With the advent of satellite and digital TV broadcasting, the question arises more and more often which cable for a TV is better to choose — because the quality of the received signal depends on it. So, for example, when switching to satellite or digital broadcasting from analog TV, often the equipment is not tuned to certain channels, the image may become fuzzy, blurry, sometimes ripples and interference appear on the TV screen, although a completely different quality is expected from modern technologies. The main cause of such defects is the technical discrepancy between the old line and the new signal characteristics. It is logical that for the high-quality operation of television equipment, you will have to change the cable.
The structure of the television cable
Speaking about the internal structure, we can say with accuracy that all models have a similar content.
- Inner conductor — it can be made as a single or stranded wire, copper tube. The signal range and the possible bending radius depend on the material.
- Dielectric layer — ensures the immobility of the conductors. It can be made of polyethylene, fluoroplastic, foamed polyvinyl chloride or an air gap. The wave impedance and attenuation of the transmitted signal depend on the quality of the material.
- The outer conductor is a braid. It is made of foil, corrugated tube, aluminum film, metal wire. The degree of protection from external electromagnetic interference depends on the quality of the material.
- Shellwhich protects the internal structure of the cable.
As you can see, the principle of cable structure is the same, but the materials from which its structural parts are made differ from each other. How to choose a good option that would meet the technical characteristics of modern television broadcasting?
Criterias of choice
The quality of broadcasting largely depends on the chosen cable. Today’s market offers a variety of options for a variety of applications. Before buying, it is worth considering some critical characteristics of products.
Regardless of the manufacturer, any television cable must have a resistance of at least 75 ohms in order to accept a modern television broadcast format.
The composition of the outer shell
As a rule, either PE or PVC is used. In the first case, the shell will be white, and in the second — black. Previously, it was believed that for outdoor installation, for example, when the antenna is on the roof or balcony of the house, a cable with a black protective sheath should be preferred. But today this indicator is not critical, and therefore some types of cables with a white protective sheath, such as SAT 703, can be used for both indoor and outdoor work. The main thing to consider protective layer thickness. It is quite logical to believe that the larger it is, the better.
However, in this case, the whole structure becomes clumsy, respectively, the bending radius will be somewhat limited, this should be taken into account when planning the laying site (the presence of turns and corners).
Characteristics of the outer conductor
It should consist of two shielding layers. You should not purchase models with a single layer, such a cable does not meet modern signal transmission standards. The materials from which the shielding layers of the outer conductor are made are different. In the very first models of television cable, the most common braided wire was used as an external screen. The main advantage of such a model is its low cost, but you should definitely not count on receiving a high-quality signal, and even satellite TV. Modern models have the main metal foil screen and an additional braid, which is also made of metal alloys — it reduces the level of interference from radio equipment and household appliances.
Characteristics of the central core
As a rule, the central core is made of copper or alloys of other durable metals. To give strength, alloys can also be plated with copper. There are no confirmed facts that copper core much better than alloys of other metals, transmits a signal. But many experts recommend just such models of television cables.
The modern market provides for a large number of manufacturers, but this does not mean at all that everyone promises a quality product. It is worth paying attention to well-established manufacturers, such as Belden, Cavel, Commscope, Mediaflex. This rule also applies to the choice of antenna.
Conductor cross section
This parameter affects the signal transmission range: the larger the cross section, the more confident the broadcast will be. For conventional antennas, which are located no further than 30 meters from the receiver, classic options from 0.5 to 0.8 mm2 are suitable.
If the equipment is installed on the roof of the house, that is, at a considerable distance from the receiver, then the cable must have a conductor cross section of at least 1 mm2. Otherwise, normal TV viewing will be disturbed by noise, snow and other artifacts.
This parameter is measured in decibels (dB) and indicates amplitude loss based on 100 meters of cable. The lower the value, the better the signal will be. Manufacturers are extremely reluctant to indicate specific figures in the brief specification for the product, so it would be useful to check it with the seller.
The indicator largely depends on the quality of the winding. Good shielding minimizes signal transmission losses. While mediocre protection or even the absence of it immediately manifests itself in the background from everything and everything, from vacuum cleaners to electric clocks standing nearby. For an excellent, as well as expensive cable, this parameter fluctuates around 90 dB, while for ordinary solutions it does not rise above 60 dB.
Popular product varieties
An indicator of the quality of the cable is its cost. Available options are more picky about operating conditions, while expensive solutions are not afraid of either frost or heat, or electrical appliances working in the neighborhood.
The democratic price tag makes this option extremely popular. Depending on the specific manufacturer, the conductor goes either on bare metal or with a copper coating and with a cross section from 0.724 to 0.816 mm2. The wire is protected from the outside with PVC insulation, under which there is a polyurethane dielectric. The thickness of the latter fluctuates around 4.5-5 mm. The cable itself has a diameter of no more than 7 mm.
