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| The lightning rods may sometimes create some ionization to dissipate cloud charges, but not always. The lightning rods and ample conductors to ample (or bigger ground rods) will handle much of the current of a direct hit. And will handle it much better than the structure of the house. A tower that takes hits will protect stuff nearby, usually the umbrella is figured to have a 60 degree included angle, e,g. 30 degrees out from the tower.
There used to be a company in Florida called "Lightening Elimination Associates" that doted on an air terminal on top a tower with a large nuber of sharp points to cause the ionization to prevent lightning. Their main client was NASA at the Cape. On top of one of their towers they put three arms out several feet (maybe as much as 20) and wound a nest of barbed wire on those where the barbs were less than 3" apart and the strands about that far apart. For a decade the areas protected by their towers didn't have much lightning. Then one day one of their towers took a direct hit. They lost all their credibility in one stroke. (hiss, pun). And I think gave up on the concept.
Its important to tie all the equipment grounds together, in two way radio rooms at the bases of towers, they run an 18" wide strap of copper all the way around and tie that to the tower, the power ground, the lightning arrestor (polyphaser makes very good ones for coax cables) grounds and that strap tends to keep the lightning outside the radio equipment, so they take hits and keep on working. Having a dozen or more ground rods distributed about a rod length apart is a definite benefit. The earth is a crappy ground but its all we have to use, so the more distributed the connections the better the quality of that ground.
Gerald J. | |
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Lightning machinery question
