Complex sentence: It was co-owned with Portland NBC affiliate WCSH-TV until being sold to Saga Communications in the mid- 80's, when it began simulcasting WYNZ as WYNZ-AM.
Split into simpler sentences: It was co-owned with Portland NBC affiliate WCSH-TV. In the 1980s, WCSH was sold to Saga Communications and it then began simulcasting WYNZ as WYNZ-AM.