▁intelligence ▁monitoring ▁station ▁in ▁order ▁to ▁allow ▁anal yst s ▁to ▁understand ▁the ▁source ▁and ▁type ▁of ▁S IG INT ▁they ▁were ▁analyz ing . ▁These ▁were ▁used ▁as ▁sh orth and ▁rather ▁than ▁writing ▁or ▁typing ▁out ▁the ▁P LA ▁( P lain ▁Language ▁Address ), ▁which ▁consisted ▁of ▁the ▁formal ▁unit ▁name ▁and ▁location ▁of ▁the ▁unit ▁who ▁performed ▁the ▁signals ▁collection . ▁ ▁Period ▁of ▁Use ▁These ▁design ators ▁were ▁used ▁from ▁the ▁ 1 9 3 0 s ▁through ▁the ▁end ▁of ▁World ▁War ▁II . ▁They ▁were ▁replaced ▁after ▁the ▁end ▁of ▁the ▁war ▁with ▁S IG AD s ▁( SI G INT ▁Activity ▁Design ators ), ▁which ▁are ▁similar ▁in ▁format ▁and ▁application . ▁ ▁Two ▁facilities , ▁V int ▁Hill ▁and ▁ ▁Two ▁Rock ▁R anch , ▁were ▁operated ▁by ▁the ▁NS A ▁until ▁the ▁ 1 9 7 0 s . ▁ ▁General ▁Format ▁The ▁general ▁format ▁of ▁the ▁Mon itor ing ▁Station ▁Design ators ▁was ▁the ▁al ph ab etic ▁characters ▁MS ▁followed ▁by ▁one ▁or ▁two ▁numeric ▁characters . ▁Typ ically ▁the ▁al ph ab etic ▁characters ▁and ▁numeric ▁character ( s ) ▁were ▁separated ▁by ▁a ▁dash ▁character . ▁ ▁Example ▁Design ators ▁The ▁following ▁table ▁provides ▁several ▁examples ▁of ▁Mon itor ing ▁Station ▁Design ators ▁from ▁the ▁World ▁War ▁II ▁era . ▁S ites ▁noted ▁with ▁USA ▁were ▁run ▁by ▁the ▁United ▁States ▁Army , ▁while ▁sites ▁noted ▁with ▁US N ▁were ▁operated ▁by ▁United ▁States ▁Navy . ▁ ▁References ▁