On the recordJune 7, 1931
The stations listed herein may use other frequencies for the purpose of selecting a frequency more suitable for a particular service prior to requesting authority to change the frequency, provided a notice is first submitted to the Interdepartment Radio Advisory Committee and also a notice to the Federal Radio Commission, if the frequency is not included in the Executive order, on the proviso that it will cease operation on notice of interference from the Interdepartment Radio Advisory Committee or the Federal Radio Commission and such use shall not be for more than one month total.
Source
presidency.ucsb.edu
