 The WDAO calls came as a result of all stations East of the Mississippi which begins with "W", the "DA" is for Dayton and the "O" is for Ohio.WDAO started in the fall of 1964 at 107.7 MHz on FM (currently home to WMMX "Mix 107.7") Not only was it the first R&B-formatted station in the Miami Valley, it was also the first FM station of its kind in America; it was the sister to AM daytimer WAVI, owned and operated by H.K.