 It was around this time that Watt arranged for a major test of the CH system at Bawdsey with many aircraft involved . Dowding had been promoted to Chief of Fighter Command , and was on hand to watch . Things did not go well ; for unknown reasons the radar did not pick up the approaching aircraft until they were far too close to arrange interception . Dowding was watching the screens intently for any sign of the bombers , failing to find one when he heard them pass overhead . Bowen averted total disaster by quickly arranging a demonstration of his system in the Red Tower , which picked out the aircraft as they re @-@ formed 50 miles ( 80 km ) away . 
