According to Wikipedia:
KYW (1060 AM), "Newsradio 10-60", is a commercial AM radio station, licensed to Philadelphia, Pennsylvania. The station is owned by the CBS Radio subsidiary of CBS Corporation and broadcasts an all-news format. Its studios are located in Center City Philadelphia and its transmitter and two-tower directional antenna array are located in Lafayette Hill. KYW is one of the oldest radio stations in the United States, and also has had one of the more complicated histories. Located in Chicago, Illinois at its start in late 1921, it moved to Philadelphia in 1934. In 1956 the KYW call letters were transferred to a station in Cleveland, Ohio, only to be returned nine years later to their original Philadelphia home.
Baffling.
BTW, I discovered this year I can get Wash. Nationals games on 1500 WFED, which apparently used to be WTOP, but I got a headache trying to follow all the changes listed in that wikipedia article!