Radio pioneer Ed Walker, whose “Joy Boys” broadcasts with Willard Scott dominated Washington’s airwaves in the 1960s, has died at age 83, three hours after his final broadcast. Related Stories After cancer diagnosis, radio pioneer Ed Walker reluctantly signs off Walker, who was born blind, “died quietly in his sleep at 2 a.m.” says Ken Mellgren, Walker’s longtime friend and former boss at WWRC. “He was in no pain,” Mellgren told WTOP. Walker was recently diagnosed with cancer. Last week he recorded his final broadcast of “The Big Broadcast” for WAMU from his hospital room. The final installment was replayed...