A once-venerable AM signal in San Francisco will not be returning to the airwaves.
Cumulus Media has surrendered the license of KZAC(AM) 560 in San Francisco to the Federal Communications Commission.
KZAC’s tower site at San Francisco’s Pier 94 was among the leases Cumulus was seeking to reject as no longer necessary in its filings to go private following its prepackaged Chapter 11 bankruptcy plan this spring.
This comes at a time when Cumulus has been aggressive in taking both AM and FM stations silent.
RadioInsight also reports that there have been widespread layoffs inside Cumulus Media this week.
Cumulus had filed a silent special temporary authority in September 2025 for the 5,000-watt KZAC and extended it this past March. Just prior to that, Cumulus moved the station’s KSFO format and branding to its 50,000-watt 810 AM signal, formerly KGO.
[Related: “When It Comes to Silencing Stations, Tower Leases Loom Large”]
The media company claimed it was in the process of selling 560 AM, according to the initial STA, and an STA extension in March indicated that Cumulus was still in negotiations with a buyer.
Golden West Broadcasters
The Bay Area Radio Museum & Hall of Fame traces the history of the station back to 1925 in Oakland, when the Tenth Avenue Baptist Church constructed a 1,000-watt transmitting set for $40,000 and installed it at the church, originally at 1390 kilocycles.
Upon confirmation of a wire from the Bureau of Navigation’s Radio Division, the then-KTAB went on the air Aug. 1, 1925.
The station would change frequency positions numerous times, but by November 1929, KTAB shifted from 550 to 560 kilocycles. That’s where it would remain for nearly a century.
After mortgage banker Wesley Dumm was named president of KTAB’s license corporation in 1933, its main studios were moved from Oakland to San Francisco. Its call letters were changed to KSFO in 1935.
KSFO joined the nationwide Columbia Broadcasting System network on Jan. 1, 1937, replacing KFRC(AM) as San Francisco’s CBS outlet.
It began operating with 5,000 watts daytime — 1,000 watts at night— from a self-supported steel tower at San Francisco’s Pier 92 in 1937.
Historian and Radio World contributor John Schneider shared this staff photo of KSFO from 1942.
In early 1957, KSFO’s licensee name was changed to Golden West Broadcasters, commencing the era for which the station was best known.
That included its “Sound Of The City” musical themes, which were made available as a limited-edition phonograph record.
By the early 1960s, KSFO was in operation 24-hours-a-day from its studios at 950 California St. with a personality-driven “middle-of-the-road” music format.
By late 1981, nighttime power rose to 5,000 watts, matching its daylight power output. A second tower was added just east of its existing self-supported tower near Pier 92 at Islais Creek.
The 560 AM signal was California’s 24th-oldest continuously licensed AM broadcast station, according to the Hall of Fame.
Radio World welcomes letters to the editor on this or any story. Email [email protected].
