WASHINGTON – Radio and Television News Directors Assn. prexy David Bartlett has resigned over a dispute with his board of directors. Bartlett’s resignation is effective as of Dec. 31, according to a statement released by RTNDA.Sources said Bartlett wanted more control over a separate foundation run by the RTNDA. “David led this organization through one of the most exciting growth periods in its history. His 7-1/2-year tenure as RTNDA’s chief operating officer was exemplary,” said RTNDA board chair Mike Cavender. Cavender said the group will begin a nationwide search to replace Bartlett.