Why does the TV show badly? Some cable TV channels are not tuned in? How to determine that the wiring of the television cable is carried out correctly? Questions of this type are common. Ordinary people want to understand them in a simple way. Indeed, as practice shows, there are many home-grown TV masters today. And their services (already paid) are money thrown to the wind. So, let's try to sort out a few of the questions posed, one of which is - what is the best television cable?
TV cable
So, let's start with the appearance and design of cable for cable television. Unlike power wires, it is always round. At the same time, its optimal diameter is 4-8 mm. There are cables both smaller and larger. They will be discussed separately.
Notice the cut. It consists of several concentric layers.
- The central core, located in the middle, is a copper or steel (copper-plated) wire. Core diameter - 0.3-1.1 mm.
- From above it is enveloped by a dielectric. Usually it is white plastic.
- The third layer is the so-called screen, consisting of two layers: foil and braid. In some models of television cable, there may not be a foil layer. But remember that its presence in the design indicates the high quality of the product. A braid is a mesh of conductors that are woven together crosswise.
- And the outer layer is a protective barrier against mechanical stress, made of either PVC or polyethylene. The protective outer layer can be either black or white.
Attention! If the TV cable you are purchasing has all these layers, then do not hesitate to purchase it. If there is no layer, then look for a cable in another store.
Does more expensive mean better?
In this section, we will answer the question, how to choose a TV cable? And immediately make a reservation that in relation to this wire, the postulate, the more expensive, the better, will be illegal. Why?
It is necessary to answer the question posed from the fact that there is the main characteristic of a television cable - this is the quality of signal attenuation associated with the frequency of the signal and the length of the wire. So in this case, it will be correct to assume that the lower this indicator, the better. It should be noted that each television channel has its own attenuation rate due to a certain frequency of the incoming signal. By the way, the unit of attenuation is dB/100m. That is, a complete dependence on frequency and length.
Therefore, before choosing a cable, you must first decide on the television system that you will be installing. Why is it so important? The thing is that terrestrial television and satellite have a different frequency range. And if you installed a cable that has a signal attenuation rating suitable for terrestrial television, then the signal from satellite may not pass through. That is, it will pass for sure, but with great interference.
- Remember, we talked about the diameter of the television cable. So you should not buy a product with a diameter of less than 3.5 mm. This wire can pass the frequency only in the meter range. That is, your TV will only show channels such as ORT, NTV, RTR and others. But the UHF channels (Home, Culture, STS, TNT, and so on) you will no longer see, but forget about the satellite signal altogether. Plus, the shielding characteristics of this cable are in doubt. And this is not good either. Of course, if you try, you can make a cable with a meter range visible to all channels. To do this, you will have to install an additional head station through which decimeter channels are converted. But this will require additional costs. To summarize: the thicker the TV cable, the better (by reducing signal loss). It is he who is needed.
- There is still a RK-75 cable with one shielding layer on the market. This is an old domestic product. So he has a very high attenuation rate. You shouldn't buy it.
- There was an interesting situation with sales. Even in some specialized stores you come across low quality television products at a high price. It is perfectly packaged in a beautiful wrapper, it has a certificate, accompanying documents, but the price does not match the technical specifications. Exactly the same option on the regular market is several times cheaper. So be vigilant.
So let's sum it up. First, pay attention to the diameter of the wire. The optimal size is 6-7 mm. Second, the shielding layer. There should be two of them: the lower one is foil, the upper one is a braid of copper wires treated with tin. Thirdly, choose the right manufacturer. Of course brand names are preferable. This is a cable from Belden, Mediaflex, Commscope and so on.
Attention! If during operation the television cable will be subjected to rather harsh conditions (laying in the ground, overhead lines on the street), then it is better to purchase a special impregnated model. This must be indicated in the accompanying documents of the product.
And one more piece of advice, which concerns this question: is it possible to lay two cables side by side: power and television? You can, you just have to purchase a television with a diameter of 10 mm with increased protection against interference.
Installation
And the last question that needs to be sorted out in this article is how to connect the cable to the TV? Let's start with recommendations.
- The gasket circuit should be located as far as possible from power circuits and powerful electrical appliances (refrigerator, washing machine, dishwasher, iron, microwave oven, etc.).
- You can lay a cable for cable television next to any low-current circuits (telephone, internet, alarm).
- Try to reduce the number of connections. The best option is a one-piece TV cable for the entire apartment.
- If it is not possible to avoid splitting the loop into sections, then use factory-made separators and splitters when connecting the two ends of the cable. No twists that will reduce the quality of the incoming signal.
- If it is impossible to avoid crossing the TV wire with power circuits, then it is best if this intersection is made at an angle of 90º.
- The gasket must not be coiled or bent at an angle greater than 90º.
- The section up to the first splitter from the shield box must pass in a wide channel. Other weak current circuits can also be laid here.
- When connecting a cable in a shield box, only soldering should be used (this is a question of how to connect correctly). In this case, you should not expose the cable itself much. The smaller the unshielded area, the better.
- The splitter must be installed in easily accessible places. The best option is to put it in a special box.
Additional devices
Usually, there are several devices in the television cable wiring diagram. If an apartment building is considered, then the first device that receives a signal from the antenna is a splitter. That is, from a common antenna, the signal through this device enters the apartment. From it you can spread the wiring even in different rooms, it all depends on the number of posts.
You can also install a signal amplifier before the splitter. What this device does, it makes no sense to explain. Further, the so-called adder is used last. Its purpose is to sum signals from different frequencies into one.
Conclusion on the topic
Connecting a television cable for cable television (digital) can also be done by hand. There is nothing difficult in this. You need the tools and some knowledge that we have discussed in this article. A little wiring skills won't hurt either.