Very Small Aperture Terminal (VSAT)
A very small aperture terminal (VSAT) is a small-sized earth station used in the transmit/receive of data, voice and video signals over a satellite communication network, excluding broadcast television. A VSAT consists of two parts: a transceiver placed outdoors in direct line of sight to the satellite, and a device that is placed indoors to interface the transceiver with the end user’s communications device, such as a PC. The transceiver receives or sends a signal to a satellite transponder in the sky. The satellite sends and receives signals from a ground station computer that acts as a hub for the system. Each end user is interconnected with the hub station via the satellite, forming a star topology. The hub controls the entire operation of the network. For one end user to communicate with another, each transmission must first go to the hub station, which then retransmits it via the satellite to the other end user’s VSAT. VSAT data throughput speeds have increased significantly throughout the years and now can provide multimegabit service in downstream and upstream. Antenna/dish sizes usually range from 1.2 meters to approximately 3 meters in diameter. Generally, these systems operate in Ku-band and C-band frequencies, but with the launch of Ka-band satellites by a number of operators in North America and Asia/Pacific, and with newer Ka-band satellites planned for Europe, high-bandwidth, bidirectional VSAT services for enterprise, government and other users will increasingly migrate to these satellites.
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