KZAC
KZAC is a commercial radio station in San Francisco, California, that used the call sign KSFO from 1935 to 2024, and is currently silent. Owned by Cumulus Media, KZAC's transmitter is located near the Islais Creek Channel.
KZAC began broadcasting in 1925 as a station licensed to Oakland with the call sign KTAB, on a frequency of 1390 kHz. Owned by a Baptist church in Oakland, KTAB had a religious-focused format in its first year before changing to a commercial, non-religious format. After several frequency changes, the station moved to its current 560 kHz frequency in 1929 and became KSFO in 1935, re-licensed to San Francisco. KSFO joined the CBS Radio Network in 1937.
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 for KSFO featuring popular music, news, and sports, with a popular jingle "The Sound of the City". Golden West sold KSFO to King Broadcasting Company in 1983, after which KSFO became a pop standards station. Then in 1986, KSFO shifted its music format to reflect 1950s to 1970s oldies, before becoming a simulcast of KYA-FM in 1987. Sold again to First Broadcasting Company in 1992, KSFO had a combined oldies and sports talk format before changing to a full-time talk radio format in 1993.
Capital Cities/ABC Inc. bought KSFO in 1995 and shifted its programming to emphasize conservative talk, and was one of the most popular stations in San Francisco through the late 1990s. Michael Savage and his show The Savage Nation, which was later nationally syndicated, originated from KSFO through the majority of its run. Other local hosts included Geoff Metcalf, Melanie Morgan and Brian Sussman. Through its history, KSFO has also broadcast local sports teams, including Stanford Cardinal football, San Francisco 49ers, San Francisco Giants, Oakland Athletics, Oakland Raiders, and California Golden Bears men's basketball. A 2024 programming realignment by current owner Cumulus Media saw KSFO's format and branding moved to and this facility renamed as KZAC; in 2025, the station went silent.
History
KTAB
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 authorizing a new radio station for the Tenth Avenue Baptist Church in Oakland, California, operating on 1390 kHz. 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. 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 primarily with broadcasts of church services.
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 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 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. 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 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. Just before the start of World War II, Dumm was tapped by President Franklin D. Roosevelt to use his KSFO facility to launch international shortwave broadcast stations KWID and KWIX. These stations became the forerunners of the Voice of America. Facilities for KSFO, KWID, and KWIX were located at San Francisco's Islais Creek where the KSFO transmitter continues to operate today.
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.
"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 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.
Johnson and Jones observed that KSFO "always played from a wide spectrum of popular music" in a "free-form, but controlled" way, with "current hits, oldies, a lot of pieces from albums." Golden West turned KSFO into the most popular radio station in the San Francisco Bay Area. In the March 1964 Billboard radio response survey for San Francisco, KSFO was the top station among listeners for pop LPs, non-rock singles, folk music, and comedy; for jazz, KSFO ranked second behind KJAZ. By January 1967, RKO General's KFRC knocked KSFO out of the no. 1 spot in Bay Area ratings. Additionally, KSFO faced additional competition for its target 25-to-49 age group from FM progressive rock stations KMPX and KSAN.
From 1957 to 1980, KSFO was the radio home of the San Francisco 49ers football team. Initially, Bob Fouts was on play-by-play and Lon Simmons on color commentary. Beginning in 1961, Simmons was elevated to play-by-play. Both of the Bay Area's Major League Baseball teams had games on KSFO. From its first season moving from New York in 1958 to 1978, the San Francisco Giants broadcast their games on KSFO, with notable announcers including Russ Hodges, Lon Simmons, Al Michaels, and Joe Angel. Then starting in 1981, KSFO was the radio home of the Oakland A's, with a broadcast team of Bill King, Lon Simmons, and Wayne Hagin.
Jim Lange joined KSFO as afternoon host in January 1960. In November 1960, KSFO hired Al "Jazzbo" Collins, former host of NBC's Tonight. When Lange began hosting TV shows in Los Angeles such as The Dating Game in 1965, Lange moved to mornings on KSFO in order to accommodate his TV taping schedule. In 1968, KSFO hired Terry McGovern away from KDKA in Pittsburgh.
Beginning in the 1969–70 sports season, KSFO began 16 seasons of broadcasting Stanford University football and basketball games.
In response to market research showing that most of its daytime audience preferred watching television at night, KSFO hired John Gilliland in 1971 to host a five-hour variety block of music and entertainment evenings from 7 p.m. to midnight; Gilliland would continue as host until 1978. In addition to music, Gilliland's program featured the CBS Radio Mystery Theater, dramas and other serials from the Golden Age of Radio, comedy shows, and Gilliland's Pop Chronicles music documentaries. KSFO broadcast Mystery Theater so that local CBS Radio affiliate KCBS did not have to interrupt its all-news programming.
After a decline in ratings in the mid-1970s, KSFO began diversifying its music playlist. KSFO continued playing Frank Sinatra, Tony Bennett, and Peggy Lee, whose music had been phased out of many MOR stations. The station added tracks from Ernestine Anderson and contemporary artists like The Carpenters and Bette Midler. In the October/November 1976 Arbitron survey, KSFO was the most popular station among women aged 25 to 49 and averaged 10,800 listeners aged 18 to 49 per hour, between KCBS and KFRC. KSFO was the station that broke Elmo and Patsy's "Grandma Got Run Over by a Reindeer" to national fame.
The station's news department earned national and international journalism awards for coverage of the 1978 Peoples Temple mass suicides in Jonestown, Guyana and the assassinations of San Francisco Mayor George Moscone and Supervisor Harvey Milk by former Supervisor Dan White.