WOPA-AM in Oak Park. More here.
WOPA-AM signed on in 1950. It's call letters the Oak Park Arms, a hotel on Oak Park Avenue where their studio was originally installed. Their 250 watt signal was strongest on the west side of Chicago, and William Klein's Village Broadcasting Company wisely targeted those black demographics so the schedule was full of blues, jazz, R&B, and gospel. Most of their day was brokered time so it was also peppered with ethnic programming of every stripe. But 1490 was short spaced between WXRT-AM and WMOR-AM, so it was never going to have much more juice.
The solution in 1953 was 102.3 WOPA-FM. WMOR had gone bankrupt and they bought the license at 3,600 watts. This signal had solid Chicago coverage, though FM listener ship was low in the 50s it grew steadily. Initially the stations just simulcast all programming. But in 1966 the FCC mandated that FM simulcasts carry 50% originating programming. The brokered ethnic moved to the FM side, but Big Bill Hill remained simulcast in the evening, even after the station bumped the wattage up to 6,000 watts.
His career changed forever in 1963. He already owned a booking agency, a dry cleaner, a management company and he owned his own club, the Copa Cobana. Supposedly he did remotes from all of those locations, even the dry cleaner. In 1967 it looked like it was all going to fall apart. WOPA was born again as a free form FM station full of underground music and hippies. His already floundering club, the Copa Cobana closed. But Bill defied all odds and started a R&B TV dance show on WCIU-TV. The "Red Hot and Blues" show ran until 1971. It was overtaken by another R&B dance program... Soul Train. More here.