Locating Radio Interference with the Oscillograph

Certain kinds of radio interference travel many miles over wires and cause trouble in radio reception. Often this interference originates on one system which is coupled to another and, because of complaints, the interference investigation is started from a point near the second system. The usual methods of locating the trouble are not very effective in such cases. The oscillographic method analyzes the interference more exactly, giving its magnitude, frequency, and phase position. It is also shown that various types of interference give characteristic patterns on the oscillogram and a number of oscillograph records are included illustrating common disturbances found in radio reception. It is thus possible to point out when the interference at two widely separated points originates at a common source.