Satellite TV : A Revolution In Television Broadcasting

Satellite TV first hit the market in the early 1990s but in its early years of evolution, only the most die-hard TV fans have gone through all the hassle and expense of putting in their own dish. Those days, satellite TV was a lot harder to get than broadcast and cable TV. 

But today, we see small satellite dishes perched on rooftops all over the country. Satellite TV offers many solutions to broadcast and cable TV problems. Though satellite TV technology is still evolving, it has already become a popular choice for many TV viewers. We'll find out how satellite TV works and also learn about the changing landscape of TV viewing and some basic differences that distinguish satellite TV from cable and over-the-air broadcast TV.

Need For Satellite Television :

Satellite TV is conceptually quite similar to broadcast TV, which is a wireless system for delivering television programming directly to a viewer's house. Both these technologies use radio signals for transmission. As broadcast stations use a powerful antenna to transmit signal to surrounding area, so viewers can pick up the signal with a much smaller antenna. However, to receive signals, you have to be in the direct line of sight of the antenna, which limits the range of broadcast TV and other limitation with broadcast TV is that the signal is often distorted in the viewing area.

Satellite TV solves the problems of range and distortion by transmitting broadcast signals from satellites orbiting the Earth. Since satellites are high in the sky, there are a lot more customers in the line of sight. Satellite TV systems transmit and receive radio signals using specialized antennas called satellite dishes. Most of the satellite TV customers get their programming through a Direct Broadcast Satellite (DBS) provider, such as DISH Network. The provider selects programs and broadcasts them to subscribers as a set package. Basically, the provider's goal is to bring dozens or even hundreds of channels to viewer’s TV. Unlike earlier programming, the provider's broadcast is completely digital, which means it has much better picture and sound quality. Earlier Satellite TV was broadcasted in C-band radio -- radio in the 3.7-gigahertz (GHz) to 6.4-GHz frequency range which is switched to Ku frequency range (11.7 GHz to 14.5 GHz ) for digital programming transmission.

Components Of Satellite TV :
There are 5 major components which are involved in a direct to home (DTH) or direct broadcasting (DBS) satellite system :

• Programming Sources, the channels that provide programming for broadcast. The provider doesn't create original programming itself; it pays other companies (HBO, for example, or ESPN) for the right to broadcast their content via satellite.


• Broadcast Center, the central hub of the system. At the broadcast center, the TV provider receives signals from various programming sources and beams a broadcast signal to satellites in geosynchronous orbit.


• Satellites, which receive the signals from the broadcast station and rebroadcast them to Earth.


• Receiving Antenna (the viewer's dish), which picks up the signal from the satellite and passes it on to the receiver in the viewer's house.


• IRD, which processes the signal and passes it on to a standard TV.

Feed For Satellite TV :

Satellite TV providers get programming from two major sources, national turnaround channels (such as HBO, ESPN and CNN) which can also be categorized as paid channels and various local channels which can be categorized under free-to-air channels. Most of the turnaround channels also provide programming for cable TV, and the local channels typically broadcast their programming over the airwaves.

Turnaround channels usually have a distribution center that beams their programming to a geosynchronous satellite. The broadcast center uses large satellite dishes to pick up these analog and digital signals from several sources.

Most local stations don't transmit their programming to satellites, so the provider has to get it another way. If the provider includes local programming in a particular area, it receives local signals directly from the broadcaster through fiber-optic cable or an antenna and then transmits them to the central broadcast center.

The broadcast center converts all of this programming into a high-quality, uncompressed digital stream. At this point, the stream contains a vast quantity of data -- about 270 megabits per second (Mbps) for each channel. In order to transmit the signal from there, the broadcast center has to compress it, which simply means that unnecessary or repetitive information is removed from the signal before it is transmitted. The signal is reconstructed after transmission.

Compression Standards For Satellite TV :

Satellite TV uses a special type of video file compression standardized by the Moving Picture Experts Group (MPEG). With MPEG compression, the provider is able to transmit significantly more channels. There are currently five of these MPEG standards, each serving a different purpose. The major satellite TV providers used to use MPEG-2 in the past for compression, which can reduce the 270-Mbps stream to about 5 or 10 Mbps (depending on the type of programming). But now they started to use MPEG-4 compression as it can encode more efficiently and provide a greater bandwidth than MPEG-2. MPEG-2 remains the official standard for digital TV compression, but it is better equipped to analyze static images, like those you see on a talk show or newscast, than moving, dynamic images. MPEG-4 can produce a better picture of dynamic images through use of spatial (space) and temporal (time) compression. This is why satellite TV using MPEG-4 compression provides high definition of quickly-moving objects that constantly change place and direction on the screen, like in a F1 race.

Satellite TV Encoding And Encryption :

At the broadcast center, the high-quality digital stream of video goes through an MPEG encoder, which converts the programming to MPEG-4 video of the correct size and format for the satellite receiver in your house.

Encoding works in conjunction with compression to analyze each video frame and eliminate redundant or irrelevant data and extrapolate information from other frames. This process reduces the overall size of the file. Each frame can be encoded either as intraframe, predicted frame, or a bidirectional frame.

After the video is compressed, the provider encrypts it to keep people from accessing it for free. Encryption scrambles the digital data in such a way that it can only be decrypted (converted back into usable data) if the receiver has the correct decryption algorithm and security keys.

Once the signal is compressed and encrypted, the broadcast center beams it directly to one of its satellites. The satellite picks up the signal with an onboard dish, amplifies the signal and uses another dish to beam the signal back to Earth, where viewers can pick it up.

Satellite TV Receiver :

When the signal reaches the viewer's house, it is captured by the satellite dish. A satellite dish is just a special kind of antenna designed to focus on a specific broadcast source. The standard dish consists of a parabolic surface, which when receive a signal beam, reflects the radio signal inward and converges it to a central point known as feed horn. The signal is then passed on to the receiving equipment.

The central element in the feed horn is the low noise blockdown converter, or LNB. The LNB amplifies the radio signal bouncing off the dish and filters out the noise (radio signals not carrying programming). The LNB passes the amplified, filtered signal to the satellite receiver inside the viewer's house. The receiver has four essential jobs :

• It de-scrambles the encrypted signal.


• It takes the digital MPEG-2 or MPEG-4 signal and converts it into an analog format that a standard television can recognize.


• It extracts the individual channels from the larger satellite signal. When you change the channel on the receiver, it sends just the signal for that channel to your TV. Since the receiver spits out only one channel at a time, you can't tape one program and watch another. You also can't watch two different programs on two TVs hooked up to the same receiver. In order to do these things, which are standard on conventional cable, you need to buy an additional receiver.


• It keeps track of pay-per-view programs and periodically phones a computer at the provider's headquarters to communicate billing information.

Receivers have a number of other features as well. They pick up a programming schedule signal from the provider and present this information in an onscreen programming guide. Many receivers have parental lock-out options, and some have built-in digital video recorders (DVRs), which let you pause live television or record it on a hard drive.

Conclusion : With the continuous evolution of Satellite TV, a lot of service providers are now available in market. With its movie-quality picture and sound, satellite TV is becoming a popular investment for consumers. Digital cable, which also has improved picture quality and extended channel selection, has proven to be the fiercest competitor to satellite providers. The TV war is raging strong between satellite and digital cable technologies as well as between the providers who offer these services. Once considered luxuries in most households, satellite and digital cable are becoming quite common as providers bundle TV with Internet and phone services to offer competitive deals and win over customers.