§  22.861   Emission limitations.

   The rules in this section govern the spectral characteristics of
   emissions for commercial aviation systems in the Air-Ground
   Radiotelephone Service. Commercial aviation air-ground systems may use
   any type of emission or technology that complies with the technical
   rules in this subpart.

   (a) Out of band emissions. The power of any emission outside of the
   authorized operating frequency ranges must be attenuated below the
   transmitting power (P) by a factor of at least 43 + 10 log (P) dB.

   (b) Measurement procedure. Compliance with these rules is based on the
   use of measurement instrumentation employing a resolution bandwidth of
   100 kHz or greater. In the 1 MHz bands immediately outside and adjacent
   to the frequency block a resolution bandwidth of at least one percent
   of the emission bandwidth of the fundamental emission of the
   transmitter may be employed. A narrower resolution bandwidth is
   permitted in all cases to improve measurement accuracy provided the
   measured power is integrated over the full required measurement
   bandwidth ( i.e. , 100 kHz or 1 percent of emission bandwidth, as
   specified). The emission bandwidth is defined as the width of the
   signal between two points, one below the carrier center frequency and
   one above the carrier center frequency, outside of which all emissions
   are attenuated at least 26 dB below the transmitter power.

   (c) Alternative out of band emission limit. The licensee(s) of
   commercial aviation air-ground systems, together with affected
   licensees of Cellular Radiotelephone Service systems operating in the
   spectrum immediately below and adjacent to the commercial aviation
   air-ground bands, may establish an alternative out of band emission
   limit to be used at the 849 MHz and 894 MHz band edge(s) in specified
   geographical areas, in lieu of that set forth in this section, pursuant
   to a private contractual arrangement of all affected licensees and
   applicants. In this event, each party to such contract shall maintain a
   copy of the contract in their station files and disclose it to
   prospective assignees or transferees and, upon request, to the FCC.

   (d) Interference caused by out of band emissions. If any emission from
   a transmitter operating in this service results in interference to
   users of another radio service, the FCC may require a greater
   attenuation of that emission than specified in this section.

   [ 70 FR 19310 , Apr. 13, 2005]