§  25.252   Special requirements for ancillary terrestrial components
operating in the 2000-2020 MHz/2180-2200 MHz bands.

   (a) Applicants for an ancillary terrestrial component in these bands
   must demonstrate that ATC base stations shall not:

   (1) Exceed an EIRP of −100.6 dBW/4 kHz for out-of-channel emissions at
   the edge of the MSS licensee's selected assignment.

   (2) Exceed a peak EIRP of 27 dBW in 1.23 MHz.

   (3) Exceed an EIRP toward the physical horizon (not to include man-made
   structures) of 25.5 dBW in 1.23 MHz.

   (4) Be located less than 190 meters from all airport runways and
   aircraft stand areas, including takeoff and landing paths.

   (5) Exceed an aggregate power flux density of −51.8 dBW/m2 in a 1.23
   MHz bandwidth at all airport runways and aircraft stand areas,
   including takeoff and landing paths and all ATC base station antennas
   shall have an overhead gain suppression according to the following.

   (6) Be located less than 820 meters from a U.S. Earth Station facility
   operating in the 2200-2290 MHz band. In its MSS ATC application, the
   MSS licensee should request a list of operational stations in the
   2200-2290 MHz band.

   (7) Generate EIRP density, averaged over any two millisecond active
   transmission interval, greater than -70 dBW/MHz in the 1559-1610 MHz
   band. The EIRP, measured over any two millisecond active transmission
   interval, of discrete out-of-band emissions of less than 700 Hz
   bandwidth from such base stations, shall not exceed -80 dBW in the
   1559-1610 MHz band. A root-mean-square detector function with a
   resolution bandwidth of one megahertz or equivalent and no less video
   bandwidth shall be used to measure wideband EIRP density for purposes
   of this rule, and narrowband EIRP shall be measured with a
   root-mean-square detector function with a resolution bandwidth of one
   kilohertz or equivalent.

   (8) Use ATC base station antennas that have a gain greater than 17 dBi
   and must have an overhead gain suppression according to the following:
   Angle from direction of maximum gain, in vertical plane, above antenna
   (degrees) Antenna discrimination pattern (dB)
   0 Gmax
   2 Not to Exceed Gmax −14
   8 to 180 Not to Exceed Gmax −25

   Where: Gmax is the maximum gain of the base station antenna in dBi.

   (b) Applicants for an ancillary terrestrial component in these bands
   must demonstrate that ATC mobile terminals shall:

   (1) Observe a peak EIRP limit of 1.0 dBW in 1.23 MHz.

   (2) Limit out-of-channel emissions at the edge of a MSS licensee's
   selected assignment to an EIRP density of −67 dBW/4 kHz.

   (3) Not generate EIRP density, averaged over any two-millisecond active
   transmission interval, greater than -70 dBW/MHz in the 1559-1610 MHz
   band. The EIRP, measured over any two-millisecond active transmission
   interval, of discrete out-of-band emissions of less than 700 Hz
   bandwidth from such mobile terminals shall not exceed -80 dBW in the
   1559-1610 MHz band. The EIRP density of carrier-off-state emissions
   from such mobile terminals shall not exceed -80 dBW/MHz in the
   1559-1610 MHz band, averaged over a two-millisecond interval. A
   root-mean-square detector function with a resolution bandwidth of one
   megahertz or equivalent and no less video bandwidth shall be used to
   measure wideband EIRP density for purposes of this rule, and narrowband
   EIRP shall be measured with a root-mean-square detector function with a
   resolution bandwidth of one kilohertz or equivalent.

   (c) For ATC operations in the 2000-2020 MHz band, the power of any
   emission outside the licensee's frequency band(s) of operation shall be
   attenuated below the transmitter power (P) within the licensed band(s)
   of operation, measured in watts, in accordance with the following:

   (1) On any frequency within the 2000 to 2020 MHz band outside the
   licensee's frequency band(s) of operations, emissions shall be
   attenuated by at least 43 + 10 log (P) dB.

   (2) Emissions on frequencies lower than 1995 MHz and higher than 2025
   MHz shall be attenuated by at least 70 + 10 log P. Emissions in the
   bands 1995-2000 MHz and 2020-2025 MHz shall be attenuated by at least a
   value as determined by linear interpolation from 70 + 10 log P at 1995
   MHz or 2025 MHz, to 43 + 10 log P dB at the nearest MSS band edge at
   2000 MHz or 2020 MHz respectively.

   (3) When an emission outside of the authorized bandwidth causes harmful
   interference, the Commission may, in its discretion, require greater
   attenuation than specified in paragraphs (c)(1) and (2) of this
   section.

   (4) Compliance with these provisions is based on the use of measurement
   instrumentation employing a resolution bandwidth of 1 megahertz or
   greater.

   Note to §  25.252: The preceding rules of §  25.252 are based on cdma2000
   system architecture. To the extent that a 2 GHz MSS licensee is able to
   demonstrate that the use of a different system architecture would
   produce no greater potential interference than that produced as a
   result of implementing the rules of this section, an MSS licensee is
   permitted to apply for ATC authorization based on another system
   architecture.

   [ 68 FR 33651 , June 5, 2003, as amended at  70 FR 19318 , Apr. 13, 2005]

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