Countering Air America's recent success claims by Al Franken over Bill O'Reilly, the Radio Equalizer yesterday heard from a talk radio executive with additional information on this supposed battle. As part of recent internal company research on the strength of various syndicated hosts, the programmer learned that while O'Reilly's radio success varies somewhat nationwide, he's a powerhouse in Boston. Heard in the Hub on Boston's WTKK-FM, O'Reilly turns out to be one of the market's strongest national programs, crushing competition from Air America's two area stations, WXKS-AM and WKOX-AM.