§ 25.264 Requirements to facilitate reverse-band operation in the 17.3-17.8 GHz band. ( a ) Each applicant or licensee for a space station transmitting in the 17.3-17.8 GHz band must submit a series of tables or graphs containing predicted off-axis gain data for each antenna that will transmit in any portion of the 17.3-17.8 GHz band, in accordance with the following specifications. Using a Cartesian coordinate system wherein the X axis is tangent to the geostationary orbital arc with the positive direction pointing east, *i.e.,* in the direction of travel of the satellite; the Y axis is parallel to a line passing through the geographic north and south poles of the Earth, with the positive direction pointing south; and the Z axis passes through the satellite and the center of the Earth, with the positive direction pointing toward the Earth, the applicant or licensee must provide the predicted transmitting antenna off-axis antenna gain information: ( 1 ) In the X-Z plane, *i.e.*, the plane of the geostationary orbit, over a range of ±30 degrees from the positive and negative X axes in increments of 5 degrees or less.
( 2 ) In planes rotated from the X-Z plane about the Z axis, over a range of ±60 degrees relative to the equatorial plane, in increments of 10 degrees or less.
( 3 ) In both polarizations.
( 4 ) At a minimum of one measurement frequency at the center of the portion of the 17.3-17.8 GHz frequency band over which the space station is designed to transmit. Applicants or licensees must provide additional measurement data at 5 MHz above the lower edge of the band and/or at 5 MHz below the upper edge of the band, upon request by the Commission staff.
( 5 ) Over a greater angular measurement range, if necessary, to account for any planned spacecraft orientation bias or change in operating orientation relative to the reference coordinate system. The applicant or licensee must state the reasons for including such additional information.
( 6 ) The predictive gain information must be submitted to the Commission for each license application that is filed for a space station transmitting in any portion of the 17.3-17.8 GHz band no later than two years after license grant for the space station.
( b ) A space station applicant or licensee transmitting in any portion of the 17.3-17.8 GHz band must submit power flux density (pfd) calculations based on the predicted gain data submitted in accordance with paragraph (a) of this section, as follows: ( 1 ) The pfd calculations must be provided at the location of all prior-filed U.S. DBS space stations where the applicant's pfd level exceeds the coordination trigger of −117 dBW/m2/100 kHz in the 17.3-17.8 GHz band. In this rule, the term prior-filed U.S. DBS space station refers to any co-frequency Direct Broadcast Satellite service space station for which an application was filed with the Commission, or an authorization was granted by the Commission, prior to the filing of the information and certifications required by paragraphs (a) and (b) of this section. The term prior-filed U.S. DBS space station does not include any applications (or authorizations) that have been denied, dismissed, or are otherwise no longer valid. Prior-filed U.S. DBS space stations may include foreign-licensed DBS space stations seeking authority to serve the United States market, but do not include foreign-licensed DBS space stations that have not filed applications with the Commission for market access in the United States.
( 2 ) The calculations must take into account the aggregate pfd levels at the DBS receiver at each measurement frequency arising from all antenna beams on the space station transmitting in the 17.3-17.8 GHz band. They must also take into account the maximum permitted longitudinal station-keeping tolerance, orbital inclination and orbital eccentricity of both the space station transmitting in the 17.3-17.8 GHz band and DBS space stations, and must: ( i ) Identify each prior-filed U.S. DBS space station at whose location the coordination threshold pfd level of −117 dBW/m2/100 kHz is exceeded; and
( ii ) Indicate the extent to which the calculated pfd of the space station's transmissions in the 17.3-17.8 GHz band exceed the threshold pfd level of −117 dBW/m2/100 kHz at those prior-filed U.S. DBS space station locations.
( 3 ) If the calculated pfd exceeds the threshold level of −117 dBW/m2/100 kHz at the location of any prior-filed U.S. DBS space station, the applicant or licensee must also provide with the pfd calculations a certification that all affected DBS operators acknowledge and do not object to such higher off-axis pfd levels. No such certification is required in cases where the frequencies assigned to the DBS and to the space station transmitting in the 17.3-17.8 GHz band do not overlap.
( 4 ) The information and any certification required by paragraph (b) of this section must be submitted to the Commission for each license application that is filed for a space station transmitting in any portion of the 17.3-17.8 GHz band no later than two years after license grant for the space station.
( c ) No later than two months prior to launch, each licensee of a space station transmitting in any portion of the 17.3-17.8 GHz band must update the predicted transmitting antenna off-axis gain information provided in accordance with paragraph (a) of this section by submitting measured transmitting antenna off-axis gain information over the angular ranges, measurement frequencies and polarizations specified in paragraphs (a)(1) through (5) of this section. The transmitting antenna off-axis gain information should be measured under conditions as close to flight configuration as possible. As an alternative, licensees authorized to operate at locations one degree or greater from a prior-filed DBS space station may submit simulated transmitting antenna off-axis gain data in lieu of measured data, over the same angular ranges, frequencies and polarizations.
