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ANTENNA: The device that sends out and/or receives signals from the satellite. Also referred to as a satellite dish.

BANDWITH: The amount of spectrum a communication channel (analog or digital) uses, measured in hertz (Hz).

BIRD: The nickname for a satellite.

BROADBAND: A term used to refer to high-speed communication networks that are designed to handle bandwidth-intensive applications.

BROADCASTING: To transmit the same information to multiple receivers simultaneously over a satellite system, radio/TV station, data communications network or e-mail system.

C-BAND: Refers to the frequency in the 3.4 GHz to 7GHZ range. Portions of this band are dedicated to satellite communications. Satellite downlinks are 3.7 to 4.2 GHz.

CACHE: A place to store something temporarily. Web pages you request are stored in your browser's cache directory on your hard disk. When you return to a page you've recently viewed, the browser gets it from the cache rather than the original server, saving you time and the network additional traffic. You can usually vary the size of your cache, depending on your practical browser.

CACHE SERVER: A server relatively close to Internet users and typically within a business enterprise that saves (caches) Web pages and possibly FTP and other files that all users have requested. Successive requests for these pages or files can be satisfied by the cache server rather than the Internet. A cache server not only gets information more quickly but also reduces Internet traffic.

COMPRESSION: Reducing the amount of bandwidth needed to transmit video or audio by digitizing an analog signal, thus increasing the ability able to load multiple services on a satellite transponder.

DBS: Direct Broadcast Satellite. A service that uses satellites to broadcast multiple channels of television programming directly to small dish antennas.

DECODER: A device used to unscramble encrypted or "scrambled" television signals.

DIGITAL: A quantification scheme that allows the conversion of analog information into bits of data. Digitization allows for signal compression and for maintaining signal integrity.

DOWNLINK: The transmission of radio frequency signals from a satellite to an earth station.

EARTH STATION: A ground-based antenna and associated equipment used to receive and/or transmit telecommunications signals via satellite.

FCC: Federal Communications Commission. The U.S. federal regulatory agency responsible for the regulation of interstate and international communications by radio, television, wire, satellite, and cable.

FEEDS: Device mounted at the focal point of the antenna that gathers signals reflected from the dish. Also a television signal source.

FOOTPRINT: The coverage area of the earth's surface within which the signals of a specific satellite can be received.

FREQUENCY: The rate at which a signal (e.g. electrical current) alternates. The standard unit of frequency is the hertz, abbreviated Hz. If a signal completes one cycle per second, then the frequency is 1 Hz; 60 cycles per second equals 60 Hz.

• Hz: Hertz. The name of the basic measure of frequency with which an electromagnetic wave completes a full cycle from its positive to its negative pole and back again. Each unit is equal to one cycle per second.
  
  
• KHz: Kilohertz. Refers to a unit of frequency equal to 1,000 Hertz.
  
  
• MHz: Megahertz. Refers to a frequency equal to one million Hertz.
  
• GHz: Gigahertz. Refers to a frequency equal to one billion Hertz.

GEOSYNCHRONOUS ORBIT: An orbit 22,300 miles above the earth's equator where satellites circle at the same rate as the earth's rotation.

GMT: Greenwich Mean Time. The time zone that includes Greenwich, England is bisected by zero degrees longitude. This is the time notation that is used for booking international satellite time.

HEADEND: Location where cable television systems collect and distribute satellite programming.

HYBRID SATELLITE: A satellite that carries two or more different communications payloads (i.e. C-band and Ku-band).

INCLINED ORBIT: A condition that occurs when a satellite is no longer station-kept in the north-south plain. A satellite operator might do so to extend the life of a satellite because fuel will only be used to perform station-keeping in the east-west plain. The inclination happens gradually over time, and once it becomes excessive, the satellite is de-orbited.

ISDN: Integrated services digital network. A standard for the integrated transmission of voice, video, and data developed by the Consultative Committee on International Telephony and Telegraphy (CCITT).

JPEG: Joint pictures expert group. A subgroup of ISO, which has established international standards for the digital compression of still pictures.

Ka-BAND: Primarily used in satellites operating at 30Ghz uplink and 20 GHz downlink and is intended in support of future applications such as mobile voice. A portion of the RF spectrum located between 18 GHz and 31 GHz.

Ku-BAND: Refers to the frequency in the 12 GHz to 14 GHz range used in support of such applications as broadcast TV, DBS, and direct-to-home television.

LNB: Low noise blockdownconverter. An electronic part of a satellite earth station that is used to amplify the signal collected by the reflector and the feedhorn.

MCPC: Multi-channel per carrier. A signal comprised of multiple digital streams that are multiplexed into a single stream, which is then transmitted on single carrier. This is typically used combine multiple CDV signal into one.

MPEG: MPEG the Moving Picture Experts Group, develops standards for digital video and digital audio compression. It operates under the auspices of the International Organization for Standardization. The MPEG standards are evolving, each designed for a different purpose.

NAB: National Association of Broadcasters. A U.S.-based organization that fosters and promotes radio and television broadcasting. PanAmSat has a booth at the NAB trade show held once a year in Las Vegas.

PAYLOAD: Supports the primary mission of the satellite, the receipt and transmission of signals, and comprises systems that include receivers, multiplexers, high-powered amplifiers and signal processing.

POLARIZATION: The orientation of a transmitted/received signal. Signals can have circular or linear polarization.

SCPC: Single Channel Per Carrier. A scheme in which only one signal is loaded on a carrier.

SIMPLEX OPERATION: Transmissions sent in only one direction of a telecommunications channel.

SPACE SEGMENT: A term that describes the portion of the total communications satellite system that is physically located in orbit around the earth.

SPECTRUM: The range of electromagnetic radio frequencies used in transmission of voice, data and television.

STREAMING: Streaming video is a sequence of "moving images" that are sent in compressed form over the Internet and displayed by the viewer as they arrive. Streaming media is streaming video with sound. With streaming video or streaming media, a Web user does not have to wait to download a large file before seeing the video or hearing the sound. Instead, the media is sent in a continuous stream and is played as it arrives. The user needs a player, a special program that uncompresses and sends video data to the display and audio data to speakers. A player can be either an integral part of a browser or downloaded from the software maker's Web site.

SUN OUTAGE: When the sun passes behind a satellite in relation to the earth, and the sun's energy momentarily interferes with the satellite signals. Occurs two times each year during spring and fall equinox.

T-1: Refers to bit rate of 1.544 million b/s for the United States. The European E-1 transmission bit rate is 2.048 Mb/s.

TELEPORT: Technical ground facility used for satellite communications. PanAmSat operates six domestic teleports: Atlanta, GA; Napa, CA; Fillmore, CA; Long Beach, CA; Castle Rock, CO; Homestead, FL; and Spring Creek, NY.

TRACKING: An earth station feature that allows for tracking inclined satellites.

TRANSPONDER: A Radio frequency path through a satellite with a specific bandwidth, uplink/downlink frequency and beam. Transponders can be sold in whole or can be segmented into smaller pieces of bandwidth.

UPLINK: The transmission of radio frequency signals to a satellite from an earth station.