III – prototype 3 cm versions, six produced by December 1943 Mark IIIA – III with Type 184 display and roll stabilized scanner Mark IIIB – III with Type 184 display (introduced as an interim model before IIIA while stabilizer production improved) Mark IIIC – IIIA with the 6-foot whirligig scanner Mark IIID – IIIA with a more powerful magnetron Mark IIIE – IIIA with the Type 216 display, new scanner and using a shorter pulse length Mark IIIF – IIIE with whirligig scanner Mark IIIG – IIC systems converted to 3 cm, lacking the stabilizer. Intended primarily for long-range navigation by Tiger Force Mark IIIH – IIIG with Type 216 display Mark IV – IIIA with altitude correction, links to AMU computer and Mk. XIV bombsight. Passed over in favour of Mk. IVA Mark IVA – IV with whirligig scanner, standard model on Avro Lincoln bombers Mark V – set aside for H2X but not used Mark VI – IIIF operating at 1.25 cm wavelength, also with 28-inch scanner for Mosquitos. Also known as Lion Tamer. Mark VII – updated Mark VI with links to the navigation system, cancelled with the ending of the war Mark VIII – Mark IVA operating in the X-band, replacement for Mk. VII. Four produced. Mark IX, IXA – Mk. VIII with 200 kW magnetron and many other improvements. Used on the V bombers. See also Naxos radar detector, created by Germany to spot H2S transmissions List of World War II electronic warfare equipment Notes References Citations Bibliography Further reading Sitzungsprotokolle der Arbeitsgemeinschaft Rotterdam, minutes of the meetings of the