the Königsberg, Admiral Graf Spee and two large torpedo boats (which in German service were the size of small destroyers). The Admiral Graf Spee used this unit successfully against shipping in the Atlantic. In Dec. 1939, after heavy fighting during the Battle of the River Plate, the Admiral Graf Spee was severely damaged and the captain scuttled the ship in the neutral harbor off Montevideo, Uruguay. The ship sank in shallow water such that its radar antenna was still visible. These early-model Seetakt systems were followed in 1939 by a modified version known as Dete 1, operating between 71 and 81.5 cm wavelength (368 to 390 MHz) at 8 kW peak and a pulse repetition frequency of 500 Hz. Maximum range against a ship-sized target at sea was up to on a good day, though more typically half that. Performance was otherwise similar to the earlier system, with a range accuracy of about 50 m. This was considerably more accurate than the guns they ranged for, which typically had spreads of over 100 m. It was also much better than the typical optical rangefinding equipment of the era, which would typically be accurate to about 200 m at 20,000 m, albeit some German optical rangefinders were reportedly capable of 40-50 m accuracy at that range, which helps to explain why the Germans continued to rely on optics as their primary maritime range finding equipment for several years into the war. References Bibliography External links Radar Development in Germany on the Radar World website The Radar War (PDF) by Gehard Hepcke, translated into English By Hannah Liebmann on the Radar World website World War II German radars Naval radars German inventions of the Nazi period Military equipment introduced in the 1930s