Satellite TV Receiver

Today's communication satellites relay a more diverse range of TV programming than ever before. Your choice from among the various satellite receivers now on the market will therefore depend largely on the nature of the satellite TV program services which you desire to view from the comfort of your easy chair. Some satellite TV programs are broadcast in the clear and are therefore considered "free to air" (FTA), while others may be encrypted and only made available to subscribers living within a particular region or individual country.
There also is an important distinction to be made between satellite TV services which are transmitted in an analogue format and those that are digitally compressed. Analogue communication signals are electromagnetic waves of energy which vary in frequency (called frequency modulation, or FM) or intensity (called amplitude modulation, or AM). Digitally compressed TV signals, however, are broadcast in an alternate format consisting of a series of binary digits or "bits" which correspond to the on and off states of computer logic circuitry. Only one manufacturer currently offers a dual-purpose satellite TV receiver which can process both analogue and digital satellite TV signals and its use is restricted to the North American market
Analogue Satellite TV Receivers
The cost of an analogue satellite TV receiver will depend on the number of features which it offers to the consumer. Some low-cost satellite receivers can display TV images which equal or even exceed the picture quality offered by more expensive units. The downside is that the operator will have to remember and execute all of the little adjustments needed to tune into each and every satellite TV broadcast.
In some cases, the receiver may be a stand-alone unit which, by itself, can only receive programs from a single satellite. Most analogue satellite TV receivers these days, however, also feature built-in antenna controllers which can steer a motorized dish from one satellite to any other.
Many of today's high-end satellite TV receivers are actually task-specific computers which contain advanced microprocessors and memory storage circuits. Each receiver comes with factory installed software programs which automatically perform all the various tasks required to receive the available satellites and satellite TV services. For example, many receivers come pre-programmed with the locations and tuning parameters for all of the available satellite TV services stored in a memory circuit.
The receiver's wireless remote control can be regarded as the keyboard, while the TV set serves as a computer screen which can display a variety of menus that the installer uses during the initial installation process and which the TV viewer can also use to customize the IRD to suit his or her specific viewing needs.
All satellite TV receivers are designed to maximize the strength of the incoming satellite signal or "carrier" while at the same time limiting the amount of noise either contributed by external sources or generated by the satellite TV system's internal electronic circuitry. The figure of merit for an analogue satellite TV receiver is defined as a "threshold" point expressed in decibels (dB) at a specific carrier to noise ratio or C/N.
When the receiving system's C/N (which is measured in decibels or dB) falls below this threshold point, impulse noise or sparklies rapidly appear in the TV picture rendering it unviewable. The lower the receiver's threshold rating, the better it will operate under low signal receiving conditions such as when the antenna's diameter is insufficient for receiving a low-powered satellite transmission. Receiver threshold ratings ranging from 6.5 to 10 dB C/N commonly are encountered in the product literature. The problem with relying on this specification as a benchmark for receiver evaluation is that not all manufacturers measure the threshold performance of their products in the same way. The best way to evaluate receiver performance is to have the retailer connect it to a dish with the same diameter as the one that you intend to install at your home and actually see how it performs while receiving several different satellites