VSAT Corporate Internet Access

VSAT BRIEF

VSAT (Very Small Aperture Terminal) is the choice for those who are in remote places and need an Internet connection where there is no other infrastructure such as leased line, ADSL, ISDN, not even a phone. VSAT shaped like a large dish and facing the sky. With this equipment the digital signal is received and sent to the satellite. Serves as the successor satellite signals to be sent to another point on the earth.

VSAT dish is actually facing a geostationary satellite. Geostationary satellite that the satellite is always in the same place in line with the earth's rotation on its axis. Geostationary satellite orbit is always at the same point on the surface of the earth, say in the Monas, then he will always be up there and follow the earth's rotation on its axis.

SEND AND RECEIVE DATA

Getting data from the Internet setelit same as getting television signals from satellites. The data sent by satellite and received by the decoder on the customer side. Data received and are about to be sent via the VSAT should be decode by the first decoder. Telkom-1 satellite using C-band (4-6 GHz). In addition there are C-band Ku-Band also. But C-band is more resistant to weathering than the KU-Band. This satellite uses a different frequency between the receive and transmit data. In essence, the high frequency used for uplink (5.925 to 6.425 GHz), lower frequencies used for downlink (3.7 to 4.2 GHz).

This system adopts TDM and TDMA technology. Generally, VSAT configuration is like a star. The middle of the dish called hub and serve many other records located at a distance. Hub communicates with another disc using TDM channel and received by all other disks. Another disc hub transmit data using TDMA channel. In this way is expected to provide a good connection for data connections, voice and fax. All data traffic must pass through this hub, even if a different disk to another disk related. These hubs manage all data routes to the VSAT network.

TDM frame size is always 5760 bytes. Each frame has 240 sub-frames. Each sub-frame is 24 bytes. The length of time frame depends on the outbound data rate is selected. TDMA is always at 180 ms. TDMA synchronized to ensure that the shipment data from different stations do not collide with each other.

Public opinion says that satellite connections are the fastest connection. The fact is not. The time needed from one point on the earth to another point via satellite is about 700 milisecond, while leased line only takes about 40 milisecond. This is due to the distance that must be taken by the data from the earth to the satellite and back to earth. Geostationary satellites themselves berketinggian approximately 36,000 miles above the earth's surface.