KOSF (103.7 FM) is a radio station in San Francisco, California. The station is owned and operated by iHeartMedia. The station's studios are located in the SoMa district of San Francisco, while the transmitter is based atop San Bruno Mountains.
The former ABC Radio-owned station started on November 3, 1947 as KGO-FM. In earlier days, it simulcast its AM sister station of the same name, occasionally airing a stereo version of the Lawrence Welk show. By the late 1960s, as FM stations were required to offer separate programming from that of their AM sisters, KGO-FM, like other ABC-owned FM stations, was an outlet for ABC Love, an automated progressive rock format.
KGO-FM became KSFX in early 1971, and continued in a progressive rock format until May 1973. Then, KSFX ran a top 40 "Musicradio" approach, similar to WABC in New York. By late 1974, the station veered towards a Dance/Soul-flavored format. During the late 1970s, KSFX had a brief run with a disco format.
In late 1980, KSFX veered towards an album-oriented rock format modeled after sister station KLOS in Los Angeles. This lasted until May 1982, when stiff competition from KMEL (now an urban-formatted station) and CBS-owned KRQR forced KSFX to drop AOR for talk, featuring the ABC-syndicated 'Talkradio' network, again as KGO-FM; this complemented the primarily-local talk programming of its AM sister station.
ABC sold the station on January 1, 1984, to Weaver, Davis, Fowler (WDF), which owned KLOK in San Jose; accordingly, the station was renamed KLOK-FM. KLOK-FM had an interactive adult contemporary format called "Yes/No Radio" in which listeners would phone in their votes on whether songs should remain on the playlist.
In 1987, the station was sold to Brown Broadcasting Corporation, the call sign was changed to KKSF and under the direction of former KIFM/San Diego programmer turned consultant Bob O'Connor and associate Michael Fischer, the format was switched to new adult contemporary (NAC), which would later evolve to smooth jazz. KKSF debuted on July 31, 1987 at midnight; the first song played was by Steve Winwood. The General Manager from 1987 to 1997 was David A. Kendrick. Liner notes of the first KKSF Sampler for AIDS Relief list the members of the group responsible for the development of the KKSF concept as Willet Brown, Mike Brown, Dave Kendrick, Phil Melrose, Bob O'Connor, Michael Fischer and Steve Feinstein.
Steve Feinstein, who had previously been a format editor at trade magazine Radio and Records, was chosen by consultant Bob O'Connor and GM Dave Kendrick to be KKSF's first Program Director. Until his death in 1996, Feinstein guided KKSF to be one of the leading stations in the NAC format. He was known for being open and responsive to listener comments and suggestions, and constantly searched for new and interesting music that fit the KKSF sound, often gravitating to lesser-known imports and hard-to-find, out-of-print selections.
In 1988, the station teamed with the San Francisco AIDS Foundation to produce their first KKSF Sampler for AIDS Relief. Songs were donated by their artists so that KKSF could give all the net proceeds from the sale of the Sampler albums to the San Francisco AIDS Foundation. Often, the Sampler CDs were the only way to find certain KKSF listener favorites that had otherwise gone out of print. There were seven KKSF Samplers produced by Dave Kendrick and Steve Feinstein, with Sampler 7 being dedicated to Feinstein's memory, as he died in September 1996, during the album's creation.
KKSF was also the first commercial radio station to have a Web presence, putting up a Web site in October 1993 as kksf.tbo.com and eventually www.kksf.com, created by Chief Engineer Tim Pozar and morning host Roger Coryell.
In 1993, Brown Broadcasting purchased classical station KDFC (then at 102.1 FM). The two stations were co-located at 455 Market Street until 1997, when both were sold to Evergreen Media. Evergreen sold KDFC to Bonneville that same year, but kept KKSF, which eventually passed to Chancellor Broadcasting, AMFM Broadcasting, and finally Clear Channel Communications (which became iHeartMedia in 2014) during a short period of rapid ownership changes in the late 1990s. Studios were moved to their present location at 340 Townsend Street in 1998.
