I avidly read R V Jones book, "A Most Secret War", he was the architect of establishing a way to counteract the German system of target selection called "Knickebein." This was by way of two radio beams, one at Kleves in Germany and the other one in northern France. Broadly speaking the beams transmitted dots and dashes either side of a pre-determined centre line enabling the pilot to steer to a target. When he heard a continuous tone he was over the target and dropped his bombs. Simple really!
But the story of Chrurchill 'sacrificing' Coventry is as Pilgrim puts it 'cobblers.'
But..............................read
THIS it will banish the theories forever. Sort of!
PPP