Complex sentence: At noon on January 6,1979, CKLG-FM changed to CFOX, a call sign first used by a defunct AM radio station in Montreal, Quebec in the 1960's and 70's.
Split into simpler sentences: At noon on January 6,1979, CKLG-FM changed to the call sign CFOX. The "CFOX" call letters where used on a now defunct former AM radio station out of Montreal, Quebec back in the 1960's and 70's.