"Gary V. Deutschmann, Sr." wrote
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.
TTUL
Gary

Hi Gary, I understand completely. Lightning attaching to an object is not
where the damage comes from, it's the way the damn stuff *leaves* that
causes the problems! ;-)

Notwithstanding your hopefully unique experience where water in a tower leg
was superheated. Some private company specifications call for an air
terminal and grounding electrode conductors on all their towers, including
at each fixture (antenna) attachment point.. Even most tower manufacturers
call this unnecessary, recommending bonding of air terminals (if used) to
the tower legs only. But I suppose that a grounding electrode conductor from
tower-top to ground *could* have prevented your loss, by reducing some of
the current in the tower legs in favor of the heavy GEC coming down
alongside them.

Best regards,

Jack

Hi Jack

The damage to my tower was directly my own fault.

It was of tubular aluminum construction and DID have drain holes in
the legs so they could not readily fill with water.

I made two very dumb mistakes that contributed to the damage.
The first was using one of these holes for attaching the ground rod
strap to the tower, instead of the clamp that WAS provided for the
purpose.
And the second was backfilling over these holes when a new air
conditioner was installed, and a small retaining wall placed between
the steps, tower and A/C unit.

Had there not been water in the leg of the tower, it would have taken
the hit unscathed.

There was a grounding strap on each leg of the tower at the unions
between sections, these were installed properly or should I say, per
the instructions, hi hi.....

Ironic, I was way overboard on everything else as far as protection
from lightning. Had a copper bulkhead on the house, grounded of
course. All coax shields were grounded first to the bulkhead and then
through gas bottles which were also grounded. The station equipment
was ground, even equipment in plastic cases I installed a ground to
the chassis and they were grounded too.

I did everything right except I forgot about one old abandoned rotor
cable that was coiled up behind 4 file cabinets, out of sight out of
mind. Luck of the Irish, the day I took the hit, I had sparks flying
all over my shack. My pooch who was young then, terrified of thunder,
came to my office to be by me for protection, just when the sparks
began to fly. He never came into my office ever again!
The only damage from this rotor wire was a few burn marks on the back
of the file cabinets. The tower obviously took the main hit.

As an aside. A tree outside my mothers home was struck by lighting.
Split that sucker almost all the way to the ground. Dad bolted it
back together with threaded rods and it survived, it's still living
too.
But the reason I brought it up is that INSIDE the house, sparks danced
all over my mothers stainless steel kitchen sink, made burn marks and
pits all over it. We later discovered the aerator on her faucet spout
was fused to the spout and it too was severely burned and pitted.

Back then all the waste lines to the sink were metal, not PVC as used
today and all the water lines are copper. So I assume both the sink
and the faucet were grounded.

Makes one wonder how lightning got inside the house and bounced around
in her sink and did enough damage that the sink and faucet had to be
replaced.

TTUL
Gary

CIL wrote:
"---is there anything I can do to fix this?"

Broadcasters have towers that are often struck by lightning. AM towers
sit on base insulators which makes them vulnerable to static buildup
too. Wind carries a static charge which falls out on the tower even when
no lightning is present.

The shape and positions of charged clouds are constantly changing, so
lightning strikes can come from anywhere.

The broadcaster starts his lightning protection at the tower top with a
small lightning rod extending above and beyond the beacon to take the
hit and avoid expensive repairs at the tower top.

Tower guy insulators are doubled and tripled where they connect to the
tower so that static breakdown occurs to the earth instead of at the
tower.

An air gap is installed across the base insulator to bypass a lightning
hit to earth. Often a turn or two is made in the feed to the tower. This
discourages lightning on the feedline and encourages breakdown of the
gap across the insulator.

A static drain choke is often added if needed to provide a d-c path
between the tower and the earth. It is used to bleed off charge which
might build to dangerous levels.

"Lightning elimination" is a name given to mounting a large number of
sharp points around a protected area in an attempt to drain the
atmosphere of charge. The reviews are mixed.

I`ve worked in several broadcast stations hit by lightning nearly every
time a charged cloud passed by. None ever caused significant damage. Al
of the stations had lighted towers but their tower lighting chokes kept
lightning off the a-c power source.

Berst regards, Richard Harrison, KB5WZI

The broadcaster starts his lightning protection at the tower top with a
small lightning rod extending above and beyond the beacon to take the
hit and avoid expensive repairs at the tower top.

An air gap is installed across the base insulator to bypass a lightning
hit to earth. Often a turn or two is made in the feed to the tower. This
discourages lightning on the feedline and encourages breakdown of the
gap across the insulator.

