On Thu, 15 Oct 2009 08:45:10 -0500, "Dave" wrote:

Was talking with someone the other day and mentioned that I had just
grounded the TV antenna (the mast, actually) to protect against lightning
strikes, and they said that was not such a good idea because lightning is
more likely to strike a path that goes straight to ground.

AIUI, it's the other way around. During a lightning storm, a
negative** charge can build up on (or near?) the tops of buildings,
attracted by the positive** charge repeatedly building up in the sky.

**I might have these two backwards, at least for some/most of the
time.

The lightning is attacted to places with the opposite charge. The
grounding allows the antenna to reach equilibrium with the earth,
basically neutrality, so the charge and thus the attraction isn't
present, and it's LESS likely to get struck when it's grounded.

Same with lightning rods. The notion that the relatively small wires
grounding your antenna or a lightning rod are there to carry the
lightning to ground is false. They would melt in an instant if
lightning actually struck.

I"m still confused about the needles. Typical rods, last I looked,
have balls with iiuc store a charge, and needles maybe a foot long
pointing upwards. I heard a story about some farmers who would break
off the needles because they thought things were prettier that way,
but that ruins the rod.

Now I am not
sure what to do. Anyone have any input on this topic? Ideas are gratefully
received...

The American Radio Relay League, www.arrl.com might have stuff on
this. In the 50's and 60's the ham radio license exam included
antenna construction, but had a lot to do with how oscillators work
and other electronic internals. Based on the exam I took last year,
they are no concentrating on antenna construction, avoiding
interference with other radios, and safety. I guess because radios
are too complicated now for anyone to build one at home, unless he
just assembles a kit. So the exam used to be very hard, at least for
me as a 14 year old. This time I passed without even studying, 10%
because I remembered things I learned for the first exam, 10% because
of things I'd learned along the way, and 80% becaue it's easier.

Thanks,

Dave