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Satellite TV Glossary
The following is a list of the more commonly used terms revolving around satellite tv.
New entries contributed by forum members, will be appreciated and added to the glossary.
From now on, I will complete the glossary every time I found a new word to insert into this thread. So my work is not finished.
Regards and thanks.
A
Access
The general term for the ability of a telecommunications user to make use of a network.
Access card
An access card, also known as a smart card, is a removable credit-card-sized plastic card included with each satellite receiver. It identifies each receiver and tells your program provider your Pay-Per-View (PPV) usage each month.
Acces Line
A local loop (q.v.)
Acknowledgment
A signal sent by a receiver to a transmitter to indicate that a message was received correctly.
Acoustical coupler
A type of modem that works by placing the telephone handset into rubber cups to use the acoustical signal from the microphone and receiver.
Additional Outlet (A/O)
An additional outlet lets you connect more than one receiver to the dish, allowing other televisions in the house to be on different programs than the one connected to the primary receiver.
ACTS
Advanced Communications Technology Satellite. A NASA experimental satellite project to demonstrate the use of the Ka-Band (30/20 GHz) services.
Amplifier
A device used to boost the strength of an electronic signal.
Amplitude Modulation (AM)
The baseband signal is caused to vary the amplitude or height of the carrier wave to create the desired information content.
Analog
A form of transmitting information characterized by continuously variable quantities, as opposed to digital transmission, which is characterized by discrete bits of information in numerical steps. An analog signal is responsive to changes in light, sound, heat and pressure.
Analog-to-Digital Conversion (ADC)
Process of converting analog signals to a digital representation. DAC represents the reverse translation.
ANIK
The Canadian domestic satellite system that transmits Canadian Broadcasting Corporation's (CSC) network feeds throughout the country. This system also carries long distance voice and data services throughout Canada as well as some transborder service to the U.S. and Mexico.
Antenna
A device for transmitting and receiving radio waves. Depending on their use and operating frequency, antennas can take the form of a single piece of wire, a di-pole a grid such as a yagi array, a horn, a helix, a sophisticated parabolic-shaped dish, or a phase array of active electronic elements of virtually any flat or convoluted surface.
Aperture
A cross sectional area of the antenna which is exposed to the satellite signal.
Apogee
The point in an elliptical satellite orbit which is farthest from the surface of the earth. Geosynchronous satellites which maintain circular orbits around the earth are first launched into highly elliptical orbits with apogees of 22,237 miles. When the communication satellite reaches the appropriate apogee, a rocket motor is fired to place the satellite into its permanent circular orbit of 22,237 miles.
Apogee Kick Motor (AKM)
Rocket motor fired to circulate orbit and deploy satellite into geostationary orbit.
Apstar (Asia-Pacific Star)
Name of the Chinese satellite system which carries commercial video services in the region.
Arabsat
This is the Arabsat Satellite Organization and its is headquartered in Riyadh, Saudi Arabia. It provides regional telecommunications services for the Middle East region.
AsiaSat
A satellite system covering the Asia mainland.
Asynchronous Communications
Stream of data routed through a network as generated, rather than in organized message blocks. Most personal computers send data in this format. (See ATM)
Asynchronous Transfer Mode (ATM)
This is the new form of super-fast packet switching operating at speeds in the Gigabits/second.
Attenuation
The loss in power of electromagnetic signals between transmission and reception points.
Attitude Control
The orientation of the satellite in relationship to the earth and the sun
Audio/Video (A/V) Jacks
The A/V output jacks at the rear of a satellite receiver provide a superior picture and sound to your TV, VCR and home theater system. Three jacks provide stereo sound: one for the video, one for the right channel sound and one for the left channel sound.
Amerhis:
Processing system for multimedia communications board embarked on the Amazonas 1 satellite. Allows the interface between users with a single jump of the signal multiplexing onboard the satellite, which reduces the cost of ground equipment, better use of resources spectral power onboard the satellite.
Audio/Video (A/V) Jacks
The A/V output jacks at the rear of a satellite receiver provide a superior picture and sound to your TV, VCR and home theater system. Three jacks provide stereo sound: one for the video, one for the right channel sound and one for the left channel sound.
Audio Subcarrier
The carrier between 5 MHz and 8 MHz containing audio (or voice) information inside of a video carrier.
Automatic Frequency Control (AFC)
A circuit which automatically controls the frequency of a signal.
Automatic Gain Control (AGC)
A circuit which automatically controls the gain of an amplifier so that the output signal level is virtually constant for varying input signal levels.
AZ/EL Mount
Antenna mount that requires two separate adjustments to move from one satellite to another;
Azimuth
The azimuth is the side-to-side adjustment of a satellite dish from true north, along the horizon, to the DBS satellite, measured in degrees
B
B channel
a 64 kbqs channel, part of the ISDN system, usable for voice or data..
B-Mac
A method of transmitting and scrambling television signals. In such transmissions MAC (Multiplexed Analog Component) signals are time-multiplexed with a digital burst containing digitized sound, video synchronizing, authorization, and information.
Backhaul
A terrestrial communications channel linking an earth station to a local switching network or population center.
Backoff
The process of reducing the input and output power levels of a traveling wave **** to obtain more linear operation.
Band Pass Filter
An active or passive circuit which allows signals within the desired frequency band to pass through but impedes signals outside this pass band from getting through.
Bandwidth
A measure of spectrum (frequency) use or capacity. For instance, a voice transmission by telephone requires a bandwidth of about 3000 cycles per second (3KHz). A TV channel occupies a bandwidth of 6 million cycles per second (6 MHz) in terrestrial Systems. In satellite based systems a larger bandwidth of 17.5 to 72 MHz is used to spread or "dither" the television signal in order to prevent interference.
Baseband
The basic direct output signal in an intermediate frequency based obtained directly from a television camera, satellite television receiver, or video tape recorder. Baseband signals can be viewed only on studio monitors. To display the baseband signal on a conventional television set a "modulator" is required to convert the baseband signal to one of the VHF or UHF television channels which the television set can be tuned to receive.
Baud
The rate of data transmission based on the number of signal elements or symbols transmitted per second. Today most digital signals are characterized in bits per second.
Band BSS (Broadcast Satellite Service):
Frequencies for satellite broadcasting services. In Europe, these include the sub-frequency band from 10.7 to 11.7 GHz for reception and for transmission from 17.3 to 18.1.
Band C:
Frequency band from 3.7 to 4.2 GHz for reception. For transmission, from 5.925 to 6.425 GHz.
Band FSS (Fixed Satellite System) :
This range of frequencies between 10.7 and 11.7 GHz, is a subdivision of the Ku band.
Band-Ku:
This range used by TV and radio, ranging from 10.70 to 12.75 GHz and 12.75 at the reception to 14.50 GHz for transmission. The band is more widespread in Europe, taking into account the small size of the dishes required for reception. It is subdivided into sub-bands: Telecom, DBS and others.
Band X :
This band is reserved for government uses.
Bandwidth
The bandwidth is the complete range of frequencies over which a circuit or electronic system is allocated to function, measured in MHz.
Beacon
Low-power carrier transmitted by a satellite which supplies the controlling engineers on the ground with a means of monitoring telemetry data, tracking the satellite, or conducting propagation experiments. This tracking beacon is usually a horn or omni antenna.
Beamwidth
The angle or conical shape of the beam the antenna projects. Large antennas have narrower beamwidths and can pinpoint satellites in space or dense traffic areas on the earth more precisely. Tighter beamwidths thus deliver higher levels of power and thus greater communications performance.
Bel
A unit of strength of a signal, equal to 10 decibels (q.v.)
Bird
Slang for a communications satellite located in geosynchronous orbit.
Bit
A single digital unit of information
Bit Error Rate
The fraction of a sequence of message bits that are in error. A bit error rate of 10-6 means that there is an average of one error per million bits.
Bit Rate
The speed of a digital transmission, measured in bits per second.
Blanking
An ordinary television signal consists of 30 separate still pictures or frames sent every second. They occur so rapidly, the human eye blurs them together to form an illusion of moving pictures. This is the basis for television and motion picture systems. The blanking interval is that portion of the television signal which occurs after one picture frame is sent and before the next one is transmitted. During this period of time special data signals can be sent which will not be picked up on an ordinary television receiver.
COLOR="Blue"]Blind Scan[/COLOR]
Is the ability of the receiver to scan all the frequencies whether they are stored or not stored in the memory of the receiver without inputing the transponders parameters mentioned above by the end user.
Block Down Converter
A device used to convert the 3.7 to 4.2 KHz signal down to UHF or lower frequencies (1 GHz and lower).
BPSK (Binary Phase Shift Keying)
A digital modulation technique in which the carrier phase can have one of two possible values, namely 0 degrees or 180 degrees.
Broad beam
A single large circular beam that covers a large geographic area
Broadcast
The sending of one transmission to multiple users in a defined group (compare to unicast).
BSS (Broadcast Satellite Service)
This is the ITU designation but DBS or Direct Broadcast Service is more commonly used term in the satellite industry.
Business Television
Corporate communications tool involving video transmission of information via satellite.
Common uses of business television are for meetings, product introductions and training.
Buttonhook Feed
A shaped piece of waveguide directing signal from the feed to the LNA behind the antenna.
Bypass
Use of satellite, local area network, wide area network or metropolitan area network as an alternative transmission facility.
Broadband platform:
Infrastructure system that integrates land or HUB, satellite and VSAT (Very Small Aperture Terminal) to provide IP services such as Internet access, videoconferencing, VoIP ... inherent in satellite coverage.
C
C Band
This is the band between 4 and 8 GHz with the 6 and 4 GHz band being used for satellite communications. Specifically, the 3.7 to 4.2 GHz satellite communication band is used as the down link frequencies in tandem with the 5.925 to 6,425 GHz band that serves as the uplink.
Card Sharing
Also known as control word sharing, is a method of allowing multiple clients or digital television receivers to access a subscription television network with only one valid subscription card. This is achieved by electronically sharing a part of the legitimate conditional access smart card's output data, enabling all recipients to gain simultaneous access to scrambled DVB streams, held on the encrypted television network.
Typically, a legitimate smart card is attached to a host digital television receiver, which is equipped with software to share the decrypted 64-bit "control word" key over a computer network, such as the Internet. Once a client receives this key, they can decrypt the encrypted content as though they were using their own subscription card.
Carrier
The basic radio, television, or telephony center of frequency transmit signal. The carrier in an analog signal. is modulated by manipulating its amplitude (making it louder or softer) or its frequency (shifting it up or down) in relation to the incoming signal. Satellite carriers operating in the analog mode are usually frequency modulated.
Carrier Frequency
The main frequency on which a voice, data, or video signal is sent. Microwave and satellite communications transmitters operate in the band from 1 to 14 GHz (a GHz is one billion cycles per second).
Carrier to Noise Ratio (C/N)
The ratio of the received carrier power and the noise power in a given bandwidth, expressed in dB. This figure is directly related to G/T and S/N; and in a video signal the higher the C/N, the better the received picture.
Carterphone decision
The 1986 court decision that allowed non-Bell equipment to be connected to the telephone network.
Cassegrain Antenna
The antenna principle that utilizes a subreflector at the focal point which reflects energy to or from a feed located at the apex of the main reflector.
CATV
Originally meant Community Antenna Television. Independent smaller companies in rural communities would build a large television receiving antenna on a nearby mountain to pick up the weak TV signals from a distant metropolis. These signals were amplified, modulated onto television channels and sent along a coaxial cable strung from house to house.
CCITT (now TSS)
Comite Consultatif Internationale de Telegraphique et Telephonique. International body, associated with the ITU, which establishes worldwide standards for telecommunications. Reorganized to include CCIR (radio standards group) and renamed TSS (Telecommunications Standardization Sector).
CDMA
Code division multiple access. Refers to a multiple-access scheme where stations use spread-spectrum modulations and orthogonal codes to avoid interfering with one another.
Channel
A frequency band in which a specific broadcast signal is transmitted. Channel frequencies are specified in the United States by the Federal Communications Commission. Television signals require a 6 MHz frequency band to carry all the necessary picture detail.
Physical environment by transmitting a specific signal. The bandwidth of a television channel, for example, 6 MHz, in the United States and 8 MHz in Europe for the Hertzian cable reception. In satellites, it can reach a total of 27, 36 or 72 MHz.
Cyclical redundancy check
A mathematical algorithm to produce an error-checking code within a data stream.
CIF
Common Intermediate Format. A compromise television display format adopted by the CCITT which is relatively easy to derive from both PAL and NTSC.
Circular Polarization
Unlike many domestic satellites which utilize vertical or horizontal polarization, the international Intelsat satellites transmit their signals in a rotating corkscrew-like pattern as they are down-linked to earth. On some satellites, both right-hand rotating and left-hand rotating signals can be transmitted simultaneously on the same frequency; thereby doubling the capacity of the satellite to carry communications channels.
Clamp
A video processing circuit that removes the energy dispersal signal component from the video waveform.
Check Switch
Running a check switch procedure starts a series of tests in DISH network receivers which confirms that a good signal connection between the receiver and the multi-sat dish switch exists. At the end of the test, a list of which satellites you can receive is displayed.
Clarke Belt
Named after its founder Arthur C. Clarke, the Clarke Belt is an orbit used by satellites at a height of 22,250 miles, in which satellites make an orbit in 24 hours, yet remain in a fixed position relative to the earth’s surface.
Coax Cable
Coax or coaxial cable is the standard type of cable used by all satellite TV technicians. Coax cable carries the signal from the dish to the satellite receiver and on to your VCR and TV.
Codec
Coder/decoder system for digital transmission.
Co-Location
Ability of multiple satellites to share the same approximate geostationary orbital assignment frequently due to the fact that different frequency bands are used.
Color Subcarrler
A subcarrier that is added to the main video signal to convey the color information. In NTSC systems, the color subcarrier is centered on a frequency of 3.579545 MHz, referenced to the main video carrier.
Common Carrier
Any organization which operates communications circuits used by other people. Common carriers include the telephone companies as well as the owners of the communications satellites, RCA, Comsat, Direct Net Telecommunications, AT&T and others. Common carriers are required to file fixed tariffs for specific services.
Companding
A noise-reduction technique that applies single compression at the transmitter and complementary expansion at the receiver.
Composite Baseband
The unclamped and unfiltered output of the satellite receiver's demodulator circuit, containg the video information as well as all transmitted subcarriers.
Compression Algorithms
Software that allows codecs to reduce the number of bits required for data storage or transmission.
COMSAT
The Communications Satellite Corporation (part of Lockheed Martin) which serves as the U.S. Signatory to INTELSAT and INMARSAT.
Conformal array
An antenna that “conforms” to the surface of the structure carrying it. A conformal array may be built into the skin of an aircraft. Conformal arrays are lighter and smaller than conventional flat arrays.
Conus
Contiguous United States. In short, all the states in the U.S. except Hawaii and Alaska.
Cross Modulation
A form of signal distortion in which modulation from one or more RF carrier(s) is imposed on another carrier.
CSU
Channel service unit. A digital interface device that connects end-user equipment to the local digital telephone loop. CSU is frequently coupled with DSU (see below) as CSU/DSU.
C/T
Carrier-to-noise-temperature ratio.
D
D-Channel
A 16 kbps channel within the ISDN system, usable for either packet data or network signaling.
DAMA
Demand-Assigned Multiple Access - A highly efficient means of instantaneously assigning telephony channels in a transponder according to immediate traffic demands.
Datalink
The circuit and equipment that allows data to be transmitted between terminals.
Datalink protocol
A standard that governs how two terminals exchange data at the datalink level.
Data terminal equipment (DTE)
A device capable of transmitting digital data over a communications circuit.
DBS (Direct Broadcasting Satellite):
Initially referred to the Ku-band satellites that use power ****s very strong dimension, such as TDF, satellite TV and Tele X. DBS also designates the portion of Ku-band between 11.7 and 12.5 GHz, whichever is the satellite used.
dBi
The dB power relative to an isotropic source.
dBW
The ratio of the power to one Watt expressed in decibels.
De-BPSK
Differential Binary Phase Shift Keying
De-QPSK
Differential Quadrature Phase Shift Keying.Decibel (dB)
The standard unit used to express the ratio of two power levels. It is used in communications to express either a gain or loss in power between the input and output devices.
Declination
The offset angle of an antenna from the axis of its polar mount as measured in the meridian plane between the equatorial plane and the antenna main beam.
Decoder:
Team, in conjunction with a smart card allows the user to access the service. In the case of digital reception, the decoder is built into the receiver (IRD).
