One or more metal pins, or probes, protrude into the waveguide at right angles to the axis and act as antennas, feeding the signal to a printed circuit board inside the LNB's shielded box for processing. The microwave signal from the dish is picked up by a feedhorn on the LNB and is fed to a section of waveguide. The LNB is usually a small box suspended on one or more short booms, or feed arms, in front of the dish reflector, at its focus (although some dish designs have the LNB on or behind the reflector).
#Lb link setup sky tv#
This downconversion allows the signal to be carried to the indoor satellite TV receiver using relatively cheap coaxial cable if the signal remained at its original microwave frequency it would require an expensive and impractical waveguide line. It serves as the RF front end of the satellite receiver, receiving the microwave signal from the satellite collected by the dish, amplifying it, and downconverting the block of frequencies to a lower block of intermediate frequencies (IF).
The LNB is a combination of low-noise amplifier, frequency mixer, local oscillator and intermediate frequency (IF) amplifier. Also called a low-noise block, low-noise converter ( LNC), or even low-noise downconverter ( LND), the device is sometimes inaccurately called a low-noise amplifier ( LNA).
Here the microwave signal is coupled into microstrips on the LNB's circuit board, in order for the RF signal to be amplified and downconverted into lower frequencies, which are output at the two F connector sockets at the bottom.Ī low-noise block downconverter ( LNB) is the receiving device mounted on satellite dishes used for satellite TV reception, which collects the radio waves from the dish and converts them to a signal which is sent through a cable to the receiver inside the building. A waveguide carrying the microwave signal ends at the hole in the center, where for this LNB two pins act as antennas (for two different polarizations).
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