The impact of Fighter Command's massive daylight operations were offset by the tactical deployment of German units which enjoyed radar-based guidance. They skilfully used this to outweigh their numerical inferiority. 32 Freya radar and 57 Würzburg radar sets were employed from Heligoland to the Bay of Biscay. Fighter Command flew 6,875 sorties from January to June and lost 112 aircraft—57 in June. From July to December this increased to 20,495 with 416 losses. The pressure grew on JG 2, allotted to "Jagdfliegerführer" 3, JG 1, assigned to "Jagdfliegerführer" 1 and JG 26. There were 4,385 "alarmstarts" in July 1941 and another 4,258 in August. September saw a reduction to 2,534 and to 2,553 in October before falling to 1,287. Nevertheless, the fighter wings still retained 430 fighters on 27 September 1941. August proved the costliest to the Luftwaffe in the second half of the year with 42 losses which fell to 18 in September and 15 in October. In September 1941 JG 26 began requipping with the Fw 190, and by year's end had mostly adopted the type. The Fw 190 A proved troublesome initially but soon proved formidable and superior to the Spitfire V. Walter Adolph became the first Fw 190 commander and pilot killed and he was replaced by Müncheberg at the head of II. "Gruppe".