Allied attacks in May 1944 against bases had a devastating impact on "Luftflotte" 3 capabilities. ULTRA gave the Allies intelligence on the location and strength of German fighter units as well as the effectiveness of attacks. They knew when repairs to bases had been completed and when the Germans decided to abandon particular locations. The Allies pursued an intensive, well-planned campaign that destroyed the German structure near the English Channel and invasion beaches and forced Sperrle's air fleet to abandon efforts to prepare bases close to the Channel. Further damage was done to Sperrle's air defence network. Some 300,000 personnel worked in "Luftflotte" 3, 56,000 in signals. The fortification of radar sites after Dieppe had only highlighted them, and 76 of the 92 were knocked out by D-Day, blinding his "Jagdkorps".