 Development continued largely at the urging of the Admiralty , who saw it as a solution to detecting the conning towers of partially submerged U @-@ Boats . After a visit by Tizard to GEC 's Hirst Research Centre in Wembley in November 1939 , and a follow @-@ up visit by Watt , the company took up development and developed a working 25 cm set using modified VT90s by the summer of 1940 . With this success , Lovell and a new addition to the Airborne Group , Alan Lloyd Hodgkin , began experimenting with horn @-@ type antennas that would offer significantly higher angular accuracy . Instead of broadcasting the radar signal across the entire forward hemisphere of the aircraft and listening to echoes from everywhere in that volume , this system would allow the radar to be used like a flashlight , pointed in the direction of observation . This would greatly increase the amount of energy falling on a target , and improve detection capability . 
