The week-long Battle of Hamburg in July 1943 proved disastrous for the "Luftwaffe", when the first use of Window by Bomber Command knocked out the "Himmelbett" radar defence system. Window jammed the GCI system, airborne radar sets, gun-laying radar and searchlight controls and British losses to "Flak" and night-fighters declined. The raids were aided by fortunate weather conditions resulting in a firestorm. As a result, every other promising measure of preventing such a recurrence was considered and Hermann's proposal was put into effect. His original experimental unit was rapidly expanded into "Jagdgeschwader 300". "Jagdgeschwader 301" and "Jagdgeschwader 302" were also raised to use the "Wilde Sau" tactic under the new Fighter Division 30 ("30. Jagddivision"), which was commanded by Herrmann.