The SCR-584 was extremely advanced for its era. To achieve high accuracy and measure both azimuth and elevation with one antenna, it used a conical scanning system, in which the beam is rotated around the antenna's axis to find the maximum signal point, thus indicating which direction the antenna should move in order to point directly at the target. The idea was proposed by Alfred Loomis, the director of section D-1 of the National Defense Research Committee. In October 1940, it was adopted for the "wholly-automatic-tracking" radar project. Conical scanning was also adopted in 1941 for the Navy's 10 cm fire-control radar system, and it was used in the German Würzburg radar in 1941. The SCR-584 developed the system much further, and added an automatic tracking mode. Once the target had been detected and was within range, the system would keep the radar pointed at the target automatically, driven by motors mounted in the antenna's base. For detection, as opposed to tracking, the system also included a helical scanning mode that allowed it to search for aircraft. This mode had its own dedicated PPI display for easy interpretation. When used in this mode the antenna was mechanically spun at 4 rpm while it was nudged up and down to scan vertically.