We used to call em "johnny balls" at the base of the AM towers. One
station I was chief engineer of was hit constantly without any damage. NOT
fun to be in the transmitter room when lightning was hitting tho! I felt
like Dr. Frankenstein in my lab during the storms, when I had to go into the
xmitter room.

A static drain choke is often added if needed to provide a d-c path
between the tower and the earth. It is used to bleed off charge which
might build to dangerous levels.

A static drain choke is an EXCELLENT idea, I have used it on my ham
antennas in the past.

73
WB7FFI

I HAD a tower up on the north side of the house for about 15 years, it
, top out at about 100feet. I built a 'tilt over' that is 52 feet tall
with a mast of about 25, = 77 give or take. been 'up' about 1.5 years
and lighting has 'hit' it twice. One was higher, never hit, this one
is lower, hit is there anything I can do to 'fix this'? Lost
antennas, need to do 'something'. thanks in advance. cl
73



Can you describe how each tower was configured at the top and how it was
grounded?
What is important to know if the top ended up with sharp point (mast, VHF
vertical antenna, etc.) or Yagi type antenna, like tribander etc. without
anything pointy protruding above.

Yuri, K3BU

I would suspect a poor grounding system on the tower. If the ground is a
rod driven into the Earth, then the impedance needs to be as low as
possible. Once the ground system takes a surge, glass crystalls will form
in the dirt on and around the rod. The impedance then climbs and the number
of strikes to the tower increase. The amount of impedance in your ground
network determines the amount of static charge that can build on the tower
and how fast the charge can bleed. The formula for calculating the bleed
rate is 5 times (Resistance times Capacitance). The resistance is the
ground impedance and the capacitance is the amount of surface area of the
tower relative to the air flow over it (think of two plates on a capacitor
with a dielectric between them). Any charge above that of the Earth makes
that point more likely to get hit by lightning. The tower is only one item
to concern yourself about because a floating antenna can be just as bad.
Ground everything on the tower during a storm if it is not in operation such
as a repeater. Surge arrestors on the antenna feeds then become imparative
for repeater installations. A very large grounding system is required to
mitigate the potential for lightning strikes on a tower. If a strike does
occur, then the grounding structure needs to be able to dissipate the charge
back into the Earth very quickly or the ground will be lost until the
voltage on the ground falls. Again, R x C for the Earth.

Good Luck,
Frank N1SIF


wrote in message
...
I HAD a tower up on the north side of the house for about 15 years, it
, top out at about 100feet. I built a 'tilt over' that is 52 feet tall
with a mast of about 25, = 77 give or take. been 'up' about 1.5 years
and lighting has 'hit' it twice. One was higher, never hit, this one
is lower, hit is there anything I can do to 'fix this'? Lost
antennas, need to do 'something'. thanks in advance. cl
73

I would suspect a poor grounding system on the tower. If the ground is a
rod driven into the Earth, then the impedance needs to be as low as
possible. Once the ground system takes a surge, glass
(( (crystalls?)))
will formin the dirt on and around the rod. The impedance then climbs
and the numberof strikes to the tower increase. The amount of
impedance in your groundnetwork determines the amount of static charge
that can build on the towerand how fast the charge can bleed.

(((The tower sites are only about 100 feet apart, ground substance is
the same, clay/rocks, 1st foot then clay…… The first tower ground, is
a 4 ft hole, with ¾" rebar then driven deeper,1.5ft, w/ horz bars 1ft
on center from bottom of hole to top, where a ¾ steel plate was welded
to vertical bars, and to the plate, strong hinge plate connected to 25
rohn tower. The 'other site', is two 4" pipe, 5ft, in the ground, and
welded to fence. Fence is 2"2/8 upset tubing that goes around
property/everything welded. ((fence is 5 foot tall) and as stated part
of the 'gournding system',,,? The first 'site' was not connected to
the primenter fence,,problem???)) If you are familur with the ''bird
tilting over and drinking from the cup", you can picture in your minds
eye, my 'tilting tower'. It is about 75ft tall, with a uhf/vhf duel
band at top of mast, four ft. below that is a two meter horz omni
ground plane.)))

Can you describe how each tower was configured at the top and how it
was grounded? What is important to know if the top ended up with sharp
point (mast, VHF vertical antenna, etc.) or Yagi type antenna, like
tribander etc. without anything pointy protruding above.
Yuri, K3BU

((( Both towers carried almost the same 'items', vhf/uhf , and 4 ft
below that, clover leaf horz ground plane.)))


but their tower lighting chokes kept
lightning off the a-c power source.

((( What do you call these chokes, I know I have read about, but at
the moment I am blank.)))


The broadcaster starts his lightning protection at the tower top with
a small lightning rod extending above and beyond the beacon to take
the hit and avoid expensive repairs at the tower top.


