1.5. Radio stations and systems
station: One or more transmitters or receivers or a combination of transmitters and receivers, including the accessory equipment, necessary at one location for carrying on a radiocommunication service, or the radio astronomy service.
Each station shall be classified by the service in which it operates permanently or temporarily.
terrestrial station: A station effecting terrestrial radiocommunication.
In these Regulations, unless otherwise stated, any station is a terrestrial station.
earth station: A station located either on the Earth's surface or within the major portion of the Earth's atmosphere and intended for communication:
– with one or more space stations; or
– with one or more stations of the same kind by means 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.
survival craft station: A mobile station in the maritime mobile service or the aeronautical mobile service intended solely for survival purposes and located on any lifeboat, life-raft or other survival equipment.
fixed station: A station in the fixed service.
high altitude platform station: A station located on an object at an altitude of 20 to 50 km and at a specified, nominal, fixed point relative to the Earth.
mobile station: A station in the mobile service intended to be used while in motion or during halts at unspecified points.
mobile earth station: An earth station in the mobile-satellite service intended to be used while in motion or during halts at unspecified points.
land station: A station in the mobile service not intended to be used while in motion.
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.
base station: A land station in the land mobile service.
base earth station: An earth station in the fixed-satellite service or, in some cases, in the land mobile-satellite service, located at a specified fixed point or within a specified area on land to provide a feeder link for the land mobile-satellite service.
land mobile station: A mobile station in the land mobile service capable of surface movement within the geographical limits of a country or continent.
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.
coast station: A land station in the maritime mobile service.
coast earth station: An earth station in the fixed-satellite service or, in some cases, in the maritime mobile-satellite service, located at a specified fixed point on land to provide a feeder link for the maritime mobile-satellite service.
ship station: A mobile station in the maritime mobile service located on board a vessel which is not permanently moored, other than a survival craft station.
ship earth station: A mobile earth station in the maritime mobile‑satellite service located on board ship.
on-board communication station: A low-powered mobile station in the maritime mobile service intended for use for internal communications on board a ship, or between a ship and its lifeboats and life-rafts during lifeboat drills or operations, or for communication within a group of vessels being towed or pushed, as well as for line handling and mooring instructions.
port station: A coast station in the port operations service.
aeronautical station: A land station in the aeronautical mobile service.
In certain instances, an aeronautical station may be located, for example, on board ship or on a platform at sea.
aeronautical earth station: An earth station in the fixed-satellite service, or, in some cases, in the aeronautical mobile-satellite service, located at a specified fixed point on land to provide a feeder link for the aeronautical mobile-satellite service.
aircraft station: A mobile station in the aeronautical mobile service, other than a survival craft station, located on board an aircraft.
aircraft earth station: A mobile earth station in the aeronautical mobile-satellite service located on board an aircraft.
broadcasting station: A station in the broadcasting service.
radiodetermination Station: A station in the radiodetermination service.
radionavigation mobile station: A station in the radionavigation service intended to be used while in motion or during halts at unspecified points.
radionavigation land station: A station in the radionavigation service not intended to be used while in motion.
radiolocation mobile station: A station in the radiolocation service intended to be used while in motion or during halts at unspecified points.
radiolocation land station: A station in the radiolocation service not intended to be used while in motion.
radio direction-finding station: A radiodetermination station using radio direction-finding.
radiobeacon station: A station in the radionavigation service the emissions of which are intended to enable a mobile station to determine its bearing or direction in relation to the radiobeacon station.
emergency position-indicating radiobeacon station: A station in the mobile service the emissions of which are intended to facilitate search and rescue operations.
satellite emergency position-indicating radiobeacon: An earth station in the mobile-satellite service the emissions of which are intended to facilitate search and rescue operations.
standard frequency and time signal station: A station in the standard frequency and time signal service.
amateur station: A station in the amateur service.
radio astronomy station: A station in the radio astronomy service.
experimental station: A station utilizing radio waves in experiments with a view to the development of science or technique.
This definition does not include amateur stations.
ship's emergency transmitter: A ship's transmitter to be used exclusively on a distress frequency for distress, urgency or safety purposes.
radar: A radiodetermination system based on the comparison of reference signals with radio signals reflected, or retransmitted, from the position to be determined.
primary radar: A radiodetermination system based on the comparison of reference signals with radio signals reflected from the position to be determined.
secondary radar: A radiodetermination system based on the comparison of reference signals with radio signals retransmitted from the position to be determined.
radar beacon (racon): A transmitter-receiver associated with a fixed navigational mark which, when triggered by a radar, automatically returns a distinctive signal which can appear on the display of the triggering radar, providing range, bearing and identification information.
instrument landing system (ILS): A radionavigation system which provides aircraft with horizontal and vertical guidance just before and during landing and, at certain fixed points, indicates the distance to the reference point of landing.
instrument landing system localizer: A system of horizontal guidance embodied in the instrument landing system which indicates the horizontal deviation of the aircraft from its optimum path of descent along the axis of the runway.
