Detuning Power Lines by Isolating Towers for the Suppression of Resonsnces

Abstract

An AM "standard" broadcast array is often required to maintain a low level of radiation in specified directions, to avoid interference with other stations on the same frequency in distant cities. Reradiation from a nearby power line can give rise to field strengths in excess of protection limits. This paper presents a technique for detuning a steel-lattice tower power line on which the tower tops are connected together by an overhead "skywire". Reradiation from such a power line is primarily a problem when the closed-loop path of two adjacent towers, the interconnecting skywire, and their images in ground is resonant at the operating frequency. This paper is concerned with detuning a power line by open-circuiting resonant paths by disconnecting one tower from the overhead skywire.