1. Check the integrity of the insulation medium
The cross-section of a standard coaxial cable is very round, and the outer conductor and aluminum conductor of the cable are attached to the outer surface of the insulation medium. The rounder the outer surface of the medium, the smaller the gap between the aluminum foil and its surface, and the larger the gap if it is not round. Practice has shown that the smaller the gap, the better the performance of the cable. In addition, the larger the gap, the easier air is to penetrate the shielding layer and affect the service life of the cable.
2. Consistency of insulation medium for measuring coaxial cables
The fluctuation of the diameter of the coaxial cable edge medium mainly affects the echo coefficient of the cable. This inspection can cut out a section of the insulation medium of the cable, and carefully check the outer diameter of each point with a micrometer to see if it is consistent.
3. Braided mesh for measuring coaxial cables
The textile network cable of coaxial cables plays an important role in the shielding performance of coaxial cables, and it is also the circuit line of the power supply in centralized power supply cable TV lines. Therefore, the quality inspection of coaxial cables must check whether the textile network is tight and flat. The method is to cut open the outer sheath of the coaxial cable, cut a small section of the coaxial cable woven network, and evaluate the number of woven networks. If it matches the given indicator value, it is qualified, In addition, a spiral micrometer is used to measure a single textile mesh wire. At the same price, the thicker the wire diameter, the better the quality.
4. Check the quality of aluminum foil
Aluminum foil plays an important shielding role in coaxial cables, which plays an important role in preventing interference from external open circuit signals and confusion with cable TV signals. Therefore, the quality of aluminum foil should be checked for new coaxial cables. Firstly, cut open the protective layer and observe whether the surface of the braided wire and aluminum foil layer maintains good gloss; Next, take a section of cable and wrap it tightly around a small metal shaft. Straighten it and rotate it in the opposite direction several times, then cut open the cable sheath layer to observe whether the aluminum foil is cracked. You can also cut out a small section of aluminum foil and rub and stretch it repeatedly in your hand. If it has not broken after multiple rubs and stretches, it is considered a qualified product, otherwise it is considered a defective product.
5. Check the squeezing tightness of the outer protective layer
The outer protective layer of high-quality coaxial cables is tightly wrapped, which can narrow the gap inside 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 too tightly can cause inconvenience in head stripping and increase construction difficulty. The inspection method is to take a 1m long cable, remove the protective layer at the end, and use force not to pull out the wire core as appropriate