Hi CIL

Where lightning will hit, if it hits, can almost be calculated with a
fair degree of accuracy.

We did a small project in a college class and made a scale model of a
small city. We knew from past history some of the structures that
were hit and where. From this knowledge we made balls of certain
sizes so they would touch if sitting on the ground the place that was
actually hit. We ended up with only 4 such balls, each a similar size
factor to the others.

On our scale model town we outlined in red lines the most likely
places lightning would hit if it did hit in that area.

Every strike since that time, up until the project was abandoned, has
hit somewhere on the red lines we have drawn.
One such line was on a small single story U-Stor-It building between
two very tall radio station towers, that was assumed to be lightning
proof due to it's location. It was hit and hit hard when neither
tower was hit. We also indicated that if those towers were ever hit,
the location on those towers where the lightning would hit them.
Neither location was near the top either. Two small strikes to one of
the towers were both within 1 foot of where our red line was indicated
on the scale model.

We were so successful in our project we thought for sure some agency
would pick it up and make use of it. But long after I was at school
there, the project was abandoned with something like a record of 94%
accuracy on pinpointing areas where lightning can hit.

TTUL
Gary

On 19 Oct 2004 09:32:10 EDT, am (Gary V.
Deutschmann, Sr.) wrote:
It was hit and hit hard when neither tower was hit.

Hi Gary,

If lightning strikes a tower, and it doesn't burn down, did any power
dissipate? (Apologies to the trees falling in the forest cliche.)

How did your team "know" what was struck?

73's
Richard Clark, KB7QHC

Hi Richard

If you recall, I lost a tower to a lightning strike.
Took us forever to figure out why it came down, but we finally did.
Water built up in the leg of the tower, the lighting turned the water
to steam causing the leg to explode.

In some minor cases we found the places where lightning struck through
burn and/or pit marks combined with visual observations of bystanders!
Other times, the foot long melted out section of guttering was a dead
giveaway along with the distortion of the rest of the guttering to
ground.

TTUL
Gary

Gary Deutschmann wrote:
"If you recall, I lost a tower to a lightning strike."

Yes. I was saddened by Gary`s misfortune.. My recollection of the event
is that the tower was aluminum. It seems there may have been a poor
electrical connection between tower sections which generated first great
heat. There was a lightning induced failure of one of the tower legs, if
I remember.

The commercial towers erected by one of the companies I worked for, all
had a copper cable about like a welding or jumper cable riunning the
length of the tower, connecting the top plate to the ground system for
the tower. Deep ground rods were connected to each tower leg.

I encountered these towers upon joining the company. I would not have so
specified those tower-length cables in those big steel towers, but it
must have worked as we never had any lightning damage to the towers. In
Gary`s case, such a cable might have prevented a melt-down.

Best regards, Richard Harrison, KB5WZI

On 20 Oct 2004 12:21:27 EDT, am (Gary V.
Deutschmann, Sr.) wrote:
In some minor cases we found the places where lightning struck through
burn and/or pit marks combined with visual observations of bystanders!
Other times, the foot long melted out section of guttering was a dead
giveaway along with the distortion of the rest of the guttering to
ground.

Hi Gary,

By this, I suppose you to mean that any report of strikes to a tower
were those chance occurrences of being seen as a direct hit, and no
one regularly inspected all metal structures for evidence after a
storm to verify unobserved strikes.

73's
Richard Clark, KB7QHC

Hi Richard

I was just a lowly sophomore peon in a class of mostly upperclassmen
who had started the project a few years before I went to skewl there.

The project was a side assignment for extra credit that just seemed to
carry on for all the years I was there and a few years thereafter.

I was an avid model railroader quite adept at building miniature
structures to emulate their full sized counterparts.
This was my contribution to the project, the modeling end of it.
When a new building was built in the town, I would make a scale model
of it for the project layout board.
I had to pay special attention to what objects of a structure
consisted of metal components and how they were attached to the
structure and if they led to a grounding source, as all of these
factors played an important part in the experimentation that was going
on.

I knew what the project was about and what they were trying to prove
with it. But I truly was not that interested in the purpose of the
project as much as I was in the authenticity of detail in the
structures used on the project layout board.

In other words, I learned just enough to be dangerous in my
observations, hi hi.....

However, the success ratio of known lightning strikes to the red zones
on our layout board was phenominal.
The data was collected by a whole different team than the team I was
on, but the layout board was loaded with bright orange lightning bolts
glued to places of known lightning strikes and all but 2 of them were
in our red zones.

I should note that a red zone was simply a 1/8 to 1/4 inch wide line
drawn on for example, the edges of gutters, at certain elevations on
taller structures not shielded by another object.

Naturally we did not know about many lightning strikes that did no
damage or were not observed.

My own antenna farm has been hit several times, but never was their
any damage because of it.

In fact, one year we had a strange phenomenon that caused neighbors to
call the fire department on a couple occassions. One of my Yagi's
appeared to have orange sparks flying from it, sometimes for as long
as a half-hour, but usually only for a few seconds or minutes. I was
only priviledged to see this myself in person one time. Scared the
bejesus out of me when I did too!

One of the firemen knew a man who worked on tall commercial chimneys
or something like that and told him about it.
The many came to my house, checked a few things out, talked to a
couple of neighbors and showed them some photo's he had taken of a
similar phenominon on other structures.
Turns out what was happening was weather conditions and the charge in
the air was just right to cause what was termed as St. Elmo's Fire, a
phenominon discovered on old sailing ships at sea during a storm.

