In May 1940, the Federal Communications Commission (FCC) announced that effective January 1, 1941 it was establishing a broadcast band for FM stations, operating on 40 channels spanning 42–50 MHz, with the first five channels reserved for educational stations. That same month the San Francisco Unified School District filed an application to construct a new educational FM station, operating on 42.1 MHz with 1,000 watts. The original station application, filed May 24, 1940, specified use of General Electric transmitters, but this was changed in January 1941 to specify an RCA FM-1-B transmitter.