KSFO (560 AM), known as KZAC from 2025 to 2026, was a commercial radio station in San Francisco, California, United States. The station operated from 1925 until 2025, and its license was surrendered by its final owner, Cumulus Media, and cancelled by the Federal Communications Commission (FCC) in August 2026. Its transmitter facility was located near the Islais Creek Channel.
The station began broadcasting in 1925 as KTAB, licensed to Oakland on 1390 kHz and owned by the Tenth Avenue Baptist Church. After becoming a commercial station and undergoing several frequency changes, it moved to 560 kHz in 1929. The station was renamed KSFO and relicensed to San Francisco in 1935, and became the city's CBS Radio Network affiliate in 1937.
Under owner Wesley I. Dumm, the Islais Creek transmitter site was expanded during World War II to accommodate the international shortwave stations KWID and KWIX. Built following a request from the administration of President Franklin D. Roosevelt, the high-powered stations transmitted programming overseas and were part of the development of U.S. international wartime broadcasting.
In 1956, KSFO was purchased by Golden West Broadcasters, a company co-owned by Gene Autry and Bob Reynolds. Golden West programmed a full-service format featuring popular music, news and sports, promoted by the jingle "The Sound of the City". Golden West sold KSFO to King Broadcasting Company in 1983, after which the station adopted a pop standards format. In 1986, KSFO shifted to an oldies format emphasizing music from the 1950s through the 1970s and began simulcasting KYA-FM in 1987. First Broadcasting Company acquired the station in 1992 and introduced a mixture of oldies and sports talk before KSFO became a full-time talk station in 1993.
Capital Cities/ABC Inc. acquired KSFO in 1995 and developed it as a conservative talk station. Michael Savage originated The Savage Nation at KSFO before the program became nationally syndicated; other longtime local hosts included Geoff Metcalf, Melanie Morgan and Brian Sussman. During its history, the station also broadcast games of the Stanford Cardinal, San Francisco 49ers, San Francisco Giants, Oakland Athletics, Oakland Raiders and California Golden Bears.
In November 2024, Cumulus transferred the KSFO programming, branding and staff from 560 AM to the more powerful facility formerly known as KGO. The KSFO call sign followed in January 2025 and 560 AM became KZAC. KZAC ceased broadcasting on March 3, 2025. Cumulus subsequently considered selling the station but surrendered its license to the FCC in August 2026, ending the 560 AM facility's approximately century-long broadcasting history. History
KTAB The origins of KTAB can be traced to The Hour of Prayer, a daily morning religious program presented on KGO beginning in 1924 by the Reverend George W. Phillips, pastor of the Tenth Avenue Baptist Church in Oakland. The program generated a substantial response from listeners, convincing Phillips that radio could benefit the church. After KGO discontinued the program, Phillips proposed that Tenth Avenue Baptist establish its own radio station. The congregation approved the proposal and raised approximately $35,000 toward construction of the station.
Until 1927, radio in the United States was regulated by the Bureau of Navigation within the Department of Commerce. On August 1, 1925, the bureau sent a telegram"Date First Licensed", FCC History Cards for KSFO authorizing a new radio station for the Tenth Avenue Baptist Church in Oakland, California, operating on 1390 kHz."New stations", Radio Service Bulletin, August 1, 1925, page 3. The station's call letters, KTAB, reflected its owner's name.
KTAB's debut broadcast, at 8 p.m. on August 1, 1925, featured a doxology from the church choir, a classical music performance from trumpeter Grace Adams East and a speech by the Reverend George W. Phillips, the church's pastor. A more detailed program guide for KTAB is two columns to the left. KTAB was issued a formal broadcast license on August 10, 1925, and began broadcasting daily at 1250 kHz eight days later. In its early months, KTAB had a noncommercial format emphasizing church services and other religious programming. The Hour of Prayer resumed on KTAB after the station began broadcasting and remained associated with the station after its operation was leased to commercial interests.
On March 25, 1926, The Associated Broadcasters, a company founded by Tenth Avenue Baptist Church attendees, entered a 20-year lease agreement with the church to operate KTAB. The lease required the station to continue carrying certain Tenth Avenue Baptist Church programs, including The Hour of Prayer. The Associated Broadcasters converted KTAB into a commercial station, and owing to a temporary lack of U.S. Department of Commerce regulation of radio station wavelengths or power levels under the Radio Act of 1912, KTAB moved to a better frequency of 990 kHz in June 1926.
Following the passage of the Radio Act of 1927 in April of that year, the newly formed Federal Radio Commission (FRC) relicensed KTAB to broadcast on 1070 kHz with a power of 500 watts, effective June 1, 1927. Following an appeal, the FRC allowed KTAB to broadcast with 1,000 watts on Sundays in July and August 1927.
After the Pickwick Broadcasting Corporation purchased The Associated Broadcasters on August 1, 1928, KTAB's studios moved from Oakland to the Pickwick Hotel at Fifth and Mission Streets in San Francisco on September 29, 1928. Around that time, KTAB moved from 1070 to 1280 kHz, before sharing airtime with KLX at 550 kHz on November 11, 1928. By early 1929, KTAB broadcast full time on 550 kHz after KLX moved to 880 kHz, and KTAB had an on-air backronym slogan, "Knowledge, Truth, And Beauty." KTAB moved to the station's present frequency of 560 kHz in November 1929.
