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本帖最後由 WSUgocouars 於 2012-3-20 00:12 編輯
我想你心中早有一把尺. 看了幾篇文章, 找了這一篇比較容易懂. 但也只是證明你的想法是有一致性.... 但看現有RG-213規格的纜線, 沒人敢秀 100% 的覆蓋率. Braid+Al. foil 或 double braid 有的廠商也只秀到 97% 覆蓋率.http://www.epanorama.net/documents/wiring/coaxcable.html.
其中這段有提到它們的特性.... 但可靠度是看各家的製程和用料, 在此不討論!!
Typical coaxial cable constructions are: Flexible (Braided) Coaxial Cable is by far the most common type of closed transmission line because of its flexibility. It is a coaxial cable, meaning that both the signal and the ground conductors are on the same center axis. The outer conductor is made from fine braided wire, hence the name "braided coaxial cable". This type of cable is used in practically all applications requiring complete shielding of the center conductor. The effectiveness of the shielding depends upon the weave of the braid and the number of braid layers. One of the draw-backs of braided cable is that the shielding is not 100% effective, especially at higher frequencies. This is because the braided construction can permit small amounts of short wavelength (high frequency) energy to radiate. Normally this does not present a problem; however, if a higher degree of shielding is required, semirigid coaxial cable is recommended. In some high frequency flexible coaxial cables the outer shield consists if normal braids and an extra aluminium foil shield to give better high frequency shielding.
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發表於 2012-3-19 17:01:29
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發表於 2012-3-19 23:13:06
