What is a ground loop?

An AC current that can be produced in a cable. This is usually caused by parts of the system being fed from different electrical sources resulting in different earth potentials at each end. The result is interference on the signal, usually in the form of dark bands across the monitor and on occasion tearing in the top third of the image.

How can I eliminate ground loop faults?

This can be achieved in a number of ways, the easiest of which is the installation of a Ground Loop Isolation Transformer. This is best installed at the monitor or recording end of the system.