Having operated the station since 1926, Associated Broadcasters outright bought KTAB from Tenth Avenue Baptist Church in early 1930, and KTAB began broadcasting at 1,000 watts day and night beginning in October 1930. On March 14, 1933, the KTAB studios returned to Oakland, this time at Sweet's Ballroom, then at 1424 Franklin Street. Pickwick sold The Associated Broadcasters to mortgage banker Wesley I. Dumm and business partner Philip G. Lasky in the fall of 1933. As part of the arrangement, Dumm agreed to continue providing the church with a daily half-hour of airtime for The Hour of Prayer, as well as five hours on Sundays.
The Dumm–Lasky group moved KTAB's studios from Oakland to the Russ Building in San Francisco. KTAB moved from a penthouse apartment to the entire 31st floor of the Russ Building on April 11, 1935.
Early history as KSFO (1935–1955) KTAB changed its call signs to KSFO and city of license to San Francisco on May 2, 1935. Some early programming on KSFO was rebroadcast from KNX in Los Angeles. National programs on KSFO included Alka-Seltzer Newspaper of the Air, Cowboy Church with Stuart Hamblen, and Father Coughlin. As early as 1936, KSFO broadcast Stanford University football games.
On January 1, 1937, KSFO replaced KFRC as San Francisco's CBS Radio affiliate. Nearly seven months after the Federal Communications Commission (FCC) granted a construction permit, KSFO began broadcasting at its current power of 5,000 watts from a new 389-foot steel transmitter at Pier 92 and Islais Creek. KSFO's studios moved from the Russ Building to the Palace Hotel on August 12, 1938.
After purchasing a stake in KROW, Lasky resigned from KSFO in 1940 to manage KROW. Effective December 31, 1941, KSFO was no longer affiliated with CBS Radio, after the network moved to KQW in San Jose. Going forward, KSFO had an independent music and news format.
KSFO again moved its studios in August 1943, this time to the Mark Hopkins Hotel, with which The Associated Broadcasters signed a long-term lease in 1942. In 1948, KSFO sought a construction permit to exchange frequencies with KQW, which then had a 50,000 watt signal at 740 kHz. The construction permit was withdrawn in 1950 after KSFO's new co-owned television station KPIX became a CBS affiliate. After nine years at the Hopkins Hotel, in February 1952, KSFO moved to a shared office space with KPIX at 2655 Van Ness.
On March 6, 1953, Don Sherwood debuted on KSFO as host of the morning show. KSFO's licensee was renamed San Francisco Broadcasters on May 25, 1954, in advance of the Dumm–Lasky ownership group selling KPIX to Westinghouse Broadcasting.
On February 15, 1955, KSFO moved studio quarters to the Fairmont Hotel, on California Street (1955-1983).
World War II shortwave broadcasting Following the United States' entry into World War II, KSFO owner Wesley I. Dumm became involved in the development of American international broadcasting. At the request of the administration of President Franklin D. Roosevelt, Dumm established two international shortwave stations at KSFO's Islais Creek transmitter site, KWID and KWIX.
The shortwave facilities were constructed rapidly following the December 1941 attack on Pearl Harbor. KWID operated with 100,000 watts and KWIX with 50,000 watts; the two stations were broadcasting within weeks of the attack. Accommodating the transmitters required an expansion of KSFO's 1937 transmitter building, while additional antenna arrays were erected on land surrounding the Islais Creek site.
The stations were used to transmit programming overseas during the war and became part of the expansion of U.S. government international broadcasting that produced the Voice of America. Dumm was also involved in organizing the emerging international broadcasting service. The wartime operations made the Islais Creek property a combined domestic and international broadcasting facility housing KSFO and the high-powered shortwave transmitters.
The shortwave operation also affected KSFO's studio facilities. The combined activities of KSFO, KWID and KWIX required expanded production facilities, and Associated Broadcasters developed a new studio complex at the Mark Hopkins Hotel on Nob Hill.
The U.S. government continued leasing KWID and KWIX after World War II. The shortwave stations ceased operation on June 30, 1953, when the government terminated its lease of the facilities. Associated Broadcasters elected not to continue the international service, and the shortwave transmitting equipment was subsequently sold.
"The Sound of the City" (1956–1983)
In June 1956, San Francisco Broadcasters sold KSFO for nearly $1 million to Golden West Broadcasters, a company co-owned by Western movie actor Gene Autry and former football player Bob Reynolds. On the morning of December 19, 1956, AFTRA union members went on strike at KSFO after being unable to reach an agreement for a new contract. As a result, KSFO joined three other Bay Area radio stations, KLX, KROW, and KYA, in a collective bargaining agreement.
Golden West launched a full service format that featured personality-driven middle of the road (MOR) music programs, local news, and local sports. Additionally, KSFO's slogan was "The World's Greatest Radio Station." Its signature jingle, "The Sound of the City" with words and music composed by Johnny Mann, was sung a cappella by eight studio singers at the United Western Recorders studio in Hollywood. According to San Diego State University communications professors Joseph S. Johnson and Kenneth K. Jones, the jingle "has such a lovely melody and lyrics that station listeners request it, and records of the jingle have sold in music stores. Outside of San Francisco, similarly formatted stations adapted "The Sound of the City" for their markets.