CBO-FM's a Canadian radio station. It's the CBC Radio One station in Ottawa, airing at 91.5 FM, and serves much of Eastern Ontario through a network of relay transmitters. History CNRO was launched in 1924 as a Canadian National Railway radio network station. It operated on AM 690 and later switched to 600. In 1933, the station was taken over by the CBC's predecessor, the Canadian Radio Broadcasting Commission and became CRCO on 880 kHz AM. The call sign changed to CBO in 1937 when ownership wa… (More on Cbo-fm)