Originally, MPR played a mix of classical music and NPR news/talk programming. However, as NPR expanded its offerings, Kling made plans to split MPR into separate classical and news/talk networks. MPR sought to buy a second FM frequency in the Twin Cities from the late 1970s onward. As a fallback, in 1980 it bought WLOL (AM 1330), one of the oldest stations in Minnesota, and changed its calls to KSJN (AM), a simulcast of KSJN-FM. In 1989, AM 1330 changed its calls to KNOW and began airing an expanded lineup of NPR programming. In 1991, MPR bought WLOL-FM, AM 1330's former FM sister, allowing it to finally split its services into two networks. The KNOW call letters and intellectual unit, including the NPR news and talk format, moved to KSJN's old frequency of 91.1. The KSJN calls moved to WLOL-FM's former frequency of 99.5, which began playing classical music full-time.