How to judge the quality of communication cable

1. Check the weaving of the shielding layer: is the weaving enough? Copper mesh, check the weldability, will be tinned copper computer wire, see whether there is copper wire, aluminum magnesium alloy wire hardness is obviously greater than copper wire; Sparse mesh, uneven distribution, insulation layer is not strictly wrapped. Bad cable; Burn the core wire with a lighter. If it is copper coated aluminum, it is easy to see that the color inside is different from the copper outside. Peel off the skin, look at the shielding layer knitting Angle, if the basic stand up, then the basic can be seen that the knitting Angle is relatively large, is the product of jerry-built;

2. PVC sheath: From the surface, it can be seen that the woven mesh inside the compression has regular "uneven", indicating that the processing technology is good, there will be no relative sliding, is a good cable. The appearance is smooth, can not see the compressed woven net "uneven", feel loose sheath with hand pinch, for inferior cable;

3. Check the binding force between the core wire and the insulation layer: cut the insulation layer diagonally and pull the core wire in the peeling direction to see whether the core wire and the insulation layer are combined with the process material; Good cable has a larger adhesive force, poor cable without adhesion;

4. Check core wire: diameter: 0.78-0.8mm for SYV wire, 1.0mm for SYWV wire; Recently, there has been a SYV75-5 cable with core diameter of 1.0mm. The characteristic impedance of this cable is definitely not 75 ohm and is not suitable for 75 ohm transmission systems. Check cable inner core diameter with vernier caliper;

5. Longitudinal tensile test: Take a one-meter long security cable, peel off the core wire, insulation layer, shielding layer and outer sheath layer by layer, and leave 10cm length for each layer. The method is: hold the two adjacent layers of the cable with two hands and pull in opposite directions; Good cables can't be pulled out with ordinary strength, and bad ones can be pulled out easily with little effort.

6, unwrap a roll of wire to measure the length, or weigh the rough judgment;

Communication cable procurement solutions

1, if the transmission distance is more than 800 meters, the use of SYV-75-5 cable found no image or image jumping, you can use video amplification anti-interference device, the use of video segment amplification, video signal can be amplified 10 times, so as to effectively extend the transmission distance (can not use a simple amplifier, otherwise the signal loss is great);

2. If multiple cables interfere with each other, multi-signal multiplexing equipment can be used to transmit 8-channel video images and control signals simultaneously on one video cable;

3. When encountering wire welding problems, it is recommended to buy pure tin solder wire, use high-power soldering iron for rapid welding, and do not slow tin;

4. Finally, if you're not sure about video cables, you can also use RF cables to transmit multiple video signal devices. One RF cable can simultaneously transmit 20 channels of image and control signals. The transmission distance can be up to 3 kilometers, so the cost will be more cost-effective.

The above is how to judge the quality of communication cables. Engineering enterprises must sharpen their eyes and carefully identify the advantages and disadvantages of cables.