47 CFR § 95.2179 - LPRS unwanted emission limits.
The requirements in this section apply to each LPRS transmitter type both with and without the connection of attachments, such as an external microphone, power cord and/or antenna.
(a) Emission masks. Emission masks applicable to transmitting equipment in the LPRS are defined by the requirements in the following table. The numbers in the paragraphs column refer to attenuation requirement rule paragraph numbers under paragraph (b) of this section.
| Channels | Paragraphs |
|---|---|
| narrowband 5 kHz | (1), (2) |
| standard band 25 kHz | (3), (4) |
| extra band 50 kHz | (5), (6) |
| AMTS 250 kHz | (7), (8) |
(b) Attenuation requirements. The power of unwanted emissions must be attenuated below the transmitter output power in Watts (P) by at least:
(1) 30 + 20(fd − 2) dB, 55 + 10 log (P) dB, or 65 dB, whichever is the least attenuation, on any frequency removed from the center of the authorized bandwidth by a displacement frequency (fd, in kHz) of more than 2 kHz, up to and including 3.75 kHz.
(2) 55 + 10 log (P) dB on any frequency removed from the center of the authorized bandwidth by more than 3.75 kHz.
(3) 30 dB on any frequency removed from the channel center frequency by 12.5 kHz to 22.5 kHz.
(4) 43 + 10 log (P) dB on any frequency removed from the channel center frequency by more than 22.5 kHz.
(5) 30 dB on any frequency removed from the channel center frequency by 25 kHz to 35 kHz.
(6) 43 + 10 log (P) dB on any frequency removed from the channel center frequency by more than 35 kHz.
(7) 30 dB on any frequency removed from the channel center frequency by 125 kHz to 135 kHz.
(8) 43 + 10 log (P) dB on any frequency removed from the channel center frequency by more than 135 kHz.
(c) Measurement conditions and procedures. The power of unwanted emissions in the frequency bands specified in paragraphs (b)(1), (3), (5), and (7) of this section is measured with a reference bandwidth of 300 Hz. The power of unwanted emissions in the frequency ranges specified in paragraphs (b)(2), (4), (6), and (8) is measured with a reference bandwidth of at least 30 kHz.