SAT (Very Small Aperture Terminal) is a satellite communication technology that allows users to establish reliable, secure, and cost-effective two-way communication links via satellite. It utilizes small, compact antennas (usually between 0.75 and 2.4 meters in diameter) for transmitting and receiving data, voice, and video signals. This technology has become increasingly popular due to its versatility and ability to provide coverage in remote areas where terrestrial networks may not be available.

Satellites play a central role in VSAT communication, acting as a relay for signals between remote terminals and the hub station. Depending on the network’s coverage area and desired performance, various satellite types and frequency bands may be used.

The service provider’s satellite hub station, also known as the teleport or Network Operations Center (NOC), is a central facility that manages the overall network, including the allocation of bandwidth and the routing of signals between remote terminals and the satellite. It also provides a connection to the terrestrial networks.

Remote terminals are the individual VSAT units installed at user locations, responsible for transmitting and receiving signals to and from the satellite. They have the following components:

The antenna, also known as a dish, is the key component of a VSAT system, responsible for transmitting and receiving signals to and from the satellite. It is typically mounted on a fixed structure, such as a building, or on a mobile platform, like a vehicle or ship. The size of the antenna depends on the frequency band used and the desired link performance.

The transceiver is responsible for converting the baseband signals into radio frequency (RF) signals for transmission and vice versa for reception. It includes a low-noise block downconverter (LNB) to amplify the received signal and a block upconverter (BUC) to convert the transmit signal to the appropriate frequency.

The modem is the central processing unit of the VSAT system, which manages the transmission and reception of data, voice, and video signals. It is responsible for modulation, demodulation, error correction, and communication protocols, ensuring reliable and efficient communication.
The office equipment, connected to the modem, includes other devices needed for interfacing with the user’s devices, such as routers, switches, or telephony equipment. It connects the subscriber’s devices to the VSAT system and manages the flow of data.

Frequency Bands

VSAT systems operate in a range of frequency bands, including C-band, Ku-band, and Ka-band. Each frequency band has its own advantages and drawbacks in terms of signal strength, bandwidth, and susceptibility to weather-related interference. For instance, C-band is less susceptible to rain fade but has lower available bandwidth compared to Ku-band and Ka-band.

VSAT Customers and Applications

VSAT can cater to a wide range of customers from different sectors, including both commercial and government entities. Here’s a list of potential customers and their applications for VSAT technology: