▁ 1 9 4 1 . ▁This ▁was ▁a ided ▁by ▁the ▁deployment ▁of ▁more ▁rad ar ▁and ▁search light s ▁and ▁more ▁effective ▁use ▁of ▁them . ▁ ▁Oper ational ▁research ▁One ▁of ▁the ▁oper ational ▁sites ▁in ▁Th ames ▁South , ▁T S 2 1 , ▁was ▁taken ▁over ▁by ▁AA ▁Command ' s ▁Oper ational ▁Research ▁Group ▁to ▁combat - test ▁and ▁develop ▁new ▁techn ologies ▁coming ▁forward ▁such ▁as ▁gun - lay ing ▁( GL ) ▁rad ar ▁and ▁search light ▁control ▁( S LC ) ▁Rad ar . ▁Im pro ved ▁GL ▁Mark ▁I ▁E / F ▁sets ▁began ▁to ▁appear ▁in ▁November ▁ 1 9 4 0 , ▁replacing ▁sound - location ▁for ▁H AA ▁sites , ▁and ▁the ▁number ▁of ▁r ounds ▁that ▁were ▁fired ▁on ▁average ▁for ▁each ▁" kill " ▁began ▁to ▁fall . ▁The ▁GL ▁rad ar ▁was ▁also ▁effective ▁in ▁providing ▁target ▁height s ▁for ▁f igh ters , ▁and ▁the ▁SL ▁batter ies ▁were ▁able ▁to ▁pass ▁these ▁to ▁the ▁night ▁f ighter ▁controllers ▁at ▁R AF ▁Ken ley . ▁ ▁Order ▁of ▁Battle , ▁Winter ▁ 1 9 4 0 – 4 1 ▁On ▁ 1 5 ▁September ▁ 1 9 4 0 , ▁ 8 9 th ▁H AA ▁R gt ▁was ▁rel ieved ▁of ▁oper ational ▁duties ▁and ▁ordered ▁to ▁prepare ▁to ▁move ▁over se as . ▁It ▁sa iled ▁on ▁ 1 5 ▁December ▁for ▁Egypt ; ▁its ▁batter ies ▁later ▁fought ▁in ▁the ▁Battle ▁of ▁Cre