sentences:  Coventry's air defences consisted of twenty-four 3.7 inch AA guns and twelve 40 mm Bofors.The AA Defence Commander of 95th (Birmingham) Heavy Anti–Aircraft Regiment, Royal Artillery, had prepared a series of concentrations to be fired using sound-locators and GL Mk.I gun-laying radar, and 128 concentrations were fired before the bombing severed all lines of communication and the noise drowned out sound-location.