sentences:  KFRC continues to broadcast classic hits on KFRC-FM HD2.The station's calls were not converted to KCBS-FM, because its Los Angeles sister adult hits station on 93.1 holds those calls, and Nielsen Audio's Portable People Meter ratings system does not require call letter verification by panelists.CBS Radio retained the calls to keep control of the historic callsign rather than risk having another Bay Area station take them and trade on their nine-decade heritage in the area.