earth station

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earth station

[′ərth ‚stā·shən]
(communications)
A facility with a land-based antenna used to transmit and receive information to and from a communications satellite.

earth station

A ground-based receiving or transmitting/receiving station in a satellite communications system. The counterpart to the earth station is the satellite in orbit, which is the "space station." Earth stations use dish-shaped antennas, the diameters of which can be under two feet for satellite TV to as large as fifty feet for satellite operators. Antennas for space exploration have diameters reaching a hundred feet.

Multiplex, Modulate and Upconvert
An earth station is generally made up of a multiplexor, a modem, up and downconverters, a high power amplifier (HPA) and a low noise amplifier (LNA). Almost all transmission to satellites is digital, and the digital data streams are combined in a multiplexor and fed to a modem that modulates a carrier frequency in the 50 to 180 MHz range. An upconverter bumps the carrier into the gigahertz range, which goes to the HPA and dish.

Downconvert, Demodulate and Demultiplex
For receiving, the LNA boosts the signals to the downconverter, which lowers the frequency and sends it to the modem. The modem demodulates the carrier, and the digital output goes to the demultiplexing device and then to its destinations. See earth station on board vessel and base station.


Earth Station
Earth stations use dish-shaped antennas to transmit and receive microwave signals to and from satellites.







On Board a Ship
Earth stations on board vessels (ESVs) are used to receive TV, make phone calls and access the Internet while traveling near the coast or on the high seas. Encased in a waterproof container, the ESV must be able to track the satellite with great precision. If the ESV deviates by a half a degree, it must shut down transmission immediately in order to not interfere with other satellites. (Image courtesy of Sea Tel Inc., www.seatel.com)
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Sixteen frame studies result in larger EDVs, smaller ESVs and higher LVEFs as compared to 8-frame studies.
5] cells/mL in 96-well microplates and treated with ESV (0-100 [micro]g/mL) for 24 h.
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Thus, argued the taxpayer, the ESVs were needed to maintain the status quo of the aircraft.
Aside from power, the ESV shares other similarities with its Stryker brethren.
ESV estimates that the economic situation is still weak although it has improved somewhat since the previous forecast was published, which has led to an upgrade of the estimates for the state's taxation revenue.
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FedEx would replace that engine with an engine that had completed all ESV.