Does anyone know of cases where houses have fried as a consequence of
ham wire antennas, "protected" or otherwise?

We all know of cases where electronics gets zapped but Jerry is
concerned about his house.

Be interesting to hear of actual cases, wouldn't it? Statistics would be
even better, but I won't hold my breath.

Chuck

Jerseyj wrote:
Hi all,
For years I lived in an apartment and just had antenna's in the attic ,
but now having moved to a house in a few months I'll be putting up a
10-160 wire type antenna in my trees. Given the recent spate of serious
thunderstorms, and the accompanying lightning, I'm a bit concerned about
properly grouding the antenna so that I don't fry the house *smile*. I
know about some articles on the ARRL site, but was wondering if anyone
else had some ideas or pointers on how to practically do this ?

Jerry

Chuck wrote:
"We all know of cases where electronics gets zapped but Jerry is
concerned about his house."

Ben Franklin promoted lightning rods to protect people and houses before
electronics was. These rods would not have sold had they not seemed to
work. Tell me a drowning man will grasp at straws!

Best regards, Richard Harrison, KB5WZI

On Mon, 18 Jul 2005 10:59:41 -0500, (Richard
Harrison) wrote:

Chuck wrote:
"We all know of cases where electronics gets zapped but Jerry is
concerned about his house."

Ben Franklin promoted lightning rods to protect people and houses before
electronics was. These rods would not have sold had they not seemed to
work. Tell me a drowning man will grasp at straws!

Best regards, Richard Harrison, KB5WZI


Franklin, defying the gods, performed his kite flying experiment in
June of 1752, and by late June or July, the first "lightning rods"
were installed on structures in Philadelphia. Ol' Ben kinda made up
his own "nec code".

bob
k5qwg

Chuck wrote:
"We all know of cases where electronics gets zapped but Jerry is
concerned about his house."

I`ve worked in many protected structures struck repeatedly by lightning
to their air terminals, rods, and towersm resulting in not one scintilla
of damage to occupants or equipment.

Transportation vehicles are struck by lightning every day and seldom
experience anything inside. An open convertible is not safe in a
lightning strike however.

Best regards, Richard Harrison, KB5WZI

Richard, we both know that a transportation vehicle makes a pretty good
Faraday[sp?] Cage.

Lightning attaching to a wire will instantly vaporize the wire.

Physical damage is generally caused by direct strike. The energy in the
action intergral [I^2*R*dt] generates local heat. The thermal shock
causes the damage. [And fire].

Richard Harrison wrote:
Chuck wrote:
"We all know of cases where electronics gets zapped but Jerry is
concerned about his house."

I`ve worked in many protected structures struck repeatedly by lightning
to their air terminals, rods, and towersm resulting in not one scintilla
of damage to occupants or equipment.

Transportation vehicles are struck by lightning every day and seldom
experience anything inside. An open convertible is not safe in a
lightning strike however.

Best regards, Richard Harrison, KB5WZI

Ham Op wrote:
"Physical damage is generally caused by direct strikes."

Lightning can produce awsome distruction from its millions of volts and
thousands of amps. Stories about it are informative, amusing, and
abundant.

Damage is mostly avoidable. High towers are nearly certain to be struck
repeatedly in passing thunderstotms. I`ve worked in medium wave
broadcasting, Short wave broadcasting, land-mobile radio, aircraft
radio, and microwave relay systems aplenty. I worked decades with a
worldwide corporation that had towers across the U.S.A. and several
other countries in the world. That corporation had its many towers
fitted with inverted Copperweld ground rods at the top to serve as
lightning rods to take most of the hits the towers received. At their
bottoms, the towers` lightning energy was shunted off to the earth
through ground rods driven into the soil around the towers. It worked.
There was no vaporized coax, tower lighting wires, or anything else.

We had to operate perpetually. We couldn`t pull the switch and throw the
coax out the window, even if someone were on hand to do so.

Evidence of lightnong strikes were the small pits it made in the
lightning rods.

Best regards, Richard Harrison, KB5WZI

I understand the concept, but if I have a wire antena , going to ladder
line, the trasitioning to coax, all outside, with the coax finally
snaking into the house and hooking up to the antenna tuner...

Where would I put grounds, how would I attach them, etc...???

I'm having trouble visualizing doing this grounding without it affecting
the antena performance.

Jerry

(who was generalizing when talking about house damage, but was really
just looking for help with ideas for grounding and thank you all who
have responded)

In article ,
(Richard Harrison) wrote:

Ham Op wrote:
"Physical damage is generally caused by direct strikes."

Lightning can produce awsome distruction from its millions of volts and
thousands of amps. Stories about it are informative, amusing, and
abundant.

