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Satellite internet is perhaps the best option for remote areas and mobile locations such as seafaring vessels and vehicles - where there is no access to terrestrial internet (DSL). High speed internet, with an 'always-connected' feature, is provided without the use of cable or telephone lines.

The satellite dish provides a two-way data communication for both transmission and reception of data. The system provides a download speed of about 500Kbps (kilobytes per second) and the upload speed is around one-tenth the download, which is 50Kbps. The satellite connection is ten times faster than normal dial-up modems.

Satellites orbiting the earth are located over the equatorial region, so the satellite dish (1.2m diameter) at the user's location must be pointed precisely towards the north to avoid interference with other satellites. The satellite modem converts digital signals into analog form. For two-way data communication (upload and download), the system requires two satellite modems and coaxial cables (cables having common axis) to connect the dish to the modem.

The dish at the user's end sends radio frequency waves or data (received from the transceiver that connects to the computer) to the transponder (satellite). At the other end, the transponder sends the relay frequencies to a hub teleport at a ground station. The teleport then forwards the data through the terrestrial internet. For receiving the requested information, the same process is followed in a reverse order to direct the data back to the user's dish, and the installed modem delivers the desired webpage to the computer.

The two-way technology uses the Internet Protocol (IP) multi-casting feature. This feature allows a communication of around 5000 channels, through one single satellite. This is achieved by transmitting compressed data with smaller bandwidth. This is not in case of terrestrial internet systems, as their bandwidth optimisation is limited.

There are, however, some limitations of satellite internet. The entire process of sending and receiving data should ideally take about half a second, however due to latency the process gets delayed. Latency is defined as the sum of time taken by the requested data to get from one point to another and the round-trip time (RTT) in getting the response. The latency in satellite internet access is higher than normal land-based terrestrial internet, due to the location of the geostationary satellites. The data or the frequency has to cover a total distance of 35,000 km, from the earthly surface to the satellite and then back to the earth again.

Satellite internet access promises reliable service. Web surfing can be achieved at a higher speed and unlike dial-up internet services, there is no wastage of time of the internet user. This internet technology allows the user to surf the internet even during peak usage times. And, the 'always-connected' feature, keeps your computer connected to the internet, no matter in which corner of the world you are.

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