Bill,
Thanks for a very timely and well-presented summary of what lightening damage
can do.
As I read your piece, I kept thinking of the charged atmosphere as a
potential difference against ground. Since E=IR, the lower the R,
theoretically the higher the I, and hence the greater the potential for
damage. I believe that there is a fundamental dilemma when dealing with
lightning protection schemes. It seems that the largest grid discharge
system available at most locations to defuse lightning is AC Ground. Putting
several ground rods at each tower location cannot provide as great a "current
sink" as that of house wiring that is connected to a larger electrical grid.
What, then, is the strategy for dealing with lightning? The bigger the
"fuse" is that blows, the greater the collateral damage will be. As Bill
mentioned, control cables became the "fuse" and the results were devastating.
It seems that there may be two schools of thought on grounding, one that says
ground everything, and one that says isolate everything to prevent a current
path. Have there been any experiments dealing with passive lightning
protection? The more extensively we ground an antenna system and the lower
the ohmic value of the ground, don't we create a more attractive and
potentially more devastating discharge path?
I don't want to start an ozone layer debate, but aren't there really two
sides to this story?
Paul, KB8N
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