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The ODU or antenna includes the dish, or reflector, and the feed arm, which holds the active elements (transmitter and receiver). These are pictured above

The Dish or 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.

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 outroute (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 HughesNet satellite modem. For those who are interested, this is discussed in more detail, below.

The Low-Noise Block down-converter (LNB) is used to amplify and frequency convert outroute 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 outroute 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.

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

Communications satellites send and receive electromagnetic Ku-band signals, which are in the super high-frequency range. Microwave phone signals, which are relayed between tall towers, are in this same frequency range. However, satellite Ku-band signals are usually not susceptible to interference from these towers.
Satellite Mobility Support Network (SMSN) HughesNet User Guide

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