I was lucky to in the late 1960’s live within reception of the San Francisco stations. On AM were KYA and KEWB (it’s sister station in Los Angeles was KFWB). Then in 1967 Tom Donahue---one of the KYA disc jockeys and co-owner of Autumn Records, home of The Beau Brummels---launched the first "underground" FM Rock ’n Roll station in the U.S.A.---KMPX. The station was staffed by renegades (as opposed to the fast-talking "Key kids!" AM jockeys), the playlist not 45 RPM singles, but LP cuts, or whole LP sides, or even entire LP’s. When Sgt. Pepper was released they played the complete LP non-stop.
In 1968 (iirc) some problem developed between the station owner(s) and Donahue, who took his staff and relocated to KSAN radio, which continued the free-form programming style. A VERY influential station, copied all over the U.S.A.