Discuss important characteristics and the relative advantage...

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Answer by mmmmna
Submitted on 1/26/2007
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Major issues involve signal integrity and availability or reliability. Terrestrial links are land lines in most instances. Such connections involve telephone or dedicated data lines. Physical wires. Which can break. And are usually used for the shortest of distances because the signals degrade over distance and over the different portions of the connection. Satellite links are microwave radio signals; radio and microwave are almost identical in characteristics, advantages or disadvantages. Depending on microwave carrier frequencies, clouds might block the signal or severely or mildly degrade the signal, much like driving into a tunnel can cause FM radio stations to fade out. Usually, radio links will not suffer the cloud issues. Both Microwave and radio signals need transmitters, and distance between receiver and transmitter defines how much transmitter power is needed. The power required is in direct proportion, squared: greater distances require greater power, squared. If the distance doubles, you need 2 squared time the power that the first distance needed. Hence, both microwave and radio place the cost burden on the supplier side. For some links, for example, building to building, both sides are the same entity. Optical data links usually refer to fiber optics, but I once saw a demonstration of data over a laser which was crossing a room.... similar issues for the non-fiber transmission as for the radio link: something can come between the transmitter and the receiver and degrade the signal. While we could discuss the physics of light beams, lets leave that for the Physics FAQ, please. Optical data transfer over fiber optics has similar disadvantages as normal wire based terrestrial links: the medium is breakable. One important ranking is distance. Fiber presently crosses the ocean, between continents. Wires can span a continent, and in some instances it has crossed the ocean. Radio can cross the ocean, but transmitter costs usually keep the distances smaller. Microwave can span from satellites to ground, and those distances easily exceed intercontinental spans. Yet the costs of satellites are usually more than the costs of a radio transmitter, and repairs for microwave satellites is on the order of the expenses for a space agency for a few weeks. For other links, repairs are a bit less expensive: wires are usually within locations that a truck and person can access. Transoceanic cables, however, are not usually repairable if the failure occurs under the water. There are other issues, I am no expert, but this is a fair start.

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<< Back to: Anonymous FTP: Sitelist Part 01 of 23 [01/23]

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Question by Sunil
Submitted on 4/8/2004
Related FAQ: Anonymous FTP: Sitelist Part 01 of 23 [01/23]
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Discuss important characteristics and the relative advantages and disadvantages of the following: 1. Terrestrial links 2. Satellite links 3. Radio links 4. Optical links

Answer by prabhat goel
Submitted on 4/11/2004
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Discuss important characteristics and the relative advantages and disadvantages of the following: 1. Terrestrial links 2. Satellite links 3. Radio links 4. Optical links

Answer by maddy
Submitted on 4/17/2004
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I want the answer for Discuss important characteristics and the relative advantages and disadvantages of the following: 1. Terrestrial links 2. Satellite links 3. Radio links 4. Optical links

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