RF coaxial Cable I believe that you are not unfamiliar with this product, RF coaxial cable has now been used more and more widely. The RF coaxial cable refers to two concentric conductors, while the conductor and shielding layer share the same axis. The RF coaxial cable insulation material is composed of a physical cannon-made polyethylene insulated copper conductor, outside the inner insulating material is another layer of annular conductor namely outer conductor, the outer conductor uses the copper belt to form, weld, tie the grain, or adopts the aluminum tube structure, or uses the knitting structure, then the entire cable is covered by the PVC material. This is RF coaxial cable.
(1) The characteristic impedance of coaxial cable is 50, and the impedance of coaxial cables along the single axis is the sine wave, the center mean is Yan, and its length is less than 2 meters.
(2) The attenuation of coaxial cable generally refers to the attenuation value of the 500-meter-long cables. When measured with a 10MHz sine wave, its value is no more than 8.5db (17db km); while the 5MHz sine wave is measured, its value is no more than 6.0db (12 b km).
(3) The propagation speed of coaxial cable requires a minimum propagation speed of 0.77C (c is the speed of light).
(4) The resistance of the center conductor of the DC Loop resistance cable of the coaxial cable is not more than 10 millisieverts/m (measured under 20 Shan). The RF coaxial cable refers to two concentric conductors, while the conductor and shielding layer share the same axis. It is another kind of wire used widely in computer network. Because it wraps in the main line insulation material, outside the insulating material has a layer of mesh woven shielded metal cable, so it can be very good to block the external electromagnetic interference, improve communication quality.
The advantage of RF coaxial cable is that it can support high-bandwidth communication on a relatively long circuit without repeaters, and its drawbacks are obvious: one is the size, the diameter of the cable is 3/8 inches thick, to occupy a large amount of space in the cable pipeline; the second is the inability to withstand entanglement, pressure and severe bending, which can damage the cable structure, prevent the transmission of the signal, and finally the cost is high, and all these shortcomings are the twisted pair can overcome, so in the current LAN environment, Basically has been replaced by the specification of the Ethernet physical layer based on twisted pair.