"Rick (W-A-one-R-K-T)" wrote in
news
On Mon, 16 Jul 2007 21:26:16 +0000, Owen Duffy wrote:

It is my view that there is a significant risk that an inadequate
lightning protection scheme may be much worse than doing nothing.

Owen, certainly optimal is better than sub-optimal, but I don't
understand why sub-optimal can be worse than nothing at all. So far
you have been exceedingly helpful and I have learned a lot. Can you
explain why something isn't necessarily better, and in fact can be
much worse, than nothing?



Rick,

I guess to some extent it goes to the meaning of do nothing.

If you did not install a lightning protection system, but only connected
antennas at a time of low risk, then you might be much better off than
trusing an inadequate protection scheme.

It does reach a point where the disconnect strategy is not convenient /
practical / effective, so you are faced with performing a risk assessment
and designing a solution to mitigate the high risk factor risks. (Risk
factor considers the likelihood of an outcome and the severity of an
outcome.)

Owen

On Tue, 17 Jul 2007 03:29:55 +0000, Owen Duffy wrote:

If you did not install a lightning protection system, but only connected
antennas at a time of low risk, then you might be much better off than
trusting an inadequate protection scheme.

Ah, I see your point.

My main objective in all this is keeping the house from burning down. I
have a very low level of confidence that ANYTHING I do will prevent the
radio from receiving damage if the tower gets a direct lightning hit
while the antenna is connected to the radio. So, I'll continue to
disconnect antennas, ground feedlines, etc. when a storm is near or we're
going to be away for a while.

Maybe I'll get lucky and end up with a ground system that will protect
everything so I can continue to merrily yak or tap away during the worst
thunderstorm, but I'll be satisfied if I can just be confident that any
hit on the tower will go to ground and not to the house. If I have to
replace lengths of coax after a hit, I can live with that.

We aren't exactly in a high-occurrence area, here. In 22 years of living
here we have only had one lightning hit on our property, which hit (and
utterly destroyed) a tree in our backyard, damaged my Internet router,
tripped the main house circuit breaker, and blew out the timer and display
on the microwave oven. The tower was 10 feet shorter then and wasn't hit.
Now the tower is 10 feet taller AND will have a 25-foot-high VHF antenna
and mast on it, so it's time to do something to improve protection.