side of the transmitter antenna direction. Put into production in 1942, the Hohentwiel was highly successful. It was first used on large reconnaissance aircraft such as the Fw 200 Condor. In 1943, the Hohentwiel-U, an adaptation for use on submarines, provided a range of 7 km for surface vessels and 20 km for aircraft. Altogether, some 150 sets per month were delivered. The use of the accurate Freya and Würzburg radars in their air-defense systems allowed the Germans to have a somewhat less vigorous approach to the development of airborne radar. Unlike the British, whose inaccurate CH systems demanded some sort of system in the aircraft, the Würzburg was accurate enough to allow them to leave the radar on the ground. This came back to haunt them when the British discovered the mode of operation of the Himmelbett tactic, and the development of an airborne system became much more important. In early 1941, Air Defense recognized the need for radar on their night-fighter aircraft. The requirements were given to Runge at Telefunken, and by the summer a prototype system was tested. Code-named Lichtenstein, this was originally a low-UHF band, (485-MHz), 1.5-kW system in its earliest B/C model, generally based on the technology now well established by Telefunken for the Würzburg. The design problems were reduction in weight, provision of a good minimum range (very important for air-to-air combat), and an appropriate antenna design. An excellent minimum range of 200 m was achieved by carefully shaping the pulse. The Matratze (mattress) antenna array in its full form had sixteen dipoles with reflectors (a total of 32 elements), giving a wide searching field and a typical 4-km maximum range (limited by ground clutter and dependent on altitude), but producing a great deal of aerodynamic drag. A rotating phase-shifter was inserted in the transmission lines to produce a twirling beam. The elevation and azimuth of a target relative to the fighter were shown by corresponding positions on a triple-tube CRT display. The first production sets (Lichtenstein B/C) became available in February 1942, but were not accepted into combat until September. The Nachtjäger (night fighter) pilots found to their dismay, that the 32-element Matratze array was slowing their aircraft up by as much as 50 km/h. In May 1943, a B/C-equipped Ju 88R-1 night fighter aircraft landed in Scotland, which still survives as a restored museum piece; it had been flown into Scotland by