This document provides an example calculation for determining distance to fault using an 860 DSPi device. The distance to fault formula uses the velocity of propagation and difference in frequency between two markers on the standing wave pattern. In the example, with a velocity of 0.84 and a frequency difference of 35.97, the calculated distance to fault is 11 feet. A note indicates the markers need to be placed on a full cycle of the standing wave for an accurate measurement.