Very Small Aperture Terminal (VSAT)

A Very Small Aperture Terminal (VSAT) is small Earth stations used for satellite communications, typically operating in C-band and Ku-band (and increasingly Ka-band), and characterized by the use of relatively small-diameter antennas. VSAT antennas are generally less than about 1.8 m in diameter, significantly smaller than those used in traditional satellite Earth stations, with the objective of reducing terminal size, cost, and installation complexity. Hub stations supporting VSAT networks typically employ much larger antennas, often in the range of 5–11 m.

VSATs are commonly deployed in private and enterprise networks that support point-to-multipoint communications, particularly for applications such as retail transaction processing, inventory management, telemetry, and corporate data distribution. Such networks can be large, sometimes comprising thousands of remote terminals connected to a central hub.

Most VSAT networks use a hub-and-spoke architecture, although modern systems may also support meshed connectivity, allowing direct terminal-to-terminal communication via the satellite. Early VSAT systems typically supported data rates of around 9.6 kbps, with later systems commonly providing 64 kbps per channel. Contemporary VSAT systems, particularly those using higher frequency bands and adaptive modulation and coding, can support uplink data rates of the order of a few megabits per second and downlink rates an order of magnitude higher.