Deemphasis
Reinstatement of a uniform baseband frequency response following demodulation.
Delay
The time it takes for a signal to go from the sending station through the satellite to the receiving station. This transmission delay for a single hop satellite connection is very close on one-quarter of a second.
Demodulator
A satellite receiver circuit which extracts or "demodulates" the "wanted "signals from the received carrier.
Deviation
The modulation level of an FM signal determined by the amount of frequency shift from the frequency of the main carrier.
Digital:
System in which information is processed by electrical impulses of "on-off" (on-off), "high-low" (high-low) or "1-0" instead of signals or states in constant flux as happens with analog systems.
Digital Speech Interpolation
DSI - A means of transmitting telephony. Two and One half to three times more efficiently based on the principle that people are talking only about 40% of the time.
Discriminator
A type of FM demodulator used in satellite receivers.
Direct Broadcast Satellite (DBS)
DBS is the signal frequency range (11.70-12.40ghz) intended for DirecTV broadcast by satellite TV program providers.
Digital Compression
Digital compression is a process of translating video images into a digital code. Its purpose is to take up less transmission space than the original signal would have, allowing more channels per satellite transponder.
Direct broadcasting satellite provider
direct broadcasting satellite provider is a company that transmits a variety of channels to subscribers via satellite dish. Like cable companies, they offer a set package of channels at a variety of prices. In the United States, the providers are DirecTV and DISH Network
DirecTV System
A DirecTV System, trademarked for the consumer hardware and created to receive DirecTV programming, includes a dish (standard size is 18"), a remote control and the DirecTV Receiver.
DirecWay
DirecWay is the new name for the DirecPC satellite internet access system offered by Hughes Networking. Two connection types are offered. A dial-return-system (DRS) uses your existing dial-up service to provide a connection to the internet for all out going data and the satellite is used to route all returning data via satellite. The DRS systems offer a very nice Internet browsing experience at about half the upfront and monthly cost. The satellite-return-system (SRS) uses no phone lines after the initial setup and provides a 24/7 connection.
DISH Network System
DISH Network System, trademarked for the consumer hardware and created to receive DISH Network programming, includes a dish (standard size is a 20" multi-sat dish, called DISH 500), a remote control, and the DISH Network Receiver.
DISH 500
A DISH 500 is a multi-satellite dish used to receive DISH Network programming. Some programming for DISH Network is only available if you have a DISH 500 dish or a 2nd single satellite dish pointed to the 110 satellite for DISH Network. The DISH 500 dish is used to receive simultaneous satellite signals from the 119 and 110 satellite slots.
Dithering
he process of shifting the 6-MHz satellite-tv signal up and down the 36-MHz satellite transponder spectrum at a rate of 30 times per second (30 Hertz). The satellite signal is "dithered" to spread the transmission energy out over a band of frequencies far wider than a terrestrial common carrier microwave circuit operates within, thereby minimizing the potential interference that any one single terrestrial microwave transmitter could possibly cause to the satellite transmission.
Dolby Digital/AC-3 Compatible
Dolby Digital provides 6 independent sound track channels through the optical output jack. When connected to your AC3 compatible home theater audio setup, this connection provides Dolby Digital Surround Sound (when Dolby Digital is part of the programming being viewed).
Dolby Pro Logic
Dolby Pro Logic (known as Dolby Surround in the theaters) is based on the use of an amplitude-phase matrix. This is a method of encoding four channels of information into two tracks of stereo media and then decoding them back into four channels for playback.
DOMSAT
Domestic communications satellite.
Down-Converter
That portion of the Fixed Satellite Service (FSS) television receiver that converts the signals from the 4-GHz microwave range to (typically) the more readily used baseband or intermediate frequency (IF) 70-MHz range.
Downlink
The satellite to earth half of a 2 way telecommunications satellite link. Often used to describe the recieve dish end of the link.
DSU
Data service unit. A device used in digital transmission that adapts the physical interface on a DTE device to a transmission facility such as T1 or E1. The DSU is also responsible for such functions as signal timing. DSU is freqnetly coupled with a CSU (see above) as CSU/DSU.
DSS
DSS is an acronym for Digital Satellite System. It’s also a common name used to refer to a DirecTV satellite system or component.
DTH
DTH, or Direct-To-Home, is the official term used by the Federal Communications Commission to refer to the satellite television and broadcasting industries.
It refers to the transmission of radio signals from a satellite directly to user's home, through a small dish.
Dual LNB
A dual LNB is an LNB, or Low Noise Block-Down Converter) system that features two outputs rather than one and allow satellite television subscribers to watch multiple channels on separate television sets simultaneously. Dual LNB systems use only one parabolic satellite dish, but have two cable connections that are connected to separate televisions in the user’s house. When the LNB collects television signals, it splits them into two equal signals that are received by each television at the same time. Like dual LNB systems, triple and quadruple LNB systems are also .
Dual offset dish antenna
This type of satellite dish has two dishes, a larger receiving dish and a small dish facing the opposite direction that takes the signal and transfers it to the LNC. The dual offset dish antenna has an 80% efficiency.
Free to air satellite system (FTA): An FTA satellite system refers to a satellite receiver that is configured to receive encrypted FTA satellite transmissions. FTA broadcasts are public domain and you do not have to pay for a subscription to any type of satellite provider to receive them.
Dual Spin
Spacecraft design whereby the main body of the satellite is spun to provide altitude stabilization, and the antenna assembly is despun by means of a motor and bearing system in order to continually direct the antenna earthward. This dual-spin configuration thus serves to create a spin stabilized satellite.
Dual tone multifrequency
A signaling system in which each digit dialed is indicated by two tones.
Duplex Transmission
Capability for simultaneous data transmission between a sending station and a receiving station.
DVB
Digital Video Broadcasting - The European-backed project to harmonise adoption of digital video.
It is a European specification for digital broadcast television, associated with the compression format MPEG-2.
E
E1
Wide-area digital transmission facility used predominantly in Europe that carries data at a rate of 2.048 Mbit/s.
E3
Wide-area digital transmission facility used predominantly in Europe that carries data at a rate of 34.368 Mbit/s.
Earth Exploration Satellite Service
A radio communications service between an earth station and one or more space stations. The service may include links between space stations in which information relating to the characteristics of the earth and its natural phenomena is obtained from active or passive sensors on earth satellites. Similar information is collected from airborne or earth-based platforms and such information may be distributed to earth stations within the systems concerned. Platform interrogation may be included and the service may also include feeder links necessary for its operation.
Earth Station
The term used to describe the combination or antenna, low-noise amplifier (LNA), down-converter, and receiver electronics. used to receive a signal transmitted by a satellite. Earth Station antennas vary in size from the.2 foot to 12 foot (65 centimeters to 3.7 meters) diameter size used for TV reception to as large as 100 feet (30 meters) in diameter sometimes used for international communications. The typical antenna used for INTELSAT communication is today 13 to 18 meters or 40 to 60 feet.
Echo Canceller
An electronic circuit which attenuates or eliminates the echo effect on satellite telephony links. Echo cancellers are largely replacing obsolete echo suppressors.
Echo Effect
A time-delayed electronic reflection of a speaker's voice. This is largely eliminated by modern digital echo cancellers.
Eclipse
When a satellite passes through the line between the earth and the sun or the earth and the moon.
Eclipse Protected
Refers to a transponder that can remain powered during the period of an eclipse.
El/Az
An antenna mount providing independent adjustments in elevation and azimuth.
Edge of Coverage
Limit of a satellite's defined service area. In many cases, the EOC is defined as being 3 dB down from the signal level at beam center. However, reception may still be possible beyond the -3dB point.
Effective Monopoleradiated Power (EMRP) (In a given direction)
The product of the lower supplied to the antenna and its gain relative to a short vertical antenna in a given direction.
EIRP(PIRE) (effective isotropic radiated power)
Effective Isotropic Radiated Power - This term describes the strength of the signal leaving the satellite antenna or the transmitting earth station antenna, and is used in determining the C/N and S/N. The transmit power value in units of dBW is expressed by the product of the transponder output power and the gain of the satellite transmit antenna.
Electronic Program Guide (EPG)
A chronological listing of all available programming covering an extended time period (typically 36 hours or more). This listing displays on your TV screen.
Elevation
The upward tilt to a satellite antenna measured in degrees required to aim the antenna at the communications satellite. When. aimed at the horizon, the elevation angle is zero. If it were tilted to a point directly overhead, the satellite antenna would have an elevation of 90 degrees.
Encoder
A device used to electronically alter a signal so that it can only be viewed on a receiver equipped with a special decoder.
Energy Dispersal
A low-frequency waveform combined with the baseband signal prior to modulation, to spread the FM signal's peak power across the available transponder bandwidth in order to reduce the potential for creating interference to ground-based communications services.
EOL
End of Life of a satellite.
Equatorial Orbit
An orbit with a plane parallel to the earth's equator.
Equivalent satellite link noise temperature
The noise station temperature of the receiving antenna of the earth station corresponding to the radio frequency noise power that produces the total observed noise at the ouput of the satellite link excluding noise due to interference coming from satellite links using other satellites and form terrestrial systems.
ESC
Engineering Service Circuit - The 300-3,400 Hertz voice plus teletype (S+DX) channel used for earth station-to-earth station and earth station-to-operations center communications for the purpose of system maintenance, coordination and general system information dissemination. In analog (FDM/FM) systems there are two S+DX channels available for this purpose in the 4,000-12,000 Hertz portion of the baseband. In digital systems there are one or two channels available which are usually convened to a 32 or 64 Kbps digital signal and combined with the earth station traffic digital bit stream. Modern ESC equipment interfaces with any mix of analog and digital satellite carriers, as well as backhaul terrestrial links to the local switching center.
Eutelsat
The European Telecommunications Satellite Organization which is headquartered in Paris, France. It provides a satellite network for Europe and parts of North Africa and the Middle East.
Extended binary-codec decimal interchange code (EBCDIC)
An IBM originated 8-bit code used to represent characters internally in IBM equipment and sometime for external communications.
F
FCC (Federal Communications Commission)The U.S. federal regulatory body, consisting of five members, one of who is designated chairman, appointed by the President and confirmed by the Senate, which regulates interstate communications under the Communications Act of 1934.
F/D
Ratio of antenna focal length to antenna diameter. A higher ratio means a shallower dish.
FDMA
Frequency division multiple access. Refers to the use of multiple carriers within the same transponder where each uplink has been assigned frequency slot and bandwidth. This is usually employed in conjunction with Frequency Modulation.
Feed
This term has at least two key meanings within the field of satellite communications. It is used to describe the transmission of video programming from a distribution center. It is also used to describe the feed system of an antenna. The feed system may consist of a subreflector plus a feedhorn or a feedhorn only.
Feeder link
A radio link from an earth station at a specified fixed point to a space station, or vice versa, that conveys information for a space radio communications service other than for the fixed satellite service.
Feedhorn
A satellite TV receiving antenna component that collects the signal reflected from the main surface reflector and channels this signal into the low-noise amplifier (LNA).
Fiber optics
The technology in which a modulated beam of light carries information through a thin glass or plastic fiber
Filter
A device designed to allow only a predetermined range of frequencies t pass through it.
Filter Satellite service (FSS)
The telecommunications service between nonmoving Earth stations (but the antennas may be moveable, just not in motion at the time of use).
Flat antenna:
A flat antenna is the most compact type of satellite dish. This type of antenna does not have an exterior LNC. It is located within the dish. These types of satellite dishes are best for homes near the center of the satellite footprint area.
FM
Frequency ModulationA modulation method whereby the baseband signal varies the frequency of the carrier wave.
FM Threshold
That point at which the input signal power is just strong enough to enable the receiver demodulator circuitry successfully to detect and recover a good quality television picture from the incoming video carrier.
Focal Length
Distance from the center feed to the center of the dish.
Focal Point
The area toward which the primary reflector directs and concentrates the signal received.Footprint*A map of the signal strength showing the EIRP contours of equal signal strengths as they cover the earth's surface. Different satellite transponders on the same satellite will often have different footprints of the signal strength. The accuracy of EIRP footprints or contour data can improve with the operational age of the satellite. The actual EIRP levels of the satellite, however, tends to decrease slowly as the spacecraft ages.
Forward Error Correction (FEC)
Adds unique codes to the digital signal at the source so errors can be detected and corrected at the receiver.
Frame
A unit block of data.
Frequency
The number of times that an alternating current goes through its complete cycle in one second of time. One cycle per second is also referred to as one hertz; 1000 cycles per second, one kilohertz; 1,000,000 cycles per second, one megahertz: and 1,000,000,000 cycles per second, one gigahertz.
Frequency Coordination
A process to eliminate frequency interference between different satellite systems or between terrestrial microwave systems and satellites. In the U.S. this activity relies upon a computerized service utilizing an extensive database to analyze potential microwave interference problems that arise between organizations using the same microwave band. As the same C-band frequency spectrum is used by telephone networks and CATV companies when they are contemplating the installation of an earth station, they will often obtain a frequency coordination study to determine if any problems will exist.
Frequency derived channel
A channel within a frequency divided multiplexed group of channels.
Frequency Reuse
A technique which maximizes the capacity of a communications satellite through the use of specially isolated beam antennas and/or the use of dual polarities.
Full duplex
A circuit which carriers information in both directions at the same time.
G
Gain
A measure of amplification expressed in dB.
Gateway
Any device which is an interface between difference networks.
GE Americon
This is a large U.S. corporation providing satellite systems for domestic communications. Has ownership in some international satellites.
Geostationary
Refers to a geosynchronous satellite angle with zero inclination. so the satellite appears to hover over one spot on the earth's equator.
Geostationary Transfer Orbit
This orbit is in the equatorial plane. This type of orbit has an elliptical form, with a perigee at 200 km and an apogee at 35870 km.
Geosynchronous
The Clarke circular orbit above the equator. For a planet the size and mass of the earth, this point is 22,237 miles above the surface.
Gigahertz (GHz)
One billion cycles per second. Signals operating above 3 Gigahertz are known as microwaves. above 30 GHz they are know as millimeter waves. As one moves above the millimeter waves signals begin to take on the characteristics of Iightwaves.
Global Beam
An antenna down-link pattern used by the Intelsat satellites, which effectively covers one-third of the globe. Global beams are aimed at the center of the Atlantic, Pacific and Indian Oceans by the respective Intelsat satellites, enabling all nations on each side of the ocean to receive the signal. Because they transmit to such a wide area, global beam transponders have significantly lower EIRP outputs at the surface of the Earth as compared to a US domestic satellite system which covers just the continental United States. Therefore, earth stations receiving global beam signals need antennas much larger in size (typically 10 meters and above (i.e.30 feet and up).
Gregorian Dual-reflector antenna system employing a paraboloidal main reflector and a concave ellipsoidal subreflector.
Globalstar
A mobile satellite system that deployes a network of 48 satellites to create a global voice and data service. This system is backed by Qualcomm, Loral, and Alcatel.
G/T
A figure of merit of an antenna and low noise amplifier combination expressed in dB. "G" is the net gain of the system and "T" is the noise temperature of the system. The higher the number, the better the system.
Grade of service
A measure of the probability of a user being unable to use a network because it is busy.
Guard Channel
Television channels are separated in the frequency spectrum by spacing them several megahertz apart. This unused space serves to prevent the adjacent television channels from interfering with each other.
H
HDTV
HDTV, or High Definition Television, is a digital television format, that combines high-resolution video and theater-like sound to create a movie theater-quality TV viewing experience.
Half-Duplex (HDX)
A circuit which can carry information in both directions, but on in one direction at a time.
Half Transponder
A method of transmitting two TV signals through a single transponder through the reduction of each TV signal's deviation and power level. Half-transponder TV carriers each operate typically 4 dB to 7 dB below single-carrier saturation power.
Hard Reset
A hard reset is the same as rebooting a computer touching the on/off button (Hardware).
Harmonic distortion
Overtones (harmonics) produced when a simple signal wave is sent through a circuit with nonlinear electrical characteristics.
Headend
Electronic control center - generally located at the antenna site of a CATV system - usually including antennas, preamplifiers, frequency converters, demodulators and other related equipment which amplify, filter and convert incoming broadcast TV signals to cable system channels.
Heliosynchronous Orbit
At an altitude of 600 to 800 km and situated in a quasi-polar plane. The satellite is permanently visible from that part of the Earth in sunlight. Heliosynchronous orbits are used for Earth observation or solar-study satellites.
HEO
Highly Elliptical Orbit. This is type of orbit used by the Russian Molniya Satellite system. It is also referred to as Extremely Elliptical Orbit (EEO).
