Complex sentence: Field Communications started a news department shortly before putting the station up for sale and began a 10 p.m. weeknight newscast, which initially was a pair of ten-minute locally-produced inserts in what otherwise was an hour-long simulcast of CNN Headline News.
Split into simpler sentences: Field Communications started a news department shortly before putting the station up for sale. It began producing a 10 p.m. weeknight newscast which initially was a pair of ten-minute locally-produced inserts in what otherwise was an hour-long simulcast of CNN Headline News.