Be aware that antennas on the sides of tall structures are not protected
from lightning strikes by the structure. The "cone of protection"
concept applies only to relatively short structures and lightning rods.
A more correct concept for protection offered by tall, over 20 to 50
meters, structures is the "rolling ball" concept. A lightning leader
descending toward earth within 20 to 50 meters to the side of such
structures may reach a point below the top of the structure and then
turn toward the structure.
For more information, read, "Lightning: Physics and Effects," Dr.
Vladimir A. Rakov and Dr. Martin A. Uman. 2003. Cambridge University
Press. This is an undergraduate text, not too technical , that provides
useful explanations of why lightning does what it does as well as the
latest findings and data from lightning research and information
regarding lightning protection. It is not commonly available at local
public libraries. I borrowed a copy via inter-library loan from U of MN.
I have observed one such strike to about the midpoint of a TV antenna
tower near my home.
73 de WOØW
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