Damage is mostly avoidable. High towers are nearly certain to be struck
repeatedly in passing thunderstotms. I`ve worked in medium wave
broadcasting, Short wave broadcasting, land-mobile radio, aircraft
radio, and microwave relay systems aplenty. I worked decades with a
worldwide corporation that had towers across the U.S.A. and several
other countries in the world. That corporation had its many towers
fitted with inverted Copperweld ground rods at the top to serve as
lightning rods to take most of the hits the towers received. At their
bottoms, the towers` lightning energy was shunted off to the earth
through ground rods driven into the soil around the towers. It worked.
There was no vaporized coax, tower lighting wires, or anything else.

We had to operate perpetually. We couldn`t pull the switch and throw the
coax out the window, even if someone were on hand to do so.

Evidence of lightnong strikes were the small pits it made in the
lightning rods.

Best regards, Richard Harrison, KB5WZI

Jerry wrote:
"I`m having trouble visualizing doing this grounding without affecting
antenna performance."

Shortwave radio antennas I`ve used were all made from Copperweld wire to
withstand lightning and weather. Also, copper wire can stretch and
fatigue. Copperweld`s steel core prevents this.

Signal Corps rhombic kits use (3) No.12 Copperweld wires twisted
together to make a cable used for antenna and transmission line. A
special Wihd Turbine Company insulator is included to space the line for
600-ohm impedance. These bolt atop short tower secttons used as
transmission line supports. Unless military surplus is available,
substitutions would be necessary. But, open-wire line is rugged and
withstands the challenges.

Pick a place outside your shack to drive ground rods to serve as a
ground bed for your antenna system to dump your lightning strikes to.
Place the rods at about the length of your ground rods away from each
other. The more rods, the better. Cost will prevent too many rods.

Interconnect all the ground rods and connect this ground system to your
electric service ground system. It`s the law in most jurisdictions.

Run your open-wire line from your antenna to a point above your ground
bed. You need arc-gaps between each transmission line cable and the
earth. Form copper vees to make arc-gaps. The vertex of one Vee is going
to face another to make a pair. Connect one Vee firectly to the earth.
Connect the other of the pair directly to the transmission line cable.
Do the sane for the other transmission line cable.

When the gaps are completed, adjust the space between them until they
flash over from your transmitter power, then back off until they just
don`t flash over. You should now be ready for lightning on the
transmission line. Connect your ladder line, twin lead, coax or whatever
you will use to complete the connection to your radio to your open-wire
line here above your ground bed.

Isolate the radio from the powerline through a brute-force filter with
MOV`s added for lightning suppression.

Audio, control, and any other wires connected to the radio also need
filters with MOV`s added but the current carrying capacity of the
filters can be lower than that required for the power wires in most
cases. A common ground point is required for all these filters.

If you don`t use coax somewhere between your radio and antenna, you will
lose some of the protection it provides. Its close internal spacing
couples its conductors tightly. We found even solid-state receiver
front-ends weren`t endangered by lightning because of grounded antennas
and the coax. It would flash over before it let lightning through.

Best regards, Richard Harrison, KB5WZI

Lightning attaching to a wire will instantly vaporize the wire.

Not always. Depends on the resistance of the
ground connection. If the resistance is low, a # 6 wire
can take a direct strike, and barely warm up at all.
Even a #10 is ok, if the connection to ground is good.
You might see a tiny pit where the point of contact
was. But a high resistance ground connection, and
yes, it will fry. I've taken two direct strikes on my mast,
and can see no damage at all. You can see a tiny pit
where the strike connected to the mast top, but even
it could be easily missed. According to my experience,
I think the quality of the ground connection also effects
the sound of the strike, not counting the sonic boom overhead.
A strike hitting my mast is very quiet. It's like a light bulb
being thrown on the ground, "plink", and you hear the overhead
sonic boom. But when it hits the trees with their high resistance
to ground, the strike is earsplitting. "CRACK-BAAAAAMMMM".
Thats the "local" sound, not the sonic boom, although they mix.
I don't operate during storms, and doubt I would, even if I could.
I unplug the antennas, and ground them out to ground outside
the window. If I *had* to operate during a storm, I would use my
attic dipole. It's the least likely to take a hit, in general.
MK

Richard Harrison wrote:
Chuck wrote:
"We all know of cases where electronics gets zapped but Jerry is
concerned about his house."

I`ve worked in many protected structures struck repeatedly by lightning
to their air terminals, rods, and towersm resulting in not one scintilla
of damage to occupants or equipment.

Transportation vehicles are struck by lightning every day and seldom
experience anything inside. An open convertible is not safe in a
lightning strike however.

The occasional stain on the seat tho' 8^)

- Mike KB3EIA -