low noise converter (Sat) (LNC)
As the name Low Noise Converter (LNC) or Low Noise Blockconverter( LNB) implies, it is a low- noise converter that amplifies and frequency converts the antenna signals from parabolic antennas that are focused in the feedhorn. Since parabolic antennas for television satellite reception operate in the microwave range at 10.70 GHz to 12.75 GHz, these RF signals must be converted to lower frequencies in order to be transmitted and received.
The LNC, which is installed at the focal point of the parabolic antenna and is part of the Outdoor Unit( ODU), mixes the receive frequencies with a local oscillator frequency( LOF) and filters out the lower sideband as an intermediate frequency. The intermediate frequencies are in the F-band between 950 MHz and 2.150 GHz. These frequencies are fed to the Indoor Unit( IDU), which is the receiver, which uses them to select the individual satellite channels and demodulates the FBAS signal.
There are LNCs and LNBs for one or more frequency bands. With universal LNCs for several frequency bands, the switching of the frequency bands is done with a 22 kHz control signal. In addition, the polarization plane of the LNC can be changed. This is done by different DC voltage levels.
There are also dual-band LNBs for receiving the frequency ranges from 10.70 GHz to 11.7 GHz for analog TV and 11.7 GHz to 12.75 GHz for digital TV, twin LNBs with two outputs and quattro LNBs with four connections that are permanently assigned to the polarization planes and frequency bands.