For twenty-five years, the call letters KDIA were synonymous with soul music in the Bay Area. Descended from the pioneering Oakland station KLS — which itself was born from an early experimental station, 6XAM, in 1921 and became KWBR in 1945 — the 1,000-watt station had begun emphasizing programs that targeted the local African-American audience around the end of World War II.
By the late 1950s, while still known as KWBR, the station was competing with KSAN/1450 in San Francisco for black listeners with rhythm-and-blues music and popular disc jockeys, including Big Don Barksdale and Bouncin' Bill Doubleday. In July 1959, KWBR was sold for $550,000 to the Sonderling Stations group, operator of the legendary Memphis station, WDIA. On September 4, 1959, KWBR became KDIA, reflecting its new parentage. (Sonderling also owned KFOX in Los Angeles and WOPA in the Chicago suburb of Oak Park.)
Under Sonderling ownership and the management of Walter Conroy, KDIA directed its full programming effort toward the emerging black audience, keeping Don Barksdale and Bill Doubleday on its staff and adding high-caliber talent over the years that included Bay Area Radio Hall of Famer George Oxford (previously a competitor at KSAN), John Hardy, Belva Davis (later known for her television work at KRON, KPIX and KQED), Rosko (nom de radieux of William Roscoe Mercer), Roland Porter, Bob White, Bill Hall, Johnny Morris and Bob Jones. The station leveraged its dial position — 1310 AM — into its identity as "KDIA Lucky 13."
In 1965, KDIA's power was raised to 5,000 watts from a new transmitter facility near the Bay Bridge Toll Plaza which also housed the station's new studios and offices. The five-fold increase in power made KDIA a veritable powerhouse and helped to hasten the demise of the old KSAN, which had become KSOL in 1964. (Going full circle, it was another KSOL — this time on 107.7 FM — that would eventually end KDIA's supremacy in the late 1970s.)
In September 1969, John W. Doubleday — "Bouncin' Bill" — became KDIA's general manager, a position he held until September 1974, when J. Walter Carroll assumed the role. Mr. Carroll served as KDIA's general manager until his death on January 20, 1976; Kernie L. Anderson became the station's GM in 1977.
The station thrived through the 1970s, but was sold by Sonderling to Viacom International in 1980. KDIA continued with an Urban Contemporary music format under Viacom until 1983, when the station was sold again (along with WDIA) to Ragan Henry. In 1984, KDIA changed hands once more, becoming the property of Adam Clayton Powell III, who flipped the station to All News KFYI.
After the failure of KFYI's news format, the station went off the air on April 9, 1985, only to be revived under new ownership as KDIA in October of that year. In subsequent years, the station was owned by future San Francisco Mayor Willie Brown and Oakland Mayor Elihu Harris, and by James Gabbert, who had also owned KIOI and KOFY. In 1997, Mr. Gabbert entered into an agreement to air the syndicated "Radio Disney" programming format on KDIA in advance of selling the station to ABC, Inc. The station's call letters were changed to KMKY on January 20, 1998, and ABC purchased the station for $6.25-million in May 1998.
The KDIA call letters are currently assigned to the religious-formatted station known as "The Light For San Francisco," licensed in the city of Vallejo and operating at 1640 kHz.