A coaxial (television) cable is the link between the antenna and the TV. The strength of the signal and its purity depend on its quality. To choose the right coaxial device, you need to know what types of television cables exist, be able to read the markings on the outer sheath and visually distinguish a good product from a fake.
Marking
The coaxial cable device is the same for all types of connected information receiving devices, whether it be a satellite dish or the simplest analog signal transmission device. Antenna cable for TV consists of:
- Inner aluminum or copper wire.The range of signal transmission depends on its cross section.
- Dielectric protective film made of polyethylene or PVC. Its purpose is to protect the center rod from contact with the outer ground conductor.
- Metal interlayer (aluminum film, steel wire, foil layer or copper braid). It protects the rod from external electromagnetic influences, thereby ensuring high signal quality.
- outer protective shell.
The properties of the layers may differ, so you need to know how the marking is read, what type of coaxial cable and purpose the manufacturer offers. There are 2 ways of marking - domestic and European. In the first case, everything is simple:
- The letters "RK", standing in the first place, are deciphered as a radio frequency cable.
- They are immediately followed by a numerical indicator indicating the degree of resistance. The higher it is, the clearer the signal will be.
- The next number is the diameter of the central channel. Immediately after it is the designation of the heat resistance of the insulation and the serial number of the development.
- The marking line ends with a reference to the specifications, in accordance with which the antenna cable was manufactured.
Western labeling is slightly different and includes many more features:
- The name of the manufacturer's company is written first.
- Then comes the type of cable (RG, DG, SAT).
- The English letters following it indicate the material of the conductor and braid.
- They are followed by a numerical value for the thickness of the central core.
- Two numbers, written through an asterisk, display information about the thickness and density of the metal braid.
- The type of protective sheath and cable resistance are required.
- At the end is the alphanumeric designation of the certificate of conformity (ISO).
Choosing a quality cable
Before choosing an antenna cable, you should analyze the type of receiving device and the number of TVs, measure the length and determine the location of the product, pay attention to the presence of mechanical impact factors. After that, you can proceed to the selection of the required characteristics.
Outer shell strength
The outer layer of protection may have different properties, depending on the application. So, for pulling the cable indoors, a PVC coating is enough, and for outdoor use, a more durable sheath is required. This can be protection from light-stabilized polyethylene with additional equipment with a gel-like layer that protects the structure from moisture penetration.
You can check the quality of the sheath by stretching and bending the cable. The section clearly shows the thickness of the coating and the presence of additional layers.
Shield layer quality
Responsibly, you need to approach the choice of braid (the shielding factor can be indicated in the marking line before the “%” sign). It will protect the conductor from external electromagnetic radiation and not let the signal out.
The most reliable cables in this regard are those in which this layer is glued to the dielectric. During the bending of the product, the braid does not move, a complete screen is formed.
Braid density
As a protective screen, foil, a braid of copper or aluminum wire with a cross section of 0.12 mm, wound around the dielectric in a spiral, is most often used.
Its quality is estimated by the density of the threads and the frequency of their passage. To obtain a high-quality signal, the grid must be thick and firmly held in place.
Dielectric test
In all models of television cable, a dielectric plays an important role, which isolates the protective screen from the conductor. The service life of the signal transmission line largely depends on its quality.
It is not possible to visually determine how well it is made, but it is recommended to check its density and bonding strength with metal layers.
Coax class
The cable class depends on the internal insulation, which prevents signal dispersion and external interference, i.e. the density of winding the braid and the presence of additional screens. By type of coaxial products are:
- with braid and foil screen;
- with an alternate arrangement of the screen, then the braids and again the foil;
- with 4 layers - braid / foil / braid / foil.
To check the class of the model, you need to carefully remove the protective shell and stratify the screen.
Core type and thickness
The signal transmission rate and the resistance of the television cable depend on the material of manufacture of the core and its thickness. The core can be copper or copper-plated.
