Despite the ubiquitous distribution of online television, many homes still have one or even several TVs. Some watch the channels received by the receiver from a conventional antenna, others - from a satellite dish, but a third enjoy the benefits of progress in the form of cable TV broadcasting. In the first two cases, an antenna cable for the TV is used to transmit the signal from the source to the television receiver. Obviously, the quality of the rendered image depends to a large extent on its characteristics. It would seem that it can be simpler than to measure the home the right distance, go to the market or shop and purchase an antenna cable? However, this statement is only partially true. The fact that a person who wants to buy an antenna cable, sellers will be offered several options for this type of product. Which one to choose?
Theoretical basis
Any antenna cable, as the name suggests, is a pair of conductors that are isolated from each other and covered with a common insulating layer. Since its task is to transmit to the TV induced in the antenna interference, then, obviously, the magnitude of the current and voltage are minimal. Therefore, the antenna cable has conductors with a small core diameter. The received signal is high-frequency, and for the normal operation of the entire system it is very important that the resistance values of the internal circuit of the TV, cable and antenna are the same (matched). However, to measure with a multimeter the amount of Ohm does not follow - it's useless. Antenna cable is characterized by wave impedance, and its value is calculated by special formulas. For a TV signal, its value is 75 ohms. Hence follows the conclusion: any "extra" connections of conductors cause additional extinction of the signal. Also note one more important point: the cable for a satellite dish is not any special, but the same television. When choosing it, it is necessary to adhere to the principles that we will point out below.
Varieties of TV cable
Usually large retail outlets offer 3 to 6 types of cable for a TV set. The first obvious difference is the cost. Sometimes it is twofold. A person wishing to choose a good cable is asked a logical question about the reasons for this difference. And they are really quite important.
When buying, you should pay attention to the quality of insulation. In cheap options, it is too fragile, so there can be no question of building a line on the street. Check is very simple - bend the cable. If isolation breaks, then you can take such a copy only with a strong budget constraint.
The quality of the reception is affected by the material of the central conductor. The core can be completely copper or steel with a pressure on the coupler. The first option is more preferable, however it costs more. Sometimes you can find steel-colored veins - tinning (tin coating), used to protect against oxidation.
The next layer covering the central core and its insulation is the screen. It is a layer of foil. Can be rolled or twisted. It is necessary to prevent mutual interference in conductors. Although there are cable modifications without this layer, its presence indirectly indicates the quality of the product.
Then follows the second conductor - braid. It is a few thin metal hairs, specially intertwined. The more of them, the better. In addition, it is important that they are copper (tinning allowed), and not steel.