47 CFR 5.77 - Change in equipment and emission characteristics.
(a) The licensee of a conventional or broadcast experimental radio station may make any changes in equipment that are deemed desirable or necessary provided:
(1) That the operating frequency is not permitted to deviate more than the allowed tolerance;
(2) That the emissions are not permitted outside the authorized band;
(3) That the ERP (or EIRP) and antenna complies with the license and the regulations governing the same; and
(b) For conventional experimental radio stations, the changes permitted in paragraph (a) of this section may be made without prior authorization from the Commission provided that the license supplements its application file with a description of such change. If the licensee wants these emission changes to become a permanent part of the license, an application for modification must be filed.
(c) Prior authorization from the Commission is required before the following antenna changes may be made at a station at a fixed location:
(1) Any change that will either increase the height of a structure supporting the radiating portion of the antenna or decrease the height of a lighted antenna structure.
(2) Any change in the location of an antenna when such relocation involves a change in the geographic coordinates of latitude or longitude by one second or more, or when such relocation involves a change in street address.