One of the clear advantages of RG-6 is its flexibility: it is easy to pull the cable through difficult angles. In pluses, you can also record a low attenuation rate — only 9.2 dB.
RG-6 is picky about temperature changes, so you can’t lay it outside the house. Thin PVC insulation will crumble after the first winter or melt in hot summers in direct sunlight. High humidity also adversely affects the performance of the product.
Prices for RG-6U start at 10 rubles per meter.
This is the closest analogue of RG-6U from domestic manufacturer. The cable has an impressive number of varieties: a large selection of braids, screens and sections. The latter can vary widely — from 0.75 to 1.63 mm2.
The conductor braid is made of tinned copper and the insulation is made of reinforced PVC. Unlike RG-6U RK-75 tolerates low and high temperatures – from -60 to +60С⁰. The cable is also resistant to direct sunlight and high humidity. But it is slightly inferior to the RG-6U in terms of bending (a corner margin of at least 3 cm), so it is not suitable for bypassing narrow door frames.
Prices for RK-75 start at 15 rubles per meter.
This is the brainchild of the European company Cavel. The cable is designed to transmit high frequency content. The cross section of the conductor is in the region of 1 mm2. As protection against external interference, thin (0.12 mm2) aluminum filaments are used, shielded by several layers of foil. At the same time, the signal improvement indicator is within 60 dB. The activity of household electrical appliances does not affect the operation of the cable in any way, with the exception of high-power vacuum cleaners.
The wire diameter is 6.6 mm. Insulating protection withstands direct sunlight, rain with snow and sudden temperature changes. cable good suitable for street laying.
The manufacturer promises up to 15 years of uninterrupted operation of the product in the absence of critical kinks.
The cost of SAT-50 is around 40 rubles per meter.
This is a more advanced version of the previous solution, designed to gaskets in difficult conditions and at considerable distances from the receiver. The conductor cross section has been increased to 1.13 mm2, as well as the shielding. Even powerful models of household vacuum cleaners will not cause a specific background.
The SAT-703 signal gain is around 80 dB, which implies broadcasting without quality loss, as well as the ability to connect multiple TVs using special splitters. The weak point of the product is the amount of bending. 43 mm will be clearly not enough for laying at home.
The price of SAT-703 is about 50 rubles per meter.
This is the best this segment has to offer. The cable from the same Cavel company is designed to transmit a high-quality signal in any format. The gain indicator is located in the region of 90 dB. Product well shielded and eliminates the appearance of noise, artifacts and other background from household appliances.
Reliable braid protects the cable from any climatic adversity: frost, heat, sunlight and water. The service life of the product is 15 years.
DG-113 is used in the most difficult cases when you need to connect several TVs to one splitter, which is located outside the building. Laying cable around the house is impractical, given its price.
The cost of DG-113 is about 60 rubles per meter.
If we are talking about ordinary apartments in high-rise buildings with an antenna installed somewhere nearby, for example, on a balcony, then an inexpensive version of the RG-6U will do. When you need to connect two TVs or the distance to the source is more than 20 meters, it is better to stop at RK-75.
In difficult cases, where the antenna is located at a considerable distance from the receiver and / or the cable runs outside the house, it is more practical to use higher quality, as well as expensive solutions from the SAT series.
Cable and digital broadcasts
Here we have broadcasting in the range from 49 to 800 MHz. All terrestrial, digital and cable Russian channels fall under these frequencies. Any of the above types of products calmly covers these parameters. That is, in this case, you need to focus primarily on the performance of the cable: reliability, insulation thickness and shielding features.
Broadcasting is organized at frequencies of thousands of megahertz. The higher the score, the greater the risk of loss. Moreover, through this cable, voltage will be supplied to the set-top box or receiver, along with additional impulses.
Satellite broadcasting is easily disrupted by electronic interference. That’s why the presence of sensible shielding — required condition. The plate itself is located outside the house, that is, part of the cable will be on the street, and these are temperature changes, direct sunlight and high humidity.
The best option for organizing satellite broadcasting is an expensive cable with good protection, decent shielding and low attenuation. The SAT or DG series will come in handy.
Using more than one adapter per TV to extend these cables is not recommended.
When choosing a cable, it is worth remembering that the longer the network is, the thicker the model must be chosen. In the event that the cable is purchased for an antenna that is located on the roof, it is better to purchase a wire with a large cross section. In addition, before purchasing a particular model, it is worth clarifying whether there are additional conditions for installation. All this information will be useful to you if you decide to make an antenna yourself.
To receive a high-quality signal from a satellite, you will need information on how to properly install and connect a satellite dish.