47 CFR § 95.2173
LPRS authorized bandwidths
February 16, 2021
Each LPRS transmitter type must be designed such that the occupied bandwidth does not exceed the authorized bandwidth for the channel bandwidth used.
(a) The authorized bandwidth for emissions transmitted on the narrowband channels listed in §95.2163(c) is 4 kHz.
(b) The occupied bandwidth for emissions transmitted on the standard band, extra band or AMTS channels listed in §95.2163(a), (b), or (d), respectively, is limited through compliance with the unwanted emissions rule (§95.2179).