Hertz (Hz)
The name given to the basic measure of radio frequency characteristics. An electromagnetic wave completes a full oscillation from its positive to its negative pole and back again in what is known as a cycle. A single Hertz is thus equal to one cycle per second.
High Frequency (HF)
Radio frequencies within the range of 3,000 to 30,000 kilohertz. HF radio is known as shortwave.
Hierarchical Network
A telecommunications network in which a message is passed through nodes or different classes.
High Level Datalink Control (HDLC)
A bit-oriented datalink protocol standardized by the ISO.
High-Power Satellite
Satellite with 100 watts or more of transponder RF power.
Hour Angle
Steering direction of a polar mount. An angle measured in the equatorial plane between the antenna beam and the meridian plane.
Hub
The master station through which all communications to, from and between micro terminals must flow. in the future satellites with on-board processing will allow hubs to be eliminated as MESH networks are able to connect all points in a network together.
I
Interactive TV
Interactive TV lets you use the enclosed remote control to access up-to-the-minute news, sports, financial information, weather, get program trivia, respond to free offers and shop, all while you watch TV.
IBS
INTELSAT Business Services.
IFRB
International Frequency Registration Board of the ITU - International Telecommunications Union. The IFRB regulates the allocation of satellite orbital locations.
Inclination
The angle between the orbital plane of a satellite and the equatorial plane of the earth.
INMARSAT
The International Maritime Satellite Organization operates a network of satellites for international transmissions for all types of international mobile services including maritime, aeronautical, and land mobile.
INTELSAT
The International Telecommunications Satellite Organization operates a network of satellites for international transmissions.
Interchange carrier
A common carrier which carries traffic between LATA’s.
Interchange channel
A link between two changes
Interference
Energy which tends to interfere with the reception of the desired signals, such as fading from airline flights, RF interference from adjacent channels, or ghosting from reflecting objects such as mountains and buildings.
Inter Satellite Link - ISL
Radio or optical communications links between satellites. They serve to interconnect constellations of satellites.
INTERSPUTNIK
The international entity formed by the Soviet Union to provide international communications via a network of Soviet satellites.
IRD
An integrated receiver and decoder for reception of a transmission of voice, video and data.
Iridium Satellite System
This was a 66 satellite network designed for mobile telephone use and is now defunct.
ISDN - Integrated Services Digital Network.
A CCITT standard for integrated transmission of voice, video and data. Bandwidths include: Basic Rate Interface - BR (144 Kbps - 2 B & 1 D channel) and Primary Rate - PRI (1.544 and 2.048 Mbps).
ISO
International Standards Organization. Develops standards such as JPEG and MPEG. Closely allied with the CCITT.
Isotropic Antenna
A hypothetical omnidirectional point-source antenna that serves as an engineering reference for the measurement of antenna gain.
ITU
International Telecommunication Union.
ISP:
Internet Service Provider
J
Jammer -
An active electronic counter-measures (ECM) device designed to deny intelligence to unfriendly detectors or to disrupt communications.
JPEG
ISO Joint Picture Expert Group standard for the compression of still pictures.
K
Ka Band
The frequency range from 18 to 31 GHz.
Kbps
Kilobits per second. Refers to transmission speed of 1,000 bits per second.
Kelvin (K)
The temperature measurement scale used in the scientific community. Zero K represents absolute zero, and corresponds to minus 459 degrees Fahrenheit or minus 273 Celsius. Thermal noise characteristics of LNA are measured in Kelvins.
Kilohertz (kHz)
Refers to a unit of frequency equal to 1,000 Hertz.
Klystron
A microwave **** which uses the interaction between an electron beam and the RF energy on microwave cavities to provide signal amplification. The klystron operates on principles of velocity modulation very similar to those in a TWT except that klystron interaction takes place at discrete locations along the electron beam. Common types of klystrons are the reflex klystron (an oscillator having only one cavity), two-cavity klystron amplifiers and oscillators, and multi-cavity klystron amplifiers.
Ku Band
The frequency range from 10.9 to 17 GHz.
L
Land mobile satellite service
A mobile satellite service in which mobile earth stations are located on land.
LATA
See Local Acess and Transport Area.
Leased facility
A telecommunications facility leased for the sole use of on e customer. Also called a private line.
Line conditioning
See Conditioning.
Line switching
Circuit switching.
Line termination device
Any device, such as a modern, which connects a data machine to a transmission facility.
Link
See Channel.
Link access protocol (LAP)
A CCITT standard bit-oriented protocol. Link Access Protocol Balanced (LAPB) is a variant. Both are subsets of HDLC.
LNA (Low noise converter)
A preamplifier used to strengthen a weak satellite signal. The LNA is used at the feedhorn of the TVRO satellite antenna and typically features a nosie figure to 120 degrees Kelvin.
Leased Line
A dedicated circuit typically supplied by the telephone company.
Loading
The adding of loading, or inductance, coils to a transmission circuit to minimize distortion.
Local access and transport area (LATA)
A geological area within which a local telephone company provides service. Service between LATA’s os carried by IEC’s.
Local area network (LAN)
A private data communication network connecting terminals usually within a limited geological range, and operating at high speed.
Local exchange
Also called an end office, the exchange in a telephone network where the user’s line terminate.
Local loop
A (usually 2-wire) connection between a telephone exchange office and a subscriber.
Longitudinal redundancy check
A technique for detecting errors in transmitted blocks of information.
Low Noise Amplifier (LNA)
This is the preamplifier between the antenna and the earth station receiver. For maximum effectiveness, it must be located as near the antenna as possible, and is usually attached directly to the antenna receive port. The LNA is especially designed to contribute the least amount of thermal noise to the received signal.
Low Noise Block Downconverter (LNB)
A combination Low Noise Amplifier and downconverter built into one device attached to the feed.
Low Noise Converter (LNC)
A combination Low Noise Amplifier and down converter built into one antenna-mounted package.
Low Orbit
At an altitude of 200 to 300 km this orbit is used for certain types of scientific or observation satellites, which can view a different part of the Earth beneath them on each orbit revolution, as they overfly both hemispheres.
Low-Power Satellite
Satellite with transmit RF power below 30 watts.
L-Band
An L-Band is the frequency range from 0.5 to 1.5 GHz. All satellite TV systems use this frequency (950 to 1450 MHz) to carry the satellite signal from the dish to the receiver.
LNBF
An LNBF (usually called an LNB) is a Low Noise Block Converter with Integrated Feed. It amplifies received signals and converts them from microwaves to lower L-band frequency signals which are then sent along a cable to the satellite receiver.
LMDS (Local Multipoint Distribution System):
LMDS is a radio technology that has been developed for wireless local access broadband. Enables access to voice, data, Internet and video. Use the radio band of 25 GHz (or higher).
M
MAC (A, B, C, D2)
Multiplexed analog component color video transmission system. Subtypes refer to the various methods used to transmit audio and data signals.
Margin
The amount of signal in dB by which the satellite system exceeds the minimum levels required for operation.
Master Antenna Television (MATV)
An antenna system that serves a concentration of television sets such as in apartment buildings, hotels or motels.
Medium-Power Satellite
Satellite generating transmit power levels ranging from 30 to 100 watts.
Megahertz (MHz)
Refers to a frequency equal to one million Hertz, or cycles per second.
Microwave
Line-of sight, point-to-point transmission of signals at high frequency. Many CATV systems receive some television signals from a distant antenna location with the antenna and the system connected by microwave relay. Microwaves are also used for data, voice, and indeed all types of information transmission. The growth of fiber optic networks have tended to curtail the growth and use of microwave relays.
Microwave Interference
Interference which occurs when an earth station aimed at a distant satellite picks up a second, often stronger signal, from a local telephone terrestrial microwave relay transmitter. Microwave interference can also be produced by nearby radar transmitters as well as the sun itself. Relocating the antenna by only several feet will often completely eliminate the microwave interference.
Modem
A communications device that modulates signals at the transmitting end and demodulates them at the receiving end.
Modulation
The process of manipulating the frequency or amplitude of a carrier in relation to an incoming video, voice or data signal.
Modulator
A device which modulates a carrier. Modulators are found as components in broadcasting transmitters and in satellite transponders. Modulators are also used by CATV companies to place a baseband video television signal onto a desired VHF or UHF channel. Home video tape recorders also have built-in modulators which enable the recorded video information to be played back using a television receiver tuned to VHF channel 3 or 4.
Molniya
The Russian domestic satellite system which operated with highly elliptical satellites which overlooked the high latitudes of the territories of the USSR.
MPEG
The Moving Pictures Experts Group, the television industry's informal standards group.
MPEG-2
The agreed standard covering the compression of data (coding and encoding) for digital television.
MPEG-2 MP@HL
Main Provile at High Level - The agreed much higher bit-rate system adopted to provide high definition television in wide screen format.
Multiple Access
The ability of more than one user to have access to a transponder.
Multiple System Operator (MSO)
A company that operates more than one cable television system.
Multipoint Distribution System (MDS)
A common carrier licensed by the FCC to operate a broadcast-like omnidirectional microwave transmission facility within a given city typically carrying television signals
Multicast
Multicast is a subset of broadcast that extends the broadcast concept of one to many by allowing "the sending of one transmission to many users in a defined group, but not necessarily to all users in that group."
Multiplexing
Techniques that allow a number of simultaneous transmissions over a single circuit.
Mux
A Multiplexer. Combines several different signals (e.g. video, audio, data) onto a single communication channel for transmission. Demultiplexing separates each signal at the receiving end.
Matrix Switch
By using a Matrix switch you can add more than two receivers to a dual LNB.
MPEG2/MPEG4
MPEG2/MPEG4 is a video compression method. Compression is used to combine several programs into one satellite transponder.
Multi-satellite dish
It's often necessary for consumers to use a multi-satellite system, such as the DirecTV Oval Dish or DISH Networks DISH 500 because some programming extends beyond the satellite provider's "core" programming, like HDTV programs, and local channels in many areas.
Multi-satellite switch
To accommodate the multi-sat dishes offered by DirecTV and DISH Network, you must use a multi-sat switch. You can’t intermix DirecTV and DISH Network switches. DirecTV controls a multi-sat switch with a 22kHz signal and DISH Network use a digital signal to communicate with their switches.
Must Carry
Effective at the beginning of 2002, the FCC established a condition that if a satellite service provider is going to carry one local network in a specific market place or DMA then they must carry all local networks in that market place.
MMDS (Multipoint Microwave Distribution System):
It's wireless cable without cable or wires. Terrestrial broadcast system that uses the band 2.5 to 2.7 GHz MMDS broadcast can be analog (Pal, Secam, NTSC) or digital. It is very common in some countries, especially Africa.
Multiplex:
Is the signal that brings together a set of tablets and broadcast programs simultaneously on the same frequency.
N
NAB
National Association of Broadcasters.
NASA (National Aeronautics and Space Administration)
The U.S. agency which administers the American space program, including the deployment of commercial and military satellites via a fleet of space shuttle vehicles.
NASDA
National Space Development Agency of Japan.
NCTA
National Cable Television Association.
Noise
Any unwanted and unmodulated energy that is always present to some extent within any signal.
Noise Figure (NF)
A term which is a figure of merit of a device, such as an LNA or receiver, expressed in dB, which compares the device with a perfect device.
NTIA
The National Telecommunications and Information Administration is a unit of the Department of Commerce that address U.S. government telecommunications policy, standards setting and radio spectrum allocation.
Nutation Damping
The process of correcting the nutational effects of a spinning satellite which are similar in effect to a wobbling top. Active nutation controls use thruster jets.
NTSC - National Television Standards Committee
A video standard established by the United States (RCA/NBC} and adopted by numerous other countries. This is a 525-line video with 3.58-MHz chroma subcarrier and 60 cycles per second.
O
Offset dish antenna
The offset dish antenna has the LNC located to the side of the dish. This way, the LNC does not interfere with the signal path, which can reach the dish unobstructed. Because this offers better performance, these dishes can be much smaller than the prime feed focus dishes.
OFTEL
The Office of Telecommunications of the United Kingdom government. This unit a part of the Department of Industries regulates telecommunications in the United Kingdom.
Orbital Period
The time that it takes a satellite to complete one circumnavigation of its orbit.
Orbital Slots
Orbital slots refer to the location of satellites around the globe. Their are 6 main slots used for DBS TV.
OSD
On screen display. Menu that appears on the screen/display of multimedia applications.
OTA (Over the Air)
This is the acronym commonly used to describe standard television broadcast signals received by a rooftop antenna, sometimes called off-air.
P
Packet Switching
Data transmission method that divides messages into standard-sized packets for greater efficiency of routing and transport through a network.
PAL - Phase Alternation System
The German developed TV standard based upon 50 cycles.per second and 625 lines.
Parabolic Antenna
The most frequently found satellite TV antenna, it takes its name from the shape of the dish described mathematically as a parabola. The function of the parabolic shape is to focus the weak microwave signal hitting the surface of the dish into a single focal point in front of the dish. It is at this point that the feedhorn is usually located.
PBS (Public Broadcasting System)
A domestic USA television and radio broadcast network.
Perigee
The point in an elliptical satellite orbit which is closest to the surface of the earth.
Perigee Kick Motor (PKM)
Rocket motor fired to inject a satellite into a geostationary transfer orbit from a low earth orbit especially that of a STS or Shuttle-based orbit of 300 to 500 miles altitude.
Period
The amount of time that a satellite takes to complete one revolution of its orbit.
Phase Alternation System (PAL)
A European color television system incompatible with the US NTSC television system.
Phase-Locked Loop (PLL)
A type of electronic circuit used to demodulate satellite signals.
Polarization
A technique used by the satellite designer to increase the capacity of the satellite transmission channels by reusing the satellite transponder frequencies. In linear cross polarization schemes, half of the transponders beam their signals to earth in a vertically polarized mode; the other half horizontally polarize their down links. Although the two sets of frequencies overlap, they are 90 degree out of phase, and will not interfere with each other. To successfully receive and decode these signals on earth, the earth station must be outfitted with a properly polarized feedhorn to select the vertically or horizontally polarized signals as desired.
In some installations, the feedhorn has the capability of receiving the vertical and horizontal transponder signals simultaneously, and routing them into separate LNAs for delivery to two or more satellite television receivers. Unlike most domestic satellites, the Intelsat series use a technique known as left-hand and right-hand circular polarization.
Polarization Rotator
A device that can be manually or automatically adjusted to select one of two orthogonal polarizations.
Polar Mount
Antenna mechanism permitting steering in both elevation and azimuth through rotation about a single axis. While an astronomer's polar mount has its axis parallel to that of the earth, satellite earth stations utilize a modified polar mount geometry that incorporates a declination offset.
Polar Orbit
An orbit with its plane aligned in parallel with the polar axis of the earth
Protected-Use Transponder
A satellite transponder provided by the common carrier to a programmer with a built-in insurance policy. If the protected-use transponder fails, the common carrier guarantees the programmer that it will switch over to another transponder, sometimes pre-empting some other non-protected programmer from the other transponder.
PTT - Post Telephone and Telegraph Administration
Refers to operating agencies directly or indirectly controlled by governments in charge of telecommunications services in most countries of the world.
Pulse Code Modulation
A time division modulation technique in which analog signals are sampled and quantized at periodic intervals into digital signals. The values observed are typically represented by a coded arrangement of 8 bits of which one may be for parity.
Pay Per View (PPV)
A pay-per-view event may be purchased separately from any package or subscription. This could include a movie, special event, sporting event, or an ***** program.
Parental Lockout
Parental Lockout allows users to set a password to control access to programming based on channel, rating or content.
Platform:
Also called the Service Module, is responsible for maintaining operational satellites in its orbital lifetime.
Broadband platform:
Infrastructure system that integrates land or HUB, satellite and VSAT (Very Small Aperture Terminal) to provide IP services such as Internet access, videoconferencing, VoIP ... inherent in satellite coverage.
PIRE (EIRP) (effective isotropic radiated power):
Equivalent to the power radiated by an antenna that emits in all directions. It is the transmitter power and antenna gain. The EIRP is expressed in dBW (decibel / watt). Its value is a factor in the quality of reception.
Pixelization
Pixelization occurs due to errors in decoding the MPEG bit stream where areas or patches of color appear instead of the higher resolution image. It might be described as the picture "breaking up". The patches of blocks appear and disappear, and can happen anywhere on the screen but usually are "part" of the image "in motion". Pixelization most often occurs during rain fade or if the satellite system has too low a signal strength to operate properly.