instrument landing system glide path: A system of vertical guidance embodied in the instrument landing system which indicates the vertical deviation of the aircraft from its optimum path of descent.
marker beacon: A transmitter in the aeronautical radionavigation service which radiates vertically a distinctive pattern for providing position information to aircraft.
radio altimeter: Radionavigation equipment, on board an aircraft or spacecraft, used to determine the height of the aircraft or the spacecraft above the Earth's surface or another surface.
radiosonde: An automatic radio transmitter in the meteorological aids service usually carried on an aircraft, free balloon, kite or parachute, and which transmits meteorological data.
adaptive system: A radiocommunication system which varies its radio characteristics according to channel quality.
space system: Any group of cooperating earth stations and/or space stations employing space radiocommunication for specific purposes.
satellite system: A space system using one or more artificial earth satellites.
satellite network: A satellite system or a part of a satellite system, consisting of only one satellite and the cooperating earth stations.
satellite link: A radio link between a transmitting earth station and a receiving earth station through one satellite.
A satellite link comprises one up-link and one down-link.
multi-satellite link: A radio link between a transmitting earth station and a receiving earth station through two or more satellites, without any intermediate earth station.
A multi-satellite link comprises one up-link, one or more satellite-to-satellite links and one down-link.
feeder link: A radio link from an earth station at a given location to a space station, or vice versa, conveying information for a space radiocommunication service other than for the fixed-satellite service. The given location may be at a specified fixed point, or at any fixed point within specified areas.
public correspondence: Any telecommunication which the offices and stations must, by reason of their being at the disposal of the public, accept for transmission (CS).
telegraphy: A form of telecommunication in which the transmitted information is intended to be recorded on arrival as a graphic document; the transmitted information may sometimes be presented in an alternative form or may be stored for subsequent use (CS 1016).
telegram: Written matter intended to be transmitted by telegraphy for delivery to the addressee. This term also includes radiotelegrams unless otherwise specified (CS).
In this definition the term telegraphy has the same general meaning as defined in the Convention.
radiotelegram: A telegram, originating in or intended for a mobile station or a mobile earth station transmitted on all or part of its route over the radiocommunication channels of the mobile service or of the mobile-satellite service.
radiotelex call: A telex call, originating in or intended for a mobile station or a mobile earth station, transmitted on all or part of its route over the radiocommunication channels of the mobile service or the mobile-satellite service.
frequency-shift telegraphy: Telegraphy by frequency modulation in which the telegraph signal shifts the frequency of the carrier between predetermined values.
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.
telephony: A form of telecommunication primarily intended for the exchange of information in the form of speech (CS 1017).
radiotelephone call: A telephone call, originating in or intended for a mobile station or a mobile earth station, transmitted on all or part of its route over the radiocommunication channels of the mobile service or of the mobile-satellite service.
simplex operation: Operating method in which transmission is made possible alternately in each direction of a telecommunication channel, for example, by means of manual control.
duplex operation: Operating method in which transmission is possible simultaneously in both directions of a telecommunication channel2
semi-duplex operation: A method which is simplex operation at one end of the circuit and duplex operation at the other2.
television: A form of telecommunication for the transmission of transient images of fixed or moving objects.
individual reception (in the broadcasting-satellite service): The reception of emissions from a space station in the broadcasting-satellite service by simple domestic installations and in particular those possessing small antennae.
community reception (in the broadcasting-satellite service): The reception of emissions from a space station in the broadcasting-satellite service by receiving equipment, which in some cases may be complex and have antennae larger than those used for individual reception, and intended for use:
– by a group of the general public at one location; or
– through a distribution system covering a limited area.
telemetry: The use of telecommunication for automatically indicating or recording measurements at a distance from the measuring instrument.
radiotelemetry: Telemetry by means of radio waves.
space Telemetry: The use of telemetry for the transmission from a space station of results of measurements made in a spacecraft, including those relating to the functioning of the spacecraft.
telecommand: The use of telecommunication for the transmission of signals to initiate, modify or terminate functions of equipment at a distance.
space telecommand: The use of radiocommunication for the transmission of signals to a space station to initiate, modify or terminate functions of equipment on an associated space object, including the space station.
space tracking: Determination of the orbit, velocity or instantaneous position of an object in space by means of radiodetermination, excluding primary radar, for the purpose of following the movement of the object.
1.7. Characteristics of emissions and radio equipment
radiation: The outward flow of energy from any source in the form of radio waves.
emission: Radiation produced, or the production of radiation, by a radio transmitting station.
