47 CFR § 90.361 - Interference from part 15 and Amateur operations.
Operations authorized under parts 15 and 97 of this chapter may not cause harmful interference to LMS systems in the 902–928 MHz band. These operations will not be considered to be causing harmful interference to a multilateration LMS system operating in one of the three EA sub-bands (see § 90.357(a)) if they are non-video links operating in accordance with the provisions of parts 15 or 97 of this chapter and at least one of the following conditions are met:
(a) It is a field disturbance sensor operating under § 15.245 of this chapter and it is not operating in the 904–909.750 or 919.750–928.000 MHz sub-bands; or
(b) It does not employ an outdoor antenna; or
(c) If it does employ an outdoor antenna, then if:
(1) The directional gain of the antenna does not exceed 6 dBi, or if the directional gain of the antenna exceeds 6 dBi, it reduces its transmitter output power below 1 watt by the proportional amount that the directional gain of the antenna exceeds 6 dBi; and
(2) Either:
(i) The antenna is 5 meters or less in height above ground; or
(ii) The antenna is more than 5 meters in height above ground but less than or equal to 15 meters in height above ground and either:
(A) Adjusts its transmitter output power below 1 watt by 20 log (h/5) dB, where h is the height above ground of the antenna in meters; or
(B) Is providing the final link for communications of entities eligible under subpart B or C of this part, or is providing the final link for communications of health care providers that serve rural areas, elementary schools, secondary schools or libraries.