§ 25.103   Definitions.

   Terms with definitions including the “(RR)” designation are defined in
   the same way in § 2.1 of this chapter and in the Radio Regulations of
   the International Telecommunication Union.

   1.5/1.6 GHz Mobile-Satellite Service. Mobile-Satellite Service provided
   in any portion of the 1525-1559 MHz space-to-Earth band and the
   1626.5-1660.5 MHz Earth-to-space band, which are referred to in this
   rule part as the “1.5/1.6 GHz MSS bands.”

   1.6/2.4 GHz Mobile-Satellite Service. A Mobile-Satellite Service that
   operates in the 1610-1626.5 MHz and 2483.5-2500 MHz bands, or in any
   portion thereof.

   2 GHz Mobile-Satellite Service. A Mobile-Satellite Service that
   operates in the 2000-2020 MHz and 2180-2200 MHz bands, or in any
   portion thereof.

   17/24 GHz Broadcasting-Satellite Service (17/24 GHz BSS). A
   radiocommunication service involving transmission from one or more
   feeder-link earth stations to other earth stations via geostationary
   satellites, in the 17.3-17.7 GHz (space-to-Earth) (domestic
   allocation), 17.3-17.8 GHz (space-to-Earth) (international allocation)
   and 24.75-25.25 GHz (Earth-to-space) bands. For purposes of the
   application processing provisions of this part, the 17/24 GHz BSS is a
   GSO-like service. Unless specifically stated otherwise, 17/24 GHz BSS
   systems are subject to the rules in this part applicable to FSS.

   Ancillary Terrestrial Component (ATC). A terrestrial communications
   network used in conjunction with a qualifying satellite network system
   authorized pursuant to these rules and the conditions established in
   the Orders issued in IB Docket No. 01-185, Flexibility for Delivery of
   Communications by Mobile-Satellite Service Providers in the 2 GHz Band,
   the L-Band, and the 1.6/2.4 GHz Band.

   Ancillary Terrestrial Component (ATC) base station. A terrestrial fixed
   facility used to transmit communications to or receive communications
   from one or more ancillary terrestrial component mobile terminals.

   Ancillary Terrestrial Component (ATC) mobile terminal. A terrestrial
   mobile facility used to transmit communications to or receive
   communications from an ancillary terrestrial component base station or
   a space station.

   Blanket license. A license for multiple fixed or mobile earth stations
   or SDARS terrestrial repeaters that may be operated anywhere within a
   geographic area specified in the license, or for multiple
   non-geostationary-orbit space stations.

   Conventional C-band. The 3700-4200 MHz (space-to-Earth) and 5925-6425
   MHz (Earth-to-space) FSS frequency bands.

   Conventional Ka-band. The 18.3-18.8 GHz (space-to-Earth), 19.7-20.2 GHz
   (space-to-Earth), 28.35-28.6 GHz (Earth-to-space), and 29.25-30.0 GHz
   (Earth-to-space) frequency bands, which the Commission has designated
   as primary for GSO FSS operation.

   Conventional Ku-band. The 11.7-12.2 GHz (space-to-Earth) and 14.0-14.5
   GHz (Earth-to-space) FSS frequency bands.

   Coordination distance. When determining the need for coordination, the
   distance on a given azimuth from an earth station sharing the same
   frequency band with terrestrial stations, or from a transmitting earth
   station sharing the same bidirectionally allocated frequency band with
   receiving earth stations, beyond which the level of permissible
   interference will not be exceeded and coordination is therefore not
   required. (RR)

   Direct Broadcast Satellite (DBS) Service. A radiocommunication service
   in which signals transmitted or retransmitted by Broadcasting-Satellite
   Service space stations in the 12.2-12.7 GHz band are intended for
   direct reception by subscribers or the general public. For the purposes
   of this definition, the term direct reception includes individual
   reception and community reception.

