§  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)(3) 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)(3) 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.

   (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 § 25.218(i)(1),
   (2), and (4) 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.

   (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]

   [ 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;  81 FR 55336 , Aug. 18, 2016;  83 FR 34491 , July 20, 2018;  84 FR 53655 , Oct. 8,
   2019]