The first type has the most suitable characteristics. The larger the cross section, the larger the conductive surface. Such a cable is expensive, so some manufacturers use aluminum coated with a thin layer of copper to reduce costs.
It is easy to check the core: if the core is soft and does not change color during scraping, then the central core is copper, but if the wire is hard and silver in section, the conductor is copper-plated.
Purpose of the cable
Since the advent of satellite and digital television with high quality of the transmitted signal, users have been faced with the problem of fuzzy and blurry pictures, ripples and other interference. Sometimes some channels are not displayed.
The reason for this may be an inappropriate legacy line. In this case, the question is decided which television cable is better to choose in order to meet technological requirements, determine the brand and characteristics.
If possible, you should pay attention to the designation on the laying diagram of electrical and radio transmission lines. Perhaps there is accurate data on the products used.
For digital and cable TV
The signal transmission frequency of digital and cable television is in the range of 49-800 MHz, so there are no special requirements for the cable. Especially if the length of the entire line will not exceed 30 m. To ensure a high-quality picture, you can choose any, even the most budgetary SAT, DG or RK models.
For satellite dish
Satellite signal transmission is measured in thousands of megahertz. What is the best conductor to use for satellite television is a matter of paramount importance, otherwise, instead of the expected clean image, you can get a black screen and an inscription about the absence of a signal. The core must be necessarily copper and with the maximum possible cross section.
The sensitivity of satellite transmission to various radio interference should also be taken into account, so the protective screen should be of the highest class.
Another important factor is the location of the plate on the street, which indicates the constant impact of the environment (wind, precipitation, temperature changes). For this reason, special requirements are put forward for the upper shell and the presence of carbon protection, otherwise there is a high risk of cracks and gaps through which water can enter.
For indoor laying
The cable running inside the building must have high transmitting and reflecting abilities. The strength of the protective shell does not play a special role. In this case, the budget model of the conductor will perfectly cope with the task.
For outdoor laying
If the laying of a television cable involves outdoor installation of some sections or long-term structures, the strength of the product, the ability to withstand the effects of the external environment and ultraviolet radiation, comes first.
The highest quality, capable of serving the maximum number of years is a special cable equipped with a supporting steel core. Due to the high cost of such a conductor, some craftsmen prefer to choose a durable protective coating, and reinforce the line with supporting wire structures.
Overview of popular models
In order to decide which cable to choose, many carefully study television cables, their varieties, properties and performance. Do not forget about the manufacturer. There are a huge number of different manufacturers of coaxial cable on the market at the moment, but their quality is different. One of the proven manufacturers is the Italian cable factory CAVEL, which has been operating since 1968.
Consider an overview of the most suitable models of television conductors:
- RG-6U is the most popular product due to its affordable price and high performance. It is massively used to replace old lines. The central core is made of copper. An aluminum tape is wound as a screen. The only significant disadvantage is the fragility of the outer sheath made of white or black polyethylene, which excludes the location of the cable on the street.
- SAT-50 refers to higher quality products. The product is equipped with a copper core with a section of 1 mm, a screen made of aluminum and copper. The outer shell is made of polyester. The conductor has the most optimal resistance - 75 ohms and a service life of up to 15 years.
- DG-113 is a product from the highest price category, which is explained by excellent characteristics that provide high-quality signal transmission and complete absence of interference.
- SAT-703 is most often chosen for connecting a satellite dish. It not only provides an excellent signal, but also perfectly tolerates outdoor use. The cable is double shielded and has a strong core. Service life - over 15 years.
- RG-59U is recommended to choose if you need to stretch the line for long distances. Along with high technical characteristics such as double screen, low resistance, flexibility, the cable is equipped with an internal steel wire, which ensures the strength of the stretched sections and prevents them from breaking and breaking.
So that the choice of a coaxial cable in a hardware store does not confuse, given the amount of market filling with goods of this type, you need to decide on the most suitable product and only then go shopping.
Similar articles:
