Complex sentence: In 1986, WMAQ-TV became the first station in the Chicago metropolitan area to broadcast its newscasts in full stereo sound, prior to this, all of the NBC network programming broadcast on the station began their commercial stereo broadcasts in 1985.
Split into simpler sentences: In 1986, WMAQ-TV became the first station in the Chicago metropolitan area to broadcast its newscasts in full stereo sound. Prior to this, all of the NBC network programming began their commercial stereo broadcasts in 1985.