Buy and price of wire coaxial cable
The technical information on wire and cable is almost endless. Solid or stranded, coated or uncoated, sheathed or not, data transmission like coaxial or power transmission like ACSR, and the list goes on.
wire coaxial cable
Having all the information you need in one place is like a gold mine. Here we gathered all the needed information about the coax cable so read to the end of this article.
Coaxial cable, also known as coax, is a type of electrical cable that consists of an inner conductor that is surrounded by a concentric conducting shield, with the two conductors being separated by a dielectric (insulating material).
in addition, the majority of coaxial cables also have a protective outer sheath or jacket.
The inner conductor and the outer shield both have the same geometric axis, which is what is meant by the phrase "coaxial."
Transmission lines come in a variety of forms, one of which is the coaxial cable, which is designed to convey high-frequency electrical communications while minimizing signal loss.
It is utilized in a variety of applications including telephone trunk lines, high-speed computer data busses, cable television signal transmissions, and the connection of radio transmitters and receivers to their antennas.
The size of the cable and connections are managed to offer precise and constant conductor spacing, which is required for it to function successfully as a transmission line. This sets it apart from other shielded cables in a significant way.
Oliver Heaviside demonstrated in the British patent that he received in 1880 how the use of coaxial wire might prevent signal interference between parallel cables.
Although coaxial cable was utilized in the initial (1858) and subsequent transatlantic cable constructions, the theory behind it was not described until 1880 by Oliver Heaviside, an English physicist, engineer, and mathematician who also received a patent for the design of the cable in that same year.
Radio frequency signals are sent by coaxial cable, which is utilized as a transmission line.
Applications for this technology include the use of feedlines to connect radio transmitters and receivers to their antennas, connections to computer networks (such as Ethernet), digital audio (S/PDIF), and the dissemination of cable television signals.
coaxial cable wire connector
The electromagnetic field that carries the signal occurs solely in the area between the inner and outer conductors in an ideal coaxial cable. This is one benefit that coaxial has over other types of radio transmission lines.
Because of this, it is possible to lay coaxial cable runs near metal objects like gutters without experiencing the power losses that are typical of other forms of transmission lines.
The transmission is additionally shielded from any electromagnetic interference that may come from the outside using coaxial wire.
An inner conductor, which is typically made of solid copper, stranded copper, or copper-plated steel wire, is used by coaxial cable to carry electrical signals.
This inner conductor is surrounded by an insulating layer, and the entire assembly is protected by a shield, which typically consists of one to four layers of woven metallic braid and metallic tape.
An outer insulating jacket surrounds the cable to provide protection for it. In a typical configuration, the potential of the ground is maintained on the outside of the shield, while a signal-carrying voltage is applied to the center conductor.
When differential signaling is utilized, the use of coaxial cable offers the benefit of having equal push-pull currents on the inner conductor and inside of the outer conductor.
These currents confine the signal's electric and magnetic fields to the dielectric, with very little leakage occurring outside of the shield.
In addition, if uneven currents are filtered out at the receiving end of the line, the electric and magnetic fields that are outside the cable are substantially prevented from interfering with the signals that are being transmitted over the cable.
Because of this property, a coaxial cable is an excellent option for transmitting weak signals that are not able to withstand interference from their surrounding environment.
It is also an excellent option for transmitting stronger electrical signals that must not be allowed to radiate or couple into neighboring structures or circuits. There is less leakage in cables that have a larger diameter and cables that have several shields.
Coaxial cable is used for a variety of purposes, including but not limited to video and CATV distribution, RF and microwave transmission, as well as data connectivity in computers and equipment.
The characteristic impedance of the cable, denoted by Z0, is established by taking into account the radii of the inner and outer conductors in addition to the dielectric constant of the inner insulator.
coaxial cable types
In radio frequency systems, when the length of the cable is comparable to the wavelength of the signals being broadcast, having a cable characteristic impedance that is consistent throughout is essential for minimizing signal loss.
In order to achieve both maximum power transfer and minimum standing wave ratio, the impedance of both the source and the load is optimized to correspond with the impedance of the cable.
Attenuation as a Function of Frequency, Capability of Handling Voltage, and Shield Quality are Other Important Features of Coaxial Cable Other important properties of coaxial cable include:
The physical size, frequency, attenuation, power handling, flexibility, strength, and cost of coaxial cables are all affected by the design decisions that are made.
The inner conductor could be solid or it could be stranded; nevertheless, stranded conductors are more flexible. Silver plating can be applied to the inner conductor in order to improve its performance at high frequencies.
The inner conductor of cable in the cable TV industry is frequently a copper-plated steel wire. This wire is utilized in the cable.
It's possible for the insulator that surrounds the inner conductor to be made of solid plastic, foam plastic, air, or spacers that support the inner wire.
Some of the cable's electrical properties are determined by the characteristics of the dielectric insulator that surrounds it. Insulators made of solid polyethylene (PE) are frequently used in lower-loss cables and are a popular choice.
Insulation can also be made out of solid Teflon, which is known as PTFE. Plenum-rated cables always utilize PTFE insulation. Some coaxial lines make use of air (or another gas), and all of them include spacers to prevent the inner conductor from coming into contact with the shield.
In many common types of conventional coaxial cables, the shield is formed from braided copper wire.
Because of this, the cable is able to be flexible; however, this also means that there are gaps in the shield layer, and the inner size of the shield changes slightly due to the fact that the braid cannot be flat. There are times when the braid has a silver plating.
