The station began broadcasting December 14, 1966.[1] For many years, the station was a sister station to KWG. The station's original call sign was KSRT (for Stereo Radio Tracy). From the late 1960s to the early 1970s, the station aired a Spanish language format.[6][7] In the early to mid 1970s (1973) through the very early 1980s (1981) KSRT aired an album-oriented rock format.[8][9] On May 6, 1981, the station's call sign was changed to KWGF.[2] In 1983, the station's call sign was changed to KYBB[3] (B-101). From the mid to late 1980s, the station aired an adult contemporary format.[10][11] By 1989, the station was airing an Oldies format,[1][12] and on June 26, 1990, the station's call sign was changed to KSGO[4] (Stockton's Golden Oldies). On December 1, 1992, the station's call sign was changed to KEXX[4] (Xtra 101). By 1995, the station's oldies format had evolved to a playlist centered on hits of the 1970s.[13][14]
KEXX dropped 1970s oldies for country music in 1995, changing its letters to KMIX.[15] By 1997, KMIX was airing a Spanish language format.[16]