again on May 2, 2014 at 5 p.m., this time to "Big 103.7". No programming changes were made in either case. The first song on "Big" was "Born to Be Wild" by Steppenwolf. On June 6, 2016, iHeartMedia announced that KOSF would flip to all-1980s hits as "iHeart80s @ 103.7" that day at noon. The change came after its namesake webstream was ranked the most-listened-to stream on the iHeartRadio streaming platform and mobile application for 2016. The last song on Big was "Last Dance" by Donna Summer, and the first song on iHeart80s was "We Built This City" by San Francisco band Starship. KOSF aired commercial-free for its first eight days. Legendary MTV VJ Martha Quinn began hosting the station's morning show on June 14. This marks the second station in the San Francisco market that has aired an all-1980s format, the first being sister station KIOI from November 2000 to January 2002. On May 24, 2021, at 10 a.m., KOSF relaunched with a broader-based classic hits format as "80s Plus 103.7"; while 1980s hits still remain the focus of the format, the change saw the station being augmented by songs from the late 1970s and the 1990s, to a certain extent bringing the station closer to what it was prior to the debut of the prior format. The last song as "iHeart '80s" was "Oh Sherrie" by Hanford native Steve Perry, while the first song as "80s Plus" was "I Love Rock 'n' Roll" by Joan Jett & the Blackhearts. Shortly after the move, in January 2022, likely due to popularity of the show, Martha Quinn's morning show was moved to middays and expanded to become a national show across all of iHeart's classic hits stations, including KOSF; to fill in the morning show gap, KOSF promoted Christie James, former midday DJ and co-host of the Martha Quinn Show, to the slot as "Morning Drive with Christie Live", also promoting former show producer Karena Velasquez to co-host. HD Radio The station broadcasts digitally using the HD Radio system from iBiquity. KOSF broadcasts two subchannels that can be picked up using an HD Radio-capable receiver: KOSF-HD1 is a digital simulcast of the analog FM signal. KOSF-HD2 broadcasts a business news format, branded "Bloomberg Radio", as a simulcast of KNEW (960 AM). Booster KOSF is rebroadcast on the following FM booster: Technical facts KOSF is a Class B FM station, transmitting