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Basics: Limitations |
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Temporal
Copyright protection is limited in time. Many countries have adopted a term of protection that starts at the time of the creation of the work and ends 50 years (in some cases 70 years) after the death of the author. Under some national laws exist exceptions either for certain kinds of creations or for certain uses. After the protection has expired works pass into the public domain. In recent years a tendency towards the lengthening of the term of protection has emerged.
Geographic
The owner of a copyrighted work is protected against acts restricted by copyright under the law of a certain country. To gain protection against such acts in other countries he must refer to the respective national legislation. If both countries are members of one of the international conventions on copyright, the practical problems arising from this geographical limitation are eased.
Non-Material Works
In some countries works that are not fixed in some material form are excluded from copyright protection. Also under certain national legislations, the texts of laws and decisions of courts and administrative bodies cannot be copyrighted (which is possible in several countries; then the government is the owner of the copyright in such works and can exercise his rights in accordance with the public interest).
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Satellites
Communications satellites are relay stations for radio signals and provide reliable and distance-independent high-speed connections even at remote locations without high-bandwidth infrastructure.
On point-to-point transmission, the transmission method originally employed on, satellites face increasing competition from  fiber optic cables, so point-to-multipoint transmission increasingly becomes the ruling satellite technology. Point-to-multipoint transmission enables the quick implementation of private networks consisting of  very small aperture terminals (VSAT). Such networks are independent and make mobile access possible.
In the future, satellites will become stronger, cheaper and their orbits will be lower; their services might become as common as satellite TV is today.
For more information about satellites, see How Satellites Work (http://octopus.gma.org/surfing/satellites) and the Tech Museum's satellite site (http://www.thetech.org/hyper/satellite).
 http://www.whatis.com/vsat.htm
http://octopus.gma.org/surfing/satellites
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