Modern (directional) taps are built using a combination of a directional coupler feeding a splitter arrangement. Response problems beyond a directional tap will not show gross response problems at the subscribers drop. Problems will exist beyond the damage but they are usually not as severe as what would have been seen before the damage... due to reflections.
A Pressure Tap is merely a resistive, capacitively coupled, non directional device allowing some of the through signal to be "tapped" from the feeder line. Since a pressure tap is not directional, reflections from beyond can be of good strength and will cause response problems at the subscribers drop; due to constructive and destructive interference. If a cable is broken or unterminated beyond a pressure tap, reflections occur and this is seen as a ghost or ghosts on the subscribers screen. The distance from the left part of the screen to the ghost bar is directly related to the distance to the damage and the channel frequencies involved.
Copyright © 1999 Kevin Custer.
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