Z - FM ' s ▁replacement , ▁and ▁renamed ▁W LS - FM ▁as ▁W DA I ; ▁W ABC - FM ▁selected ▁W PL J ▁as ▁a ▁replacement ▁call ▁sign . ▁ ▁As ▁part ▁of ▁this ▁new ▁FM ▁initi ative ▁by ▁ABC , ▁all ▁six ▁FM ▁stations ▁dropped ▁the ▁" L ove " ▁progress ive ▁rock ▁format ▁and ▁each ▁adopted ▁album - orient ed ▁rock ▁formats . ▁At ▁age ▁ 1 9 , ▁Jim ▁K err ▁hosted ▁m orn ings ▁at ▁W DA I ▁and ▁did ▁additional ▁work ▁at ▁W LS ▁before ▁finding ▁future ▁success ▁at ▁W PL J ▁and ▁W AX Q . ▁W DA I ▁became ▁the ▁original ▁Chicago ▁radio ▁home ▁of ▁Steve ▁D ahl ▁in ▁January ▁ 1 9 7 8 , ▁and ▁used ▁the ▁s log an ▁" Ch icago ' s ▁Best ▁Rock " ▁with ▁the ▁Mor ning ▁S ick ness ▁with ▁Steve ▁D ahl . ▁ ▁W DA I ▁switched ▁to ▁all - dis co ▁as ▁" Dis co ▁DA I " ▁at ▁the ▁stroke ▁of ▁mid night ▁on ▁New ▁Years ▁ 1 9 7 9 ▁- ▁mark ing ▁the ▁switch ▁by ▁going ▁from ▁Don ▁Mc Le an ' s ▁" American ▁Pie " ▁to ▁" St ay ing ▁A live " ▁by ▁the ▁Be e ▁Ge es . ▁Steve ▁D ahl ▁would ▁wind ▁up ▁the ▁morning ▁host ▁at ▁former ▁c ros st own ▁rival ▁W L UP , ▁and ▁would ▁anchor ▁the ▁" Dis co ▁Dem ol ition ▁Night " ▁promotion ▁in ▁July ▁ 1