Ever wondered why we have satellite television? I know I have, particularly when we already have terrestrial or broadcast television available. They both seem very similar, the only difference being that with satellite you get lots more choice of channel. Of course there is cable television too, a fierce competitor for both services, but in this article I am going to stick to satellite television.
Sattelite television really becomes important in areas where it is not possible to install cable and the broadcast television reception is poor. Both systems use radio wave signals to transmit and the waves travel in straight lines. That means for broadcast television, which is transmitted and received via land-based antenna, that the natural curvature of the earth will eventually break the signals' line of sight. It also means that other land based signals and obstructions are likely to interfere with the TV signal and cause some distortion.
Using satellites to transmit the signals solves the problem. Stationed more than 22,000 miles above Earth they revolve around this planet once every 24hrs, which is the same time as it takes the Earth to make one full rotation. Therefore the satellite always stays above the same spot on the ground and is said to be in geostationary orbit. Because the satellite is high in the sky the transmission of the waves 'hits' large numbers of customers and people that are in normally inaccessible places are able to receive television. The satellites not only transmit direct to Earth, but they are also linked to each other, making a network to distribute to the largest possible numbers. It also means that once you have set your TV satellite dish in the best position to receive a signal, you shouldn't ever have to move it again.
When satellite television was first introduced the dishes required to receive the signal were very expensive and people were able to set them up to receive programmes that were not really intended for everybody to see. Nowadays people tend to subscribe to a 'Direct Broadcast Satellite' (DBS) provider such as DirecTV or Dish Network in the US and Sky in the UK. These providers are able to select programs and broadcast them to people as set packages, for example the 'Family', 'Sports' or 'Movie' packages. Cost will depend on which one you choose to buy.
To enable the whole system to make money for the organisations involved in the provision of satellite television, three techniques are commonly employed:
* Advertising
Organisations pay the network to broadcast adverts. We all hate it but it does pay for our entertainment, or part of it at least.
* Subscriptions
Users pay a monthly fee to receive a channel or group of channels. In actual fact you pay for the means to decrypt the signal that you receive. There is no way to stop anyone from receiving a signal transmitted from a satellite so they encrypt the signal to make it impossible to view without the special equipment and secret codes needed to unscramble the signal.
* Licence Fee
In the UK the law insists that you must purchase a TV licence if you possess any equipment capable of receiving a TV signal of any kind. The revenue from this 'tax' is used to fund the BBC. In the early years of TV this method of funding ensured that the BBC provided some of the best Television in the world.
Free satellite TV is available when the broadcaster uses only advertising to pay for the content and network.
There are five components needed to link the programme makers and the satellite television customer:
* The DBS provider does not create the programmes themselves, they pay for the right to be able to broadcast them via satellite television. They act as a 'middleman' between the 'programming sources' or channels and you.
* The sattelite television provider receives signals from the programming sources at the 'broadcast centre' and transmits the signals out to the satellites in orbit around Earth.
* Satellites receive the signals from the centre and rebroadcast them back to the land.
* Usually a DBS provider will provide you with the equipment to receive the signal. This will include a dish to be fixed to your house by professional installers to receive the signal.
* That signal is then transferred to and decoded by the receiver, which is usually sited next to your television so that you can view the channels you have chosen to purchase.
So, there is a lot more to satellite TV than meets the eye but it provides us with high quality television, which is available almost everywhere on the earth. We have come a long way in a very short time with television.
Steve is a software engineer and owner of www.sattelite-television.thegrandfatherclock.com
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