Black Box Explains...UTP cable and color drift
UTP cable is often used with video or KVM extenders to extend the reach of a video signal. It’s popular for this application because it’s lightweight, easy to handle, and inexpensive. But when you transmit video over long stretches of twisted-pair cable, you sometimes run into a phenomenon called color drift or color split.
Color drift shows up as that annoying colored shadow you occasionally see around objects on a video screen. It sometimes happens with UTP cable because the pairs of wire in the cable are twisted at slightly different rates to reduce crosstalk between pairs. Because of these differences between wire pairs, video signals for different colors often travel different distances before they reach the remote receiver. When one color signal arrives behind the others because its wire is longer, you get that red, green, or blue shadow around the objects on your video screen.
UTP cable varies widely by manufacturer, so before installing video extenders, it’s difficult to determine whether or not you’re going to have a color drift problem. You’re more likely to experience color drift with higher grades (CAT5e or CAT6) of cable, on longer cable runs, and on high-resolution screens.
If you experience color drift, there are several possible solutions. You can use a shorter length of cable, switch from CAT5e or CAT6 cable to CAT5 cable, use a lower screen resolution, or use a video skew compensator.
A video skew compensator removes color drift by delaying some color signals to compensate for differences in wire pairs.