Sec.  25.209   Antenna performance standards.

   

   (a) The gain of any antenna to be employed in transmission from an
   earth station in the geostationary satellite orbit fixed-satellite
   service (GSO FSS) shall lie below the envelope defined as follows:

   (1) In the plane of the geostationary satellite orbit as it appears at
   the particular earth station location:
   [MATH:  :MATH]

   where Theta is the angle in degrees from the axis of the main lobe,
   and dBi refers to dB relative to an isotropic radiator. For the
   purposes of this section, the peak gain of an individual sidelobe may
   not exceed the envelope defined above for Theta between 1.0 and 7.0
   degrees. For Theta greater than 7.0 degrees, the envelope may be
   exceeded by no more than 10% of the sidelobes, provided no individual
   sidelobe exceeds the gain envelope given above by more than 3 dB.

   (2) In all other directions, or in the plane of the horizon including
   any out-of-plane potential terrestrial interference paths:

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

   where Theta and dBi are defined above. For the purposes of this
   section, the envelope may be exceeded by no more than 10% of the
   sidelobes provided no individual sidelobe exceeds the gain envelope
   given above by more than 6 dB. The region of the main reflector
   spillover energy is to be interpreted as a single lobe and shall not
   exceed the envelope by more than 6 dB.

   (b) The off-axis cross-polarization gain of any antenna to be employed
   in transmission from an earth station to a space station in the
   domestic fixed-satellite service shall be defined by:
   [MATH:  :MATH]

   (c) Earth station antennas licensed for reception of radio
   transmissions from a space station in the fixed-satellite service are
   protected from radio interference caused by other space stations only
   to the degree to which harmful interference would not be expected to
   be caused to an earth station employing an antenna conforming to the
   referenced patterns defined in paragraphs (a) and (b) of this section,
   and protected from radio interference caused by terrestrial radio
   transmitters identified by the frequency coordination process only to
   the degree to which harmful interference would not be expected to be
   caused to an earth station conforming to the reference pattern defined
   in paragraph (a)(2) of this section.

   (d) The patterns specified in paragraphs (a) and (b) of this section
   shall apply to all new earth station antennas initially authorized
   after February 15, 1985 and shall apply to all earth station antennas
   after March 11, 1994.

   (e) The operations of any earth station with an antenna not conforming
   to the standards of paragraphs (a) and (b) of this section shall
   impose no limitations upon the operation, location or design of any
   terrestrial station, any other earth station, or any space station
   beyond those limitations that would be expected to be imposed by an
   earth station employing an antenna conforming to the reference
   patterns defined in paragraphs (a) and (b) of this section.

   (f) An earth station with an antenna not conforming to the standards
   of paragraphs (a) and (b) of this section will be routinely authorized
   after February 15, 1985 upon a finding by the Commission that
   unacceptable levels of interference will not be caused under
   conditions of uniform 2° orbital spacings. An earth station antenna
   initially authorized on or before Feburary 15, 1985 will be authorized
   by the Commission to continue to operate as long as such operations
   are found not to cause any unacceptable levels of adjacent satellite
   interference. In either case, the Commission will impose appropriate
   terms and conditions in its authorization of such facilities and
   operations.

   (g) The antenna performance standards of small antennas operating in
   the 12/14 GHz band with diameters as small as 1.2 meters starts at
   1.25° instead of 1° as stipulated in paragraph (a) of this section.

   (h)(1) The gain of any antennas to be employed in transmission from a
   gateway earth station antenna operating in the frequency bands
   10.7-11.7 GHz, 12.75-13.15 GHz, 13.2125-13.25 GHz, 13.8-14.0 GHz, and
   14.4-14.5 GHz and communicating with NGSO FSS satellites shall lie
   below the envelope defined as follows:

   29 - 25log[10] (TH) dBi - 10 dBi

   1^B =< TH =< 36^B

   36^B =< TH =< 180^B

   Where: TH is the angle in degrees from the axis of the main lobe, and
   dBi refers to dB relative to an isotropic radiator.

   (2) For the purposes of this section, the peak gain of an individual
   sidelobe may not exceed the envelope defined in paragraph (h)(1) of
   this section.

   [ 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]