Earth directly to the viewer’s location. Satellite television provides a wide range of channels and services. Consequently, these systems were nicknamed “big dish” systems, and were more expensive and less popular. Different receivers satellite technology principles and applications pdf required for the two types.
Back view of a linear polarised LNB. The advantage of this orbit is that the satellite’s orbital period equals the rotation rate of the Earth, so the satellite appears at a fixed position in the sky. Thus the satellite dish antenna which receives the signal can be aimed permanently at the location of the satellite, and does not have to track a moving satellite. The increased diameter results in more accurate aiming and increased signal strength at the satellite. The leg of the signal path from the satellite to the receiving Earth station is called the downlink. Typical transponders each have a bandwidth between 27 and 50 MHz.
The latter is even more adversely affected by ice crystals in thunder clouds. The channel selection was controlled typically by a voltage tuned oscillator with the tuning voltage being fed via a separate cable to the headend, but this design evolved. Central to these designs was concept of block downconversion of a range of frequencies to a lower, more easily handled IF. The advantages of using an LNB are that cheaper cable can be used to connect the indoor receiver to the satellite television dish and LNB, and that the technology for handling the signal at L-band and UHF was far cheaper than that for handling the signal at C-band frequencies. 70 MHz, where it was demodulated. US dollars were built, to a far more commercial one of mass production. 2150 MHz to carry the signal from the LNBF at the dish down to the receiver.