Complex sentence: In 1978, the show was first aired by the WTTW station (PBS in Chicago) on Saturday nights and by the 80's, as many as 150,000 people tuned in for the hour-long episodes.
Split into simpler sentences: In 1978, the show was first aired by the WTTW station (PBS in Chicago) on Saturday night. By the 80s, as many as 150,000 people tuned in for the hour-long episodes.