In 1945 the FCC announced that, due to interference concerns, it was reallocating the current FM "low band" frequencies to other services and existing FM band stations would be relocated to 88–106 MHz (later expanded to 108 MHz). In July 1946 the FCC directed that FM stations currently operating on 42–44 MHz would have to move to new frequencies by the end of the year, and KALW changed its frequency from 42.1 to 44.3 MHz as an interim step. The station's initial assignment on the new FM band was 91.3 MHz, and a subsequent reallocation in the fall of 1947 reassigned it to its current frequency of 91.7 MHz.