§ 25.209   Earth station antenna performance standards.

   (a) Except as provided in paragraph (f) of this section, the
   co-polarization gain of any earth station antenna operating in the FSS
   and transmitting to a GSO satellite, including earth stations providing
   feeder links for satellite services other than FSS, may not exceed the
   following limits:

   (1) In the plane tangent to the GSO arc, as defined in § 25.103, for
   earth stations not operating in the conventional Ku-band, the
   24.75-25.25 GHz band, or the 28.35-30 GHz band:

   29-25log10θ dBi for 1.5° ≤ θ ≤ 7°.
   8           dBi for 7° < θ ≤ 9.2°.
   32-25log10θ dBi for 9.2° < θ ≤ 48°.
   −10         dBi for 48° < θ ≤ 180°.

   Where θ is the angle in degrees from a line from the earth station
   antenna to the assigned orbital location of the target satellite, and
   dBi refers to dB relative to an isotropic radiator. This envelope may
   be exceeded by up to 3 dB in 10% of the range of θ angles from ±7-180°,
   and by up to 6 dB in the region of main reflector spillover energy.

   (2) In the plane tangent to the GSO arc, for earth stations operating
   in the conventional Ku-band:

   29-25log10θ dBi for 1.5° ≤ θ ≤ 7°.
   8           dBi for 7° < θ ≤ 9.2°.
   32-25log10θ dBi for 9.2° < θ ≤ 19.1°.
   0           dBi for 19.1° < θ ≤ 180°.

   Where θ and dBi are as defined in paragraph (a)(1) of this section.
   This envelope may be exceeded by up to 3 dB in 10% of the range of θ
   angles from ±7-180°, and by up to 6 dB in the region of main reflector
   spillover energy.

   (3) In the plane tangent to the GSO arc, for earth stations operating
   in the 24.75-25.25 GHz or 28.35-30 GHz bands:

   29-25log10θ dBi for 2° ≤ θ ≤ 7°.
   8           dBi for 7° < θ ≤ 9.2°.
   32-25log10θ dBi for 9.2° < θ ≤ 19.1°.
   0           dBi for 19.1° < θ ≤ 180°.

   Where θ and dBi are as defined in paragraph (a)(1) of this section.
   This envelope may be exceeded by up to 3 dB in 10% of the range of θ
   angles from ±7-180°, and by up to 6 dB in the region of main reflector
   spillover energy.

   (4) In the plane perpendicular to the GSO arc, as defined in § 25.103,
   for earth stations not operating in the conventional Ku-band, the
   24.75-25.25 GHz band, or the 28.35-30 GHz band:

   Outside the main beam, the gain of the antenna shall lie below the
   envelope defined by:

   32-25log10θ dBi for 3° < θ ≤ 48°.
   −10         dBi for 48° < θ ≤ 180°.

   Where θ and dBi are as defined in paragraph (a)(1) of this section.
   This envelope may be exceeded by up to 6 dB in 10% of the range of θ
   angles from ±3-180°, and by up to 6 dB in the region of main reflector
   spillover energy.

   (5) In the plane perpendicular to the GSO arc, for earth stations
   operating in the conventional Ku-band:

   Outside the main beam, the gain of the antenna shall lie below the
   envelope defined by:

   32-25log10θ dBi for 3° < θ ≤ 19.1°.
   0           dBi for 19.1° < θ ≤ 180°.

   Where θ and dBi are as defined in paragraph (a)(1) of this section.
   This envelope may be exceeded by up to 6 dB in 10% of the range of θ
   angles from ±3-180°, and by up to 6 dB in the region of main reflector
   spillover energy.

   (6) In the plane perpendicular to the GSO arc, for earth stations
   operating in the 24.75-25.25 GHz or 28.35-30 GHz bands:

   Outside the main beam, the gain of the antenna shall lie below the
   envelope defined by:

   32-25log10θ dBi for 3.5° < θ ≤ 7°.
   10.9        dBi for 7° < θ ≤ 9.2°.
   35-25log10θ dBi for 9.2° < θ ≤ 19.1°.
   3           dBi for 19.1° < θ ≤ 180°.

   Where θ and dBi are as defined in paragraph (a)(1) of this section.
   This envelope may be exceeded by up to 6 dB in 10% of the range of θ
   angles from ±3-180°, and by up to 6 dB in the region of main reflector
   spillover energy.

