47 CFR 73.1665 - Main transmitters.
(a) Each AM, FM, TV and Class A TV broadcast station must have at least one main transmitter which complies with the provisions of the transmitter technical requirements for the type and class of station. A main transmitter is one which is used for regular program service having power ratings appropriate for the authorized operating power(s).
(b) There is no maximum power rating limit for FM, TV or Class A TV station transmitters, however, the maximum rated transmitter power of a main transmitter stalled at an AM station shall be as follows:
|0.25, 0.5, or 1 kW||1|
|5 or 10 kW||10|
|25 or 50 kW||50|
(c) A licensee may, without further authority or notification to the FCC, replace an existing main transmitter or install additional main transmitter(s) for use with the authorized antenna if the replacement or additional transmitter(s) has been verified for compliance. Within 10 days after commencement of regular use of the replacement or additional transmitter(s), equipment performance measurements, as prescribed for the type of station are to be completed.
Pending the availability of AM broadcast transmitters that are approved or verified for use in the 1605-1705 kHz band, transmitters that are approved or verified for use in the 535-1605 kHz band may be utilized in the 1605-1705 kHz band if it is shown that the requirements of § 73.44 have been met. Verification or FCC approval of the transmitter will supersede the applicability of this note.