Prime feed focus dish
This is a large parabolic dish, with a diameter over 1.4 meters, with the LNC mounted centrally in the dish facing outward. Because it is located in the center of the dish, the LNC blocks a lot of the incoming signals. For that reason, this type of satellite is only 50% effective in receiving radio signals.
PVR
A Personal Video Recorder PVR satellite receiver) has a built in hard drive for digitally recording satellite television programs, with high time recording capability and two internal satellite receivers. Dual tuners allow the user to record one program while watching another or record two programs at the same time. But not only have PVR satellite receivers with two tuners inside. You can record the same channel you are watching. You can record your favourite sat tv program at HD, USB pendrives or memory cards.
The PVRs are, usually, building into a TV set, set top box or pcsat receiver.
Q
QPSK (Quaternary Phase Shift Keying):
It is a method of modulation used for digital satellite broadcasts. The information is in the phase of the modulated signal, in four states.
Quad LNBF
A combination LNBF and multi-sat switch component for DISH 500 systems can accommodate up to 4 DISH Network receivers.
R
Radio waves
Radio waves are an invisible form of electromagnetic radiation that varies in wavelength from one millimeter to 100,000 km. Satellites send your television signal via radio waves to your satellite dish antenna.
Rain Outage / Fade
Loss of signal at Ku or Ka Band frequencies due to absorption and increased sky-noise temperature caused by heavy rainfall.
Receiver (Rx)
An electronic device which enables a particular satellite signal to be separated from all others being received by an earth station, and converts the signal format into a format for video, voice or data.
Receiver Sensitivity
Expressed in dBm this tells how much power the detector must receive to achieve a specific baseband performance, such as a specified bit error rate or signal to noise ratio.
RF Adaptor
An add-on modulator which interconnects the output of the satellite television receiver to the input (antenna terminals) of the user's television set. The RF adaptor converts the baseband video signal coming from the satellite receiver to a radio frequency RF signal which can be tuned in by the television set on VHF channel 3 or 4.
Router
Network layer device that determines the optimal path along which network traffic should be forwarded. Routers forward packets from one network to another based on network layer information.
Rating Limit:
The rating limit is set by the customer using the main menu. When a system lock is active, this limit controls the viewing of programs that have been assigned a rating level.
Remote Extender
A remote extender is an after-market device that allows you to use an Infrared (IR) remote to control a satellite receiver from another room.
RG-59
An RG-59 is a common coax cable used in many homes for the last 40 years.
RG-6:
An RG-6 coax cable is recommended for digital satellite TV installations. RG-6 is a larger-size cable than the lower-grade RG-59 cable found in some homes.
R/F connectors
The R/F connectors are the output/input screws on connections for coaxial cable. They won’t provide stereo from the satellite receiver to the TV or stereo.
S
Satellite
A sophisticated electronic communications relay station orbiting 22,237 miles above the equator moving in a fixed orbit at the same speed and direction of the earth (about 7,000 mph east to west).
Satellite footprint
The footprint of a satellite is the ground area where its transponders offer coverage. Basically, every satellite has a geographic area where its signal can be received.
Satellite Terminal
A receive-only satellite earth station consisting of an antenna reflector (typically parabolic in shape), a feedhorn, a low-noise amplifier (LNA), a down converter and a receiver.
SAW (Surface Acoustic Wave)
A type of steep-skirted filter used in the baseband or IF section of satellite reception and transmission equipment.
S-Video Jack
Some televisions have an input for an S-Video cable. This is better than audio/video jacks or R/F connectors. It is for the video, not the sound.
Satellite Dish
A satellite dish is used to collect signals from a satellite in orbit and focus them to the front of the dish where a feed horn collects them and passes the signals on to the LNB to be amplified and sent to a satellite receiver.
SBCA
The SBCA (Satellite Broadcasting Communication Association) is an organization of satellite TV manufacturers, program providers, distributors and dealers. They are the leading voice for the satellite industry in congress and all across the U.S.
Scalar Feed
A type of horn antenna feed which uses a series of concentric rings to capture signals that have been reflected toward the focal point of a parabolic antenna.
Scrambler
A device used to electronically alter a signal so that it can only be viewed or heard on a receiver equipped with a special decoder.
Secam
A color television. system developed by the French and used in the USSR. Secam operates with 625 lines per picture frame and 50 cycles per second, but is incompatible in operation with the European PAL system or the U.S. NTSC system.
Set Top Box
A set-top box (STB) or set-top unit (STU) is an information appliance device that generally contains a tuner and connects to a television set and an external source of signal, turning the signal into content which is then displayed on the television screen or other display device
SFD - Stauration Flux Density
The power required to achieve saturation of a single repeater channel on the satellite.
Sidelobe
Off-axis response of an antenna.
Signal to Noise Ratio (S/N)
The ratio of the signal power and noise power. A video S/N of 54 to 56 dB is considered to be an excellent S/N, that is, of broadcast quality. A video S/N of 48 to 52 dB is considered to be a good S/N at the headend for Cable TV.
SILVO
An organization formed in the mid 1980's to monitor frequency re-use.
Simplex Transmission
Capability for transmission in only one direction between sending station and receiving station.
Single-Channel-Per-Carrier (SCPC)
A method used to transmit a large number of signals over a single satellite transponder.
Single Sideband (SSB)
A form of amplitude modulation (AM) whereby one of the sidebands and the AM carrier are suppressed.
Skew
An adjustment that compensates for slight variance in angle between identical senses of polarity generated by two or more satellites.
Slant Range
The length of the path between a communications satellite and an associated earth station.
Slot
That longitudinal position in the geosynchronous orbit into which a communications satellite is "parked". Above the United States, communications satellites are typically positioned in slots which are based at two to three degree intervals.
SMATV (Satellite Master Antenna System)
The adding of an earth station to a MATV system to receive satellite programs.
SNG
Satellite news gathering usually with a transportable uplink truck.
Snow
A form of noise picked up by a television receiver caused by a weak signal. Snow is characterized by alternate dark and light dots appearing randomly on the picture ****. To eliminate snow, a more sensitive receive antenna must be used, or better amplification must be provided in the receiver (or both).
Solar Outage
Solar outages occur when an antenna is looking at a satellite, and the sun passes behind or near the satellite and within the field of view of the antenna. This field of view is usually wider than the beamwidth. Solar outages can be exactly predicted as to the timing for each site.
Sparklies
A form of satellite television "snow" caused by a weak signal. Unlike terrestrial VHF and UHF television snow which appears to have a softer texture, sparklies are sharper and more angular noise "blips". As with terrestrial reception, to eliminate sparklies, either the satellite antenna must be increased in size, or the low noise amplifier must be replaced with one which has a lower noise temperature.
Spectrum
The range of electromagnetic radio frequencies used in transmission of voice, data and television.
Spillover
Satellite signal that falls on locations outside the beam pattern's defined edge of coverage.
Spin Stabilization
A form of satellite stabilization and attitude control which is achieved through spinning the exterior of the spacecraft about its axis at a fixed rate.
Splitter
A passive device (one with no active electronic components) which distributes a television signal carried on a cable in two or more paths and sends it to a number of receivers simultaneously.
Spot Beam
A focused antenna pattern sent to a limited geographical area. Spot beams are used by domestic satellites to deliver certain transponder signals to geographically well defined areas such as Hawaii, Alaska and Puerto Rico.
Spread Spectrum
The transmission of a signal using a much wider bandwidth and power than would normally be required. Spread spectrum also involves the use of narrower signals that are frequency hopped through various parts of the transponder. Both techniques produce low levels of interference Between the users. They also provide security in that the signals appear as though they were random noise to unauthorized earth stations. Both military and civil satellite applications have developed for spread spectrum transmissions.
SSMA
Spread spectrum multiple access. Refers to a frequency multiple access or multiplexing technique.
SSPA
Solid state power amplifier. A VSLI solid state device that is gradually replacing Traveling Wave ****s in satellite communications systems because they are lighter weight and are more reliable.
Stationkeeping
Minor orbital adjustments that are conducted to maintain the satellite's orbital assignment within the allocated "box" within the geostationary arc.
Subcarrier
A second signal "piggybacked" onto a main signal to carry additional information. In satellite television transmission, the video picture is transmitted over the main carrier. The corresponding audio is sent via an FM subcarrier. Some satellite transponders carry as many as four special audio or data subcarriers whose signals may or may not be related to the main programming.
Subsatellite Point
The unique spot over the earth's equator assigned to each geostationary satellite.
Superband
The frequency band from 216 to 600 MHz, used for fixed and mobile radios and additional television channels on a cable system.
Synchronization (Sync)
The process of orienting the transmitter and receiver circuits in the proper manner in order that they can be synchronized . Home television sets are synchronized by an incoming sync signal with the television cameras in the studios 60 times per second. The horizontal and vertical hold controls on the television set are used to set the receiver circuits to the approximate sync frequencies of incoming television picture and the sync pulses in the signal then fine tune the circuits to the exact frequency and phase.
SNG (Satellite News Gathering):
Transportable stations for accessing the satellite.
Solar Outage
Solar outages occur when a satellite dish is looking at a satellite, and the sun passes behind the satellite and within the field of view of the dish antenna. Solar outages occur during the spring and fall as the sun moves up and down the sky during the equinox. The outages only last a few minutes for a few days a year.
Splitter
A splitter is a passive device (one with no active electronic components) which distributes a television signal carried on a cable in two or more paths and sends it to a number of receivers simultaneously.
Spot Beam
A spot beam is a satellite transmission that is focused on a specific area within the footprint, or broadcast area, of the satellite. Both DISH Network and DirecTV use spot beams to increase the capacity of channels they can provide, thus allowing the broadcast of more local networks.
T
T1
The transmission bit rate of 1.544 millions bits per second. This is also equivalent to the ISDN Primary Rate Interface for the U.S. The European T1 or E1 transmission rate is 2.048 million bits per second.
T3 Channel (DS-3)
In North America, a digital channel which communicates at 45.304 Mbps.
Teleconference
An electronic multilocation, multiperson conference using audio, computer, slow-scan, or full-rate video systems.
Teledesic
The name of the U.S. proposed LEO satellite system that would deploy 840 satellites for global telecommunications services.
Telstar
The AT&T Corporation has maintained its trademark for the Telstar name and currently operates its domestic satellite system under the Telstar name.
Terrestrial TV (DVB-T)
Ordinary "over the air" VHF (very high frequency) and UHF (ultrahigh frequency) television transmissions which are usually limited to an effective range of 100 miles or less. Terrestrial tv transmitters operate at frequencies between 54 megahertz and 890 megahertz, far lower than the l4/l2 and 6/4 billion hertz (gigahertz) microwave frequencies used by satellite transponders. Digital Video Broadcasting Terrestial.
Three-Axis Stabilization
Type of spacecraft stabilization in which the body maintains a fixed attitude relative to the
orbital track and the earth's surface. The reference axes are roll, pinch, and yaw, by nautical analogy.
Threshold Extension
A technique used by satellite television receivers to improve the signal-to noise ratio of the receiver by approximately 3 db (50%). When using small receive-only antennas, a especially equipped receiver with a threshold extension feature can make the difference between obtaining a decent picture or no picture at all.
Thruster
A small axial jet used during routine stationkeeping activities. These are often fueled bydrazine or bi-propellant. In time ion-engines will probably replace such thrusters.
TI - Terrestrial Interference
Interference to satellite reception caused by ground based microwave transmitting stations.
Transfer Orbit
A highly elliptical orbit which is used as an intermediate stage for placing satellites into geostationary orbit.
Transmitter
An electronic device consisting of oscillator, modulator and other circuits which produce a radio or television electromagnetic wave signal for radiation into the atmosphere by an antenna.
Transponder
A combination receiver, frequency converter, and transmitter package, physically part of a communications satellite. Transponders have a typical output of five to ten watts, operate over a frequency band with a 36 to 72 megahertz bandwidth in the L, C, Ku, and sometimes Ka Bands or in effect typically in the microwave spectrum, except for mobile satellite communications. Communications satellites typically have between 12 and 24 onboard transponders although the INTELSAT VI at the extreme end has 50.
Transponder Hopping
A single TDMA equipped earth station can extend its capacity by having access to several down-link beams by hopping from one transponder to another. In such a configuration the number of available transponders must be equivalent to the square of the number of beams that are interconnected or cross-strapped.
TSS
Telecommunications Standardization Sector. The world standards setting organization resulting from the combination of the CCITT (Consultative Committee on Telephony and Telegraphy) and the CCIR (Consultative Committee on International Radio).
Turnkey
Refers to a system that is supplied, installed and sometimes managed by one vendor or manufacturer.
TVRO
Television Receive Only terminals that use antenna reflectors and associated electronic equipment to receive and process television and audio communications via satellite. Typically small home systems.
Tweeking
The process of adjusting an electronic receiver circuit to optimize its performance.
TWT (Traveling-wave ****)
A microwave **** of special design using a broadband circuit in which a beam of electrons interacts continuously with a guided electromagnetic field to amplify microwave frequencies.
TWTA (Traveling-wave-**** amplifier)
A combination of a power supply, a modulator (for pulsed systems), and a traveling-wave ****, often packaged in a common enclosure.
TCP / IP (Transmission Control Protocol / Internet Protocol):
Protocols to which the Internet is based. The former is responsible for dividing information into packets at source and then back together at destination, while the latter is responsible for adequately addressed through the network.
TDMA (Multiple Access Time Division):
Techniques through which a transponder can be shared between several stations. In the TDMA to each user is assigned all the available bandwidth, but only for a limited period of time that recurs periodically.
Transponder
A transponder is a satellite component that receives, modulates, amplifies, and retransmits a signal. More than one television or audio channel can be transmitted over a signal transponder using MPEG compression.
Twin 500 LNB
A twin 500 LNB is a combination of an LNBF and a multi-sat switch component for DISH 500 systems, accommodating up to 2 DISH Network receivers.
U
Unicast
A unicast application transmits a copy of every packet to every receiver.
Uplink
The earth station used to transmit signals to a satellite
USAT
Ultra Small Aperture Terminal. This refers to very small terminals for DBS and other satellite applications where the terminal can be very small (under 50 cms).
UHF:
Abbreviation of the term Ultra High Frequencies, used to designate the frequency band between 300 and 3000 MHz bands correspond to European television channels from 21 to 69.
USB (Universal Serial Bus)
USB is an industry standard developed in the mid-1990s that defines the cables, connectors and protocols used for connection, communication and power supply between computers and electronic devices.
USB was designed to standardize the connection of computer peripherals, such as keyboards, pointing devices, digital cameras, printers, portable media players, disk drives and network adapters to personal computers, both to communicate and to supply electric power. It has become commonplace on other devices, such as smartphones, PDAs and video game consoles. USB has effectively replaced a variety of earlier interfaces, such as serial and parallel ports, as well as separate power chargers for portable devices.
V
V.35
ITU-T standard describing a synchronous, physical layer protocol used for communications between a network access device and a packet network. V.35 is most commonly used in the United States and in Europe, and is recommended for speeds up to 48 Kbit/s.
Van Allen radiation belts
These are two high level radiation belts discovered by an Explorer Satellite designed by Dr. Van Allen of Cal Tech. These belts which are highly destructive to communications satellites consists of two belts of highly charged particles and high energy neutrons.
VBI
Vertical blanking interval.
Vertical Interval Test Signal
A method whereby broadcasters add test signals to the blanked portion of the vertical interval. Normally placed on lines 17 through 21 in both field one and two.
Very High Frequencies (VHF)
The range of frequencies extending from 30 to 300 MHz; also television channels 2 through 13.
VSAT
Very small aperture terminal. Refers to small earth stations, usually in the 1.2 to 2.4 meter range. Small aperture terminals under 0.5 meters are sometimes refered to Ultra Small Aperture Terminals (USAT's)
VSWR
Voltage Standing Wave Ratio. A measurement of mismatch in a cable, waveguide, or antenna system.
W
WARC
World Administrative Radio Conference sponsored by the ITU
Waveguide
A metallic microwave conductor, typically rectangular in shape, used to carry microwave signals into and out of microwave antennas.
X
X-Band
The frequency band in the 7-8 GHz region which is used for military satellite communications
X.25
A set of packet switching standards published by the CCITT.
X.400
A set of CCITT standards for global messaging.
Z
Zulu Time
This is the same a Greenwich Meridian Time (GMT). This is the time standard used in global satellite systems such as INTELSAT and INMARSAT in order to achieve global synchronization.
Just as I'll be adding more entries as they appear in different sites to complete the glossary.
This is an exclusive contribution from findeciclo to Satlover forum.
