47 CFR 90.221 – Adjacent channel power limits
(a) For the frequency bands indicated below, operations using equipment designed to operate with a 25 kHz channel bandwidth may be authorized up to a 22 kHz bandwidth if the equipment meets the adjacent channel power (ACP) limits below. The table specifies a value for the ACP as a function of the displacement from the channel center frequency and a measurement bandwidth of 18 kHz.
(b)(1) Maximum adjacent power levels for frequencies in the 450-470 MHz band:
| Frequency offset | Maximum ACP (dBc) for devices 1 watt and less | Maximum ACP (dBc) for devices above 1 watt |
|---|---|---|
| 25 kHz | ?55 dBc | ?60 dBc |
| 50 kHz | ?70 dBc | ?70 dBc |
| 75 kHz | ?70 dBc | ?70 dBc |
(2) In any case, no requirement in excess of ?36 dBm shall apply.
(c)(1) Maximum adjacent power levels for frequencies in the 809-824/854-869 MHz band:
| Frequency offset | Maximum ACP (dBc) for devices less than 15 watts | Maximum ACP (dBc) for devices 15 watts and above |
|---|---|---|
| 25 kHz | ?55 dBc | ?55 dBc |
| 50 kHz | ?65 dBc | ?65 dBc |
| 75 kHz | ?65 dBc | ?70 dBc |
(2) In any case, no requirement in excess of ?36 dBm shall apply.
(d) On any frequency removed from the assigned frequency by more than 75 kHz, the attenuation of any emission must be at least 43 + 10 log (P