By Norman Weinhouse, Norman Weinhouse Associates
This article treats the subject of Ku Band satellite TV transmissions from the viewpoint of the ground segment or the receiving earth station. It is, therefore, intended as a tutorial for cable television engineers who are planning or will plan to receive the programming available from Ku Band satellites. Uplink and satellite performance parameters are discussed and included only to the extent that they affect the overall performance and serve as a benchmark for design of the receiving earth station.
Ku Band transmission has its pluses and minuses in comparison to the more familiar C Band transmission. The advantages and disadvantages are discussed without bias. The main thrust of this paper is; once given a Ku Band transmission, and a range of parameters on the signal from the satellite, how does one go about accommodating this signal to provide quality programming to subscribers?
The primary advantage of Ku Band is that it does not share the same frequencies on a co-equal basis with terrestrial microwave systems. It is, therefore, essentially a clear channel. The only terrestrial users are Local Television Transmission Services (LTTS) which operate on a secondary basis. This means that the earth station can be located anywhere as long as there is line of sight and clearance to the satellite orbital arc. The FCC will not even accept application for license in this band for receiving stations. This does not mean that a receiving station is totally free from interference. The receiving station must have sufficient discrimination against other Ku Band satellites in the orbital arc.
The primary disadvantage of Ku Band is that it is subject to weather related fading to a greater extent than C Band. The fading is explained and it will be shown that the reliability or availability of a signal of whatever quality desired can be controlled by design of the receiving earth station, usually in a cost effective manner.
In addition, the article will discuss certain precautions to be taken in installing the hardware used in the receiving earth stations.