Sec. 74.751  Modification of transmission systems.

    (a) No change, either mechanical or electrical, may be made in 
apparatus

[[Page 441]]

which has been type accepted by the Commission without prior authority 
of the Commission. If such prior authority has been given to the 
manufacturer of type accepted equipment, the manufacturer may issue 
instructions for such changes citing its authority. In such cases, 
individual licensees are not required to secure prior Commission 
approval but shall notify the Commission when such changes are 
completed.
    (b) Formal application (FCC Form 346) is required for any of the 
following changes:
    (1) Replacement of the transmitter as a whole, except replacement 
with a transmitter of identical power rating which has been type 
accepted by the FCC for use by low power TV, TV translator, and TV 
booster stations, or any change which could result in a change in the 
electrical characteristics or performance of the station.
    (2) Any change in the transmitting antenna system, including the 
direction of radiation, directive antenna pattern, antenna gain, 
transmission line loss characteristics, or height of antenna center of 
radiation.
    (3) Any change in the overall height of the antenna structure, 
except where notice to the Federal Aviation Administration is 
specifically not required under Sec. 17.14(b) of this chapter.
    (4) Any horizontal change of the location of the antenna structure 
which would (i) be in excess of 152.4 meters (500 feet), or (ii) require 
notice to the Federal Aviation Administration pursuant to Sec. 17.7 of 
the FCC's Rules.
    (5) A change in frequency assignment.
    (6) Any changes in the location of the transmitter except within the 
same building or upon the same pole or tower.
    (7) A change of authorized operating power.
    (c) Other equipment changes not specifically referred to in 
paragraphs (a) and (b) of this section may be made at the discretion of 
the licensee, provided that the FCC in Washington, DC notified in 
writing upon completion of such changes.
    (d) Upon installation of new or replacement transmitting equipment 
for which prior FCC authority is not required under the provisions of 
this section, the licensee must place in the station records a 
certification that the new installation complies in all respects with 
the technical requirements of this part and the station authorization.

[ 28 FR 13722 , Dec. 14, 1963, as amended at  38 FR 6827 , Mar. 13, 1973;  39 FR 38652 , Nov. 1, 1974;  45 FR 26067 , Apr. 17, 1980;  47 FR 21501 , May 18, 
1982;  48 FR 41423 , Sept. 15, 1983;  50 FR 23710 , June 5, 1985;  52 FR 31405 , Aug. 20, 1987]