28-06-2013, 12:46 PM
VSAT Technology
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INTRODUCTION
Orbital Data Net specializes in the design and construction of VSAT networks as well as using other more exotic technologies. VSAT stands for “Very Small Aperture Terminal” and refers to receive/transmit terminals installed at dispersed sites connecting to a central hub via satellite using small diameter antenna dishes (.75 to 3.8 meter).
VSAT technology represents a cost effective solution for users seeking an independent communications network connecting a large number of geographically dispersed sites. VSAT networks offer value-added satellite-based services capable of supporting the Internet, LAN, voice/fax communications, video, security, and provide powerful, dependable private and public network communications solutions.
Most VSAT networks like Direcway and Spacenet’s are STAR based, TDM/TDMA VSAT network works using a hub station, usually six meters or more in size and small VSAT antennas (between .75 meters and 2.4 meters). All the channels are shared and the remote terminals are always listening online, offering fast response times. Consequently, TDM/TDMA systems are comparable with terrestrial X.25 or frame relay connections. The exception to this strategy is that they are employed by Gilat through Spacenet. They use FTDMA technology that greatly reduces bottlenecks in the transmission side of the network and also provides an additional layer of security, as the signal is frequency hopping every few fractions of a second. This network design is very efficient and supplies literally tens of thousands of well-known customers served by Spacenet in the commercial markets and Starband (which also uses similar technology from Gilat) in the residential markets.