What is a Coax Cable?

All of you may have seen the coaxial cables in your homes. But have you ever wondered that what is the use of this cable and how is it different from other cables?

Coaxial cables are used around the world for delivering voice, video and data. However, coaxial cable has some limitations due to which it has been widely replaced by fibre optics or wireless signals in the recent years but even then it is not possible to eliminate the use of coaxial cable. The reason of its success is its shielded design. The shielded design allows the copper core of the cable to transmit the data at a faster pace without getting damaged from environmental factors. 

The coax cable comes in three common sizes i.e., RG-6, RG-11 and RG-59. For connecting coaxial cables, the F-style connectors are the most common ones. However, some systems also use N-type connectors. There are many types of F-type connectors for RG-6 cables i.e.

·         Compression connectors

·         Screw-on connectors

·         Crimp-style connectors

What is coaxial cable?

In coaxial cable the inner conductor is surrounded by an insulating layer which is then surrounded by a conductive shielding. Most of the coaxial cables also contain an insulating outer jacket. The electrical signal flows through the core of the cable which is usually made up of copper conductor. Below is the detailed construction of a coaxial cable:

1. Center conductor is made up of copper-clad steel.
2. Center conductor bond is a clean stripping polymer which is used to block the moisture.
3. The dielectric layer is made up of polyethylene which is used for providing mechanical stability. It is a closed cell foam with high VP.
4. The first outer conductor is shielded with an aluminum-polymer-aluminum tape and is bonded to the dielectric core.
5. The second outer conductor is an additional aluminum-polymer-aluminum tape which is used in tri-shield and quad-shield constructions. This outer conductor is used to further enhance HF shield isolation in case of cable bending.
6. The third outer conductor is also an additional aluminum-polymer-aluminum tape. This layer is also used in tri-shield and quad-shield constructions. The main purpose of third outer conductor is same as the second one. It enhances the HF shield isolation.
7. The fourth outer conductor is the last outer conductor. It is an additional 34 or 36 AWG aluminum braid which is used in quad-shield constructions. The purpose of this conductor is to improve LF shield isolation in environments where the RF noise is at extreme level.
8. Corrosion resistant protectant is of two types: Indoor and aerial - it is a non-drip material which is designed to eradicate the migration of moisture into construction of cable.Underground - this flowing compound can seal small jacket ruptures.
9. The outer jacket is UV stable which is made up of polyethylene (PE) or flame retardant polyvinyl chloride (PVC). This outer jacket is used for the protection of the cable.
10. The last part is an integral messenger which is a galvanized, carbon steel wire support member. It is attached to the cable by a separable web.

We hope that this article will help you to get a better understanding of the coaxial cables. Stay tuned to our website for more information about communication hardware.

The Role of Coaxial Cable in Broadband Networks

The cable operators, telephone companies, and internet providers use coaxial cables for delivering data, video, and voice communications to customers. This technology is in use since the early 20^th century and it provides reliable communication services.

In broadband communication, the data, voice and video are converged on a single infrastructure for better use of bandwidth.  Usually, optical fiber is used as for transporting the signals over larger distances and coaxial cable is deployed for distributing the signal across the network. Hence, before deploying the coaxial cable, it is very important for engineers to understand its characteristics. In this article, we have explained the basic role of coaxial cable in broadband networks.

RF Transmission

The cables are classified into different categories. The coaxcable falls into "RF-transmission line" category because it can transmit the radio-frequency (RF) signals efficiently. Due to its physical characteristics, it transports the RF signals rather than radiating them. The physical characteristics of this cable depend on the bandwidth; the greater the bandwidth carried by this cable, the more critical the physical characteristics. Hence, it is necessary to properly install the cables and connectors for better performance.

The attenuation of a coaxial cable can be determined by three major factors i.e., resistance, dielectric material, and radiation. The greatest amount of attenuation per unit length in the coaxial cable is produced by the resistance. Resistance depends on the cable materials, frequency of the transported signal, diameter of the conductors, and ambient temperature.

The attenuation is not greatly affected by cable dielectric. The major use of dielectric material is to maintain the spacing between the shield and center conductor. A small amount of signal energy dissipates in the dielectric as this material is not a perfect insulator. For reducing the attenuation in coaxial cable, dielectric materials with better insulating properties can be used.

Almost all the cables face some attenuation due to radiation. It is not possible achieve perfect cable dimensions hence, a small amount of energy leakage can occur due to the symmetry of the cables. However, it is very important that the RF signals do not escape from the coaxial cable otherwise these signals can interrupt with the wireless services.

Moreover, it is very important that the impedance of the transmission medium matches with the impedance of the devices used in the system. If there is a mismatching between the two then it can lead to transmission problems.

The Right Connections

Another challenge is to make the right connections in order to maintain network performance. The connector must be capable of maintaining RF characteristics as well as the characteristic impedance of the cable. The connectors that are used for connecting the rigid coaxial cable are usually a three-piece design. For flexible coaxial cables, usually, F-type connectors are used which is normally a one-piece connector.

Hence, by making the right connections and reducing the losses, rf signals can be transmitted successfully across the broadband networks by using coaxial cable. If you have any question related to the article, please feel free to ask in the comment box below: