The difficulties of fighter interception were especially acute at night and in poor weather. He urged the development of homing equipment that could fit into the cockpit of a fighter plane. The idea was that 'ground controllers' could vector the plane to the general location of the enemy planes and then the pilot's own onboard radar could be employed for the final 'lock on'.

In September 1936,'Taffy' Bowen was set the task of solving this problem. Bowen had been already been experimenting with shorter wavelengths. He began with 6.7 metres but this still required an uncomfortably long half-wave dipole (initially slung between the wheels of a Heyford bomber!) aerial. The detection range was a respectable 8-10 miles. At this point, the receiver was in the aircraft but the (much larger and power hungry) transmitter was still on the ground.