47 CFR §2.103

1. (a)Federal stations may be authorized to use non-Federal frequencies in the bands above 25 MHz (except the 758-775 MHz and 788-805 MHz public safety bands) if the Commission finds that such use is necessary for coordination of Federal and non-Federal activities: Provided, however, that:
   1. (1)Federal operation on non-Federal frequencies shall conform with the conditions agreed upon by the Commission and NTIA (the more important of which are contained in paragraphs (a)(2), (a)(3) and (a)(4) of this section);
   2. (2)Such operations shall be in accordance with Commission rules governing the service to which the frequencies involved are allocated;
   3. (3)Such operations shall not cause harmful interference to non-Federal stations and, should harmful interference result, that the interfering Federal operation shall immediately terminate; and
   4. (4)Federal operation has been certified as necessary by the non-Federal licensees involved and this certification has been furnished, in writing, to the Federal agency with which communication is required.
2. (b)Federal stations may be authorized to use channels in the 769-775 MHz, 799-805 MHz and 4940-4990 MHz public safety bands with non-Federal entities if the Commission finds such use necessary; where:
   1. (1)The stations are used for interoperability or part of a Federal/non-Federal shared or joint-use system;
   2. (2)The Federal entity obtains the approval of the non-Federal (State/local government) licensee(s) or applicant(s) involved;
   3. (3)Federal operation is in accordance with the Commission's Rules governing operation of this band and conforms with any conditions agreed upon by the Commission and NTIA; and
   4. (4)Interoperability, shared or joint-use systems are the subject of a mutual agreement between the Federal and non-Federal entities. This section does not preclude other arrangements or agreements as permitted under part 90 of the rules. See 47 CFR 90.179 and 90.421 of this chapter.
3. (c)Federal stations may be authorized by the First Responder Network Authority to use channels in the 758-769 MHz and 788-799 MHz public safety bands.