 Electronically, the Type 7 was essentially a larger and more powerful version of the CHL concept, with a larger ground-level antenna.However, the antenna was continuously spun through a complete circle, and returns were plotted in a map-like form known as a plan-position indicator (PPI).Whereas CHL operators had to calculate a single target's position from the range and bearing, Type 7 operators saw all of the aircraft in their area simultaneously and could determine their map location directly.