Some cables include a dual layer of shielding to improve their overall performance as a shield. It is possible that the shield is comprised of only two braids; however, it is currently more popular to have a thin foil shield that is covered by a wire braid.
coaxial cable for internet
Some cables may invest in more than two layers of shielding, such as the "quad-shield," which consists of four layers of foil and braid that alternate with one another.
Other shield designs exclude flexibility in exchange for improved performance; some shields consist of a tube made entirely of metal.
These wires cannot be bent sharply since doing so will cause the shield to kink, which will result in signal loss. When a foil shield is utilized, the process of soldering the shield termination is simplified by the incorporation of a short wire conductor inside the foil itself.
Coaxial cable with a solid copper outer conductor is readily available in sizes ranging from 0.25 inches and upwards for use in high-power radio-frequency transmissions up to approximately 1 GHz.
The outer conductor is made to seem like a bellows so that it can be flexible, while the inner conductor is kept in place by a plastic spiral that is made to look like air. Heliax is a brand name of cable that fits this description.
In order to preserve the distance that exists between the center conductor and the shield, coaxial cables need to have an interior structure that is composed of an insulating (dielectric) substance.
Following is a list of materials in increasing order of their dielectric losses: an ideal dielectric (one with no loss), a vacuum, air, polytetrafluoroethylene (PTFE), polyethylene foam, and solid polyethylene.
In order to prevent current hotspots, an inhomogeneous dielectric needs to have a non-circular conductor added to it as compensation.
Many cables utilize a solid dielectric, while many others employ a foam dielectric that contains as much air or another gas as possible. This helps to reduce losses by enabling the use of a central conductor with a greater diameter, which in turn helps to reduce losses.
Foam coax will have roughly 15% less attenuation, but certain types of foam dielectric can collect moisture in humid settings, particularly on its many surfaces, greatly increasing the loss. Foam coax will have lower attenuation than foam dielectric.
Supports in the shape of spokes or stars are even more effective, but they are also more expensive and more prone to the invasion of moisture.
In the middle of the 20th century, some inter-city connections were carried out using air-spaced coaxial cables, which were even more expensive.
coaxial cable splitter
The polyethylene discs that were placed every few centimeters served to suspend the center conductor.
The inner conductor of certain low-loss coaxial cables, such as the RG-62 type, is supported by a helical strand of polyethylene. As a result, an air space occurs between the majority of the conductor and the interior of the jacket.
Because air has a lower dielectric constant than other materials, it is possible to have a larger inner diameter while maintaining the same impedance and a larger outer diameter while maintaining the same cutoff frequency.
This results in reduced ohmic losses. Sometimes the inner conductors will have a silver plating applied to them so that the surface will be smoother and the skin effect losses would be reduced.
The current route is lengthened by a rough surface, and the current is concentrated at peaks, which leads to an increase in ohmic loss
There are a variety of materials from which the insulating jacket can be constructed. PVC is a popular option, but certain applications can call for materials that are fire-resistant instead.
For use in the great outdoors, the jacket may need to be resistant to things like ultraviolet light, oxidation, rat damage, or even direct burial.
To prevent water from entering the cable through punctures or other small openings in the jacket, flooded coaxial cables are protected by a water-blocking gel. When making connections on the inside of the chassis, the insulating jacket can be left off.
The electromagnetic wave that is traveling along a twin-lead transmission line has the property of expanding into the space that is surrounded by the parallel wires. This trait is possessed by twin-lead transmission lines.
These lines have a low loss, but they also have other qualities that are not desired.
They cannot be bent, tightly twisted, or shaped in any other way without generating a change in their characteristic impedance, which results in the signal being reflected back toward its original source.
Because the extended fields will induce currents in the neighboring conductors, they cannot be buried, run along, or linked to anything conductive because this will cause unwanted radiation and detuning of the line.
coaxial cable modem
In order to avoid them from coming into contact with parallel metal surfaces, standoff insulators are utilized.
Because they contain almost entirely of the electromagnetic pulse within the cable itself, coaxial lines are a significant part of the solution to this problem.
Therefore, coaxial lines can be bent and moderately twisted without having any negative effects, and they can be strapped to conductive supports without inducing unwanted currents in them, so long as provisions are made to ensure differential signaling push-pull currents are present in the cable.
This is the case as long as provisions are made to ensure that push-pull currents in the cable are differential.
The wave travels largely in the transverse electric magnetic (TEM) mode in radio-frequency applications up to a few gigahertz. This mode indicates that the electric and magnetic fields are both perpendicular to the direction in which the wave is moving.
However, once the frequency is increased over the cutoff point, transverse electric (TE) or transverse magnetic (TM) modes can also propagate, just as they would in a hollow waveguide.
It is generally not a good idea to send signals at a frequency that is higher than the cutoff frequency since doing so can create several modes with varying phase velocities to propagate, which can result in interference with one another.
The relationship between the outer diameter and the cutoff frequency is approximately inversely proportional.
In a coaxial cable with a standard design and a common impedance, a surface-wave mode that propagates and only includes the central conductor is effectively suppressed.
However, this mode does exist. Electric field lines for this particular TM mode feature a longitudinal component, and the required line lengths are at least equal to half of a wave's length.
It is possible to consider coaxial cable to be a form of the waveguide. When power is transmitted via the TEM mode, it does so via the radial electric field as well as the circumferential magnetic field.
This is the dominant mode from a frequency of zero (DC) up to a maximum that is set by the electrical dimensions of the cable.
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