Glossary of Terms

Nobody is born knowing every TLA (three-letter acronym) or buzzword of every hobby or field of study. That's okay, really. Most of the time, you don't even need to know what a word means; if all you do with a PID is type it into your receiver, who cares what PID stands for?

But thankfully, most FTA explorers are of a curious bent. They're looking for new channels with new experiences. And curious people often want to know what a word or TLA really means. If that sounds like you, here are some FTA-related definitions and explanation of terms you'll hear as a satellite hobbyist.

At the end of most of these definitions, there's a link to a Wikipedia entry for a lengthier explanation.

(If you find a related term that isn't covered here, please let us know so we can tell you and add that term here.)

Analog The old style of TV delivery, where the amplitude or frequency variations corresponded to the intensity of particular colors.

Antenna For most satellite TV signals, it's a parabolic dish. For over-the-air TV reception, it's usually shaped pointy, bow-tied, or round.

APID Audio payload identifier. The number associated with a particular audio channel within a multiplexed stream.

ATSC The standard developed by the Advanced Television Systems Committee for digital TV transmission. In the Americas, it replaced the NTSC analog system.

Attenuation The amount of strength that a signal loses as it travels through space.

Azimuth In pointing satellite dishes, it's the compass direction of the satellite.

Bandwidth The range of frequencies used by a given signal.

Bird Slang for satellite.

Bit The one-or-zero basic unit of digital communication.

Bit Rate The amount of information sent per unit of time, typically expressed in kilobits (kbps) or megabits (Mbps) per second.

Broadcast Distribution from one sender to many recipients.

C Band The range of frequencies used by large (six feet or wider) dishes.

Carrier An electromagnetic wave that carries program content in its signal.

CATV Originally Community Antenna Television, where a local system would put an antenna on a nearby hill to pick up regional over-the-air TV signals. Later used for all cable TV.

Channel Depending on how it's used, a channel can be a specific frequency for a given information source, or it can be the information source itself.

Circular Polarization The polarization method in which the signal is transmitted in a clockwise or counter-clockwise sequence. Used by Dish Network and Bell TV.

Clarke Belt The only place where satellites can stay in geosynchronous orbit. It's a narrow band about 22,000 miles above the equator. The idea of geostationary orbit was first widely popularized by Arthur C. Clarke in 1945.

Coaxial Cable The thick wires with (typically) screw-on connectors that link LNBs to switches and receivers. It's also used by cable TV providers. For FTA, use RG-6 grade or better, not RG-59.

Conus Short for CONtinental United States. You could also say it means the contiguous 48 states.

DBS Direct broadcast satellite, or satellite programming intended for direct reception by home viewers.

Declination (Magnetic) The difference between true north and magnetic north at a given point.

Digital Any technology expressed numerically, as opposed to analog.

Down Converter A device which converts the received signal to a frequency better able to travel to the receiver. Typically found in the antenna feedhorn.

Downlink The link from a satellite to a ground station.

DTV Digital TV. All HDTV is DTV, but some DTV is not HDTV.

DVB The digital video broadcasting standards maintained by an international consortium. Some of those standards of interest to FTA viewers are DVB-S, used in almost all FTA receivers, and DVB-S2, which is capable of HDTV.

Earth Station A place on the ground designed to communicate with satellites. Usually used to describe large teleports, but technically, any active satellite dish is part of an earth station.

EIRP Equivalent isotropically radiated power, or in small words, the strength of a signal at a particular spot.

Elevation The up angle a dish needs to point to a given satellite.

FCC The Federal Communications Commission, the independent government agency in charge of regulating all radio-wave signals.

Feed Any digital stream. Typically used to describe temporary streams on satellite.

Feedhorn The part of a satellite antenna positioned at the focal point of the dish's parabola.

Footprint The area of the earth's surface from which a particular satellite's signals can be received.

FEC Forward error correction, or added bits used to compensate for reception errors.

Frequency The measurement of how often a cycle repeats.

FTA Free-to-air, meaning unencrypted. FTA TV channels can be viewed without a subscription by anyone with a matching FTA receiver.

Geosynchronous The kind of orbit where the satellite stays in the same position relative to earth. While the earth spins, a geosynchronous satellite has travel almost 2 miles per second to keep up.

IRD An integrated receiver and decoder. Y'know, a typical satellite receiver.

Ka Band Called K-above, it's covers the microwave frequencies of 26.5 to 40 GHz.

Ku Band Refers to K-under and pronounced kay-you. It's the set of frequencies used by relatively small dish antennas.

Linear Polarization The polarization method in which the signal is transmitted in a vertical or horizontal sequence. Used by most FTA Ku-band and C-band channels.

LNB(F) Low-noise block converter, sometimes including the feedhorn. Converts satellites' high frequencies to lower frequencies better suited to traveling through coax to a receiver.

MPEG A set of audio and video compression standards set by the Motion Picture Experts Group.

Mux Short for multiplexing, the way of sandwiching multiple channels into one stream. Sometimes used to describe the channels within one stream.

NAB The National Association of Broadcasters, the trade organization for over-the-air radio and TV stations.

NTSC The analog TV system previously common in the Americas, named for the National Television System Committee.

OTA Over-the-air, or terrestrial broadcasting. In other words, an earth-only signal that you get directly from a station a few miles away.

PAL Phase alternating line, the analog TV format used in most of Europe and elsewhere.

Signal Rate The rate of raw data flow in bits or kilobits per second.

SNG Satellite news gathering. Typically a temporary feed, it can be fun to watch reporters prepare themselves.

Solar Outage When the sun lines up with a particular satellite for a few minutes near midday around the equinoxes. The shadows cast during those times can be helpful in showing where line-of-sight to that satellite may be blocked.

Spot Beam A satellite signal with a small footprint. Often used to send a local OTA station's signal to pay-TV satellite viewers near that station.

Station-keeping The adjustment a satellite makes to stay in the same apparent position.

TLA Three-letter acronym, or three-letter abbreviation. TLA is a TLA.

Transponder Short for transmitter-responder, it's a device that receives a signal and sends it back out using a different frequency.

TVRO Television receive-only. An old term used to distinguish typical home viewer setups from more elaborate earth stations that both send and receive signals.

Uplink The link from a ground station to a satellite.

VPID Video payload identifier. The number associated with a particular video channel within a multiplexed stream.