   Earth station. A station located either on the Earth's surface or
   within the major portion of the Earth's atmosphere intended for
   communication:

   (1) With one or more space stations; or

   (2) With one or more stations of the same kind by means of one or more
   reflecting satellites or other objects in space. (RR)

   Earth Station on Vessel (ESV). An earth station onboard a craft
   designed for traveling on water, receiving from and transmitting to
   geostationary-orbit Fixed-Satellite Service space stations.

   Earth Stations Aboard Aircraft (ESAA). Earth stations operating aboard
   aircraft that receive from and transmit to geostationary-orbit
   Fixed-Satellite Service space stations pursuant to the requirements in
   § 25.227.

   Emergency Call Center. A facility that subscribers of satellite
   commercial mobile radio services call when in need of emergency
   assistance by dialing “911” on their mobile earth station terminals.

   Equivalent diameter. When circular aperture reflector antennas are
   employed, the size of the antenna is generally expressed as the
   diameter of the antenna's main reflector. When non-reflector or
   non-circular-aperture antennas are employed, the equivalent diameter is
   the diameter of a hypothetical circular-aperture antenna with the same
   aperture area as the actual antenna. For example, an elliptical
   aperture antenna with major axis a and minor axis b will have an
   equivalent diameter of [a × b]1/2. A rectangular aperture antenna with
   length l and width w will have an equivalent diameter of [4(l ×
   w)/π]1/2.

   Equivalent Power Flux Density (EPFD). The sum of the power flux
   densities produced at a geostationary-orbit receive earth or space
   station on the Earth's surface or in the geostationary orbit, as
   appropriate, by all the transmit stations within a
   non-geostationary-orbit Fixed-Satellite Service system, taking into
   account the off-axis discrimination of a reference receiving antenna
   assumed to be pointing in its nominal direction. The equivalent power
   flux density, in dB(W/m2) in the reference bandwidth, is calculated
   using the following formula:
   eCFR graphic er12fe14.001.gif

   View or download PDF

   Where:

   Na is the number of transmit stations in the non-geostationary orbit
   system that are visible from the GSO receive station considered on the
   Earth's surface or in the geostationary orbit, as appropriate;

   i is the index of the transmit station considered in the
   non-geostationary orbit system;

   Pi is the RF power at the input of the antenna of the transmit station,
   considered in the non-geostationary orbit system in dBW in the
   reference bandwidth;

   θi is the off-axis angle between the boresight of the transmit station
   considered in the non-geostationary orbit system and the direction of
   the GSO receive station;

   Gt(θi) is the transmit antenna gain (as a ratio) of the station
   considered in the non-geostationary orbit system in the direction of
   the GSO receive station;

   di is the distance in meters between the transmit station considered in
   the non-geostationary orbit system and the GSO receive station;

   φi is the off-axis angle between the boresight of the antenna of the
   GSO receive station and the direction of the ith transmit station
   considered in the non-geostationary orbit system;

   Gr(θi) is the receive antenna gain (as a ratio) of the GSO receive
   station in the direction of the ith transmit station considered in the
   non-geostationary orbit system;

   Gr,max is the maximum gain (as a ratio) of the antenna of the GSO
   receive station.

   Extended C-band. The 3600-3700 MHz (space-to-Earth), 5850-5925 MHz
   (Earth-to-space), and 6425-6725 MHz (Earth-to-space) FSS frequency
   bands.

   Extended Ku-band. The 10.95-11.2 GHz (space-to-Earth), 11.45-11.7 GHz
   (space-to-Earth), and 13.75-14.0 GHz bands (Earth-to-space) FSS
   frequency bands.

   Feeder link. A radio link from a fixed earth station at a given
   location to a space station, or vice versa, conveying information for a
   space radiocommunication service other than the Fixed-Satellite
   Service. The given location may be at a specified fixed point or at any
   fixed point within specified areas. (RR)

   Fixed earth station. An earth station intended to be used at a fixed
   position. The position may be a specified fixed point or any fixed
   point within a specified area.

