Section 74.651 - Equipment changes(a) Modifications may be made to an existing authorization in accordance with §§ 1.929 and 1.947 of this chapter.(b) Multiplexing equipment may be installed on any licensed TV broadcast STL, TV relay or translator relay station without authority from the Commission.(c) Permissible changes in equipment operating in the bands 18.3-18.58 GHz and 19.26-19.3 GHz. Notwithstanding other provisions of this section, licensees of stations that remain co-primary under the provisions of § 74.602(g) may not make modifications to their systems that increase interference to satellite earth stations, or result in a facility that would be more costly to relocate.28 FR 13718, Dec. 14, 1963, as amended at 38 FR 6827, Mar. 13, 1973; 47 FR 55938, Dec. 14, 1982; 49 FR 7131, Feb. 27, 1984; 58 FR 19776, Apr. 16, 1993; 61 FR 4368, Feb. 6, 1996; 63 FR 36605, July 7, 1998; 65 FR 54173 , Sept. 7, 2000; 68 FR 12771 , Mar. 17, 2003; 68 FR 16967 , Apr. 8, 2003