Reception Zone and how apply radio waves
If you tune your TV to the reception of any station and you are not dependent on weather conditions the picture is not changing, then it means that your town or village is in the area of reliable reception of the signal from the transmitting station and distributed radio waves that are not specifically prevents. If you see the antenna of the repeater, then you obviously reception zone, but it so happens that not see the antenna, but the path from it to you to signal that does not interfere, in this case, a coverage area can be separated and need, to raise above the receiving antenna and agree on a long piece of cable with an input impedance of the receiving node...
probably Not worth it to tell you where and how the waves go, suffice it to say that the waves propagate in all directions with a speed of three to ten to 8 degree. The oscillation frequency of the TV signal is in the VHF range, this radiation or waves go in a straight line, they are like a ray of light from a flashlight or you see it, or it closes the Bush. VHF waves are not reflected from the upper atmosphere, as for example the KV range and it is for this reason and the examples have been so bad if you and your antenna either in the pit or under the mountain.
So the farther away from the TV center, the confidence in the receive signal disappears. There are many formulas which can calculate at what distance will the coverage, but there are a lot of factors that are in the formula will not stick, but they affect the result. So for example the Ostankino TV tower was broadcasting to the entire Moscow region and everywhere was reliable reception of TV signal, but if you rig will take in our Hatsapetovka, the coverage ends at the corner of the building where the tower stands.. So that here everything is very not just. There is such a thing as diffraction in the propagation of VHF waves it occurs. This occurs when the path of a wave is the obstacle. Wave as it goes around the obstacle and with a loss of power goes on. So say all the world is waves comparable and the degree of penetration of the obstacle in the line depends on the size of the obstacles. There is a dependence between wavelength and size of the obstacles. Thus, if the wavelength increases, the sensitivity increases. Short waves bend around any obstacle and VHF waves have not any, as are commensurate with the wavelength, because the effect of diffraction is small . The effect of diffraction is obvious on DV and SV.
If waves can bounce off the stratosphere, it is possible to overcome the obstacle it is easier for them, so to speak, the effect of tropospheric refraction or refraction of the beam. At what latitudes and in what climate zone you are willing to make the signal reception depends on the quality of reception and distribution so to say the waves themselves.
What is the longest wavelength and the smaller the phenomenon of diffraction is weaker and the obstacles more. Yes, and the dust and dirt in the air also absorbs radio waves to some extent, but if it is snowing, sometimes the signal drops by 10 dB at least. Here now lies the clue is in the quality of reception in different frequency channels. Now all Yano, why if on the same channel snows, on the other band either no signal or the signal is normal and the reception is better, the fact that you are watching any channel with a higher frequency of the incoming signal, or less. If telecast has a powerful hardware, 1-2 channel is surely an operating distance of up to 220 km, 3-5 channel is already at 160 km and from 6 to 12 150 km and no more. Here is the gist of the question on the passage of radio waves and reception zone TV signal.
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