§  25.204   Power limits.

   (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) For operations at frequencies above 10 GHz, earth station operators
   may exceed the uplink e.i.r.p. and e.i.r.p. density limits specified in
   the station authorization under the 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.
   The e.i.r.p. levels shall be returned to normal as soon as the
   attenuating weather pattern subsides. The maximum power level for power
   control purposes shall be coordinated between and among adjacent
   satellite operators.

   (f) In the band 13.75–14 GHz, an earth station in the fixed-satellite
   service shall have a minimum antenna diameter of 4.5 m and the e.i.r.p.
   of any emission should be at least 68 dBW and should not exceed 85 dBW.
   The e.i.r.p. density of emissions from any earth station in the FSS
   operating with a space station in geostationary-satellite orbit shall
   not exceed 71 dBW in any 6 MHz band from 13.77 to 13.78 GHz. The
   e.i.r.p. density of emissions from any earth station in the FSS
   operating with a space station in non-geostationary-satellite orbit
   shall not exceed 51 dBW in any 6 MHz band from 13.77 to 13.78 GHz.
   Automatic power control may be used to increase the e.i.r.p. density in
   the 6 MHz band in this frequency range to compensate for rain
   attenuation, to the extent that the power flux-density at the FSS space
   station does not exceed the value resulting from use by an earth
   station of an e.i.r.p. of 71 dBW or 51 dBW, as appropriate, in the 6
   MHz band in clear-sky conditions.

   (g) All earth stations in the Fixed Satellite Service in the 20/30 GHz
   band, and feeder link earth stations operating in the 24.75–25.25 GHz
   band (Earth-to-space) and providing service to geostationary satellites
   in the 17/24 GHz BSS, shall employ uplink adaptive power control or
   other methods of fade compensation such that the earth station
   transmissions shall be conducted at the power level required to meet
   the desired link performance while reducing the level of mutual
   interference between networks.

   (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.

   [ 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]