He concluded that the only way to address this would be to have the radar operators control the fighters directly, eliminating the middle-men. He went on to describe a radar system that rotated the antenna and the cathode ray tube (CRT) display at the same rate. When the time base generator triggered at the start of a broadcast, it would draw a line along the tube in the direction the radar was currently pointing. In CH, the amplified return signal deflected the CRT beam to cause a "blip" to appear; in this new system, the signal would instead cause the beam to briefly brighten, producing a small dot on the display. Using a long-lasting phosphor in the CRT, only these brighter spots would remain on the display when the radar rotated away from that angle. Hanbury Brown called this system the "plan position indicator" (PPI). The result would be a number of bright dots on the display, directly indicating the angle and range of an aircraft. The display as a whole represented a map of the airspace around the radar station, showing every aircraft within that station's view. An operator looking at the display could calculate an interception by examining the locations of the dots on the display, instead of having to calculate the aircraft locations on a separate map and arrange it there. Better yet, any inaccuracy in the radar would apply to the fighter and its target equally, whereas the Dowding system tracked these using separate systems and were subject to large differences in measurements. At the time there were more pressing issues getting CH and CHL into operation. These problems had improved by 1940, and in May a team at the newly renamed Telecommunications Research Establishment (TRE) had successfully motorized a CHL antenna to spin it, and had combined the separate transmit and receive antennas onto a single mount. The next month they successfully tested the first PPI display, which rotated the CRT display coils using a selsyn connected to the antenna motor. As the Battle of Britain wound down, the "Luftwaffe" turned their efforts to the night bombing effort that became The Blitz. The RAF found that the problems predicted in Brown's paper were proving true. In early night operations, most of the night fighters ended up flying around searching for targets they never found. The PPI would solve this problem, but it was clear it would not be ready for some time. The TRE began a rushed effort to develop some sort of stop-gap solution. One solution was experimented with at RAF Foreness Point. Foreness was in the right position to see German bombers on their way to dropping mines in the Thames River, and was one of the first stations to receive a CHL in 1939.