Coaxial Cables

An important property of high-frequency coaxial cables is impedance. In a signal amplification system that uses a repeater, only coaxial cable with an impedance of 50 ohms should be used. And we warn you that cables intended for TV networks or video surveillance systems are not suitable for amplifying a cellular signal. These types of cables have a much higher resistance than is required to transmit a cellular signal, and if you use a cable with too high resistance at high device power, the cellular repeater can fail.

The systems for amplification of a cellular signal require the received signal to be transmitted over 10-15 meters, and for such purposes a coaxial cable is used. The purpose of such a cable is to transmit the signal from the repeater to the antenna and the signal received from the antenna to the repeater. It is not uncommon for a considerable distance to be covered - for example, from an antenna on the roof of a building to a repeater located on one of the lower floors of an apartment. In this case, it is important to choose a coaxial cable with the lowest signal attenuation (8d- FB, 10d- FB), otherwise even a powerful signal amplifier will not help.

So what is a coaxial cable?

A high frequency cable, also called a coax cable consists of:

• center conductor - a stranded wire or tube made of copper,
• aluminum, or an alloy of these metals;
• insulation - dielectric filling, which ensures the alignment of the
• conductors, semi-air or solid;
• main shield - aluminum or other metal foil;
• braid - wire of aluminum, copper, or other metal;
• jacket - polyethylene, polyvinyl chloride or other UV-resistant insulation.

The losses of electromagnetic energy are balanced and the cable itself is protected from external influences of electromagnetic fields. In practice, the energy losses can not be avoided, but by concentrating the components of the electromagnetic field between the conductors within the insulation, they are minimized.

The choice of a cable to connect antennas and a repeater (amplifier system) is not random. Judge for yourself - at an attenuation of more than 3 dB, the gain parameters begin to deteriorate, at an attenuation of 3-5 dB, the deterioration is already noticeable, and at an attenuation of more than 6 dB, the cable can no longer be used to improve the signal over long distances, the loss of quality will be too high.

When choosing a coaxial cable, you must first consider the distance at which the antenna will be located from the signal booster. If the distance is relatively short, an inexpensive cable can be used. However, if the distance is more than 10 meters, a significant signal attenuation is observed when using inexpensive options. Also pay attention to the stiffness and cross-section of the cable - the lower the stiffness and the smaller the cross-section, the easier it is to install the cable.

The decay rate of a signal in a coaxial cable depends on several factors. One of these factors is the operating frequency of the signal amplifier, as well as the length of the interconnecting cable and its quality as an electrical conductor.

The most common types of RF coaxial cables

RG-58

is the most common type of antenna cable, mainly because of its small diameter and low price. It comes in sets with antennas for wired connection to various mobile devices (modems, routers, boosters). However, due to its high attenuation coefficient, it is effective only with a good external signal and a short cable length of 3 meters (maximum 10m). Depending on the modification, a different center conductor is used: at RG-58A/U a solid (standard) or twisted center conductor made of pure copper is used, at RG-58A/U a physically foamed dielectric and an additional foil shielding provides an increased shielding coefficient and low losses in a wide frequency range.

5D-FB

A kind of "classic" for professionals in the installation of amplifiers for mobile signals 698-2700 MHz. Small diameter cable with dense double shielding, solid copper or cooper clad aluminium (CCA) center conductor with even higher performance due to the use of physically foamed dielectric (PEEG). The linear attenuation coefficient of the 5D-FB is not worse than that of the RG-213/U cable, which has a diameter 1.5 times larger. The cable jacket is made of UV-resistant material It has no analogs in terms of price / quality ratio on the domestic market.

8D-FB

A high-quality 50-ohm coaxial cable with an outer diameter of 11.1 mm, which uses PEEG technology and fully meets the requirements of the equipment of most modern mobile communication standards. In terms of attenuation coefficient, this model is in no way inferior to the most popular semi-air cable DX-10A (analog of BELDEN 9913A), while being completely insensitive to moisture and possessing a number of other advantages inherent to cables with physically foamed dielectric (PEEG). In the 8D-FB version, CCA is manufactured with a central core and a braid of copper-coated aluminum, for harsh operating conditions in a climatic version of the 8D-FB PE modification. Recommended in the amplification of high-frequency mobile communications (GSM-1800 / 3G-2100 / LTE-2600) or when pulling long cable runs. It has no analogs in terms of price / quality ratio.

10D-FB

The professional coaxial cable 10D-FB PVC (diameter 13.1 mm) of very high quality for the construction of various amplification systems of cellular communication with long feeder distances. The use of a physically foamed PEEG dielectric ensures low attenuation over a wide frequency band and long-term stability of the parameters over the entire service life. The increased shielding factor is due to the dense tinned copper braid in combination with double-sided aluminum foil. The cable jacket of the 10D-FB is made of UV-resistant material. In the modification 10D-FB CCA is manufactured with a central core and a braid of copper-plated aluminum.