Coaxial cables from garg associates, ghaziabad is constructed to overcome the problems in which signals and energy is contained within an enclosed space. It consists of a core conductor, surrounded by pure ptfe dielectric [solid or foamed or air-spaced], covered with a metal shield, and finally encased in an overall jacket. The shield provides the return path as well as the confinement for rf energy, and is generally grounded. Transmission through coaxial cables is called an unbalanced transmission because the centre conductor and the shield are not reversible [as opposed to the balanced construction of a twisted pair]. Features:non reversibility -jackets provide outer cover to keep the cable clean, smooth and to prevent ingress of moisture into shield, as well as for isolation of shield. -shield can be spc [silver plated copper] round wire single or double braid, round wire served [helically wrapped], flat foil served [helically wrapped with drain wires], foil and braid combination with drain wires, and other materials. -high temperature, melt extrudible jackets such as fep [fluorinated ethylene propylene] and pfa [per fluoro alkoxy] are also likely to be available in future. - supple enough to be used in delicate systems [such as echography], and yet far more reliable than corresponding expanded/unsintered ptfe tape wrapped cables in respect of crush-resistance and long-term stability in hostile surroundings. Technical specifications: materials used are ptfe, vfg [fibre glass braid covered with lacquer varnish, over sintered ptfe tape moisture seal], pvc or pu. Tested on a time domain reflectometer [tdr] to control characteristic impedance within the permissible range [say, 50 +/-2 ohms, 75 +/-3 ohms etc.]