For example, the energy radiated by the local oscillator of a radio receiver would not be an emission but a radiation.
class of emission: The set of characteristics of an emission, designated by standard symbols, e.g. type of modulation of the main carrier, modulating signal, type of information to be transmitted, and also, if appropriate, any additional signal characteristics.
single-sideband emission: An amplitude modulated emission with one sideband only.
full carrier single-sideband emission: A single-sideband emission without reduction of the carrier.
reduced carrier single-sideband emission: A single-sideband emission in which the degree of carrier suppression enables the carrier to be reconstituted and to be used for demodulation.
suppressed carrier single-sideband emission: A single-sideband emission in which the carrier is virtually suppressed and not intended to be used for demodulation.
out-of-band emission*: Emission on a frequency or frequencies immediately outside the necessary bandwidth which results from the modulation process, but excluding spurious emissions.
spurious emission: Emission on a frequency or frequencies which are outside the necessary bandwidth and the level of which may be reduced without affecting the corresponding transmission of information. Spurious emissions include harmonic emissions, parasitic emissions, intermodulation products and frequency conversion products, but exclude out-of-band emissions.
unwanted emissions: Consist of spurious emissions and out-of-band emissions.
assigned frequency band: The frequency band within which the emission of a station is authorized; the width of the band equals the necessary bandwidth plus twice the absolute value of the frequency tolerance. Where space stations are concerned, the assigned frequency band includes twice the maximum Doppler shift that may occur in relation to any point of the Earth's surface.
assigned frequency: The centre of the frequency band assigned to a station.
characteristic frequency: A frequency which can be easily identified and measured in a given emission.
A carrier frequency may, for example, be designated as the characteristic frequency.
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 centre of the frequency band occupied by the emission.
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 in parts in 106 or in hertz.
necessary bandwidth: For a given class of emission, the width of the frequency band which is just sufficient to ensure the transmission of information at the rate and with the quality required under specified conditions.
occupied bandwidth: The width of a frequency band such that, below the lower and above the upper frequency limits, the mean powers emitted are each equal to a specified percentage ß/2 of the total mean power of a given emission.
Unless otherwise specified in an ITU-R Recommendation for the appropriate class of emission, the value of ß/2 should be taken as 0.5%.
right-hand (clockwise) polarized wave: An elliptically-or circularly-polarized wave, in which the electric field vector, observed in any fixed plane, normal to the direction of propagation, whilst looking in the direction of propagation, rotates with time in a right-hand or clockwise direction.
left-hand (anticlockwise) polarized wave: An elliptically-or circularly-polarized wave, in which the electric field vector, observed in any fixed plane, normal to the direction of propagation, whilst looking in the direction of propagation, rotates with time in a left-hand or anticlockwise direction.
power: Whenever the power of a radio transmitter, etc. is referred to it shall be expressed in one of the following forms, according to the class of emission, using the arbitrary symbols indicated:
– peak envelope power (PX or pX);
– mean power (PY or pY);
– carrier power (PZ or pZ).
For different classes of emission, the relationships between peak envelope power, mean power and carrier power, under the conditions of normal operation and of no modulation, are contained in ITU-R Recommendations which may be used as a guide.
For use in formulae, the symbol p denotes power expressed in watts and the symbol P denotes power expressed in decibels relative to a reference level.
peak envelope power (of a radio transmitter): The average power supplied to the antenna transmission line by a transmitter during one radio frequency cycle at the crest of the modulation envelope taken under normal operating conditions.
mean power (of a radio transmitter): The average power supplied to the antenna transmission line by a transmitter during an interval of time sufficiently long compared with the lowest frequency encountered in the modulation taken under normal operating conditions.
carrier power (of a radio transmitter): The average power supplied to the antenna transmission line by a transmitter during one radio frequency cycle taken under the condition of no modulation.
gain of an antenna: The ratio, usually expressed in decibels, of the power required at the input of a loss-free reference antenna to the power supplied to the input of the given antenna to produce, in a given direction, the same field strength or the same power flux-density at the same distance. When not specified otherwise, the gain refers to the direction of maximum radiation. The gain may be considered for a specified polarization.
Depending on the choice of the reference antenna a distinction is made between:
absolute or isotropic gain (Gi), when the reference antenna is an isotropic antenna isolated in space;
gain relative to a half-wave dipole (Gd), when the reference antenna is a half-wave dipole isolated in space whose equatorial plane contains the given direction;
gain relative to a short vertical antenna (Gv), when the reference antenna is a linear conductor, much shorter than one quarter of the wavelength, normal to the surface of a perfectly conducting plane which contains the given direction.
equivalent isotropically radiated power (e.i.r.p.): The product of the power supplied to the antenna and the antenna gain in a given direction relative to an isotropic antenna (absolute or isotropic gain).
effective radiated power (e.r.p.) (in a given direction): The product of the power supplied to the antenna and its gain relative to a half-wave dipole in a given direction.
effective monopole radiated power (e.m.r.p.) (in a given direction): The product of the power supplied to the antenna and its gain relative to a short vertical antenna in a given direction.
tropospheric scatter: The propagation of radio waves by scattering as a result of irregularities or discontinuities in the physical properties of the troposphere.
ionospheric scatter: The propagation of radio waves by scattering as a result of irregularities or discontinuities in the ionization of the ionosphere.