For those who are interested in German radar, there's a good book: David Pritchard, "The Radar War: Germany's Pioneering Achievement 1904-45", 1989 which covers their systems in some detail. There's also: Martin Streetly, "Confound and Destroy: 100 Group and the Bomber Support Campaign", 1978 which contains a very interesting chapter about an exercise called "Post Mortem", run immediately after the close of hostilities, from 25 June to 7 July, 1945, in which the Allies observed (from inside) the workings of the German air warning network, including things like how well it coped with various kind of jamming (window, as well as active). Noel