I am considering connecting a coil from the base of my vertical antenna to
ground, not for impedance matching, but to allow the charge on the ground to
slowly leak off at the top of the antenna. I will also use a lightning
arrestor but wonder if this additional step will further reduce the chance of a
lightning strike.

About a week ago I posted the above message. Several people responded and there
was a general feeling that the idea of allowing a gradual leak off of charge at
the top of the antenna would not prevent or even be likely to reduce the chance
of a lightning strike.

Tonight I was looking through my old "Elements of Physics" by Shortly and
Williams, fourth edition, page 697 and came across the following statement:

"The action of a well-grounded and sharply pointed lightning rod is primarily to
discharge quietly into the air the charge that is induced in the surrounding
earth by a charged thundercloud above. The electric intensity in the vicinity of
the sharp point is high enough to break down the immediately surrounding air and
the continual discharge prevents building up sufficient voltage over the whole
cloud-to-ground path to break down this long path and give rise to a stroke of
lightning at this location."

Comments?

Ron, W4TQT

Ron:

Because lightning is a difficult process to study, you will find that the
references change with time, as more is learned. Blue jets and red sprites
come to mind, for example. One startling example is the National Fire
Protection Agency Lightning Protection Code. The one I used and became
familiar with in the 80s and early 90s was withdrawn and canceled when it
was understood that some of the premises on which it was based were simply
wrong. The new code, which has finally been released, is very different
from the previous one. I no longer have current references to this
discipline available, but I suggest reading the recent issues of Journal of
Atmospheric and Terrestrial Physics, and Journal of Geophysical Research for
more up to date information than an old textbook. The fact is that the
phenomenon you cite does not bleed off anywhere near enough charge to make
any difference. Yes, it does drain off charge. No, the quantity is like
trying to empty the ocean with a leaky coffee can.

--
Crazy George
Remove NO and SPAM from return address
"Ron" wrote in message
...
I am considering connecting a coil from the base of my vertical antenna
to
ground, not for impedance matching, but to allow the charge on the
ground to
slowly leak off at the top of the antenna. I will also use a lightning
arrestor but wonder if this additional step will further reduce the
chance of a
lightning strike.

About a week ago I posted the above message. Several people responded and
there
was a general feeling that the idea of allowing a gradual leak off of
charge at
the top of the antenna would not prevent or even be likely to reduce the
chance
of a lightning strike.

Tonight I was looking through my old "Elements of Physics" by Shortly and
Williams, fourth edition, page 697 and came across the following
statement:

"The action of a well-grounded and sharply pointed lightning rod is primar
ily to
discharge quietly into the air the charge that is induced in the
surrounding
earth by a charged thundercloud above. The electric intensity in the
vicinity of
the sharp point is high enough to break down the immediately surrounding
air and
the continual discharge prevents building up sufficient voltage over the
whole
cloud-to-ground path to break down this long path and give rise to a
stroke of
lightning at this location."

Comments?

Ron, W4TQT

"Crazy George" wrote in message ...
Ron:
The fact is that the
phenomenon you cite does not bleed off anywhere near enough charge to make
any difference. Yes, it does drain off charge. No, the quantity is like
trying to empty the ocean with a leaky coffee can.

Very true. Also, you sure wouldn't want to rely on that discharge
theory to prevent a strike. Will be the other way around if it's a
pointed tip. It will be struck sooner or later. But, if that tip were
hit by lightning, the lightning would have struck in that close area
anyway. I have tall trees in the yard in both the front and back. The
last two close strikes, which BTW, have been in the last few weeks,
have hit the trees instead of my mast. But my mast is not pointed.
It's just pipe. Not as good a streamer as a point. Lightning has no
idea where it's going until it gets to about the last step of it's
travel and finds a streamer to hook up with. In a strike zone, there
will be many, many streamers poking up all looking for attention.
Which gets the call is akin to throwing a dice. Many times, the best
streamer in the area is not in the right location to get the job. I
always assume any object I stick up in the air will be struck sooner
or later. To think anything else is foolish. The brush dischargers
work on the same "theory". They are still struck at times. Trying to
discharge fast enough in a storm to avoid a strike is like taking a
whiz in a whirlwind. You may still get something on you...:/ MK

Ron, W4TQT wrote:
"---Shortly and Williams, fourth edition."

Hang on to your Shortly and Williams. That was one if my textbooks long
ago and I found it usually reliable.

There are lightning elimination companies which erect spikes said to
drain the charge difference at your site. This, they say, drains your
site of charge which might initiate a strike.

Yet, I`ve seen towertop lightning damage where the tower was the most
salient item in the area. So, why didn`t it successfully discharge the
site and obviate the strokes?

Cecil`s 400-pound gorilla analogy may apply.

Protection relies upon residence within a conductive enclosure and
clamping the voltage level on every conductor which penetrates.

Best regards, Richard Harrison, KB5WZI