Satellite TV is no longer a know-how in the world of information technology. With the help of satellite television, you have a unique opportunity to watch not only a lot of new channels, but also significantly improve the quality of broadcasting of national channels.
Satellite television is a specific educational program of the 21st century. If you pick up Telesputnik magazine - a monthly publication on satellite and cable television, you will see how many satellites are placed in our near-Earth orbit. In fact, the journal contains information about only a part of the satellites from a large number of spacecraft. In fact, there are many more of them and they are all in geostationary orbit, located in the plane of the earth's equator. This is the only circular orbit with a radius of 35785 km, where the satellite seems to be motionless to an earth observer, provided that the angular velocity of the satellite's rotation around the earth's axis coincides with the angular velocity of the earth's rotation around its axis. This means that if the satellite dish is correctly tuned to receive from the satellite and is securely fixed, it will not be necessary to correct its position in the future.
Every European country strives to place its television satellites in geostationary orbit, but there is not enough space for everyone. Therefore, in the struggle for a "place under the sun", satellites, like birds, gather in "flocks". For example, the name of the satellite "HotBird" refers to a number of closely spaced (by space standards) spacecraft (about 100 km) occupying an orbital position of approximately 13 degrees east longitude. Since all satellites are in the plane of the equator, their geographic latitude is zero, and they differ in longitude. The prime meridian, we recall, passes through London and separates the western and eastern longitudes. A television satellite is launched to a given point in the orbit in order to serve a certain territory of the earth's surface, therefore, it has its own radiation pattern. Since several transponders (receiver-transmitters) are installed on each spacecraft, each of which is capable of transmitting several TV programs in one stream, the total number of broadcast channels can be measured in tens. For clarity, the satellite can be imagined as a "spotlight" or a group of "spotlights" "hovering" in the night sky above the equator, which, with its "rays", snatches out of the darkness a part of the earth's surface. In this case, depending on the area of the "illuminated" surface, each beam can be classified: narrow, zone, regional, global, etc. The highest density of electromagnetic waves is concentrated in the center of the beam. The greater the power of the signal radiated from the satellite reaches the earth's surface at the location of the satellite dish, the smaller the diameter of the antenna mirror is required. This advantage has a narrow beam. The wider the coverage area, the lower the power flux density at the earth's surface. For example, in order to receive TV programs of the global beam satellite "Intelstat 905" in Kyiv, 27.5 degrees. h. covering the entire part of the earth's surface visible from it, an antenna with a diameter of at least three meters is required. The territory of Ukraine is, in principle, “illuminated” by the rays of many satellites, but most of them create a low power flux density. Of greatest interest to us, residents of Ukraine, are satellites from which national TV channels are broadcast, as well as Russian TV channels, which can be received on small satellite dishes.
Satellite TV is time well spent, especially since it allows you to watch many more channels than cable TV. Today the standard package of satellite TV is 500 channels! Imagine a sea of diverse information right on your TV screen!
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May 9, 2024 00:59:18 +0300 GMT
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