((( Is this something like the antennas I have seen that have a
'center core' copper rod???)))

Tower guy insulators are doubled and tripled where they connect to the
tower so that static breakdown occurs to the earth instead of at the
tower.


((( Where do I 'see/read' about this??)))


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

……"How did your team "know" what was struck?

"""…my question was and is,,,, why?




(((((((((((((((((((This statement is the one that makes the
most sense to me)))))))))))))))

Lightning is Female. 20 million volts & 100 thousand Amps will do as
it damm
well pleases!

((((Last, but not least,,,,,,, thank you, WILL implement input,
cl&73))))

Sorry for the spelling error crystalls should be crystals. When lightning
hits the Earth, the heat it generates is enough to make glass which is an
insulator. The ground rod becomes isolated from the Earth. If you spread
out the contact area with the Earth as with the fence around the perimeter
of the property, then the energy is not concentrated to one spot. The over
all impedance is also much lower. I would install a ring grounding system
around the tower. A 32ft. diameter ring would do nicely in a clay/rocky
soil. Place 8ft. ground rods in the ground every 16 ft along the 32 ft.
diameter circle (approx. 6 rods). Each rod is then connected to the tower
base with a multistrand 00 copper wire and a ring of 00 copper to connect
each rod together. The connections should be cad welded or at least treated
with a deoxit coating to prevent corrosion. I have had excellent luck with
this approach, no lightning hits and my tower sits up at 870ft. ASL or 650
ft. above average terrain. Note: the tower has a strike counter hooked up
to it so I know no hits have happened. Go to this link to read more
http://www.polyphaser.com/ppc_pen_home.asp .

Frank N1SIF

"CIL" wrote in message
...

I would suspect a poor grounding system on the tower. If the ground is a
rod driven into the Earth, then the impedance needs to be as low as
possible. Once the ground system takes a surge, glass
(( (crystalls?)))
will formin the dirt on and around the rod. The impedance then climbs
and the numberof strikes to the tower increase. The amount of
impedance in your groundnetwork determines the amount of static charge
that can build on the towerand how fast the charge can bleed.

(((The tower sites are only about 100 feet apart, ground substance is
the same, clay/rocks, 1st foot then clay.. The first tower ground, is
a 4 ft hole, with ¾" rebar then driven deeper,1.5ft, w/ horz bars 1ft
on center from bottom of hole to top, where a ¾ steel plate was welded
to vertical bars, and to the plate, strong hinge plate connected to 25
rohn tower. The 'other site', is two 4" pipe, 5ft, in the ground, and
welded to fence. Fence is 2"2/8 upset tubing that goes around
property/everything welded. ((fence is 5 foot tall) and as stated part
of the 'gournding system',,,? The first 'site' was not connected to
the primenter fence,,problem???)) If you are familur with the ''bird
tilting over and drinking from the cup", you can picture in your minds
eye, my 'tilting tower'. It is about 75ft tall, with a uhf/vhf duel
band at top of mast, four ft. below that is a two meter horz omni
ground plane.)))

Can you describe how each tower was configured at the top and how it
was grounded? What is important to know if the top ended up with sharp
point (mast, VHF vertical antenna, etc.) or Yagi type antenna, like
tribander etc. without anything pointy protruding above.
Yuri, K3BU

((( Both towers carried almost the same 'items', vhf/uhf , and 4 ft
below that, clover leaf horz ground plane.)))


but their tower lighting chokes kept
lightning off the a-c power source.

((( What do you call these chokes, I know I have read about, but at
the moment I am blank.)))


The broadcaster starts his lightning protection at the tower top with
a small lightning rod extending above and beyond the beacon to take
the hit and avoid expensive repairs at the tower top.


((( Is this something like the antennas I have seen that have a
'center core' copper rod???)))

Tower guy insulators are doubled and tripled where they connect to the
tower so that static breakdown occurs to the earth instead of at the
tower.


((( Where do I 'see/read' about this??)))


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

.."How did your team "know" what was struck?

""".my question was and is,,,, why?




(((((((((((((((((((This statement is the one that makes the
most sense to me)))))))))))))))

Lightning is Female. 20 million volts & 100 thousand Amps will do as
it damm
well pleases!

((((Last, but not least,,,,,,, thank you, WILL implement input,
cl&73))))

Grounding a tower does not help prevent it from getting hit by
lightning. It does however help route the charge safely to ground when
hit. A tower may actually be a little less likely to be hit if not
grounded but that is not a good thing to do.

