§ 25.204   Power limits for earth stations.

   (a) In bands shared coequally with terrestrial radio communication services,
   the equivalent isotropically radiated power transmitted in any direction
   towards the horizon by an earth station, other than an ESV, operating in
   frequency bands between 1 and 15 GHz, shall not exceed the following limits
   except as provided for in paragraph (c) of this section:

   + 40 dBW in any 4 kHz band for θ ≤0°

   + 40 + 3θ dBW in any 4 kHz band for 0° <θ ≤5°

   where θ is the angle of elevation of the horizon viewed from the center of
   radiation of the antenna of the earth station and measured in degrees as
   positive above the horizontal plane and negative below it.

   (b) In bands shared coequally with terrestrial radiocommunication services,
   the equivalent isotropically radiated power transmitted in any direction
   towards the horizon by an earth station operating in frequency bands above
   15 GHz shall not exceed the following limits except as provided for in
   paragraph (c) of this section:

   + 64 dBW in any 1 MHz band for θ ≤0°

   + 64 + 3 θ dBW in any 1 MHz band for 0° <θ ≤5°

   where θ is as defined in paragraph (a) of this section.

   (c) For angles of elevation of the horizon greater than 5° there shall be no
   restriction as to the equivalent isotropically radiated power transmitted by
   an earth station towards the horizon.

   (d) Notwithstanding the e.i.r.p. and e.i.r.p. density limits specified in
   the  station  authorization,  each earth station transmission shall be
   conducted at the lowest power level that will provide the required signal
   quality as indicated in the application and further amended by coordination
   agreements.

   (e) To the extent specified in paragraphs (e)(1) through (e)(4) of this
   section, earth stations in the Fixed-Satellite Service may employ uplink
   adaptive power control or other methods of fade compensation to facilitate
   transmission  of  uplinks  at  power  levels required for desired link
   performance while minimizing interference between networks.

   (1) Except when paragraphs (e)(2) through (e)(4) of this section apply,
   transmissions from FSS earth stations in frequencies above 10 GHz may exceed
   the  uplink  EIRP  and  EIRP  density  limits specified in the station
   authorization under conditions of uplink fading due to precipitation by an
   amount  not to exceed 1 dB above the actual amount of monitored excess
   attenuation over clear sky propagation conditions. EIRP levels must be
   returned to normal as soon as the attenuating weather pattern subsides. The
   maximum power level for power control purposes must be coordinated with
   adjacent satellite operators.

   (2) An FSS earth station transmitting to a geostationary space station in
   the 13.77-13.78 GHz band must not generate more than 71 dBW EIRP in any 6
   MHz band. An FSS earth station transmitting to a non-geostationary space
   station in the 13.77-13.78 GHz band must not generate more than 51 dBW EIRP
   in any 6 MHz band. Automatic power control may be used to increase the EIRP
   density in a 6 MHz uplink band in this frequency range to compensate for
   rain fade, provided that the power flux-density at the space station does
   not exceed the value that would result when transmitting with an EIRP of 71
   dBW or 51 dBW, as appropriate, in that 6 MHz band in clear-sky conditions.

   (3) FSS earth stations transmitting to geostationary space stations in the
   28.35-28.6 GHz and/or 29.25-30.0 GHz bands may employ uplink adaptive power
   control or other methods of fade compensation. For stations employing uplink
   power  control, the values in paragraphs (a)(1), (a)(2), and (a)(4) of
   § 25.138 may be exceeded by up to 20 dB under conditions of uplink fading due
   to precipitation. The amount of such increase in excess of the actual amount
   of monitored excess attenuation over clear sky propagation conditions must
   not exceed 1.5 dB or 15 percent of the actual amount of monitored excess
   attenuation  in dB, whichever is larger, with a confidence level of 90
   percent  except over transient periods accounting for no more than 0.5
   percent of the time during which the excess is no more than 4.0 dB.

   (4) Transmissions in the 24.75-25.25 GHz band from 17/24 GHz BSS feeder-link
   earth stations employing power control may exceed the values in paragraphs
   (b)(1), (b)(2), and (b)(4) of § 25.223 by up to 20 dB under conditions of
   uplink fading due to precipitation. The amount of such increase in excess of
   the actual amount of monitored excess attenuation over clear sky propagation
   conditions must not exceed 1.5 dB or 15 percent of the actual amount of
   monitored excess attenuation in dB, whichever is larger, with a confidence
   level of 90 percent except over transient periods accounting for no more
   than 0.5 percent of the time during which the excess is no more than 4.0 dB.

   (f) An earth station in the Fixed-Satellite Service transmitting in the
   13.75-14 GHz band must have a minimum antenna diameter of 4.5 m, and the
   EIRP of any emission in that band should be at least 68 dBW and should not
   exceed 85 dBW.

   (g) [Reserved]

   (h) ESV transmissions in the 5925-6425 MHz (Earth-to-space) band shall not
   exceed an e.i.r.p. spectral density towards the radio-horizon of 17 dBW/MHz,
   and shall not exceed an e.i.r.p. towards the radio-horizon of 20.8 dBW. The
   ESV network shall shut-off the ESV transmitter if the e.i.r.p. spectral
   density towards the radio-horizon or e.i.r.p. towards the radio-horizon are
   exceeded.

   (i)  Within  125  km  of the TDRSS sites identified in § 25.222(d), ESV
   transmissions in the 14.0-14.2 GHz (Earth-to-space) band shall not exceed an
   e.i.r.p. spectral density towards the horizon of 12.5 dBW/MHz, and shall not
   exceed an e.i.r.p. towards the horizon of 16.3 dBW.

   (j) Within 125 km of the Tracking and Data Relay System Satellite (TDRSS)
   sites identified in § 25.226(c), VMES transmissions in the 14.0-14.2 GHz
   (Earth-to-space) band shall not exceed an EIRP spectral density towards the
   horizon of 12.5 dBW/MHz, and shall not exceed an EIRP towards the horizon of
   16.3 dBW.

   (k)  Within  radio line-of-sight of the Tracking and Data Relay System
   Satellite (TDRSS) sites identified in § 25.227(c), ESAA transmissions in the
   14.0-14.2  GHz (Earth-to-space) band shall not exceed an EIRP spectral
   density towards or below the horizon of 12.5 dBW/MHz, and shall not exceed
   an EIRP towards or below the horizon of 16.3 dBW.

   [ 48 FR 40255 , Sept. 6, 1983, as amended at  58 FR 13420 , Mar. 11, 1993;  61 FR 52307 , Oct. 7, 1996;  62 FR 61457 , Nov. 18, 1997;  66 FR 10623 , Feb. 16, 2001;
    70 FR 4784 , Jan. 31, 2005;  70 FR 32255 , June 2, 2005;  72 FR 50029 , Aug. 29,
   2007;  74 FR 57098 , Nov. 4, 2009;  78 FR 8427 , Feb. 6, 2013;  78 FR 14927 , Mar.
   8, 2013;  79 FR 8322 , Feb. 12, 2004]

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