The cross-section of the coaxial cable is very round, and the outer conductor of the cable and the aluminum foil is attached to the outer surface of the insulating medium. The more rounded the outer surface of the medium, the smaller the gap between the aluminum foil and its surface, and the less rounded the gap will be. The practice has proved that the smaller the gap, the better the performance of the cable. Besides, the large gap air is likely to invade the shielding layer and affect the service life of the cable.
The fluctuation of the diameter of the coaxial cable edge media mainly affects the echo coefficient of the cable. This inspection can cut out the insulation medium of a section of the cable, and carefully check the outer diameter of each point with a micrometer to see if it is consistent.
The textile network cable of the coaxial cable plays an important role in the shielding performance of the coaxial cable, and it is also the power return line in the centralized power supply cable TV line. Therefore, coaxial cable quality inspection must check whether the textile net is tight and flat. The method is to cut off the outer sheath of the coaxial cable, cut a short section of the coaxial cable braided net, and appraise the number of braided nets. If it accords with the given index value, it is qualified. Besides, measure a single textile wire with a spiral micrometer. At the same price, the thicker the wire diameter, the better the quality.
Aluminum foil plays an important shielding role in coaxial cables, which plays an important role in preventing external open-circuit signal interference and cable TV signal exposure. Therefore, the quality of aluminum foil should be checked for new coaxial cables. First, cut open the sheath layer to observe whether the surface of the woven mesh wire and aluminum foil layer maintains good gloss. The second is to take a piece of cable, wind it tightly on a small metal shaft, straighten it and turn it in the opposite direction, and repeat it several times. Then cut the cable sheath to see whether the aluminum foil is broken or not. You can also cut out a small section of aluminum foil and rub and stretch it repeatedly in your hands. After many times of rubbing and stretching, it still hasn't broken, and the one with certain toughness is cooperative vomiting, otherwise, it is defective.
The outer sheaths of high-quality coaxial cables are tightly wrapped, which can reduce the gap in the shielding layer, prevent air from entering and causing oxidation, and prevent the relative sliding of the shielding layer from causing electrical performance drift. However, squeezing the bag too tightly will cause inconvenience to strip and increase the difficulty of construction. The inspection method is to take a 1m cable and remove the protective layer at the end. It is appropriate to not pull out the core with force.
Looping of cables is not only an aesthetic problem but also a quality problem. The cables are looped and flat, and the cables are kept on the same concentric plane. The cable and the cable are in a circular arc and parallel to the whole contact, which can reduce the mutual force of the cables, and the stacking is not easy to deform and damage. Therefore, this should not be taken lightly when checking the quality of the cable.