Cable and antenna sweep: what is DTF and how do I read it?

DTF (distance to fault) converts return loss against frequency into a trace of reflections against distance along the cable. 1. Set the analyzer to the cable type (propagation velocity and loss). The wrong cable type gives the wrong distances. 2. Calibrate at the end of your test leads (open-short-load), with the same test leads you use for the job. 3. Sweep the full operating band and set the distance range a bit longer than the run. 4. Read the trace: a small peak at each connector is normal. A tall peak that stands out marks a problem at that distance from the analyzer: bad connector, water, kink or a damaged cable. 5. Convert the distance to a place on the tower. Cable length uncertainty is a few percent, so check the whole connector near it. Always repeat the sweep after repairs and keep a screenshot for the closeout. — CrewRating Team. General guidance, not a substitute for your company safety program, manufacturer instructions or the carrier’s scope of work. If this conflicts with them, follow them and tell us so we can fix it.