postheadericon Fine Layers for the Proper Insulators Now

The thickness of the layer of this dielectric insulator is the same along the entire length of the coaxial cable, so that the performance of the cable over its entire length is the same. Dielectrics made of porous or foamed polyurethane lessen the video signal than dielectrics made from solid polyethylene. When calculating the loss by length, smaller length losses are desirable for any cable. In addition, a foamed dielectric gives the cable more flexibility, which facilitates the work of installers. But while the electrical characteristics of a coaxial power connector with foamed dielectric material are higher, such a material can absorb moisture, which worsens these characteristics.

The Feature of Solid Polyethylene

Solid polyethylene is stiffer and better retains its shape than the foam polymer, more resistant to squeezing and squeezing, but laying such a hard cable is somewhat more difficult. In addition, the signal loss per unit length is greater than for a cable with a foamed dielectric, and this should be taken into account if the cable length should be large.

  • It is worth noting that some manufacturers foil the dielectric chemically. As a result, a low-density polyethylene compound is obtained, subject to mechanical damage and unstable to the environment in the form of temperature and humidity.

Cable Quality

The highest quality of the cable is obtained with a physically foamed dielectric. It contains up to 60% of air bubbles, due to which the attenuation of high frequencies of the signal decreases. For strength, physically foamed polyethylene does not differ from conventional solid non-foamed polyethylene, providing the necessary flexibility and resistance to mechanical stress. And, finally, having a high resistance to temperature fluctuations and humidity, physically foamed dielectric will ensure the stability of parameters and long-term operation of the cable.

The Outside Part

Outside, the dielectric material is covered with a copper braid (shield), which is the second (usually grounded) signal conductor between the camera and the monitor. The screen has two important roles. It works as a second conductor connected to a common ground wire of the equipment. At the same time, it shields the signal conductor from extraneous emissions, unwanted external signals, or interference, which is usually called electromagnetic interference (EMF) and which can adversely affect the video signal.

The quality of shielding from electromagnetic interference depends on the copper content in the braid. Co-axial cables of market quality contain a loose copper braid with a shielding effect of approximately 80%. Such cables are suitable for normal applications where electromagnetic interference is small. These cables are good in cases where they are laid in a metal conduit or metal pipe, which serves as an additional screen.

Comments are closed.