Thank you and best regards.
The following is a list of the more commonly used terms revolving around satellite tv.
New entries contributed by forum members, will be appreciated and added to the glossary.
From now on, I will complete the glossary every time I found a new word to insert into this thread. So my work is not finished.
Regards and thanks.
A
Access
The general term for the ability of a telecommunications user to make use of a network.
Access card
An access card, also known as a smart card, is a removable credit-card-sized plastic card included with each satellite receiver. It identifies each receiver and tells your program provider your Pay-Per-View (PPV) usage each month.
Acces Line
A local loop (q.v.)
Acknowledgment
A signal sent by a receiver to a transmitter to indicate that a message was received correctly.
Acoustical coupler
A type of modem that works by placing the telephone handset into rubber cups to use the acoustical signal from the microphone and receiver.
Additional Outlet (A/O)
An additional outlet lets you connect more than one receiver to the dish, allowing other televisions in the house to be on different programs than the one connected to the primary receiver.
ACTS
Advanced Communications Technology Satellite. A NASA experimental satellite project to demonstrate the use of the Ka-Band (30/20 GHz) services.
Amplifier
A device used to boost the strength of an electronic signal.
Amplitude Modulation (AM)
The baseband signal is caused to vary the amplitude or height of the carrier wave to create the desired information content.
Analog
A form of transmitting information characterized by continuously variable quantities, as opposed to digital transmission, which is characterized by discrete bits of information in numerical steps. An analog signal is responsive to changes in light, sound, heat and pressure.
Analog-to-Digital Conversion (ADC)
Process of converting analog signals to a digital representation. DAC represents the reverse translation.
ANIK
The Canadian domestic satellite system that transmits Canadian Broadcasting Corporation's (CSC) network feeds throughout the country. This system also carries long distance voice and data services throughout Canada as well as some transborder service to the U.S. and Mexico.
Antenna
A device for transmitting and receiving radio waves. Depending on their use and operating frequency, antennas can take the form of a single piece of wire, a di-pole a grid such as a yagi array, a horn, a helix, a sophisticated parabolic-shaped dish, or a phase array of active electronic elements of virtually any flat or convoluted surface.
Aperture
A cross sectional area of the antenna which is exposed to the satellite signal.
Apogee
The point in an elliptical satellite orbit which is farthest from the surface of the earth. Geosynchronous satellites which maintain circular orbits around the earth are first launched into highly elliptical orbits with apogees of 22,237 miles. When the communication satellite reaches the appropriate apogee, a rocket motor is fired to place the satellite into its permanent circular orbit of 22,237 miles.
Apogee Kick Motor (AKM)
Rocket motor fired to circulate orbit and deploy satellite into geostationary orbit.
Apstar (Asia-Pacific Star)
Name of the Chinese satellite system which carries commercial video services in the region.
Arabsat
This is the Arabsat Satellite Organization and its is headquartered in Riyadh, Saudi Arabia. It provides regional telecommunications services for the Middle East region.
AsiaSat
A satellite system covering the Asia mainland.
Asynchronous Communications
Stream of data routed through a network as generated, rather than in organized message blocks. Most personal computers send data in this format. (See ATM)
Asynchronous Transfer Mode (ATM)
This is the new form of super-fast packet switching operating at speeds in the Gigabits/second.
Attenuation
The loss in power of electromagnetic signals between transmission and reception points.
Attitude Control
The orientation of the satellite in relationship to the earth and the sun
Audio/Video (A/V) Jacks
The A/V output jacks at the rear of a satellite receiver provide a superior picture and sound to your TV, VCR and home theater system. Three jacks provide stereo sound: one for the video, one for the right channel sound and one for the left channel sound.
Amerhis:
Processing system for multimedia communications board embarked on the Amazonas 1 satellite. Allows the interface between users with a single jump of the signal multiplexing onboard the satellite, which reduces the cost of ground equipment, better use of resources spectral power onboard the satellite.
Audio/Video (A/V) Jacks
The A/V output jacks at the rear of a satellite receiver provide a superior picture and sound to your TV, VCR and home theater system. Three jacks provide stereo sound: one for the video, one for the right channel sound and one for the left channel sound.
Audio Subcarrier
The carrier between 5 MHz and 8 MHz containing audio (or voice) information inside of a video carrier.
Automatic Frequency Control (AFC)
A circuit which automatically controls the frequency of a signal.
Automatic Gain Control (AGC)
A circuit which automatically controls the gain of an amplifier so that the output signal level is virtually constant for varying input signal levels.
AZ/EL Mount
Antenna mount that requires two separate adjustments to move from one satellite to another;
Azimuth
The azimuth is the side-to-side adjustment of a satellite dish from true north, along the horizon, to the DBS satellite, measured in degrees
B
B channel
a 64 kbqs channel, part of the ISDN system, usable for voice or data..
B-Mac
A method of transmitting and scrambling television signals. In such transmissions MAC (Multiplexed Analog Component) signals are time-multiplexed with a digital burst containing digitized sound, video synchronizing, authorization, and information.
Backhaul
A terrestrial communications channel linking an earth station to a local switching network or population center.
Backoff
The process of reducing the input and output power levels of a traveling wave **** to obtain more linear operation.
Band Pass Filter
An active or passive circuit which allows signals within the desired frequency band to pass through but impedes signals outside this pass band from getting through.
Bandwidth
A measure of spectrum (frequency) use or capacity. For instance, a voice transmission by telephone requires a bandwidth of about 3000 cycles per second (3KHz). A TV channel occupies a bandwidth of 6 million cycles per second (6 MHz) in terrestrial Systems. In satellite based systems a larger bandwidth of 17.5 to 72 MHz is used to spread or "dither" the television signal in order to prevent interference.
Baseband
The basic direct output signal in an intermediate frequency based obtained directly from a television camera, satellite television receiver, or video tape recorder. Baseband signals can be viewed only on studio monitors. To display the baseband signal on a conventional television set a "modulator" is required to convert the baseband signal to one of the VHF or UHF television channels which the television set can be tuned to receive.
Baud
The rate of data transmission based on the number of signal elements or symbols transmitted per second. Today most digital signals are characterized in bits per second.
Band BSS (Broadcast Satellite Service):
Frequencies for satellite broadcasting services. In Europe, these include the sub-frequency band from 10.7 to 11.7 GHz for reception and for transmission from 17.3 to 18.1.
Band C:
Frequency band from 3.7 to 4.2 GHz for reception. For transmission, from 5.925 to 6.425 GHz.
Band FSS (Fixed Satellite System) :
This range of frequencies between 10.7 and 11.7 GHz, is a subdivision of the Ku band.
Band-Ku:
This range used by TV and radio, ranging from 10.70 to 12.75 GHz and 12.75 at the reception to 14.50 GHz for transmission. The band is more widespread in Europe, taking into account the small size of the dishes required for reception. It is subdivided into sub-bands: Telecom, DBS and others.
Band X :
This band is reserved for government uses.
Bandwidth
The bandwidth is the complete range of frequencies over which a circuit or electronic system is allocated to function, measured in MHz.
Beacon
Low-power carrier transmitted by a satellite which supplies the controlling engineers on the ground with a means of monitoring telemetry data, tracking the satellite, or conducting propagation experiments. This tracking beacon is usually a horn or omni antenna.
Beamwidth
The angle or conical shape of the beam the antenna projects. Large antennas have narrower beamwidths and can pinpoint satellites in space or dense traffic areas on the earth more precisely. Tighter beamwidths thus deliver higher levels of power and thus greater communications performance.
Bel
A unit of strength of a signal, equal to 10 decibels (q.v.)
Bird
Slang for a communications satellite located in geosynchronous orbit.
Bit
A single digital unit of information
Bit Error Rate
The fraction of a sequence of message bits that are in error. A bit error rate of 10-6 means that there is an average of one error per million bits.
Bit Rate
The speed of a digital transmission, measured in bits per second.
Blanking
An ordinary television signal consists of 30 separate still pictures or frames sent every second. They occur so rapidly, the human eye blurs them together to form an illusion of moving pictures. This is the basis for television and motion picture systems. The blanking interval is that portion of the television signal which occurs after one picture frame is sent and before the next one is transmitted. During this period of time special data signals can be sent which will not be picked up on an ordinary television receiver.
COLOR="Blue"]Blind Scan[/COLOR]
Is the ability of the receiver to scan all the frequencies whether they are stored or not stored in the memory of the receiver without inputing the transponders parameters mentioned above by the end user.
Block Down Converter
A device used to convert the 3.7 to 4.2 KHz signal down to UHF or lower frequencies (1 GHz and lower).
BPSK (Binary Phase Shift Keying)
A digital modulation technique in which the carrier phase can have one of two possible values, namely 0 degrees or 180 degrees.
Broad beam
A single large circular beam that covers a large geographic area
Broadcast
The sending of one transmission to multiple users in a defined group (compare to unicast).
BSS (Broadcast Satellite Service)
This is the ITU designation but DBS or Direct Broadcast Service is more commonly used term in the satellite industry.
Business Television
Corporate communications tool involving video transmission of information via satellite.
Common uses of business television are for meetings, product introductions and training.
Buttonhook Feed
A shaped piece of waveguide directing signal from the feed to the LNA behind the antenna.
Bypass
Use of satellite, local area network, wide area network or metropolitan area network as an alternative transmission facility.
Broadband platform:
Infrastructure system that integrates land or HUB, satellite and VSAT (Very Small Aperture Terminal) to provide IP services such as Internet access, videoconferencing, VoIP ... inherent in satellite coverage.
C
C Band
This is the band between 4 and 8 GHz with the 6 and 4 GHz band being used for satellite communications. Specifically, the 3.7 to 4.2 GHz satellite communication band is used as the down link frequencies in tandem with the 5.925 to 6,425 GHz band that serves as the uplink.
Card Sharing
Also known as control word sharing, is a method of allowing multiple clients or digital television receivers to access a subscription television network with only one valid subscription card. This is achieved by electronically sharing a part of the legitimate conditional access smart card's output data, enabling all recipients to gain simultaneous access to scrambled DVB streams, held on the encrypted television network.
Typically, a legitimate smart card is attached to a host digital television receiver, which is equipped with software to share the decrypted 64-bit "control word" key over a computer network, such as the Internet. Once a client receives this key, they can decrypt the encrypted content as though they were using their own subscription card.
Carrier
The basic radio, television, or telephony center of frequency transmit signal. The carrier in an analog signal. is modulated by manipulating its amplitude (making it louder or softer) or its frequency (shifting it up or down) in relation to the incoming signal. Satellite carriers operating in the analog mode are usually frequency modulated.
Carrier Frequency
The main frequency on which a voice, data, or video signal is sent. Microwave and satellite communications transmitters operate in the band from 1 to 14 GHz (a GHz is one billion cycles per second).
Carrier to Noise Ratio (C/N)
The ratio of the received carrier power and the noise power in a given bandwidth, expressed in dB. This figure is directly related to G/T and S/N; and in a video signal the higher the C/N, the better the received picture.
Carterphone decision
The 1986 court decision that allowed non-Bell equipment to be connected to the telephone network.
Cassegrain Antenna
The antenna principle that utilizes a subreflector at the focal point which reflects energy to or from a feed located at the apex of the main reflector.
CATV
Originally meant Community Antenna Television. Independent smaller companies in rural communities would build a large television receiving antenna on a nearby mountain to pick up the weak TV signals from a distant metropolis. These signals were amplified, modulated onto television channels and sent along a coaxial cable strung from house to house.
CCITT (now TSS)
Comite Consultatif Internationale de Telegraphique et Telephonique. International body, associated with the ITU, which establishes worldwide standards for telecommunications. Reorganized to include CCIR (radio standards group) and renamed TSS (Telecommunications Standardization Sector).
CDMA
Code division multiple access. Refers to a multiple-access scheme where stations use spread-spectrum modulations and orthogonal codes to avoid interfering with one another.
Channel
A frequency band in which a specific broadcast signal is transmitted. Channel frequencies are specified in the United States by the Federal Communications Commission. Television signals require a 6 MHz frequency band to carry all the necessary picture detail.
Physical environment by transmitting a specific signal. The bandwidth of a television channel, for example, 6 MHz, in the United States and 8 MHz in Europe for the Hertzian cable reception. In satellites, it can reach a total of 27, 36 or 72 MHz.
Cyclical redundancy check
A mathematical algorithm to produce an error-checking code within a data stream.
CIF
Common Intermediate Format. A compromise television display format adopted by the CCITT which is relatively easy to derive from both PAL and NTSC.
Circular Polarization
Unlike many domestic satellites which utilize vertical or horizontal polarization, the international Intelsat satellites transmit their signals in a rotating corkscrew-like pattern as they are down-linked to earth. On some satellites, both right-hand rotating and left-hand rotating signals can be transmitted simultaneously on the same frequency; thereby doubling the capacity of the satellite to carry communications channels.
Clamp
A video processing circuit that removes the energy dispersal signal component from the video waveform.
Check Switch
Running a check switch procedure starts a series of tests in DISH network receivers which confirms that a good signal connection between the receiver and the multi-sat dish switch exists. At the end of the test, a list of which satellites you can receive is displayed.
Clarke Belt
Named after its founder Arthur C. Clarke, the Clarke Belt is an orbit used by satellites at a height of 22,250 miles, in which satellites make an orbit in 24 hours, yet remain in a fixed position relative to the earth’s surface.
Coax Cable
Coax or coaxial cable is the standard type of cable used by all satellite TV technicians. Coax cable carries the signal from the dish to the satellite receiver and on to your VCR and TV.
Codec
Coder/decoder system for digital transmission.
Co-Location
Ability of multiple satellites to share the same approximate geostationary orbital assignment frequently due to the fact that different frequency bands are used.
Color Subcarrler
A subcarrier that is added to the main video signal to convey the color information. In NTSC systems, the color subcarrier is centered on a frequency of 3.579545 MHz, referenced to the main video carrier.
Common Carrier
Any organization which operates communications circuits used by other people. Common carriers include the telephone companies as well as the owners of the communications satellites, RCA, Comsat, Direct Net Telecommunications, AT&T and others. Common carriers are required to file fixed tariffs for specific services.
Companding
A noise-reduction technique that applies single compression at the transmitter and complementary expansion at the receiver.
Composite Baseband
The unclamped and unfiltered output of the satellite receiver's demodulator circuit, containg the video information as well as all transmitted subcarriers.
Compression Algorithms
Software that allows codecs to reduce the number of bits required for data storage or transmission.
COMSAT
The Communications Satellite Corporation (part of Lockheed Martin) which serves as the U.S. Signatory to INTELSAT and INMARSAT.
Conformal array
An antenna that “conforms” to the surface of the structure carrying it. A conformal array may be built into the skin of an aircraft. Conformal arrays are lighter and smaller than conventional flat arrays.
Conus
Contiguous United States. In short, all the states in the U.S. except Hawaii and Alaska.
Cross Modulation
A form of signal distortion in which modulation from one or more RF carrier(s) is imposed on another carrier.
CSU
Channel service unit. A digital interface device that connects end-user equipment to the local digital telephone loop. CSU is frequently coupled with DSU (see below) as CSU/DSU.
C/T
Carrier-to-noise-temperature ratio.
D
D-Channel
A 16 kbps channel within the ISDN system, usable for either packet data or network signaling.
DAMA
Demand-Assigned Multiple Access - A highly efficient means of instantaneously assigning telephony channels in a transponder according to immediate traffic demands.
Datalink
The circuit and equipment that allows data to be transmitted between terminals.
Datalink protocol
A standard that governs how two terminals exchange data at the datalink level.
Data terminal equipment (DTE)
A device capable of transmitting digital data over a communications circuit.
DBS (Direct Broadcasting Satellite):
Initially referred to the Ku-band satellites that use power ****s very strong dimension, such as TDF, satellite TV and Tele X. DBS also designates the portion of Ku-band between 11.7 and 12.5 GHz, whichever is the satellite used.
dBi
The dB power relative to an isotropic source.
dBW
The ratio of the power to one Watt expressed in decibels.
De-BPSK
Differential Binary Phase Shift Keying
De-QPSK
Differential Quadrature Phase Shift Keying.Decibel (dB)
The standard unit used to express the ratio of two power levels. It is used in communications to express either a gain or loss in power between the input and output devices.
Declination
The offset angle of an antenna from the axis of its polar mount as measured in the meridian plane between the equatorial plane and the antenna main beam.
Decoder:
Team, in conjunction with a smart card allows the user to access the service. In the case of digital reception, the decoder is built into the receiver (IRD).