( d ) No later than two months prior to launch, or when applying for authority to change the location of a space station transmitting in any portion of the 17.3-17.8 GHz band that is already in orbit, each such space station licensee must provide pfd calculations based on the measured off-axis gain data submitted in accordance with paragraph (c) of this section, as follows: ( 1 ) The pfd calculations must be provided: ( i ) At the location of all prior-filed U.S. DBS space stations as defined in paragraph (b)(1) of this section, where the applicant's pfd level in the 17.3-17.8 GHz band exceeds the coordination trigger of −117 dBW/m2/100 kHz; and
( ii ) At the location of any subsequently filed U.S. DBS space station where the pfd level in the 17.3-17.8 GHz band calculated on the basis of measured gain data exceeds −117 dBW/m2/100 kHz. In this paragraph (d)(1)(ii), the term “subsequently filed U.S. DBS space station” refers to any co-frequency Direct Broadcast Satellite service space station proposed in a license application filed with the Commission after the operator of a space station transmitting in any portion of the 17.3-17.8 GHz band submitted the predicted data required by paragraphs (a) and (b) of this section but before submission of the measured data required by this paragraph. Subsequently filed U.S. DBS space stations may include foreign-licensed DBS space stations seeking authority to serve the United States market. The term does not include any applications (or authorizations) that have been denied, dismissed, or are otherwise no longer valid, nor does it include foreign-licensed DBS space stations that have not filed applications with the Commission for market access in the United States.
( 2 ) The pfd calculations must take into account the maximum permitted longitudinal station-keeping tolerance, orbital inclination and orbital eccentricity of both the transmitting 17.3-17.8 GHz and DBS space stations, and must: ( i ) Identify each prior-filed U.S. DBS space station at whose location the coordination threshold pfd level of −117 dBW/m2/100 kHz is exceeded; and
( ii ) Demonstrate the extent to which the applicant's or licensee's transmissions in the 17.3-17.8 GHz band exceed the threshold pfd level of −117 dBW/m2/100 kHz at those prior-filed U.S. DBS space station locations.
( e ) If the aggregate pfd level calculated from the measured data submitted in accordance with paragraph (d) of this section is in excess of the threshold pfd level of −117 dBW/m2/100 kHz: ( 1 ) At the location of any prior-filed U.S. DBS space station as defined in paragraph (b)(1) of this section, then the operator of the space station transmitting in any portion of the 17.3-17.8 GHz band must either: ( i ) Coordinate its operations that are in excess of the threshold pfd level of −117 dBW/m2/100 kHz with the affected prior-filed U.S. DBS space station operator, or
( ii ) Adjust its operating parameters so that at the location of the prior-filed U.S. DBS space station, the pfd level of −117 dBW/m2/100 kHz is not exceeded.
( 2 ) At the location of any subsequently filed U.S. DBS space station as defined in paragraph (d)(1) of this section, where the aggregate pfd level submitted in accordance with paragraph (d) of this section is also in excess of the pfd level calculated on the basis of the predicted data submitted in accordance with paragraph (a) of this section that were on file with the Commission at the time the DBS space station application was filed, then the operator of the space station transmitting in the 17.3-17.8 GHz band must either: ( i ) Coordinate with the affected subsequently-filed U.S. DBS space station operator all of its operations that are either in excess of the pfd level calculated on the basis of the predicted antenna off-axis gain data, or are in excess of the threshold pfd level of −117 dBW/m2/100 kHz, whichever is greater, or
( ii ) Adjust its operating parameters so that at the location of the subsequently-filed U.S. DBS space station, either the pfd level calculated on the basis of the predicted off-axis transmitting antenna gain data, or the threshold pfd level of −117 dBW/m2/100 kHz, whichever is greater, is not exceeded.
( 3 ) No coordination or adjustment of operating parameters is required in cases where there is no overlap in frequencies assigned to the DBS and the space station transmitting in the 17.3-17.8 GH band.
( f ) The applicant or licensee for the space station transmitting in the 17.3-17.8 GHz band must modify its license, or amend its application, as appropriate, based upon new information: ( 1 ) If the pfd levels submitted in accordance with paragraph (d) of this section, are in excess of those submitted in accordance with paragraph (b) of this section at the location of any prior-filed or subsequently-filed U.S. DBS space station as defined in paragraphs (b)(1) and (d)(1)of this section, or
( 2 ) If the operator of the space station transmitting in the 17.3-17.8 GHz band adjusts its operating parameters in accordance with paragraph (e)(1)(ii) or (e)(2)(ii) or this section.
( g ) Absent an explicit agreement between operators to permit more closely spaced operations, U.S. authorized 17/24 GHz BSS or FSS space stations transmitting in the 17.3-17.8 GHz band and U.S. authorized DBS space stations with co-frequency assignments may not be licensed to operate at locations separated by less than 0.2 degrees in orbital longitude.
( h ) All operational space stations transmitting in the 17.3-17.8 GHz band must be maintained in geostationary orbits that: ( 1 ) Do not exceed 0.075° of inclination.
( 2 ) Operate with an apogee less than or equal to 35,806 km above the surface of the Earth, and with a perigee greater than or equal to 35,766 km above the surface of the Earth (*i.e.*, an eccentricity of less than 4.7 × 10−4).
( i ) U.S. authorized DBS networks may claim protection from space path interference arising from the reverse-band operations of U.S. authorized space stations transmitting in the 17.3-17.8 GHz band to the extent that the DBS space station operates within the bounds of inclination and eccentricity listed in paragraphs (i)(1) and (2) of this section. When the geostationary orbit of the DBS space station exceeds these bounds on inclination and eccentricity, it may not claim protection from any additional space path interference arising as a result of its inclined or eccentric operations and may only claim protection as if it were operating within the bounds listed in paragraphs (i)(1) and (2) of this section: ( 1 ) The DBS space station's orbit does not exceed 0.075° of inclination, and
( 2 ) The DBS space station's orbit maintains an apogee less than or equal to 35,806 km above the surface of the Earth, and a perigee greater than or equal to 35,766 km above the surface of the Earth (*i.e.,* an eccentricity of less than 4.7 × 10−4).
[76 FR 50431, Aug. 15, 2011, as amended at 81 FR 55348, Aug. 18, 2016; 87 FR 72407, Nov. 25, 2022; 89 FR 58072, 58074, July 17, 2024]