   Fixed-Satellite Service (FSS). A radiocommunication service between
   earth stations at given positions, when one or more satellites are
   used; the given position may be a specified fixed point or any fixed
   point within specified areas; in some cases this service includes
   satellite-to-satellite links, which may also be operated in the
   inter-satellite service; the Fixed-Satellite Service may also include
   feeder links of other space radiocommunication services. (RR)

   Geostationary-orbit (GSO) satellite. A geosynchronous satellite whose
   circular and direct orbit lies in the plane of the Earth's equator and
   which thus remains fixed relative to the Earth; by extension, a
   geosynchronous satellite which remains approximately fixed relative to
   the Earth.

   Inter-Satellite Service. A radiocommunication service providing links
   between artificial earth satellites.

   Ku band. In this rule part, the terms “Ku band” and “conventional Ku
   band” refer to the 11.7-12.2 GHz (space-to-Earth) and 14.0-14.5 GHz
   (Earth-to-space) bands. These paired bands are allocated to the
   Fixed-Satellite Service and are also referred to as the 12/14 GHz
   bands.

   Land earth station. An earth station in the Fixed-Satellite Service or,
   in some cases, in the Mobile-Satellite Service, located at a specified
   fixed point or within a specified area on land to provide a feeder link
   for the Mobile-Satellite Service. (RR)

   Land Mobile Earth Station. A mobile earth station in the land
   mobile-satellite service capable of surface movement within the
   geographical limits of a country or continent. (RR)

   Mobile Earth Station. An earth station in the Mobile-Satellite Service
   intended to be used while in motion or during halts at unspecified
   points. (RR)

   Mobile-Satellite Service (MSS). (1) A radiocommunication service:

   (i) Between mobile earth stations and one or more space stations, or
   between space stations used by this service; or

   (ii) Between mobile earth stations, by means of one or more space
   stations.

   (2) This service may also include feeder links necessary for its
   operation. (RR)

   NGSO. Non-geostationary orbit.

   NGSO FSS gateway earth station. An earth station or complex of multiple
   earth station antennas that supports the routing and switching
   functions of an NGSO FSS system and that does not originate or
   terminate communication traffic. An NGSO FSS gateway earth station may
   also be used for telemetry, tracking, and command transmissions and is
   not for the exclusive use of any customer.

   Non-Voice, Non-Geostationary (NVNG) Mobile-Satellite Service. A
   Mobile-Satellite Service reserved for use by non-geostationary
   satellites in the provision of non-voice communications which may
   include satellite links between land earth stations at fixed locations.

   Permitted Space Station List. A list of all U.S.-licensed
   geostationary-orbit space stations providing Fixed-Satellite Service in
   the conventional C band, the conventional Ku band, or the 18.3-18.8
   GHz, 19.7-20.2 GHz, 28.35-28.6 GHz, and 29.25-30.0 GHz bands, as well
   as non-U.S.-licensed geostationary-orbit space stations approved for
   U.S. market access to provide Fixed-Satellite Service in the
   conventional C band, conventional Ku band, or 18.3-18.8 GHz, 19.7-20.2
   GHz, 28.35-28.6 GHz, and 29.25-30.0 GHz bands.

   Plane perpendicular to the GSO arc. The plane that is perpendicular to
   the “plane tangent to the GSO arc,” as defined below, and includes a
   line between the earth station in question and the GSO space station
   that it is communicating with.

   Plane tangent to the GSO arc. The plane defined by the location of an
   earth station's transmitting antenna and a line in the equatorial plane
   that is tangent to the GSO arc at the location of the GSO space station
   that the earth station is communicating with.

   Power flux density (PFD). The amount of power flow through a unit area
   within a unit bandwidth. The units of power flux density are those of
   power spectral density per unit area, namely watts per hertz per square
   meter. These units are generally expressed in decibel form as
   dB(W/Hz/m2), dB(W/m2) in a 4 kHz band, or dB(W/m2) in a 1 MHz band.

   Power Spectral Density (PSD). The amount of an emission's transmitted
   carrier power applied at the antenna input falling within the stated
   bandwidth. The units of power spectral density are watts per hertz and
   are generally expressed in decibel form as dB(W/Hz) when measured in a
   1 Hz bandwidth, dB(W/4kHz) when measured in a 4 kHz bandwidth, or
   dB(W/MHz) when measured in a 1 MHz bandwidth.

