Satellite television is a broadcasting system that delivers television programming through the use of communication satellites orbiting the Earth. With traditional terrestrial broadcast systems radio waves transmit signals to a local area. With satellite TV, signals from space are received using a dish and a set-top box or smart TV decoder.
Definition of Satellite TV
A type of broadcast system that uses space satellites to transmit and receive radio signals between stations. The satellites for TV broadcast, are usually placed in geostationary orbit, meaning they remain stationary relative to the Earth’s surface. The signal from the tv station is transmitted up to a satellite in space. After processing it is sent back down to Earth where it can be picked up by viewers satellite dishes.
Further Reading:
More detail on the most popular type of satellite for broadcasters – Ku Band
Other bands and non geo-stationary Satellites
Read more on L,C, Ku and Ka band Satellites
Brief History of Satellite TV
The first communication satellite was launched into orbit in 1962 by the United States. It was called Telstar-1 and allowed for transatlantic television broadcasts for the first time ever. However, it was not until 1975 that HBO became the first company to distribute programming via satellite.
By 1984, there were over 5 million homes receiving satellite broadcasts. In the early days, consumers had to rent large dishes to receive these signals as well as buy expensive decoders.
In the 90s analogue transmission gave way to digital methods, giving better reception and far more channels
The industry continued to grow throughout the 80s and 90s with more companies such as DirecTV and Dish Network in America. Over in Europe there were Sky, Canal Plus and Viasat developing large networks. Today, millions subscribe to satellite television services because they provides access to such a wide range of channels. Many more than traditional terrestrial broadcasting methods. Also they offer consistent high-quality picture resolution.
How Satellite TV Works
Overview of the Process
A method of delivering television programming using signals relayed from communication satellites orbiting the earth. The process starts with a broadcaster who sends their signal to a communication satellite orbiting the earth. The satellite then beams that signal back down to earth where it can be received by satellite dishes and then decoded into audio and video.
Benefits of Satellite TV
satellite Tv has given us high quality pictures, reception over whole continents, education, entertainment, news and current affairs all at a very reasonable cost.
Read more about the benefits of satellite tv
Satellite Signal Transmission and Reception
Satellite signal transmission and reception is at the heart of how satellite TV works. Broadcasters use highly directional antennas called up-link dishes to send their signal to a communication satellite orbiting the earth. This is known as up-linking.
Once the signal reaches the communication satellite, it’s amplified and sent back down to earth. The broadcast can then be received by a dish on your roof.
These dishes are designed to pick up the signals in a highly directional manner. The lnb is designed to only receive signals of one polarity.
Read more on Satellites signals and dishes for European Channels
Up-linking and Down-linking
Broadcasters send their content via an uplink dish on Earth up to a communications satellite in space. This receives it with an onboard receiver connected to multiple transponders, each capable of processing multiple channels. A transponder then takes part of the bandwidth assigned by its frequency band that contains modulation settings needed for decoding (e.g., MPEG-4) before amplifying them for re-transmission back down toward Earth. This can be DTH (direct to home) or for distribution via cable or broadcast stations.
Downlinking is when signals are sent from space back down toward Earth. It uses high-frequency radio waves carried out over long distances as data streams. These are transmitted across various frequencies with different polarization patterns designed specifically for receiving them effectively at ground level.
Transponders and Frequencies
Satellites are equipped with transponders, which are responsible for receiving signals from earth and then amplifying them to be sent back down. Each transponder has a certain frequency range that it operates in, and each frequency range can carry many channels. Transponders also define the coverage of signals, known as the ‘footprint’. Hispasat for example is situated 30° west and has separate beams for South America and Europe.
Broadcasters pay for access to specific frequency ranges and channels on communication satellites. They can transmit their content to viewers around the world. This process is how providers can offer hundreds of channels without having to run cables all over the world.
Decoding the Signal
The final step in delivering satellite TV is decoding the signal. Once your dish receives the signal from the satellite, it needs to be decoded before it can be viewed. There are two main ways that this is done: set-top boxes and smart TVs with built-in decoders.
A set-top box is a separate device that you connect between your dish antenna and your television. It’s responsible for decoding the incoming signal into audio and video that can be displayed on your TV screen.
A smart TV with built-in decoders does not require a separate set-top box. Instead, it has all of the necessary hardware built in. You can receive and decode satellite signals directly using your television’s own CI (conditional access) interface and module.
Components of a Satellite TV System
Dish Antenna – Receiving the Signal
Satellite dishes, also known as a parabolic dish or antenna, are the most recognizable component of the tv system. They receive signals from the satellite and direct them down toward your receiver.
