WASHINGTON :The chair of the Federal Communications Commission is opening a probe into NBC-parent Comcast’s relationships with its local broadcast TV affiliates, the latest in a series of investigations into major U.S. broadcasters. FCC Chair Brendan Carr said in a letter to Comcast CEO Brian Roberts, seen by Reuters, that he was investigating after reports that NBC and other similarly situated networks are seeking "to extract onerous financial and operational concessions from local broadcast