I lived in that house roughly 20 years and this only happened for one
short rainy season in only one of those years. I had never heard of a
similar occurrance to ham antenna's before or after this event.
And I've been licensed for 45 years!

TTUL
Gary

Gary Deutschmann wrote:
"Turns out what was happening was weather conditions and the charge in
the air was just right to cause what was called St. Elmo`s fire---."

From my time in broadcast stations, I can testify these conditions
repeat.

In my experience, the radio towers took all the lightning strikes in the
area.

Charge buildup was a separate phenomenon.from lightning. This happened
in the wind ahead of an approaching thunderstorm. The insulated guy
segments would charge from the static in the air, announcing the
approaching storm with loud reports when conditions were right. Peering
out at the antennas disclosed flashes across the guy insulators
producing the reports. There were many towers with many insulators which
produced barrage fire. Noisy!

Best regards, Richard Harrison, KB5WZI

Hi Richard

Now 'that' I have seen a few times.
Probably not to the extent that you have experienced though.

When first out of skewl I took a job as a DJ, before a couple of
storms while working in the transmitter room at the tower site, I
could hear occasional pops, but never figured out where they were
coming from. Thanks for letting me know!

From my new residence I can see several radio and TV towers, I will
keep an eye on them just out of curiosity sake.

TTUL - 73+ de Gary - KGØZP

"Gary V. Deutschmann, Sr." wrote

Where lightning will hit, if it hits, can almost be calculated with a
fair degree of accuracy.

Gary, there is no nice way to say this, but I mean no disrespect to your
experience. Unfortunately, what you wrote is absolutely incorrect, and flies
in the face of thousands of lightning experts all over the world, who agree
only that a 300' sphere rolled over a surface will indicate (by touching)
the most likely points of attachment. This means that no taller object
escapes the likelihood of being a point of attachment, period. It doesn't
mean anything below it is free from side attachments and flashovers.
Everything else you followed with was erroneous, based on misconceptions or
complete falsehoods. Places you think lightning "struck", were more likely
the opposite, the point(s) where it *left* a structure.

Every once and awhile a new theory arrives claiming to predict or prevent
lightning, and these have all been discredited, especially the CTS (Charge
Transfer System) of lightning dissipators. There have been and there is no
evidence whatsover that a point of attachment can be either predicted or
prevented. This is even when the best lightning air terminal is in place at
the highest point on a structure. Take your old notes and paper the bird
cage, they offer only false predictions that cannot be replicated or
withstand the studies that have tried this a hundred similar ways.

You have left at your disposal, the ability to make it as easy as possible
for a lightning attachment or near field effect from same, to be absorbed
and routed via capable grounding and surge protection systems. There is
nothing else newsworthy about it.

We did a small project in a college class and made a scale model of a
small city. We knew from past history some of the structures that
were hit and where. From this knowledge we made balls of certain
sizes so they would touch if sitting on the ground the place that was
actually hit. We ended up with only 4 such balls, each a similar size
factor to the others.

On our scale model town we outlined in red lines the most likely
places lightning would hit if it did hit in that area.

Every strike since that time, up until the project was abandoned, has
hit somewhere on the red lines we have drawn.
One such line was on a small single story U-Stor-It building between
two very tall radio station towers, that was assumed to be lightning
proof due to it's location. It was hit and hit hard when neither
tower was hit. We also indicated that if those towers were ever hit,
the location on those towers where the lightning would hit them.
Neither location was near the top either. Two small strikes to one of
the towers were both within 1 foot of where our red line was indicated
on the scale model.

We were so successful in our project we thought for sure some agency
would pick it up and make use of it. But long after I was at school
there, the project was abandoned with something like a record of 94%
accuracy on pinpointing areas where lightning can hit.

TTUL
Gary


Jack Painter
Virginia Beach VA
http://members.cox.net/pc-usa/grounding.htm

Hi Jack

That is probably true and the reason the project was abandoned!

Step Leaders can form and reach up from almost any grounded source,
but more often than not, the eventual discharge causes no appreciable
harm.

The small study I helped with was some 25 or 30 years ago and I really
don't remember too much of the details about it, other than apparent
physical damage was almost always within our red zones.

I don't think the spheres we were using were anywhere near 300 feet in
diameter, if I recall they were like 36 feet, 72 feet and 108 feet.
Regardless of the size of the ball, on most structures the red zone
was in the same place. Only on very tall structures would the red
zones be more than one zone at varying heights along the structure.

I do remember our accuracy for the town we modeled was very high over
90%, but then too, we had a LOT of red zones as well since we were
using like 5 different sizes of balls to mark these zones.

You also have to remember, back when I was in Skewl, the correct
answer to a question was considered WRONG. And the wrong answer
correct. EG: Number of Elements, the WRONG answer the skewl demanded
as correct was 45 Elements NO MORE NO LESS, and you had better not
forget the NO MORE NO LESS phrase!
There are 92 Natural Elements and about 114 Elements Maybe More.
But if you put that on your exam, you were graded as the answer being
WRONG.

MOST of the stuff I learned in skewl was Erroneous in Real Life, I
don't doubt that our lightning experiments were also!

TTUL
Gary