StacksVerified U.S. regulatory reference

47 CFR §90.221

Verified against eCFR.gov as of June 20, 2026View official text on eCFR.gov ↗
  1. (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.
  2. (b)
    1. (1)Maximum adjacent power levels for frequencies in the 450-470 MHz band:
    2. (2)In any case, no requirement in excess of −36 dBm shall apply.
  3. (c)
    1. (1)Maximum adjacent power levels for frequencies in the 809-824/854-869 MHz band:
    2. (2)In any case, no requirement in excess of −36 dBm shall apply.
  4. (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 (Pwatts) dB.