Sec. 21.2  Definitions.

    As used in this part:
    Antenna power gain. The square of the ratio of the root-mean-square 
free space field intensity produced at one mile in the horizontal plane, 
in millivolts per meter for one kilowatt antenna input power to 137.6 
mV/m. This ratio should be expressed in decibels (dB). (If specified for 
a particular direction, antenna power gain is based on the field 
strength in that direction only.)
    Antenna power input. The radio frequency peak or RMS power, as the 
case may be, supplied to the antenna from the antenna transmission line 
and its associated impedance matching network.
    Antenna structures. The antenna, its supporting structure and 
anything attached to it.
    Assigned frequency. The centre of the frequency band assigned to a 
station.
    Authorized bandwidth. The maximum width of the band of frequencies 
permitted to be used by a station. This is normally considered to be the 
necessary or occupied bandwidth, whichever is greater.
    Authorized frequency. The frequency, or frequency range, assigned to 
a station by the Commission and specified in the instrument of 
authorization.
    Authorized power. The maximum power a station is permitted to use. 
This power is specified by the Commission in the station's 
authorization.
    Bandwidth occupied by an emission. The band of frequencies 
comprising 99 percent of the total radiated power extended to include 
any discrete frequency on which the power is at least 0.25 percent of 
the total radiated power.
    Basic Trading Area (BTA). The geographic areas by which the 
Multipoint Distribution Service is licensed. BTA

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boundaries are based on the Rand McNally 1992 Commercial Atlas and 
Marketing Guide, 123rd Edition, pp. 36-39, and include six additional 
BTA-like areas as specified in Sec. 21.924(b).
    Bit rate. The rate of transmission of information in binary (two 
state) form in bits per unit time.
    BTA authorization holder. The individual or entity authorized by the 
Commission to provide Multipoint Distribution Service to the population 
of a BTA.
    BTA service area. The area within the boundaries of a BTA to which a 
BTA authorization holder may provide Multipoint Distribution Service. 
This area excludes the protected service areas of incumbent MDS stations 
and previously proposed and authorized ITFS facilities, including 
registered receive sites.
    Carrier. In a frequency stabilized system, the sinusoidal component 
of a modulated wave whose frequency is independent of the modulating 
wave; or the output of a transmitter when the modulating wave is made 
zero; or a wave generated at a point in the transmitting system and 
subsequently modulated by the signal; or a wave generated locally at the 
receiving terminal which when combined with the side bands in a suitable 
detector, produces the modulating wave.
    Carrier frequency. The output of a transmitter when the modulating 
wave is made zero.
    Communication common carrier. Any person engaged in rendering 
communication service for hire to the public.
    Control point. A control point is an operating position at which an 
operator responsible for the operation of the transmitter is stationed 
and which is under the control and supervision of the licensee.
    Control station. A fixed station whose transmissions are used to 
control automatically the emissions or operations of another radio 
station at a specified location, or to transmit automatically to an 
alarm center telemetering information relative to the operation of such 
station.
    Coordination distance. For the purpose of this part, the expression 
``coordination distance'' means the distance from an earth station, 
within which there is a possibility of the use of a given transmitting 
frequency at this earth station causing harmful interference to stations 
in the fixed or mobile service, sharing the same band, or of the use of 
a given frequency for reception at this earth station receiving harmful 
interference from such stations in the fixed or mobile service.
    Digital modulation. The process by which some characteristic 
(frequency, phase, amplitude or combinations thereof) of a carrier 
frequency is varied in accordance with a digital signal, e.g. one 
consisting of coded pulses or states.
    Domestic fixed public service. A fixed service, the stations of 
which are open to public correspondence, for radiocommunications 
originating and terminating solely at points all of which lie within:
    (a) The State of Alaska;
    (b) The State of Hawaii;
    (c) The contiguous 48 States and the District of Columbia; or
    (d) A single possession of the United States. Generally, in cases 
where service is afforded on frequencies above 72 MHz, radio-
communications between the contiguous 48 States (including the District 
of Columbia) and Canada or Mexico, or radiocommunications between the 
State of Alaska and Canada, are deemed to be in the domestic fixed 
public service.
    Domestic public radio services. The land mobile and domestic fixed 
public services the stations which are open to public correspondence.


    Note: Part 80 of this chapter is applicable to the maritime services 
and fixed stations associated with the maritime services; part 87 of 
this chapter is applicable to aeronautical services.


