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Guy Insulator Flashover

November 2nd Fact-of-the-Day

Insulators generally should be used to break up tower guy cables into short, non-resonant lengths to minimize adverse effects of the cables on nearby antennas. Appreciable RF voltages can develop across guy insulators used in that way with high power transmitters. The insulators should have a wet flashover voltage rating approximately three times estimated peak RF voltage to have a reasonable safety margin during rain storms, because flashovers will fill the radio spectrum with splatter and have the potential to damage transmitters where there is considerable RF coupling between an antenna and one or more guy cables. Unfortunately, because the electric power industry is the largest customer for guy insulators, insulator flashover voltages usually are specified at 50 or 60 Hz. RF flashover voltages are lower and depend on both the frequency and insulator design. ©2004 Martek International All rights reserved.

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