Deemphasis
Reinstatement of a uniform baseband frequency response following demodulation.
Delay
The time it takes for a signal to go from the sending station through the satellite to the receiving station. This transmission delay for a single hop satellite connection is very close on one-quarter of a second.
Demodulator
A satellite receiver circuit which extracts or "demodulates" the "wanted "signals from the received carrier.
Deviation
The modulation level of an FM signal determined by the amount of frequency shift from the frequency of the main carrier.
Digital:
System in which information is processed by electrical impulses of "on-off" (on-off), "high-low" (high-low) or "1-0" instead of signals or states in constant flux as happens with analog systems.
Digital Speech Interpolation
DSI - A means of transmitting telephony. Two and One half to three times more efficiently based on the principle that people are talking only about 40% of the time.
Discriminator
A type of FM demodulator used in satellite receivers.
Direct Broadcast Satellite (DBS)
DBS is the signal frequency range (11.70-12.40ghz) intended for DirecTV broadcast by satellite TV program providers.
Digital Compression
Digital compression is a process of translating video images into a digital code. Its purpose is to take up less transmission space than the original signal would have, allowing more channels per satellite transponder.
Direct broadcasting satellite provider
direct broadcasting satellite provider is a company that transmits a variety of channels to subscribers via satellite dish. Like cable companies, they offer a set package of channels at a variety of prices. In the United States, the providers are DirecTV and DISH Network
DirecTV System
A DirecTV System, trademarked for the consumer hardware and created to receive DirecTV programming, includes a dish (standard size is 18"), a remote control and the DirecTV Receiver.
DirecWay
DirecWay is the new name for the DirecPC satellite internet access system offered by Hughes Networking. Two connection types are offered. A dial-return-system (DRS) uses your existing dial-up service to provide a connection to the internet for all out going data and the satellite is used to route all returning data via satellite. The DRS systems offer a very nice Internet browsing experience at about half the upfront and monthly cost. The satellite-return-system (SRS) uses no phone lines after the initial setup and provides a 24/7 connection.
DISH Network System
DISH Network System, trademarked for the consumer hardware and created to receive DISH Network programming, includes a dish (standard size is a 20" multi-sat dish, called DISH 500), a remote control, and the DISH Network Receiver.
DISH 500
A DISH 500 is a multi-satellite dish used to receive DISH Network programming. Some programming for DISH Network is only available if you have a DISH 500 dish or a 2nd single satellite dish pointed to the 110 satellite for DISH Network. The DISH 500 dish is used to receive simultaneous satellite signals from the 119 and 110 satellite slots.
Dithering
he process of shifting the 6-MHz satellite-tv signal up and down the 36-MHz satellite transponder spectrum at a rate of 30 times per second (30 Hertz). The satellite signal is "dithered" to spread the transmission energy out over a band of frequencies far wider than a terrestrial common carrier microwave circuit operates within, thereby minimizing the potential interference that any one single terrestrial microwave transmitter could possibly cause to the satellite transmission.
Dolby Digital/AC-3 Compatible
Dolby Digital provides 6 independent sound track channels through the optical output jack. When connected to your AC3 compatible home theater audio setup, this connection provides Dolby Digital Surround Sound (when Dolby Digital is part of the programming being viewed).
Dolby Pro Logic
Dolby Pro Logic (known as Dolby Surround in the theaters) is based on the use of an amplitude-phase matrix. This is a method of encoding four channels of information into two tracks of stereo media and then decoding them back into four channels for playback.
DOMSAT
Domestic communications satellite.
Down-Converter
That portion of the Fixed Satellite Service (FSS) television receiver that converts the signals from the 4-GHz microwave range to (typically) the more readily used baseband or intermediate frequency (IF) 70-MHz range.
Downlink
The satellite to earth half of a 2 way telecommunications satellite link. Often used to describe the recieve dish end of the link.
DSU
Data service unit. A device used in digital transmission that adapts the physical interface on a DTE device to a transmission facility such as T1 or E1. The DSU is also responsible for such functions as signal timing. DSU is freqnetly coupled with a CSU (see above) as CSU/DSU.
DSS
DSS is an acronym for Digital Satellite System. It’s also a common name used to refer to a DirecTV satellite system or component.
DTH
DTH, or Direct-To-Home, is the official term used by the Federal Communications Commission to refer to the satellite television and broadcasting industries.
It refers to the transmission of radio signals from a satellite directly to user's home, through a small dish.
Dual LNB
A dual LNB is an LNB, or Low Noise Block-Down Converter) system that features two outputs rather than one and allow satellite television subscribers to watch multiple channels on separate television sets simultaneously. Dual LNB systems use only one parabolic satellite dish, but have two cable connections that are connected to separate televisions in the user’s house. When the LNB collects television signals, it splits them into two equal signals that are received by each television at the same time. Like dual LNB systems, triple and quadruple LNB systems are also .
Dual offset dish antenna
This type of satellite dish has two dishes, a larger receiving dish and a small dish facing the opposite direction that takes the signal and transfers it to the LNC. The dual offset dish antenna has an 80% efficiency.
Free to air satellite system (FTA): An FTA satellite system refers to a satellite receiver that is configured to receive encrypted FTA satellite transmissions. FTA broadcasts are public domain and you do not have to pay for a subscription to any type of satellite provider to receive them.
Dual Spin
Spacecraft design whereby the main body of the satellite is spun to provide altitude stabilization, and the antenna assembly is despun by means of a motor and bearing system in order to continually direct the antenna earthward. This dual-spin configuration thus serves to create a spin stabilized satellite.
Dual tone multifrequency
A signaling system in which each digit dialed is indicated by two tones.
Duplex Transmission
Capability for simultaneous data transmission between a sending station and a receiving station.
DVB
Digital Video Broadcasting - The European-backed project to harmonise adoption of digital video.
It is a European specification for digital broadcast television, associated with the compression format MPEG-2.
E
E1
Wide-area digital transmission facility used predominantly in Europe that carries data at a rate of 2.048 Mbit/s.
E3
Wide-area digital transmission facility used predominantly in Europe that carries data at a rate of 34.368 Mbit/s.
Earth Exploration Satellite Service
A radio communications service between an earth station and one or more space stations. The service may include links between space stations in which information relating to the characteristics of the earth and its natural phenomena is obtained from active or passive sensors on earth satellites. Similar information is collected from airborne or earth-based platforms and such information may be distributed to earth stations within the systems concerned. Platform interrogation may be included and the service may also include feeder links necessary for its operation.
Earth Station
The term used to describe the combination or antenna, low-noise amplifier (LNA), down-converter, and receiver electronics. used to receive a signal transmitted by a satellite. Earth Station antennas vary in size from the.2 foot to 12 foot (65 centimeters to 3.7 meters) diameter size used for TV reception to as large as 100 feet (30 meters) in diameter sometimes used for international communications. The typical antenna used for INTELSAT communication is today 13 to 18 meters or 40 to 60 feet.
Echo Canceller
An electronic circuit which attenuates or eliminates the echo effect on satellite telephony links. Echo cancellers are largely replacing obsolete echo suppressors.
Echo Effect
A time-delayed electronic reflection of a speaker's voice. This is largely eliminated by modern digital echo cancellers.
Eclipse
When a satellite passes through the line between the earth and the sun or the earth and the moon.
Eclipse Protected
Refers to a transponder that can remain powered during the period of an eclipse.
El/Az
An antenna mount providing independent adjustments in elevation and azimuth.
Edge of Coverage
Limit of a satellite's defined service area. In many cases, the EOC is defined as being 3 dB down from the signal level at beam center. However, reception may still be possible beyond the -3dB point.
Effective Monopoleradiated Power (EMRP) (In a given direction)
The product of the lower supplied to the antenna and its gain relative to a short vertical antenna in a given direction.
EIRP(PIRE) (effective isotropic radiated power)
Effective Isotropic Radiated Power - This term describes the strength of the signal leaving the satellite antenna or the transmitting earth station antenna, and is used in determining the C/N and S/N. The transmit power value in units of dBW is expressed by the product of the transponder output power and the gain of the satellite transmit antenna.
Electronic Program Guide (EPG)
A chronological listing of all available programming covering an extended time period (typically 36 hours or more). This listing displays on your TV screen.
Elevation
The upward tilt to a satellite antenna measured in degrees required to aim the antenna at the communications satellite. When. aimed at the horizon, the elevation angle is zero. If it were tilted to a point directly overhead, the satellite antenna would have an elevation of 90 degrees.
Encoder
A device used to electronically alter a signal so that it can only be viewed on a receiver equipped with a special decoder.
Energy Dispersal
A low-frequency waveform combined with the baseband signal prior to modulation, to spread the FM signal's peak power across the available transponder bandwidth in order to reduce the potential for creating interference to ground-based communications services.
EOL
End of Life of a satellite.
Equatorial Orbit
An orbit with a plane parallel to the earth's equator.
Equivalent satellite link noise temperature
The noise station temperature of the receiving antenna of the earth station corresponding to the radio frequency noise power that produces the total observed noise at the ouput of the satellite link excluding noise due to interference coming from satellite links using other satellites and form terrestrial systems.
ESC
Engineering Service Circuit - The 300-3,400 Hertz voice plus teletype (S+DX) channel used for earth station-to-earth station and earth station-to-operations center communications for the purpose of system maintenance, coordination and general system information dissemination. In analog (FDM/FM) systems there are two S+DX channels available for this purpose in the 4,000-12,000 Hertz portion of the baseband. In digital systems there are one or two channels available which are usually convened to a 32 or 64 Kbps digital signal and combined with the earth station traffic digital bit stream. Modern ESC equipment interfaces with any mix of analog and digital satellite carriers, as well as backhaul terrestrial links to the local switching center.
Eutelsat
The European Telecommunications Satellite Organization which is headquartered in Paris, France. It provides a satellite network for Europe and parts of North Africa and the Middle East.
Extended binary-codec decimal interchange code (EBCDIC)
An IBM originated 8-bit code used to represent characters internally in IBM equipment and sometime for external communications.
F
FCC (Federal Communications Commission)The U.S. federal regulatory body, consisting of five members, one of who is designated chairman, appointed by the President and confirmed by the Senate, which regulates interstate communications under the Communications Act of 1934.
F/D
Ratio of antenna focal length to antenna diameter. A higher ratio means a shallower dish.
FDMA
Frequency division multiple access. Refers to the use of multiple carriers within the same transponder where each uplink has been assigned frequency slot and bandwidth. This is usually employed in conjunction with Frequency Modulation.
Feed
This term has at least two key meanings within the field of satellite communications. It is used to describe the transmission of video programming from a distribution center. It is also used to describe the feed system of an antenna. The feed system may consist of a subreflector plus a feedhorn or a feedhorn only.
Feeder link
A radio link from an earth station at a specified fixed point to a space station, or vice versa, that conveys information for a space radio communications service other than for the fixed satellite service.
Feedhorn
A satellite TV receiving antenna component that collects the signal reflected from the main surface reflector and channels this signal into the low-noise amplifier (LNA).
Fiber optics
The technology in which a modulated beam of light carries information through a thin glass or plastic fiber
Filter
A device designed to allow only a predetermined range of frequencies t pass through it.
Filter Satellite service (FSS)
The telecommunications service between nonmoving Earth stations (but the antennas may be moveable, just not in motion at the time of use).
Flat antenna:
A flat antenna is the most compact type of satellite dish. This type of antenna does not have an exterior LNC. It is located within the dish. These types of satellite dishes are best for homes near the center of the satellite footprint area.
FM
Frequency ModulationA modulation method whereby the baseband signal varies the frequency of the carrier wave.
FM Threshold
That point at which the input signal power is just strong enough to enable the receiver demodulator circuitry successfully to detect and recover a good quality television picture from the incoming video carrier.
Focal Length
Distance from the center feed to the center of the dish.
Focal Point
The area toward which the primary reflector directs and concentrates the signal received.Footprint*A map of the signal strength showing the EIRP contours of equal signal strengths as they cover the earth's surface. Different satellite transponders on the same satellite will often have different footprints of the signal strength. The accuracy of EIRP footprints or contour data can improve with the operational age of the satellite. The actual EIRP levels of the satellite, however, tends to decrease slowly as the spacecraft ages.
Forward Error Correction (FEC)
Adds unique codes to the digital signal at the source so errors can be detected and corrected at the receiver.
Frame
A unit block of data.
Frequency
The number of times that an alternating current goes through its complete cycle in one second of time. One cycle per second is also referred to as one hertz; 1000 cycles per second, one kilohertz; 1,000,000 cycles per second, one megahertz: and 1,000,000,000 cycles per second, one gigahertz.
Frequency Coordination
A process to eliminate frequency interference between different satellite systems or between terrestrial microwave systems and satellites. In the U.S. this activity relies upon a computerized service utilizing an extensive database to analyze potential microwave interference problems that arise between organizations using the same microwave band. As the same C-band frequency spectrum is used by telephone networks and CATV companies when they are contemplating the installation of an earth station, they will often obtain a frequency coordination study to determine if any problems will exist.
Frequency derived channel
A channel within a frequency divided multiplexed group of channels.
Frequency Reuse
A technique which maximizes the capacity of a communications satellite through the use of specially isolated beam antennas and/or the use of dual polarities.
Full duplex
A circuit which carriers information in both directions at the same time.
G
Gain
A measure of amplification expressed in dB.
Gateway
Any device which is an interface between difference networks.
GE Americon
This is a large U.S. corporation providing satellite systems for domestic communications. Has ownership in some international satellites.
Geostationary
Refers to a geosynchronous satellite angle with zero inclination. so the satellite appears to hover over one spot on the earth's equator.
Geostationary Transfer Orbit
This orbit is in the equatorial plane. This type of orbit has an elliptical form, with a perigee at 200 km and an apogee at 35870 km.
Geosynchronous
The Clarke circular orbit above the equator. For a planet the size and mass of the earth, this point is 22,237 miles above the surface.
Gigahertz (GHz)
One billion cycles per second. Signals operating above 3 Gigahertz are known as microwaves. above 30 GHz they are know as millimeter waves. As one moves above the millimeter waves signals begin to take on the characteristics of Iightwaves.
Global Beam
An antenna down-link pattern used by the Intelsat satellites, which effectively covers one-third of the globe. Global beams are aimed at the center of the Atlantic, Pacific and Indian Oceans by the respective Intelsat satellites, enabling all nations on each side of the ocean to receive the signal. Because they transmit to such a wide area, global beam transponders have significantly lower EIRP outputs at the surface of the Earth as compared to a US domestic satellite system which covers just the continental United States. Therefore, earth stations receiving global beam signals need antennas much larger in size (typically 10 meters and above (i.e.30 feet and up).
Gregorian Dual-reflector antenna system employing a paraboloidal main reflector and a concave ellipsoidal subreflector.
Globalstar
A mobile satellite system that deployes a network of 48 satellites to create a global voice and data service. This system is backed by Qualcomm, Loral, and Alcatel.
G/T
A figure of merit of an antenna and low noise amplifier combination expressed in dB. "G" is the net gain of the system and "T" is the noise temperature of the system. The higher the number, the better the system.
Grade of service
A measure of the probability of a user being unable to use a network because it is busy.
Guard Channel
Television channels are separated in the frequency spectrum by spacing them several megahertz apart. This unused space serves to prevent the adjacent television channels from interfering with each other.
H
HDTV
HDTV, or High Definition Television, is a digital television format, that combines high-resolution video and theater-like sound to create a movie theater-quality TV viewing experience.
Half-Duplex (HDX)
A circuit which can carry information in both directions, but on in one direction at a time.
Half Transponder
A method of transmitting two TV signals through a single transponder through the reduction of each TV signal's deviation and power level. Half-transponder TV carriers each operate typically 4 dB to 7 dB below single-carrier saturation power.
Hard Reset
A hard reset is the same as rebooting a computer touching the on/off button (Hardware).
Harmonic distortion
Overtones (harmonics) produced when a simple signal wave is sent through a circuit with nonlinear electrical characteristics.
Headend
Electronic control center - generally located at the antenna site of a CATV system - usually including antennas, preamplifiers, frequency converters, demodulators and other related equipment which amplify, filter and convert incoming broadcast TV signals to cable system channels.
Heliosynchronous Orbit
At an altitude of 600 to 800 km and situated in a quasi-polar plane. The satellite is permanently visible from that part of the Earth in sunlight. Heliosynchronous orbits are used for Earth observation or solar-study satellites.
HEO
Highly Elliptical Orbit. This is type of orbit used by the Russian Molniya Satellite system. It is also referred to as Extremely Elliptical Orbit (EEO).