   (b) Except as provided in paragraph (f) of this section, the off-axis
   cross-polarization gain of any antenna used for transmission from an
   FSS earth station to a GSO satellite, including earth stations
   providing feeder links for satellite services other than FSS, may not
   exceed the following limits:

   (1) In the plane tangent to the GSO arc, for earth stations not
   operating in the 24.75-25.25 GHz or 28.35-30 GHz bands:

   19-25log10θ dBi for 1.8° < θ ≤ 7°.

   Where θ and dBi are as defined in paragraph (a)(1) of this section.

   (2) In the plane perpendicular to the GSO arc, for earth stations not
   operating in the 24.75-25.25 GHz or 28.35-30 GHz bands:

   19-25log10θ dBi for 3° < θ ≤ 7°.

   Where θ and dBi are as defined in paragraph (a)(1) of this section.

   (3) In the plane tangent to the GSO arc or in the plane perpendicular
   to the GSO arc, for earth stations operating in the 24.75-25.25 GHz or
   28.35-30 GHz bands:

   19-25log10θ dBi for 2° < θ ≤ 7°.

   Where θ and dBi are as defined in paragraph (a)(1) of this section.

   (c)(1) An earth station licensed for operation with an FSS space
   station or registered for reception of transmissions from such a space
   station pursuant to § 25.131(b) and (d) is not entitled to protection
   from interference from authorized operation of other stations that
   would not cause harmful interference to that earth station if it were
   using an antenna with receive-band gain patterns conforming to the
   levels specified in paragraphs (a) and (b) of this section.

   (2) A 17/24 GHz BSS telemetry earth station is not entitled to
   protection from harmful interference from authorized space station
   operation that would not cause harmful interference to that earth
   station if it were using an antenna with receive-band gain patterns
   conforming to the levels specified in paragraphs (a) and (b) of this
   section. Receive-only earth stations in the 17/24 GHz BSS are entitled
   to protection from harmful interference caused by other space stations
   to the extent indicated in § 25.224.

   (d) [Reserved]

   (e) An earth station using asymmetrical antennas without skew angle
   adjustment capability must comply with the gain values specified in
   paragraph (a)(1) of this section, in the plane orthogonal to the to the
   main plane of the antenna, or, alternatively, in the plane
   corresponding to the maximum skew angle experienced at any location at
   which the earth station may be located.

   (f) A GSO FSS earth station with an antenna that does not conform to
   the applicable standards in paragraphs (a) and (b) of this section will
   be authorized only if the applicant demonstrates that the antenna will
   not cause unacceptable interference. This demonstration must comply
   with the requirements in § 25.138, § 25.218, § 25.220, § 25.221, § 25.222,
   § 25.226, or § 25.227, as appropriate.

   (g) [Reserved]

   (h) The gain of any transmitting antenna in a gateway earth station
   communicating with NGSO FSS satellites in the 10.7-11.7 GHz,
   12.75-13.15 GHz, 13.2125-13.25 GHz, 13.8-14.0 GHz, and/or 14.4-14.5 GHz
   bands must lie below the envelope defined as follows:

   29-25log10(θ) dBi for 1° ≤ θ ≤ 36°.
   −10           dBi for 36° ≤ θ ≤ 180°.

   Where θ and dBi are as defined in paragraph (a)(1) of this section.
   This envelope may be exceeded by up to 3 dB in 10% of the range of θ
   angles from ±7-180°.

   [ 48 FR 40255 , Sept. 6, 1983, as amended at  50 FR 2675 , Jan. 18, 1985;
    50 FR 39004 , Sept. 26, 1985;  58 FR 13420 , Mar. 11, 1993;  66 FR 10630 ,
   Feb. 16, 2001;  70 FR 32255 , June 2, 2005;  72 FR 50029 , Aug. 29, 2007;
    73 FR 70901 , Nov. 24, 2008;  74 FR 57099 , Nov. 4, 2009;  78 FR 8427 , Feb.
   6, 2013;  78 FR 14927 , Mar. 8, 2013;  79 FR 8322 , Feb. 12, 2014;  81 FR 55336 , Aug. 18, 2016;  83 FR 34491 , July 20, 2018]

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