KOIN's history traces back to a radio station at 970 AM that launched on November 9, 1925 as KQP; the station changed its call sign to KOIN on April 12, 1926. It became an affiliate of the Columbia Broadcasting System (CBS), now known as the CBS Radio Network, on September 1, 1929. During the golden years of radio, KOIN was one of Portland's major radio stations, with an extensive array of local programming, including live music from its own studio orchestra.