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    Add as FriendVSAT

    by: Shubham

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    1 : The term Very Small Aperture Terminal (VSAT) refers to a small fixed earth station. VSATs provide the vital communication link required to set up a satellite based communication network. VSATs can support any communication requirement be it voice, data, or video conferencing. The VSAT comprises of two modules - an outdoor unit and an indoor unit. The outdoor unit consists of an Antenna and Radio Frequency Transceiver. (RFT). The antenna size is typically 1.8 meter or 2.4 meter in diameter, although smaller antennas are also in use. The indoor unit functions as a modem and also interfaces with the end user equipment like stand alone PCs, LANs, Telephones or an EPABX. VSAT Very small aperture terminal
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    3 : VSAT Technology is divided into two parts Outdoor Unit (ODU) Indoor Unit (IDU) Interlink Facility
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    5 : The Dish OR The Reflector The older dish, shown on the left with the TV attachment, is made of fiberglass, with an embedded wire mesh. It measures 0.74 meter in surface area (39" x 23"). The newer Raven dish is still .74 meter, but is rounder (34 1/4" x 28 1/2") and it is made of a lightweight metal. Often, when only referring to the dish, without the feed arm, the term reflector is used. The latest Prodelin dish was shown earlier.
    6 : The feed arm Located on the fully assembled VSAT dish assembly, the Rx-Tx feed arm is normally removed and safely stored, as part of the process for moving to a new location. The feed arm consists of the feed support arm and the outdoor electronics. All of the active outdoor components connect to the support arm, which also adds strength (and weight) to the completely assembled antenna. The outdoor electronics consist of the LNB, which receives out route (from the NOC) Ku-band signals from the satellite, and the transmitter, which transmits inbound (to the NOC) Ku-band signals to the satellite. Power is supplied by the Hughes Net satellite modem.
    7 : The feed support arm and outdoor electronics All of the active outdoor components connect to the support arm, which also adds strength (and weight) to the completely assembled antenna. The outdoor unit consists of the following things:- LNB Transmitter
    8 : LNB, which receives out route (from the NOC) Ku-band signals from the satellite, and the transmitter, which transmits inbound (to the NOC) Ku-band signals to the satellite. Power is supplied by the Hughes Net satellite modem.
    9 : LNB (Low-Noise Block Down) The (LNB) is used to amplify and frequency convert out route signals received by the antenna, for input into the modem via the Sat-In cable. The antenna receives the outbound signal in the Ku-band frequency, for input to the wave guide end of the LNB. The LNB first amplifies the input Ku-band signals. It then uses a local oscillator (LO), to frequency translate input signals to L-band frequencies, which are used on the coaxial cables. The signal noise value is an electrical specification for the LNB, which is critical to out route signal (your received signal) quality performance. The lower the noise figure, the better the signal quality performance will be.The LNB is powered from the modem, via a DC power supply coupled on the coaxial RF input connector, which connects to the receive IFL cable.
    10 : TRANSMITTER The transmitter is used to frequency translate and power amplify inroute signals from the modem and output them to the antenna, for transmission to the satellite. The modem sends the inroute signal at an L-band frequency to the transmitter, using Sat-Out and the transmit coaxial cable. This signal is input to the transmitter, where it is frequency converted to the transmit Ku-band frequency, using a nominally fixed local oscillator (LO). This Ku-band signal is then power amplified to operate the transmitter at a nominal one-watt output power (at saturation). The fixed output power is input to the antenna, for transmission to the satellite. The transmitter is powered from the modem, via a DC power supply coupled on the coaxial RF output connector, which connects to the transmit IFL cable.
    11 : Input Unit
    12 : Input Unit The IDU consists of modulators which superimpose the user traffic signal on a carrier signal. This is then sent to the RFT for upconversion, amplification and transmission. It also consists of demodulators which receive the signal from the RFT in the IF range and demodulates the same to segregate the user traffic signal from the carrier. The IDU also determines the access schemes under which the VSAT would operate. The IDU also interfaces with various end user equipment, ranging from stand alone computers, LAN's, routers, multiplexes, telephone instruments, EPABX as per the requirement. It performs the necessary protocol conversion on the input data from the customer end equipment prior to modulation and transmission to the RFT. An IDU is specified by the access technique, protocols handled and number of interface ports supported.
    13 : The interlink facility The outdoor unit is connected through a low loss coaxial cable to the indoor unit. The typical limit of an IFL cable is about 300 feet.
    14 : Advantages of the VSAT Last Mile Problem Reach Reliability Time Network Management Maintenance Flexibility Cost
    15 : Thanks for viewing it. Hope you like it.
    16 : Made by:- Shubham Bansal X C

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