Sec.  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/m ^2 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      Antenna discrimination pattern
               (degrees)                               (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  Sec. 25.252: The preceding rules of  Sec. 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]