Total broadcast TV ad revenue was down 12.8 percent in the second quarter versus last year, the Television Bureau of Advertising said Friday, basing its figures on estimates proved by TNS Media Intelligence. Local broadcast ad sales were down the most -- 27 percent, while syndication was down just 1.5 percent. Revenue at the broadcast networks was down 5.8 percent. All broadcasters were particularly affected by the turmoil in the automotive sector. Automobile ads were down 54.5 percent from a year ago. (Chrysler cut its ad buying by 73.8 percent.)