Coaxial cables, otherwise known as coaxial cable, is a form of electric cable made up of an inner conductive shield surrounded by a concentric, but insulated conductor, with the two separating only by a thin dielectric layer; coaxial cables can have either a single or multiple conducting paths. There are two common forms of coaxial cable in use today. One uses a one-directional data transfer and the other a two-way data transfer. Data transmission over one direction of a coaxial cable is typically accomplished using an alternating current (AC), while data transmission over the other direction of the cable is typically done with a direct current (DC). Some coaxial cables are multi-conductor, which allows for the quick transfer of alternating currents (AC’s) and/or alternating currents and then switching to normal currents (DCs).
The two different types of Coaxial Cable that can be found in use are Low Noise and High Noise. Low Noise Coaxial Cables has no physical barriers between conductors, thereby eliminating any interference. These types of Coaxial cables are ideal for use in many different types of electronic equipment that run on low power electronic circuits. In addition to the lack of interference, low noise coaxial cables tend to be more cost effective and can offer a higher data rate than some of the higher bandwidth options. Due to the lack of physical barriers, these types of Coaxial cables tend to produce minimal noise.
High Noise Coaxial Cables can reduce or eliminate the effects of electromagnetic interference (EMI) by utilizing a different method of shielding. Some manufacturers utilize an induction spiral, which is used to create a low resistance path for the signals to travel through. Alternatively, some high bandwidth Coaxial cables use a braided metallic core, which incorporates a small amount of dielectric material within the core to create a physical barrier between the copper conductor and the insulator.
The primary differences between the above two types of Coaxial Cable is found within the manner in which they are constructed. Low Noise Coaxial Cables is typically comprised of a single strand of Coaxial Cable that consists of a single wire that is run parallel to the centre conductor of the coaxial cable. As the Coaxial Cable is run, it travels past the first set of metal core conductors which form a barrier around the entire length of the coaxial cable. Electrically, this creates a magnetic field that helps reduce or eliminate electromagnetic interference. Some manufacturers incorporate a further layer of dielectric material into the core to create a stronger barrier, which again is designed to help reduce or eliminate the effects of EMI.
High Speed Coaxial Cables operates at a much higher frequency that most conventional coaxial cables. In order for high speed Coaxial Cable to operate at its highest capacity, it needs to be constructed using a thicker core with more layers. Furthermore, some manufacturers use an extra layer of metallic film in the core which enables them to achieve much greater strength than ordinary coaxial cables. In addition, the additional layer provides greater resistance to electromagnetic interference as well as moisture and other corrosive agents. Lastly, the extra coating of metal provides a higher level of electrical and acoustic stability which further extends the life of the Coaxial Cable. Some manufacturers also use a metal strip along the core, which allows the Coaxial Cable to be further protected from moisture.
Unlike low-noise Coaxial Cables, high-speed Coaxial cables utilize an entirely different form of insulation, which is made up of a thin layer of dielectric material. Although this type of Coaxial Cable has a lower bandwidth and lesser signal power, its advantages lie in the fact that they do not experience any sort of EMI interference nor do they require the presence of a center conductor. With the use of a dielectric material, the outer braided shield can no longer act as an effective conductor of electricity and the necessary insulation is obtained. The result is that, whereas coaxial cables are often susceptible to power fluctuations, dielectric cables experience zero degrees of electromagnetic induction.
With regards to signal strength, the case for dielectric over Coaxial Cables is considerably stronger than that for other forms of Coaxial Cable. It is for this reason that coaxial cables are often utilized in industrial applications where power fluctuations are a common occurrence. The most common component that is used in the construction of dielectric Coaxial Cable is the dielectric core which is surrounded by an outer jacket. In addition to providing ample protection against electromagnetic interference, the dielectric core ensures that the outer jacket does not act as a conductor and allows for transmission of power without any sort of interference. A dielectric core is typically made from an electrically inert material like graphite or an alloy of similar material.
Another form of coaxial cables is the 75 OHM coaxial cables which suffer a lower efficiency than the previously mentioned variant. The reason behind the lower efficiency is attributed to the short wavelength operation of the former variant, which renders it incapable of transmitting signals in the form of radio waves. The low rate of efficiency observed in the 75 Ohm cables is primarily because they are made of a different material, the only material capable of achieving a high degree of voltage drop.