TV ratings watchers who might have wondered where all the broadcast networks' viewers went on Sunday night got an answer Tuesday when ratings for the cable networks were released. While no program on ABC, CBS, NBC, or Fox drew 10 million viewers, AMC's The Walking Dead at 9:00 p.m. attracted 11 million -- and that was down 8 percent from the season debut a week earlier. During the same hour, TNT's coverage of the NBA All-Star Game siphoned off more viewers from the networks with an audience of 8 million. And in addition, as if the competition from the commercial cable networks were not enough, there was a strong draw from PBS -- also during the same hour -- whose season finale of Downton Abbey bagged 8.2 million viewers.