was discovered, and microwave radar development started. Telefunken was commissioned to build a gun-laying set for Flak applications, and at the beginning of 1944, a 10-cm set code-named Marbach emerged. Using a 3-m Mannheim reflector, this set had a detection range of about 30 km. Its most important characteristic was a relative immunity to Window – the chaff used by the British as a countermeasure against the 50-cm Würzburg. The Marbach was produced in limited quantities for Flak batteries around a number of large industrial cities. Several other 10-cm sets were developed, but none made it into mass production. One was Jagdschloss Z, a Panorama-type experimental set with 100-kW pulse-power built by Siemens & Halske. Klumbach was a similar set but with only 15-kW pulse-power and using a cylindrical parabolic reflector to produce a very narrow beam; when used with Marbach, the combined fire-control system was called Egerland. Near the end of 1943, the Germans also salvaged radars containing 3-cm magnetrons, but sets operating at this wavelength were never produced. They did, however, play an important role in the German development of countermeasures, particularly radar warning receivers. Airborne In June 1941 an RAF bomber equipped with an ASV (Air-to-Surface Vessel) Mk II radar made an emergency landing in France. Although the crew had attempted to destroy the set, the remains were sufficient for the German Laboratory for Aviation to discern the operation and its function. Tests indicated the merits of such a radar, and Wolfgang Martini also saw the value and tasked Lorenz to develop a similar system. With backgrounds in aircraft navigation equipment and experience in developing their internally funded ground-radar systems, Lorenz had excellent capabilities for this project. Before the end of the year, they had built a set based on their Kurfürst/Kurmark design, but greatly reduced in size and weight, and with improved electronics. Designated FuG 200 Hohentwiel, it produced 50-kW pulse-power at low-UHF band frequencies (545 MHz) and had a very low PRF of 50 Hz. The set used two separate antenna arrangements, providing searching either forward or side-looking. The Hohentwiel demonstration detected a large ship at 80 km, a surfaced submarine at 40 km, a submarine periscope at 6 km, aircraft at 10 to 20 km, and land features at 120 to 150 km. A bearing accuracy of about 1 degree was obtained by rapidly switching between two receiver antennas aimed 30 degrees on each