Hertz (Hz)
The name given to the basic measure of radio frequency characteristics. An electromagnetic wave completes a full oscillation from its positive to its negative pole and back again in what is known as a cycle. A single Hertz is thus equal to one cycle per second.
High Frequency (HF)
Radio frequencies within the range of 3,000 to 30,000 kilohertz. HF radio is known as shortwave.
Hierarchical Network
A telecommunications network in which a message is passed through nodes or different classes.
High Level Datalink Control (HDLC)
A bit-oriented datalink protocol standardized by the ISO.
High-Power Satellite
Satellite with 100 watts or more of transponder RF power.
Hour Angle
Steering direction of a polar mount. An angle measured in the equatorial plane between the antenna beam and the meridian plane.
Hub
The master station through which all communications to, from and between micro terminals must flow. in the future satellites with on-board processing will allow hubs to be eliminated as MESH networks are able to connect all points in a network together.
I
Interactive TV
Interactive TV lets you use the enclosed remote control to access up-to-the-minute news, sports, financial information, weather, get program trivia, respond to free offers and shop, all while you watch TV.
IBS
INTELSAT Business Services.
IFRB
International Frequency Registration Board of the ITU - International Telecommunications Union. The IFRB regulates the allocation of satellite orbital locations.
Inclination
The angle between the orbital plane of a satellite and the equatorial plane of the earth.
INMARSAT
The International Maritime Satellite Organization operates a network of satellites for international transmissions for all types of international mobile services including maritime, aeronautical, and land mobile.
INTELSAT
The International Telecommunications Satellite Organization operates a network of satellites for international transmissions.
Interchange carrier
A common carrier which carries traffic between LATA’s.
Interchange channel
A link between two changes
Interference
Energy which tends to interfere with the reception of the desired signals, such as fading from airline flights, RF interference from adjacent channels, or ghosting from reflecting objects such as mountains and buildings.
Inter Satellite Link - ISL
Radio or optical communications links between satellites. They serve to interconnect constellations of satellites.
INTERSPUTNIK
The international entity formed by the Soviet Union to provide international communications via a network of Soviet satellites.
IRD
An integrated receiver and decoder for reception of a transmission of voice, video and data.
Iridium Satellite System
This was a 66 satellite network designed for mobile telephone use and is now defunct.
ISDN - Integrated Services Digital Network.
A CCITT standard for integrated transmission of voice, video and data. Bandwidths include: Basic Rate Interface - BR (144 Kbps - 2 B & 1 D channel) and Primary Rate - PRI (1.544 and 2.048 Mbps).
ISO
International Standards Organization. Develops standards such as JPEG and MPEG. Closely allied with the CCITT.
Isotropic Antenna
A hypothetical omnidirectional point-source antenna that serves as an engineering reference for the measurement of antenna gain.
ITU
International Telecommunication Union.
ISP:
Internet Service Provider
J
Jammer -
An active electronic counter-measures (ECM) device designed to deny intelligence to unfriendly detectors or to disrupt communications.
JPEG
ISO Joint Picture Expert Group standard for the compression of still pictures.
K
Ka Band
The frequency range from 18 to 31 GHz.
Kbps
Kilobits per second. Refers to transmission speed of 1,000 bits per second.
Kelvin (K)
The temperature measurement scale used in the scientific community. Zero K represents absolute zero, and corresponds to minus 459 degrees Fahrenheit or minus 273 Celsius. Thermal noise characteristics of LNA are measured in Kelvins.
Kilohertz (kHz)
Refers to a unit of frequency equal to 1,000 Hertz.
Klystron
A microwave **** which uses the interaction between an electron beam and the RF energy on microwave cavities to provide signal amplification. The klystron operates on principles of velocity modulation very similar to those in a TWT except that klystron interaction takes place at discrete locations along the electron beam. Common types of klystrons are the reflex klystron (an oscillator having only one cavity), two-cavity klystron amplifiers and oscillators, and multi-cavity klystron amplifiers.
Ku Band
The frequency range from 10.9 to 17 GHz.
L
Land mobile satellite service
A mobile satellite service in which mobile earth stations are located on land.
LATA
See Local Acess and Transport Area.
Leased facility
A telecommunications facility leased for the sole use of on e customer. Also called a private line.
Line conditioning
See Conditioning.
Line switching
Circuit switching.
Line termination device
Any device, such as a modern, which connects a data machine to a transmission facility.
Link
See Channel.
Link access protocol (LAP)
A CCITT standard bit-oriented protocol. Link Access Protocol Balanced (LAPB) is a variant. Both are subsets of HDLC.
LNA (Low noise converter)
A preamplifier used to strengthen a weak satellite signal. The LNA is used at the feedhorn of the TVRO satellite antenna and typically features a nosie figure to 120 degrees Kelvin.
Leased Line
A dedicated circuit typically supplied by the telephone company.
Loading
The adding of loading, or inductance, coils to a transmission circuit to minimize distortion.
Local access and transport area (LATA)
A geological area within which a local telephone company provides service. Service between LATA’s os carried by IEC’s.
Local area network (LAN)
A private data communication network connecting terminals usually within a limited geological range, and operating at high speed.
Local exchange
Also called an end office, the exchange in a telephone network where the user’s line terminate.
Local loop
A (usually 2-wire) connection between a telephone exchange office and a subscriber.
Longitudinal redundancy check
A technique for detecting errors in transmitted blocks of information.
Low Noise Amplifier (LNA)
This is the preamplifier between the antenna and the earth station receiver. For maximum effectiveness, it must be located as near the antenna as possible, and is usually attached directly to the antenna receive port. The LNA is especially designed to contribute the least amount of thermal noise to the received signal.
Low Noise Block Downconverter (LNB)
A combination Low Noise Amplifier and downconverter built into one device attached to the feed.
Low Noise Converter (LNC)
A combination Low Noise Amplifier and down converter built into one antenna-mounted package.
Low Orbit
At an altitude of 200 to 300 km this orbit is used for certain types of scientific or observation satellites, which can view a different part of the Earth beneath them on each orbit revolution, as they overfly both hemispheres.
Low-Power Satellite
Satellite with transmit RF power below 30 watts.
L-Band
An L-Band is the frequency range from 0.5 to 1.5 GHz. All satellite TV systems use this frequency (950 to 1450 MHz) to carry the satellite signal from the dish to the receiver.
LNBF
An LNBF (usually called an LNB) is a Low Noise Block Converter with Integrated Feed. It amplifies received signals and converts them from microwaves to lower L-band frequency signals which are then sent along a cable to the satellite receiver.
LMDS (Local Multipoint Distribution System):
LMDS is a radio technology that has been developed for wireless local access broadband. Enables access to voice, data, Internet and video. Use the radio band of 25 GHz (or higher).
M
MAC (A, B, C, D2)
Multiplexed analog component color video transmission system. Subtypes refer to the various methods used to transmit audio and data signals.
Margin
The amount of signal in dB by which the satellite system exceeds the minimum levels required for operation.
Master Antenna Television (MATV)
An antenna system that serves a concentration of television sets such as in apartment buildings, hotels or motels.
Medium-Power Satellite
Satellite generating transmit power levels ranging from 30 to 100 watts.
Megahertz (MHz)
Refers to a frequency equal to one million Hertz, or cycles per second.
Microwave
Line-of sight, point-to-point transmission of signals at high frequency. Many CATV systems receive some television signals from a distant antenna location with the antenna and the system connected by microwave relay. Microwaves are also used for data, voice, and indeed all types of information transmission. The growth of fiber optic networks have tended to curtail the growth and use of microwave relays.
Microwave Interference
Interference which occurs when an earth station aimed at a distant satellite picks up a second, often stronger signal, from a local telephone terrestrial microwave relay transmitter. Microwave interference can also be produced by nearby radar transmitters as well as the sun itself. Relocating the antenna by only several feet will often completely eliminate the microwave interference.
Modem
A communications device that modulates signals at the transmitting end and demodulates them at the receiving end.
Modulation
The process of manipulating the frequency or amplitude of a carrier in relation to an incoming video, voice or data signal.
Modulator
A device which modulates a carrier. Modulators are found as components in broadcasting transmitters and in satellite transponders. Modulators are also used by CATV companies to place a baseband video television signal onto a desired VHF or UHF channel. Home video tape recorders also have built-in modulators which enable the recorded video information to be played back using a television receiver tuned to VHF channel 3 or 4.
Molniya
The Russian domestic satellite system which operated with highly elliptical satellites which overlooked the high latitudes of the territories of the USSR.
MPEG
The Moving Pictures Experts Group, the television industry's informal standards group.
MPEG-2
The agreed standard covering the compression of data (coding and encoding) for digital television.
MPEG-2 MP@HL
Main Provile at High Level - The agreed much higher bit-rate system adopted to provide high definition television in wide screen format.
Multiple Access
The ability of more than one user to have access to a transponder.
Multiple System Operator (MSO)
A company that operates more than one cable television system.
Multipoint Distribution System (MDS)
A common carrier licensed by the FCC to operate a broadcast-like omnidirectional microwave transmission facility within a given city typically carrying television signals
Multicast
Multicast is a subset of broadcast that extends the broadcast concept of one to many by allowing "the sending of one transmission to many users in a defined group, but not necessarily to all users in that group."
Multiplexing
Techniques that allow a number of simultaneous transmissions over a single circuit.
Mux
A Multiplexer. Combines several different signals (e.g. video, audio, data) onto a single communication channel for transmission. Demultiplexing separates each signal at the receiving end.
Matrix Switch
By using a Matrix switch you can add more than two receivers to a dual LNB.
MPEG2/MPEG4
MPEG2/MPEG4 is a video compression method. Compression is used to combine several programs into one satellite transponder.
Multi-satellite dish
It's often necessary for consumers to use a multi-satellite system, such as the DirecTV Oval Dish or DISH Networks DISH 500 because some programming extends beyond the satellite provider's "core" programming, like HDTV programs, and local channels in many areas.
Multi-satellite switch
To accommodate the multi-sat dishes offered by DirecTV and DISH Network, you must use a multi-sat switch. You can’t intermix DirecTV and DISH Network switches. DirecTV controls a multi-sat switch with a 22kHz signal and DISH Network use a digital signal to communicate with their switches.
Must Carry
Effective at the beginning of 2002, the FCC established a condition that if a satellite service provider is going to carry one local network in a specific market place or DMA then they must carry all local networks in that market place.
MMDS (Multipoint Microwave Distribution System):
It's wireless cable without cable or wires. Terrestrial broadcast system that uses the band 2.5 to 2.7 GHz MMDS broadcast can be analog (Pal, Secam, NTSC) or digital. It is very common in some countries, especially Africa.
Multiplex:
Is the signal that brings together a set of tablets and broadcast programs simultaneously on the same frequency.
N
NAB
National Association of Broadcasters.
NASA (National Aeronautics and Space Administration)
The U.S. agency which administers the American space program, including the deployment of commercial and military satellites via a fleet of space shuttle vehicles.
NASDA
National Space Development Agency of Japan.
NCTA
National Cable Television Association.
Noise
Any unwanted and unmodulated energy that is always present to some extent within any signal.
Noise Figure (NF)
A term which is a figure of merit of a device, such as an LNA or receiver, expressed in dB, which compares the device with a perfect device.
NTIA
The National Telecommunications and Information Administration is a unit of the Department of Commerce that address U.S. government telecommunications policy, standards setting and radio spectrum allocation.
Nutation Damping
The process of correcting the nutational effects of a spinning satellite which are similar in effect to a wobbling top. Active nutation controls use thruster jets.
NTSC - National Television Standards Committee
A video standard established by the United States (RCA/NBC} and adopted by numerous other countries. This is a 525-line video with 3.58-MHz chroma subcarrier and 60 cycles per second.
O
Offset dish antenna
The offset dish antenna has the LNC located to the side of the dish. This way, the LNC does not interfere with the signal path, which can reach the dish unobstructed. Because this offers better performance, these dishes can be much smaller than the prime feed focus dishes.
OFTEL
The Office of Telecommunications of the United Kingdom government. This unit a part of the Department of Industries regulates telecommunications in the United Kingdom.
Orbital Period
The time that it takes a satellite to complete one circumnavigation of its orbit.
Orbital Slots
Orbital slots refer to the location of satellites around the globe. Their are 6 main slots used for DBS TV.
OSD
On screen display. Menu that appears on the screen/display of multimedia applications.
OTA (Over the Air)
This is the acronym commonly used to describe standard television broadcast signals received by a rooftop antenna, sometimes called off-air.
P
Packet Switching
Data transmission method that divides messages into standard-sized packets for greater efficiency of routing and transport through a network.
PAL - Phase Alternation System
The German developed TV standard based upon 50 cycles.per second and 625 lines.
Parabolic Antenna
The most frequently found satellite TV antenna, it takes its name from the shape of the dish described mathematically as a parabola. The function of the parabolic shape is to focus the weak microwave signal hitting the surface of the dish into a single focal point in front of the dish. It is at this point that the feedhorn is usually located.
PBS (Public Broadcasting System)
A domestic USA television and radio broadcast network.
Perigee
The point in an elliptical satellite orbit which is closest to the surface of the earth.
Perigee Kick Motor (PKM)
Rocket motor fired to inject a satellite into a geostationary transfer orbit from a low earth orbit especially that of a STS or Shuttle-based orbit of 300 to 500 miles altitude.
Period
The amount of time that a satellite takes to complete one revolution of its orbit.
Phase Alternation System (PAL)
A European color television system incompatible with the US NTSC television system.
Phase-Locked Loop (PLL)
A type of electronic circuit used to demodulate satellite signals.
Polarization
A technique used by the satellite designer to increase the capacity of the satellite transmission channels by reusing the satellite transponder frequencies. In linear cross polarization schemes, half of the transponders beam their signals to earth in a vertically polarized mode; the other half horizontally polarize their down links. Although the two sets of frequencies overlap, they are 90 degree out of phase, and will not interfere with each other. To successfully receive and decode these signals on earth, the earth station must be outfitted with a properly polarized feedhorn to select the vertically or horizontally polarized signals as desired.
In some installations, the feedhorn has the capability of receiving the vertical and horizontal transponder signals simultaneously, and routing them into separate LNAs for delivery to two or more satellite television receivers. Unlike most domestic satellites, the Intelsat series use a technique known as left-hand and right-hand circular polarization.
Polarization Rotator
A device that can be manually or automatically adjusted to select one of two orthogonal polarizations.
Polar Mount
Antenna mechanism permitting steering in both elevation and azimuth through rotation about a single axis. While an astronomer's polar mount has its axis parallel to that of the earth, satellite earth stations utilize a modified polar mount geometry that incorporates a declination offset.
Polar Orbit
An orbit with its plane aligned in parallel with the polar axis of the earth
Protected-Use Transponder
A satellite transponder provided by the common carrier to a programmer with a built-in insurance policy. If the protected-use transponder fails, the common carrier guarantees the programmer that it will switch over to another transponder, sometimes pre-empting some other non-protected programmer from the other transponder.
PTT - Post Telephone and Telegraph Administration
Refers to operating agencies directly or indirectly controlled by governments in charge of telecommunications services in most countries of the world.
Pulse Code Modulation
A time division modulation technique in which analog signals are sampled and quantized at periodic intervals into digital signals. The values observed are typically represented by a coded arrangement of 8 bits of which one may be for parity.
Pay Per View (PPV)
A pay-per-view event may be purchased separately from any package or subscription. This could include a movie, special event, sporting event, or an ***** program.
Parental Lockout
Parental Lockout allows users to set a password to control access to programming based on channel, rating or content.
Platform:
Also called the Service Module, is responsible for maintaining operational satellites in its orbital lifetime.
Broadband platform:
Infrastructure system that integrates land or HUB, satellite and VSAT (Very Small Aperture Terminal) to provide IP services such as Internet access, videoconferencing, VoIP ... inherent in satellite coverage.
PIRE (EIRP) (effective isotropic radiated power):
Equivalent to the power radiated by an antenna that emits in all directions. It is the transmitter power and antenna gain. The EIRP is expressed in dBW (decibel / watt). Its value is a factor in the quality of reception.
Pixelization
Pixelization occurs due to errors in decoding the MPEG bit stream where areas or patches of color appear instead of the higher resolution image. It might be described as the picture "breaking up". The patches of blocks appear and disappear, and can happen anywhere on the screen but usually are "part" of the image "in motion". Pixelization most often occurs during rain fade or if the satellite system has too low a signal strength to operate properly.