    Earth station. A station located either on the earth's surface or 
within the major portion of the earth's atmosphere and intended for 
communications:
    (a) With one or more space stations; or
    (b) With one or more stations of the same kind by means of one or 
more reflecting satellites or other objects in space.
    Effective radiated power (ERP). The product of the power supplied to 
the

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antenna and its gain relative to a half-wave dipole in a given 
direction.
    Equivalent Isotropically Radiated Power (EIRP). The product of the 
power supplied to the antenna and the antenna gain in a given direction 
relative to an isotropic antenna. This product may be expressed in watts 
or dB above 1 watt (dBW).
    Facsimile. A form of telegraphy for the transmission of fixed 
images, with or without half-tones, with a view to their reproduction in 
a permanent form.
    Fixed earth station. An earth station intended to be used at a 
specified fixed point.
    Fixed station. A station in the fixed service.
    Frequency tolerance. The maximum permissible departure by the centre 
frequency of the frequency band occupied by an emission from the 
assigned frequency or, by the characteristic frequency of an emission 
from the reference frequency. The frequency tolerance is expressed as a 
percentage or in Hertz.
    Harmful interference. Interference which endangers the functioning 
of a radionavigation service or of other safety services or seriously 
degrades, obstructs, or repeatedly interrupts a radiocommunication 
service.
    Incumbent. An MDS station that was authorized or proposed before 
September 15, 1995, including those stations that are subsequently 
modified, renewed or reinstated.
    Landing area. A landing area means any locality, either of land or 
water, including airports and intermediate landing fields, which is 
used, or approved for use for the landing and take-off of aircraft, 
whether or not facilities are provided for the shelter, servicing, or 
repair of aircraft, or for receiving or discharging passengers or cargo.
    Microwave frequencies. As used in this part, this term refers to 
frequencies of 890 MHz and above.
    Multichannel multipoint distribution service. Those multipoint 
distribution service channels that use the frequency band 2596 MHz to 
2644 MHz and associated response channels.
    Multipoint distribution service. A one-way domestic public radio 
service rendered on microwave frequencies from a fixed station 
transmitting (usually in an omnidirectional pattern) to multiple 
receiving facilities located at fixed points.
    Multipoint distribution service response station. A fixed station 
operated at an MDS receive location to provide communications with the 
associated station in the Multipoint Distribution Service.
    Necessary bandwidth of emission. For a given class of emission, the 
width of the frequency band that is just sufficient to ensure the 
transmission of information at the rate and with the quality required 
under specified conditions.


    Note: The necessary bandwidth for an emission may be calculated 
using the formulas in Sec. 2.202 of this chapter.


    Partitioned service area authorization holder. The individual or 
entity authorized by the Commission to provide Multipoint Distribution 
Service to the population of a partitioned service area.
    Partitioned service area (PSA). The area within the coterminous 
boundaries of one of more counties or other geopolitical subdivisions, 
drawn from a BTA, to which an authorization holder may provide 
Multipoint Distribution Service or the area remaining in a BTA upon 
partitioning any portion of that BTA. This area excludes the protected 
service areas of incumbent MDS stations and previously proposed and 
authorized ITFS stations, including registered receive sites.
    Private line service. A service whereby facilities for communication 
between two or more designated points are set aside for the exclusive 
use or availability for use of a particular customer and authorized 
users during stated periods of time.
    Public correspondence. Any telecommunication which the offices and 
stations, by reason of their being at the disposal of the public, must 
accept for transmission.
    Radio station. A separate transmitter or a group of transmitters 
under simultaneous common control, including the accessory equipment 
required for carrying on a radiocommunication service.

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    Radiocommunication. Telecommunication by means of radio waves.
    Rated power output. The term ``rated power output'' of a transmitter 
means the normal radio frequency power output capability (Peak or 
Average Power) of a transmitter, under optimum conditions of adjustment 
and operation, specified by its manufacturer.
    Record communication. Any transmission of intelligence which is 
reduced to visual record form at the point of reception.
    Reference frequency. A frequency having a fixed and specified 
position with respect to the assigned frequency. The displacement of 
this frequency with respect to the assigned frequency has the same 
absolute value and sign that the displacement of the characteristic 
frequency has with respect to the center of the frequency band occupied 
by the emission.
    Relay station. A fixed station used for the reception and 
retransmission of the signals of another station or stations.
    Repeater station. A fixed station established for the automatic 
retransmission of radiocommunications received from one or more stations 
and directed to a specified receiver site.
    Signal booster station. A low-power repeater station automatically 
retransmitting on the same frequency as the received signal, and located 
within the protected service area of a Multipoint Distribution Service 
station.
    Standby transmitter. A transmitter installed and maintained for use 
in lieu of the main transmitter only during periods when the main 
transmitter is out of service for maintenance or repair.
    Symbol rate. Modulation rate in bauds. This rate may be higher than 
the transmitted bit rate as in the case of coded pulses or lower as in 
the case of multilevel transmission.
    Television. A form of telecommunication for transmission of 
transient images of fixed or moving objects.
    Television STL station (studio transmitter link). A fixed station 
used for the transmission of television program material and related 
communications from a studio to the transmitter of a television 
broadcast station.
[ 61 FR 26671 , May 28, 1996]

                  Subpart B--Applications and Licenses

                       General Filing Requirements