The sound of KKSF changed with the new ownership. The Smooth Jazz consultancy Broadcast Architecture became more involved with the station at this time. Gradually, the station became more like other stations in the U.S. using the "Smooth Jazz" handle, dropping some of its more eclectic music along the way in favor of mass appeal R&B songs.
The 2000s brought many changes to KKSF. During 2001, many announcers left, a number of them going to former sister station KDFC. Through the next eight years, the number of live announcers on staff gradually decreased, as KKSF began airing syndicated shows in morning drive, like the national "Wake Up with Whoopi" show hosted by Whoopi Goldberg, and later The Ramsey Lewis Morning Show, featuring pianist Ramsey Lewis. In 2008, KKSF added the syndicated Dave Koz show to afternoons. By the end of the Smooth Jazz era at KKSF, only midday personality Miranda Wilson was truly live in her time slot.
On May 18, 2009, at 3 p.m., KKSF flipped to classic rock, branded as "103.7 The Band". Owner Clear Channel cited economic considerations and the results of "exhaustive market research." The first song on "The Band" was "Everybody's Everything" by Santana. The demise of Smooth Jazz on KKSF also ended one of the Bay Area's most spirited radio rivalries, as KKSF battled it out with Urban AC KBLX, which often included Smooth Jazz in its "Quiet Storm" format.
In its first few months as "The Band", KKSF gained listeners aged 25–54, considered a more desirable group by advertisers than KKSF's previous audience, which skewed considerably older. The station features mostly out-of-market personalities who voice track their shows, and has a very small local staff.
KKSF began shifting to more of a classic hits format in February 2011, after Entercom added classic rock on KUZX, using one-time sister station KDFC's former frequency. The classic hits format had previously been heard on CBS Radio's KFRC-FM, which became a simulcast of all-news KCBS in October 2008. The shift to classic hits was completed on April 8, 2011 at 3 PM, when the station rebranded as "Oldies 103.7". The last song on "The Band" was "Changes" by David Bowie, while the first song on "Oldies" was "I Got You (I Feel Good)" by James Brown. The branding was changed to simply "103.7 FM" that December; on December 13, it added the "-FM" suffix. On January 3, 2012, KKSF changed its call sign to KOSF. In November 2013, KOSF changed its name on-air to The Bay's 103.7, with no other changes. On May 2, 2014, at 5 PM, KOSF again rebranded, this time to "Big 103.7," again with no programming changes. The first song on "Big" was Born to Be Wild by Steppenwolf.
At Noon on June 6, 2016, after playing "Last Dance" by Donna Summer, KOSF flipped to All-'80s Hits as "iHeart '80s @ 103.7". The change comes after its namesake webstream was ranked the most-listened-to stream on the iHeartRadio streaming platform and mobile application for 2016. The first song on "iHeart '80s" was "We Built This City" by San Francisco band Starship. KOSF will be commercial-free for eight days to launch the format, and legendary MTV VJ Martha Quinn will host the morning show. This marks the second station in the San Francisco market that has aired an all-'80s hits format, the first being sister station KIOI from November 2000 to January 2002.
KOSF is a Class B FM station, transmitting from Mt. San Bruno at an effective radiated power of 6,400 watts. A low-powered booster in Pleasanton, California fills in East Bay coverage gaps caused by topography issues.
The station broadcasts digitally using the HD Radio system from iBiquity. KOSF's HD broadcast also makes available a second channel that can only be received with an HD Radio capable receiver. The format of the HD-2 Channel is Bloomberg Business news, simulcast with KNEW-AM 960.
From the time the station started its NAC format in 1987 to mid 1996, the station used very light audio processing in order to create a signature sound. It was based on the Schulke Beautiful Music approach of having a very light touch to the audio. KKSF's Chief Engineer, Tim Pozar, who was also one of the co-founders of San Francisco's first ISP, TLGNet, installed an Aphex Systems audio chain of a Compellor and Dominator along with a Digicoder, which was one of the first digital stereo generators.
Tim Pozar also put up the original 1993 web site through TLGNet.