WBBM (780 kHz) is an all-news radio station in Chicago, Illinois, USA. Owned by CBS Radio, the station broadcasts on a clear channel and is an affiliate of the CBS Radio Network. The station's studios are located in the combined CBS Radio facility at Two Prudential Plaza in the Loop neighborhood, and the transmitter is located in Itasca, Illinois. Since August 1, 2011, WBBM's programming has been simulcast over sister station WCFS-FM (105.9 MHz.). The FM station's call letters were retained and should not be confused with WBBM-FM (96.3 MHz.), a heritage rhythmic contemporary station; WCFS's former adult contemporary format was retained in an automated form over their HD2 subchannel.