A spot beam, in
telecommunications
Telecommunication, often used in its plural form or abbreviated as telecom, is the transmission of information over a distance using electronic means, typically through cables, radio waves, or other communication technologies. These means of ...
parlance, is a
satellite
A satellite or an artificial satellite is an object, typically a spacecraft, placed into orbit around a celestial body. They have a variety of uses, including communication relay, weather forecasting, navigation ( GPS), broadcasting, scient ...
signal that is specially concentrated in
power
Power may refer to:
Common meanings
* Power (physics), meaning "rate of doing work"
** Engine power, the power put out by an engine
** Electric power, a type of energy
* Power (social and political), the ability to influence people or events
Math ...
(i.e. sent by a
high-gain antenna
A directional antenna or beam antenna is an antenna that radiates or receives greater radio wave power in specific directions. Directional antennas can radiate radio waves in beams, when greater concentration of radiation in a certain direction ...
) so that it will cover only a limited geographic area on Earth. Spot beams are used so that only
Earth station
A ground station, Earth station, or Earth terminal is a terrestrial radio station designed for extraplanetary telecommunication with spacecraft (constituting part of the ground segment of the spacecraft system), or reception of radio waves fro ...
s in a particular intended reception area can properly receive the satellite signal.
One notable example of the use of spot beams is on
direct broadcast satellite
Satellite television is a service that delivers television programming to viewers by relaying it from a communications satellite orbiting the Earth directly to the viewer's location.ITU Radio Regulations, Section IV. Radio Stations and Systems ...
systems such as
DirecTV
DirecTV, LLC is an American Multichannel television in the United States, multichannel video programming distributor based in El Segundo, California. Originally launched on June 17, 1994, its primary service is a digital Satellite television, s ...
and
Dish Network
DISH Network L.L.C., often referred to as DISH, an abbreviation for Digital Sky Highway, is an American provider of satellite television and IPTV services and wholly owned subsidiary of EchoStar Corporation.
The company was originally establ ...
that deliver local
broadcast
Broadcasting is the data distribution, distribution of sound, audio audiovisual content to dispersed audiences via a electronic medium (communication), mass communications medium, typically one using the electromagnetic spectrum (radio waves), ...
television
Television (TV) is a telecommunication medium for transmitting moving images and sound. Additionally, the term can refer to a physical television set rather than the medium of transmission. Television is a mass medium for advertising, ...
via satellite only to viewers in the part of
North America
North America is a continent in the Northern Hemisphere, Northern and Western Hemisphere, Western hemispheres. North America is bordered to the north by the Arctic Ocean, to the east by the Atlantic Ocean, to the southeast by South Ameri ...
from which those terrestrial broadcast stations originate.
Spot beams allow satellites to transmit different data signals using the same frequency. Because satellites have a limited number of frequencies to use, the ability to re-use a frequency for different geographical locations (without different data interfering with each other at the receiver) allows for more local channels to be carried, since the same frequency can be used in several regions.
References
Radio
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