John Witherspoon, a pioneer in early public broadcasting and the first director of television at CPB, died Wednesday at his home in Coronado, Calif. He was 88. Witherspoon was the first general manager of KPBS in San Diego, which announced his death. “John was bigger than life for all of us that had the privilege to know him,” said Tom Karlo, GM of KPBS. “John was one of the smoothest leaders in our industry,” said Bill Kling, president emeritus of American Public Media/Minnesota Public Radio.