How important is shielding in video cables?
Shielding in coaxial type video cables serves two purposes: 1) shielding prevents external interference from degrading your video signal within the cable, and 2) the type of shielding and its uniformity along a given length of cable greatly affects impedance and thus signal quality. Most shielding consists of foil and/or copper braid, and some cables use both. A common problem in low quality cable is the lack of shield density or uniformity of copper braid shielding, an arrangment that leaves big gaps for outside interference and bottlenecks (impedance mismatches) that cause back reflection within a cable.
