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1) SYV75-3, 5, 7, 9..., 75 ohm, polyethylene insulated solid coaxial cable. In recent years, it has been called "video cable";
2) SYWV75-3, 5, 7, 9...75 ohm, physical foamed polyethylene insulated coaxial cable. Some people call it "RF cable";
3) Basic performance:
lSYV physical structure is 100% polyethylene insulation; SYWV is a physical foamed polyethylene insulated cable with a foaming rate of 70-80%;
Due to dielectric loss, the SYV solid cable attenuation is significantly larger than the SYWV physical foam cable; in the common engineering cable, the current physical foam cable is still the best transmission cable with the lowest price, in the video, RF, and microwave bands. Is such that. The test data given by the manufacturer also illustrates this point;
Coaxial cables can be used in DC, RF, and microwave bands. According to "RF" / "Video" to distinguish cables, not only based on the shortcomings, but also easy to mislead: it seems that video transmission must or can only choose solid cable (choose large attenuation, high price?); from the engineering application point of view, or It is more practical to distinguish between types by "solid core" and "foaming" cables;
The difference between high-profile (128) and low-grade (64) cable characteristics: eie laboratory experimental research shows that in the frequency band below 200KHz, the "low resistance" of the high-frequency cable shielding layer plays a major role, so the low-frequency transmission attenuation is less than the low-frequency cable. . However, in the video, radio frequency and microwave bands above 200-300KHz, because the "high-frequency skin effect" plays a major role, the high-knit cable has lost the advantage of "low resistance", so the high-frequency attenuation of the two cables is basically the same.
Common coaxial cable types and features
[ Huaqiang Security Network News ] Coaxial cable is still the most widely used video transmission line in the current monitoring system. Coaxial video transmission technology is also one of the most basic transmission methods in surveillance systems. "How far can coaxial cable travel?" What level of coaxial video transmission technology and anti-jamming technology has developed to the present? In-depth understanding of the transmission characteristics of coaxial cable, mastering the current status and development of coaxial video transmission technology, to improve the image quality of the monitoring system, improve system design, and effectively reduce system cost, is still of practical and positive significance. Common coaxial cable types and performance: