Transmission System Radio Influence

An economic overhead electric power transmission system which produces no radio influence is beyond the present state of the art. However, sound engineering and attention to relevant aspects of design can produce a system having an acceptable (or tolerable) influence level. Such criteria as have been proved by research or experience together with accepted practices in instrumentation and measurement of radio influence fields are presented as an aid in planning extra-high-voltage lines. Because of the many variables and parameters that influence radio noise from power lines, and because the level of a line varies with location and time, it is not presently possible to submit specific desigin criteria. Revisions in thinking in some aspects of the problem may be anticipated as operating experience is gained at the new extra-high-voltage levels.