But because 1020 AM is a clear channel frequency reserved for Class A KDKA Pittsburgh, WPEO must sign off at sunset to avoid interference.

WMMJ played big band music and broadcast sports, but it had financial difficulties and went off the air.

[1][2] WPEO signed on in August 1950, with its studios in the Jefferson Hotel downtown, and started its top 40 format in 1954, competing with 1290 WIRL.

During this time, noted disc jockey Harry Harrison was at WPEO as the "Morning Mayor of Peoria"[2] and station manager.

[1] In 1970, WPEO was bought by the Pinebrook Foundation, Inc., a Pennsylvania-based non-profit corporation, and switched to a Christian radio format.