Built by the GEMA company, who also designed the Freya radar, the basic concept had been introduced in November 1938, but little work was carried out on it initially. The Luftwaffe's Chief of Signals placed an order for 2,000 to 3,000 units in late 1939, although the prototype was not available until 1941. The system only responded to the Freya, a serious limitation as the Würzburg radar became more widely used.