a range of the target. The Mouse station sent five dots and a dash to indicate bomb release. The Mouse station included a bombsight computer, known as "Micestro", to determine the proper release time; there was no particular logic in carrying the bombsight on the Mosquito when it was under the control of the ground station. Although Oboe had been tested against Essen in January 1943, Oboe was rarely used for "big industrial plants" such as those in the Ruhr Area. The basic idea of Oboe came from Alec Reeves of Standard Telephones and Cables Ltd, implemented in a partnership with Frank Jones of the Telecommunications Research Establishment (TRE); also part of the team was Dr Denis Stops, who later became a leading physicist at University College London. Denis Stops' role in the development of Oboe was so secret that he was drafted into the RAF Pathfinder Squadron as a Wing Commander to conduct his work. His role was largely to develop the systems on the aircraft in conjunction with the land-based radar systems. The system worked by using triangulation to pin-point the target. Dr. Stops once said that one unexpected spin-off of the system was that the Germans often did not know what the British were planning to bomb. Similar systems The Germans improvised a system conceptually similar to Oboe, code named Egon, for bombing on the Eastern Front on a limited scale. It used two modified Freyas to play the roles of Cat and Mouse; these two Freya Egon sets were located about apart and the aircraft carried a two-channel IFF to respond to them. A director at each of the stations would provide course correction directions to the pilot by radio transmission. Though the Germans put considerable effort into other electronic navigation systems, they never developed this concept further. Oboe had one major limitation: it could only be used by one aircraft at a time. To address this, the British came up with a new guidance scheme using the same elements, but mounting the transmitter in the aircraft and placing the transponders in the ground stations. More than one aircraft could use the two stations because random noise was inserted into the timing of each aircraft's transmitter pulse output. The receiving gear on the aircraft could match its own unique pulse pattern with that sent back by the transponders. Each receive–reply cycle took the transponder 100 microseconds,