Reddit reviews Most Secret War (Penguin World War II Collection)

If you want the background, I'd recommend three sources:

1. Most Secret War by R. V. Jones, chief scientist to Winston Churchill during WW2 -- a bit dated (it was published in the early 1970s, before the ENIGMA crypto was declassified) and he has some axes to grind, but it gives a very readable insight into the "wizard war", the technological conflict between Britain and Germany during the war and the various secret weapons programs.
   
   
2. The Codebreakers: The Comprehensive History of Secret Communication from Ancient Times to the Internet by David Kahn, which is pretty much what the title says -- it starts with the US breaking of the PURPLE code and the decrypt of the Japanese Declaration of War on December 7th, 1941, then flashes back to give you a comprehensive history of codes and cryptographer.
   
   
3. Mother Earth, Mother Board by Neal Stephenson -- an insane journalistic essay (published sprawling across 96 pages in WIRED in 1996!) that describes the construction of the FLAG undersea fiber-optic cable, the history of intercontinental cables, and, and ... let's just say, Neal got WIRED to pay him for nine months to go all over the world with a photographer and write this essay about stuff that interested him, and I'm pretty certain it's the main body of his research project for Cryptonomicon!

Or broadcast interference, or even their own beams; R V Jones' Most Secret War is an excellent read about the battle of the beams and other scientific aspects of the war.

https://www.amazon.com/Most-Secret-Penguin-World-Collection/dp/0141042826

This thread in a World War 2 forum discusses the effectiveness of anti-aircraft fire.

One person quotes a German flak officer as saying approximately 4000 x 88 mm anti-aircraft shells were needed to down one aircraft. Another comment quotes the British general in charge of Anti-Aircraft Command, Sir Frederick Pile, as having a kill ratio of one aircraft per 6000 shells during the Blitz. In both cases these are standard anti-aircraft shells with a timed fuze set by a predictor.

In Most Secret War by Dr Reginald Jones a figure is quoted of 77 proximity-fuzed shells needed to shoot down a V-1 flying bomb. (Also published as The Wizard War in the USA. Jones was head of Scientific Intelligence for the RAF in WW2 and his book about his experiences is fascinating.)

While this is a 2-orders-of-magnitude improvement there are a few things to take into consideration:

• By the time the proximity fuze was available to the Allies they also had effective gun-laying radar and predictors working together.
  
  
• The Germans didn't have effective anti-aircraft radar and used sound detectors at night (or in bad weather,) and optical rangefinders in daylight. These were much less accurate than radar.
  
  
• The Germans didn't develop a workable proximity fuze. (Jones mentions an agent report which says they were trying to do so.) The best they could do was to set up box barrages which the bomber streams would have to fly through, as the whole mass of bombers on a mission was too unwieldy to fly around them without losing formation
  
  
• The V-1s flew at a low altitude in a straight line without taking evasive action. This made them an easy target. Allied low-altitude attack aircraft which were constantly strafing German "targets of opportunity" were a much more difficult target as they could take evasive action.