Prime feed focus dish
This is a large parabolic dish, with a diameter over 1.4 meters, with the LNC mounted centrally in the dish facing outward. Because it is located in the center of the dish, the LNC blocks a lot of the incoming signals. For that reason, this type of satellite is only 50% effective in receiving radio signals.
PVR
A Personal Video Recorder PVR satellite receiver) has a built in hard drive for digitally recording satellite television programs, with high time recording capability and two internal satellite receivers. Dual tuners allow the user to record one program while watching another or record two programs at the same time. But not only have PVR satellite receivers with two tuners inside. You can record the same channel you are watching. You can record your favourite sat tv program at HD, USB pendrives or memory cards.
The PVRs are, usually, building into a TV set, set top box or pcsat receiver.
Q
QPSK (Quaternary Phase Shift Keying):
It is a method of modulation used for digital satellite broadcasts. The information is in the phase of the modulated signal, in four states.
Quad LNBF
A combination LNBF and multi-sat switch component for DISH 500 systems can accommodate up to 4 DISH Network receivers.
R
Radio waves
Radio waves are an invisible form of electromagnetic radiation that varies in wavelength from one millimeter to 100,000 km. Satellites send your television signal via radio waves to your satellite dish antenna.
Rain Outage / Fade
Loss of signal at Ku or Ka Band frequencies due to absorption and increased sky-noise temperature caused by heavy rainfall.
Receiver (Rx)
An electronic device which enables a particular satellite signal to be separated from all others being received by an earth station, and converts the signal format into a format for video, voice or data.
Receiver Sensitivity
Expressed in dBm this tells how much power the detector must receive to achieve a specific baseband performance, such as a specified bit error rate or signal to noise ratio.
RF Adaptor
An add-on modulator which interconnects the output of the satellite television receiver to the input (antenna terminals) of the user's television set. The RF adaptor converts the baseband video signal coming from the satellite receiver to a radio frequency RF signal which can be tuned in by the television set on VHF channel 3 or 4.
Router
Network layer device that determines the optimal path along which network traffic should be forwarded. Routers forward packets from one network to another based on network layer information.
Rating Limit:
The rating limit is set by the customer using the main menu. When a system lock is active, this limit controls the viewing of programs that have been assigned a rating level.
Remote Extender
A remote extender is an after-market device that allows you to use an Infrared (IR) remote to control a satellite receiver from another room.
RG-59
An RG-59 is a common coax cable used in many homes for the last 40 years.
RG-6:
An RG-6 coax cable is recommended for digital satellite TV installations. RG-6 is a larger-size cable than the lower-grade RG-59 cable found in some homes.
R/F connectors
The R/F connectors are the output/input screws on connections for coaxial cable. They won’t provide stereo from the satellite receiver to the TV or stereo.
S
Satellite
A sophisticated electronic communications relay station orbiting 22,237 miles above the equator moving in a fixed orbit at the same speed and direction of the earth (about 7,000 mph east to west).
Satellite footprint
The footprint of a satellite is the ground area where its transponders offer coverage. Basically, every satellite has a geographic area where its signal can be received.
Satellite Terminal
A receive-only satellite earth station consisting of an antenna reflector (typically parabolic in shape), a feedhorn, a low-noise amplifier (LNA), a down converter and a receiver.
SAW (Surface Acoustic Wave)
A type of steep-skirted filter used in the baseband or IF section of satellite reception and transmission equipment.
S-Video Jack
Some televisions have an input for an S-Video cable. This is better than audio/video jacks or R/F connectors. It is for the video, not the sound.
Satellite Dish
A satellite dish is used to collect signals from a satellite in orbit and focus them to the front of the dish where a feed horn collects them and passes the signals on to the LNB to be amplified and sent to a satellite receiver.
SBCA
The SBCA (Satellite Broadcasting Communication Association) is an organization of satellite TV manufacturers, program providers, distributors and dealers. They are the leading voice for the satellite industry in congress and all across the U.S.
Scalar Feed
A type of horn antenna feed which uses a series of concentric rings to capture signals that have been reflected toward the focal point of a parabolic antenna.
Scrambler
A device used to electronically alter a signal so that it can only be viewed or heard on a receiver equipped with a special decoder.
Secam
A color television. system developed by the French and used in the USSR. Secam operates with 625 lines per picture frame and 50 cycles per second, but is incompatible in operation with the European PAL system or the U.S. NTSC system.
Set Top Box
A set-top box (STB) or set-top unit (STU) is an information appliance device that generally contains a tuner and connects to a television set and an external source of signal, turning the signal into content which is then displayed on the television screen or other display device
SFD - Stauration Flux Density
The power required to achieve saturation of a single repeater channel on the satellite.
Sidelobe
Off-axis response of an antenna.
Signal to Noise Ratio (S/N)
The ratio of the signal power and noise power. A video S/N of 54 to 56 dB is considered to be an excellent S/N, that is, of broadcast quality. A video S/N of 48 to 52 dB is considered to be a good S/N at the headend for Cable TV.
SILVO
An organization formed in the mid 1980's to monitor frequency re-use.
Simplex Transmission
Capability for transmission in only one direction between sending station and receiving station.
Single-Channel-Per-Carrier (SCPC)
A method used to transmit a large number of signals over a single satellite transponder.
Single Sideband (SSB)
A form of amplitude modulation (AM) whereby one of the sidebands and the AM carrier are suppressed.
Skew
An adjustment that compensates for slight variance in angle between identical senses of polarity generated by two or more satellites.
Slant Range
The length of the path between a communications satellite and an associated earth station.
Slot
That longitudinal position in the geosynchronous orbit into which a communications satellite is "parked". Above the United States, communications satellites are typically positioned in slots which are based at two to three degree intervals.
SMATV (Satellite Master Antenna System)
The adding of an earth station to a MATV system to receive satellite programs.
SNG
Satellite news gathering usually with a transportable uplink truck.
Snow
A form of noise picked up by a television receiver caused by a weak signal. Snow is characterized by alternate dark and light dots appearing randomly on the picture ****. To eliminate snow, a more sensitive receive antenna must be used, or better amplification must be provided in the receiver (or both).
Solar Outage
Solar outages occur when an antenna is looking at a satellite, and the sun passes behind or near the satellite and within the field of view of the antenna. This field of view is usually wider than the beamwidth. Solar outages can be exactly predicted as to the timing for each site.
Sparklies
A form of satellite television "snow" caused by a weak signal. Unlike terrestrial VHF and UHF television snow which appears to have a softer texture, sparklies are sharper and more angular noise "blips". As with terrestrial reception, to eliminate sparklies, either the satellite antenna must be increased in size, or the low noise amplifier must be replaced with one which has a lower noise temperature.
Spectrum
The range of electromagnetic radio frequencies used in transmission of voice, data and television.
Spillover
Satellite signal that falls on locations outside the beam pattern's defined edge of coverage.
Spin Stabilization
A form of satellite stabilization and attitude control which is achieved through spinning the exterior of the spacecraft about its axis at a fixed rate.
Splitter
A passive device (one with no active electronic components) which distributes a television signal carried on a cable in two or more paths and sends it to a number of receivers simultaneously.
Spot Beam
A focused antenna pattern sent to a limited geographical area. Spot beams are used by domestic satellites to deliver certain transponder signals to geographically well defined areas such as Hawaii, Alaska and Puerto Rico.
Spread Spectrum
The transmission of a signal using a much wider bandwidth and power than would normally be required. Spread spectrum also involves the use of narrower signals that are frequency hopped through various parts of the transponder. Both techniques produce low levels of interference Between the users. They also provide security in that the signals appear as though they were random noise to unauthorized earth stations. Both military and civil satellite applications have developed for spread spectrum transmissions.
SSMA
Spread spectrum multiple access. Refers to a frequency multiple access or multiplexing technique.
SSPA
Solid state power amplifier. A VSLI solid state device that is gradually replacing Traveling Wave ****s in satellite communications systems because they are lighter weight and are more reliable.
Stationkeeping
Minor orbital adjustments that are conducted to maintain the satellite's orbital assignment within the allocated "box" within the geostationary arc.
Subcarrier
A second signal "piggybacked" onto a main signal to carry additional information. In satellite television transmission, the video picture is transmitted over the main carrier. The corresponding audio is sent via an FM subcarrier. Some satellite transponders carry as many as four special audio or data subcarriers whose signals may or may not be related to the main programming.
Subsatellite Point
The unique spot over the earth's equator assigned to each geostationary satellite.
Superband
The frequency band from 216 to 600 MHz, used for fixed and mobile radios and additional television channels on a cable system.
Synchronization (Sync)
The process of orienting the transmitter and receiver circuits in the proper manner in order that they can be synchronized . Home television sets are synchronized by an incoming sync signal with the television cameras in the studios 60 times per second. The horizontal and vertical hold controls on the television set are used to set the receiver circuits to the approximate sync frequencies of incoming television picture and the sync pulses in the signal then fine tune the circuits to the exact frequency and phase.
SNG (Satellite News Gathering):
Transportable stations for accessing the satellite.
Solar Outage
Solar outages occur when a satellite dish is looking at a satellite, and the sun passes behind the satellite and within the field of view of the dish antenna. Solar outages occur during the spring and fall as the sun moves up and down the sky during the equinox. The outages only last a few minutes for a few days a year.
Splitter
A splitter is a passive device (one with no active electronic components) which distributes a television signal carried on a cable in two or more paths and sends it to a number of receivers simultaneously.
Spot Beam
A spot beam is a satellite transmission that is focused on a specific area within the footprint, or broadcast area, of the satellite. Both DISH Network and DirecTV use spot beams to increase the capacity of channels they can provide, thus allowing the broadcast of more local networks.
T
T1
The transmission bit rate of 1.544 millions bits per second. This is also equivalent to the ISDN Primary Rate Interface for the U.S. The European T1 or E1 transmission rate is 2.048 million bits per second.
T3 Channel (DS-3)
In North America, a digital channel which communicates at 45.304 Mbps.
Teleconference
An electronic multilocation, multiperson conference using audio, computer, slow-scan, or full-rate video systems.
Teledesic
The name of the U.S. proposed LEO satellite system that would deploy 840 satellites for global telecommunications services.
Telstar
The AT&T Corporation has maintained its trademark for the Telstar name and currently operates its domestic satellite system under the Telstar name.
Terrestrial TV (DVB-T)
Ordinary "over the air" VHF (very high frequency) and UHF (ultrahigh frequency) television transmissions which are usually limited to an effective range of 100 miles or less. Terrestrial tv transmitters operate at frequencies between 54 megahertz and 890 megahertz, far lower than the l4/l2 and 6/4 billion hertz (gigahertz) microwave frequencies used by satellite transponders. Digital Video Broadcasting Terrestial.
Three-Axis Stabilization
Type of spacecraft stabilization in which the body maintains a fixed attitude relative to the
orbital track and the earth's surface. The reference axes are roll, pinch, and yaw, by nautical analogy.
Threshold Extension
A technique used by satellite television receivers to improve the signal-to noise ratio of the receiver by approximately 3 db (50%). When using small receive-only antennas, a especially equipped receiver with a threshold extension feature can make the difference between obtaining a decent picture or no picture at all.
Thruster
A small axial jet used during routine stationkeeping activities. These are often fueled bydrazine or bi-propellant. In time ion-engines will probably replace such thrusters.
TI - Terrestrial Interference
Interference to satellite reception caused by ground based microwave transmitting stations.
Transfer Orbit
A highly elliptical orbit which is used as an intermediate stage for placing satellites into geostationary orbit.
Transmitter
An electronic device consisting of oscillator, modulator and other circuits which produce a radio or television electromagnetic wave signal for radiation into the atmosphere by an antenna.
Transponder
A combination receiver, frequency converter, and transmitter package, physically part of a communications satellite. Transponders have a typical output of five to ten watts, operate over a frequency band with a 36 to 72 megahertz bandwidth in the L, C, Ku, and sometimes Ka Bands or in effect typically in the microwave spectrum, except for mobile satellite communications. Communications satellites typically have between 12 and 24 onboard transponders although the INTELSAT VI at the extreme end has 50.
Transponder Hopping
A single TDMA equipped earth station can extend its capacity by having access to several down-link beams by hopping from one transponder to another. In such a configuration the number of available transponders must be equivalent to the square of the number of beams that are interconnected or cross-strapped.
TSS
Telecommunications Standardization Sector. The world standards setting organization resulting from the combination of the CCITT (Consultative Committee on Telephony and Telegraphy) and the CCIR (Consultative Committee on International Radio).
Turnkey
Refers to a system that is supplied, installed and sometimes managed by one vendor or manufacturer.
TVRO
Television Receive Only terminals that use antenna reflectors and associated electronic equipment to receive and process television and audio communications via satellite. Typically small home systems.
Tweeking
The process of adjusting an electronic receiver circuit to optimize its performance.
TWT (Traveling-wave ****)
A microwave **** of special design using a broadband circuit in which a beam of electrons interacts continuously with a guided electromagnetic field to amplify microwave frequencies.
TWTA (Traveling-wave-**** amplifier)
A combination of a power supply, a modulator (for pulsed systems), and a traveling-wave ****, often packaged in a common enclosure.
TCP / IP (Transmission Control Protocol / Internet Protocol):
Protocols to which the Internet is based. The former is responsible for dividing information into packets at source and then back together at destination, while the latter is responsible for adequately addressed through the network.
TDMA (Multiple Access Time Division):
Techniques through which a transponder can be shared between several stations. In the TDMA to each user is assigned all the available bandwidth, but only for a limited period of time that recurs periodically.
Transponder
A transponder is a satellite component that receives, modulates, amplifies, and retransmits a signal. More than one television or audio channel can be transmitted over a signal transponder using MPEG compression.
Twin 500 LNB
A twin 500 LNB is a combination of an LNBF and a multi-sat switch component for DISH 500 systems, accommodating up to 2 DISH Network receivers.
U
Unicast
A unicast application transmits a copy of every packet to every receiver.
Uplink
The earth station used to transmit signals to a satellite
USAT
Ultra Small Aperture Terminal. This refers to very small terminals for DBS and other satellite applications where the terminal can be very small (under 50 cms).
UHF:
Abbreviation of the term Ultra High Frequencies, used to designate the frequency band between 300 and 3000 MHz bands correspond to European television channels from 21 to 69.
USB (Universal Serial Bus)
USB is an industry standard developed in the mid-1990s that defines the cables, connectors and protocols used for connection, communication and power supply between computers and electronic devices.
USB was designed to standardize the connection of computer peripherals, such as keyboards, pointing devices, digital cameras, printers, portable media players, disk drives and network adapters to personal computers, both to communicate and to supply electric power. It has become commonplace on other devices, such as smartphones, PDAs and video game consoles. USB has effectively replaced a variety of earlier interfaces, such as serial and parallel ports, as well as separate power chargers for portable devices.
V
V.35
ITU-T standard describing a synchronous, physical layer protocol used for communications between a network access device and a packet network. V.35 is most commonly used in the United States and in Europe, and is recommended for speeds up to 48 Kbit/s.
Van Allen radiation belts
These are two high level radiation belts discovered by an Explorer Satellite designed by Dr. Van Allen of Cal Tech. These belts which are highly destructive to communications satellites consists of two belts of highly charged particles and high energy neutrons.
VBI
Vertical blanking interval.
Vertical Interval Test Signal
A method whereby broadcasters add test signals to the blanked portion of the vertical interval. Normally placed on lines 17 through 21 in both field one and two.
Very High Frequencies (VHF)
The range of frequencies extending from 30 to 300 MHz; also television channels 2 through 13.
VSAT
Very small aperture terminal. Refers to small earth stations, usually in the 1.2 to 2.4 meter range. Small aperture terminals under 0.5 meters are sometimes refered to Ultra Small Aperture Terminals (USAT's)
VSWR
Voltage Standing Wave Ratio. A measurement of mismatch in a cable, waveguide, or antenna system.
W
WARC
World Administrative Radio Conference sponsored by the ITU
Waveguide
A metallic microwave conductor, typically rectangular in shape, used to carry microwave signals into and out of microwave antennas.
X
X-Band
The frequency band in the 7-8 GHz region which is used for military satellite communications
X.25
A set of packet switching standards published by the CCITT.
X.400
A set of CCITT standards for global messaging.
Z
Zulu Time
This is the same a Greenwich Meridian Time (GMT). This is the time standard used in global satellite systems such as INTELSAT and INMARSAT in order to achieve global synchronization.
Just as I'll be adding more entries as they appear in different sites to complete the glossary.
This is an exclusive contribution from findeciclo to Satlover forum.
Thank you and best regards.
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