Placing ground rods out in a radius like the spokes of a wheel around
a tower is a good thing. Placing a connecting wire between rods on the
circle is a waste of wire. It would be better to use that additional
wire for additional radials. The current will travel out away from the
tower. Each ground lead going away from the tower will share the
current. There is no significant current difference between the ground
rods so the ring connection does no good.

First a few ground rods should be placed as close to the tower as
possible to have the shortest lead length from the tower. Additional
ground rods placed on the "spokes" going out away from the tower at
distances twice the rod lengths along each spoke.

Having the connecting wires buried going to the other ground rods will
increase the ground system effectiveness also.

Not being struck because you have a good ground system is not proof
that the ground system prevented it.

73
Gary K4FMX


On Tue, 19 Oct 2004 16:15:04 -0400, "leaf"
wrote:

Sorry for the spelling error crystalls should be crystals. When lightning
hits the Earth, the heat it generates is enough to make glass which is an
insulator. The ground rod becomes isolated from the Earth. If you spread
out the contact area with the Earth as with the fence around the perimeter
of the property, then the energy is not concentrated to one spot. The over
all impedance is also much lower. I would install a ring grounding system
around the tower. A 32ft. diameter ring would do nicely in a clay/rocky
soil. Place 8ft. ground rods in the ground every 16 ft along the 32 ft.
diameter circle (approx. 6 rods). Each rod is then connected to the tower
base with a multistrand 00 copper wire and a ring of 00 copper to connect
each rod together. The connections should be cad welded or at least treated
with a deoxit coating to prevent corrosion. I have had excellent luck with
this approach, no lightning hits and my tower sits up at 870ft. ASL or 650
ft. above average terrain. Note: the tower has a strike counter hooked up
to it so I know no hits have happened. Go to this link to read more
http://www.polyphaser.com/ppc_pen_home.asp .

Frank N1SIF

"CIL" wrote in message
.. .

I would suspect a poor grounding system on the tower. If the ground is a
rod driven into the Earth, then the impedance needs to be as low as
possible. Once the ground system takes a surge, glass
(( (crystalls?)))
will formin the dirt on and around the rod. The impedance then climbs
and the numberof strikes to the tower increase. The amount of
impedance in your groundnetwork determines the amount of static charge
that can build on the towerand how fast the charge can bleed.

(((The tower sites are only about 100 feet apart, ground substance is
the same, clay/rocks, 1st foot then clay.. The first tower ground, is
a 4 ft hole, with ¾" rebar then driven deeper,1.5ft, w/ horz bars 1ft
on center from bottom of hole to top, where a ¾ steel plate was welded
to vertical bars, and to the plate, strong hinge plate connected to 25
rohn tower. The 'other site', is two 4" pipe, 5ft, in the ground, and
welded to fence. Fence is 2"2/8 upset tubing that goes around
property/everything welded. ((fence is 5 foot tall) and as stated part
of the 'gournding system',,,? The first 'site' was not connected to
the primenter fence,,problem???)) If you are familur with the ''bird
tilting over and drinking from the cup", you can picture in your minds
eye, my 'tilting tower'. It is about 75ft tall, with a uhf/vhf duel
band at top of mast, four ft. below that is a two meter horz omni
ground plane.)))

Can you describe how each tower was configured at the top and how it
was grounded? What is important to know if the top ended up with sharp
point (mast, VHF vertical antenna, etc.) or Yagi type antenna, like
tribander etc. without anything pointy protruding above.
Yuri, K3BU

((( Both towers carried almost the same 'items', vhf/uhf , and 4 ft
below that, clover leaf horz ground plane.)))


but their tower lighting chokes kept
lightning off the a-c power source.

((( What do you call these chokes, I know I have read about, but at
the moment I am blank.)))


The broadcaster starts his lightning protection at the tower top with
a small lightning rod extending above and beyond the beacon to take
the hit and avoid expensive repairs at the tower top.


((( Is this something like the antennas I have seen that have a
'center core' copper rod???)))

Tower guy insulators are doubled and tripled where they connect to the
tower so that static breakdown occurs to the earth instead of at the
tower.


((( Where do I 'see/read' about this??)))


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

.."How did your team "know" what was struck?

""".my question was and is,,,, why?




(((((((((((((((((((This statement is the one that makes the
most sense to me)))))))))))))))

Lightning is Female. 20 million volts & 100 thousand Amps will do as
it damm
well pleases!

((((Last, but not least,,,,,,, thank you, WILL implement input,
cl&73))))

"CIL" wrote in message
...
but their tower lighting chokes kept
lightning off the a-c power source.

((( What do you call these chokes, I know I have read about, but at
the moment I am blank.)))


Perhaps you are thinking of an Austin Ring transformer to couple the
power to the beacon lights...........