 In the box at the focus of the dish, called a low-noise block downconverter (LNB), each block of frequencies is converted to the IF range of 950 - 2150 MHz by two fixed frequency local oscillators at 9.75 and 10.6 GHz.One of the two blocks is selected by a control signal from the set top box inside, which switches on one of the local oscillators.This IF is carried into the building to the television receiver on a coaxial cable.