Although I shared with you how to choose a good feeder, there are inevitably some misunderstandings in consciousness. This time we will help you sort out the misunderstandings that should be avoided when purchasing feeders.
1.The performance of shielded tinned copper is better than bare copper and aluminum-magnesium mesh
With the same number of shielding layers, there is not much difference between the three shielding nets. For example, in the Americas, aluminum-magnesium network cables are recognized, while in Europe, bare copper is preferred. In Asia, tin-plated copper and aluminum-magnesium are preferred. Half of it is a matter of design philosophy, with different emphasis instead of good or bad quality standards. It is as if each national standard specifies the performance standards of the cable, but does not specify what materials can only be used for the same model. We say that tinned copper is good in terms of oxidation resistance. If it is also exposed to air, the life of tinned copper is better than bare copper and aluminum-magnesium alloy. If the connector is not handled properly, the cable will age quickly, especially bare. Copper, aluminum-magnesium mesh. Therefore, the difference in material is only a problem of service life when the joint is not completed. If the joint is made up to standard, there is no difference between the three.
2.Solid polyethylene is better than foam
I often hear some friends say this, and some even think that foamed cables are not strong. The reason is that there are too many solid polyethylene cables in the market. The illusion caused by everyone has no theoretical basis. . Foamed cable not only has low loss and light weight, but also follows many technological innovations. The application of these new technologies cannot be done on solid polyethylene cables with old technology.
3.The black sheath is better than white
The material of the sheath is usually PVC (polyvinyl chloride) and PE (polyethylene). Normally, black and white are one material. There is no difference. Many friends say that only black can be used outdoors. It is only a sensory problem. Cables After a long period of UV irradiation, there will be some discoloration, white will gradually yellow and not resistant to dirt, and black will fade, but it is not obvious.
4, Teflon feeder performance is good
Teflon's scientific name is polytetrafluoroethylene, which has very good heat resistance. As a sheath, it has the advantage of being fireproof. Using Teflon in computer rooms and areas with high fire resistance requirements can effectively improve the safety level. However, Teflon is only the sheath material of the cable, and it only protects the cable. The performance of the cable itself still needs to be completed by the internal structure. I do n’t know when the myth of Teflon spread in HAM. As an insulating medium, vacuum is still ideal. The content of nitrogen in foamed cables exceeds 80%. The permeability of nitrogen is at least not surpassed by other materials. So, Those who think that Teflon cables are low-loss, high-performance cables are totally wrong.
5. The imported ones must be better than the domestic ones, and the military ones must be better than the civilian ones.
Here I think we should promote the use of domestic products. In fact, there are many good-quality and high-tech cables in China. However, due to the lack of market supervision, many poor-quality cables produced by small factories have flooded most of the civilian market. It has created a good impression that domestic is not as good as imported. Let me give an example: I have also seen some imported single-core coaxial feeders that were not physically foamed, and that physical foaming did not use self-adhesive aluminum foil with good shielding effects. The performance of such feeders is not as good as domestic ones. Foam feeder. At present, the import feeder channels in the market are generally divided into two categories. One is engineering bidding, which is a small amount out of the market; the other is foreign garbage imported as recyclable scrap metal raw materials, which are basically eliminated and replaced by foreign projects. Down, after many years of use and unprotected placement in the open air, the performance is definitely not as good as before. Because our country needs raw copper, we will choose cables with high copper content when importing. This type of cable is common in several port cities in China.
The strength and durability of military cables cannot be questioned, and the materials used are particular, but they are not necessarily suitable for our HAM. The common model should be RG213 / U. We have already mentioned above that in the same feeder, multiple feeders of solid polyethylene material are the most sturdy and durable, but the losses are too large, which is determined by the physical structure. Therefore, when choosing feeders, we cannot blindly follow imported goods and military goods, which needs to be analyzed in essence.
6.Silver-plated thin wires will perform better than thick wires
The misunderstanding of this point is mainly in the new HAM. Many friends think that the performance of the cable after silver plating is better than the thicker cable. When we talk about the silver plating process, we mainly talk about the silver plating of the inner conductor. The advantage of silver plating is to increase the conductivity. Under the same physical structure, the conductivity is better than the cable of the same level, but it cannot exceed the thicker cable because The signal transmission method has determined that under the same physical structure conditions, the loss is determined by the diameter of the cable. In addition, the silver-plated inner conductor will be oxidized and blackened after being exposed to the air for a long time. If it is constant, it must be tin-plated instead of silver-plated.