47 CFR 74.762: Frequency measurements.

(a) The licensee of a low power TV station or a TV translator station must measure the frequency of its output channel as often as necessary to ensure operation consistent with the Advanced Television Systems Committee (ATSC) standard (see § 73.682 of this chapter; for ATSC 1.0, § 73.682(d), ATSC A/53 Part 2, and for ATSC 3.0, § 73.682(f)(2)), and at least once each calendar year at intervals not exceeding 14 months.

(b) In the event that a low power TV or TV translator station is found to be operating inconsistent with the standard in paragraph (a) of this section, the licensee promptly shall suspend operation of the transmitter and shall not resume operation until the transmitter has been restored to its assigned frequency.