   Protection areas. The geographic regions where U.S. Department of
   Defense meteorological satellite systems or National Oceanic and
   Atmospheric Administration meteorological satellite systems, or both
   such systems, receive signals from low earth orbiting satellites. Also,
   areas around NGSO MSS feeder-link earth stations in the 1.6/2.4 GHz
   Mobile-Satellite Service determined in the manner specified in
   § 25.203(j).

   Radiodetermination-Satellite Service. A radiocommunication service for
   the purpose of radiodetermination involving the use of one of more
   space stations. This service may also include feeder links necessary
   for its own operation. (RR)

   Routine processing or licensing. Expedited processing of unopposed
   applications for earth stations in the FSS communicating with GSO space
   stations, that satisfy the criteria in § 25.138(a), § 25.211(d),
   § 25.212(c), § 25.212(d), § 25.212(e), § 25.212(f), or § 25.218, include all
   required information, are consistent with all Commission rules, and do
   not raise any policy issues. Some, but not all, routine earth station
   applications are eligible for an autogrant procedure under
   § 25.115(a)(3).

   Satellite Digital Audio Radio Service (SDARS). A radiocommunication
   service in which audio programming is digitally transmitted by one or
   more space stations directly to fixed, mobile, and/or portable
   stations, and which may involve complementary repeating terrestrial
   transmitters and telemetry, tracking and command facilities.

   Satellite system. A space system using one or more artificial earth
   satellites. (RR)

   Selected assignment. A spectrum assignment voluntarily identified by a
   2 GHz MSS licensee at the time that the licensee's first 2 GHz
   Mobile-Satellite Service satellite reaches its intended orbit.

   Shapeable antenna beam. A satellite transmit or receive antenna beam,
   the gain pattern of which can be modified at any time without
   physically repositioning a satellite antenna reflector.

   Skew angle. The angle between the minor axis of an axially asymmetric
   antenna beam and the plane tangent to the GSO arc.

   Space radiocommunication. Any radiocommunication involving the use of
   one or more space stations or the use of one or more reflecting
   satellites or other objects in space.

   Space station. A station located on an object which is beyond, is
   intended to go beyond, or has been beyond, the major portion of the
   Earth's atmosphere. (RR)

   Space system. Any group of cooperating earth stations and/or space
   stations employing space radiocommunication for specific purposes. (RR)

   Spacecraft. A man-made vehicle which is intended to go beyond the major
   portion of the Earth's atmosphere. (RR)

   Terrestrial radiocommunication. Any radiocommunication other than space
   radiocommunication or radio astronomy. (RR)

   Terrestrial station. A station effecting terrestrial
   radiocommunication.

   Two-degree-compliant space station. A GSO FSS space station operating
   in the conventional or extended C-bands, the conventional or extended
   Ku-bands, the 24.75-25.25 GHz band, or the conventional Ka-band within
   the limits on downlink EIRP density or PFD specified in § 25.140(a)(3)
   and communicating only with earth stations operating in conformance
   with routine uplink parameters specified in § 25.138(a), § 25.211(d),
   § 25.212(c), (d), or (f), § 25.218, § 25.221(a)(1) or (a)(3), or
   § 25.222(a)(1) or (a)(3), § 25.226(a)(1) or (a)(3), or § 25.227(a)(1) or
   (a)(3).

   Vehicle-Mounted Earth Station (VMES). An earth station, operating from
   a motorized vehicle that travels primarily on land, that receives from
   and transmits to geostationary orbit Fixed-Satellite Service space
   stations and operates within the United States pursuant to the
   requirements set out in § 25.226.

   [ 79 FR 8311 , Feb. 12, 2014, as amended at  79 FR 26868 , May 12, 2014;  81 FR 55324 , Aug. 18, 2016;  83 FR 34489 , July 20, 2018]

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