There are two types of dishes: solid and mesh or perforated. Dishes are made of coated steel or aluminium and have a smooth surface that reflects the signal to the LNB.
Mesh dishes are made out of wire mesh or perforated metal, and allow wind to pass through them, making them more durable in harsh weather conditions. The installation process for a satellite dish depends on where you live and what kind of dish you have purchased.
For optimal signal reception, it is recommended that you install your dish in an open area with an unobstructed view of the sky. Once you have found an appropriate location, secure your dish onto its mounting bracket and aim it towards the satellite.
To find out more about satellite dishes continue reading here
LNB Converter – Amplifying Signals
LNB (Low Noise Block) converter is another important component in your satellite system. It sits at the focal point of your dish reflector. The main function of an LNB is to convert the carrier frequency to a lower band. It also has a small amplifier, to stabilize the signal. That compensates for weather losses and cable losses between dish and receiver.
In the receiver, the picture signal data is filtered out.
This makes it easier for the data streams to be extracted in your receiver. There are several types of LNBs available in the market-
- Standard Universal LNBs, ( may be multiple output )
- Monobloc LNBs ( for use with 2 or more satellites )
- Quad/Switched LNBs which allows distribution to multiple rooms
- Quatro for use with multi-switch boxes for blocks of flats
- Wideband as used by Sky UK
Cables and Connectors – Transmitting Signals
Cables play an important role in carrying your signal from the dish to your receiver with minimal loss or interference. The most common cable for satellite installations is RG6 or TX100 due to its low signal loss and high bandwidth. The connectors used in the dish installation are F-connectors. RCA connectors and HDMI leads are used to connect your receiver and TV.
Putting it All Together
The satellite dish receives the satellite signal and focusses it on to the LNB, which is a frequency converter. The LNB sends this stabilized ‘IF’ signal down the coaxial cable to your receiver. This assembles and decodes it if it is scrambled, into a picture that can be viewed on your TV. Proper installation of each component can affect signal quality and reliability. Do make sure you follow all instructions carefully while setting up your system.
With an understanding of the system involved in satellite TV , you can ensure that you select the right components. Understanding how they work together will also help you diagnose issues should they arise later on.
Dish Installation Guides:
Advantages and Disadvantages of Satellite TV
Advantages
Wide Range Coverage:
One of the main advantages of using satellite is its wide range coverage. Unlike towns and cities when cable/fibre networks are common, satellite broadcasts can reach remote areas.
This makes it a great choice for people living in rural or isolated areas. It has brought education, news and communications to villages, towns and even whole countries in vast areas of Africa and Asia.
High-quality Picture
Satellite systems offers high-quality picture, especially when compared to traditional analog broadcast systems. The digital signal used by satellite TV provides better resolution, sharper images and more vibrant colors. Digital processes control the efficiency and quality of the transmission.
Access to International Channels
Another advantage, is its ability to provide access to international channels. With a wide variety of channels from around the world, viewers can enjoy programming in different languages. Satellite enables insights into different cultures.
Disadvantages
Weather Interference
One disadvantage of satellite television is weather interference. Rain, snow, and other atmospheric conditions can affect signal reception. Unless you leave a margin for this by installing a slightly bigger dish, it could lead to low signal, poor picture quality or a complete loss of service in severe cases.
Cost
Yes, Satellite systems require some specialized equipment. Installation can be hazardous, as dishes are usually on walls or roofs. Training for work at heights is essential.
The price of dishes (at least the mass produced ones) has fallen considerably since the start of satellite broadcasting. Although some set-top boxes are expensive, those associated with a particular service like Sky, are provided free with a subscription.
Customers may opt to pay ongoing subscription fees for access to certain channels which can add up over time. UK Freesat boxes are now available at just £50.
Compared to cable systems, satellite television is fairly non-disruptive, a dish only takes a half-day to install, but It will last between 10 and 20 years. Cable TV infrastructure installation causes major disruption when first installed, digging up roads for weeks and sometimes months in big towns. When equipment and cables (fibre) need updating hopefully the process will need less work, but with tech…. Who knows what will be there in 10 years?
Installation Issues
Installing a satellite system requires technical expertise and special tools which many people do not have. This is particularly true for some European services, where the signal may be weak. Moreover, finding an optimal location for antenna placement can be challenging particularly in densely populated urban areas. Trees and buildings can block the signal.
Conclusion:
Satellite TV offers a wide range of programming options, high-quality picture, and access to international channels. However, it has some disadvantages such as weather, interference and installation issues.
Despite these drawbacks, it remains a popular choice. It has unique advantages over cable and terrestrial systems, like long life span, medium install costs, multi-satellite and multi-language possiblities.
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