After the C or KU band frequencies are amplified by the LNA, they need to be processed. The
processing is done in the satellite receiver which is usually located 10 meters to 50 meters away
from the dish antenna. Microwave signals in the S, C or KU Band would suffer very high
attenuation if they were carried via coaxial cable from the LNA to the Satellite Receiver 50 meters
away.
To overcome this problem, the microwave signals are converted to a block of frequencies from 950
MHz to 2150 MHz. Hence, incoming signals received by the LNA at 2 GHz, 4 GHz and even 12 GHz
are even block converted down to 950 MHz to 2150 MHz. This range of frequencies is referred to
as Intermediate Frequencies since their range of temporary or intermediate frequencies in the
chain of satellite reception which receives microwave signals and finally yields video and audio
signals from the satellite receiver. This function is carried out by a “Block Converter” located within
the LNB. A combination of Low Noise amplifier + Block converter is referred to as an LNB. A block
diagram of a commercial LNB is shown in Figure 2.
The Block Converter consists of 4 important sections as shown in Figure 2.