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

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 -

I had the experience of a direct hit to my antenna. It was a 130 foot cage
fed with ladderline. Coax was used the last 20 feet to bring it into the
house.

Inside I had a TS-440, a TS-820 and an MFJ 989C.

The bolt destroyed the side of the antenna that went to the shield of the
coax, the largest remaining piece was about 3" in length with most of it
vaporized. The ladderline was vaporized, the other half of the dipole was
untouched.

The coax split open like a hotdog put in a microwave. The same stroke went
into the electric utilities and blew every electronic device in the house
except a cheap GE clock radio.

A stroke went through the wiring in the ceiling and the explosive expansion
of hot air blew all the vinyl siding off the front and one side of the
house.

The only fire damage was a small burn mark on the shack carpet where the
coax laid on the floor.

All antennas were grounded via the antenna switch and all ham gear was
unplugged. All antennas had blitzbuggs and coiled coax before entering the
house. These were tied to both RF ground and the single point electrical
ground.

What was strange was the stroke following paths along wood beams while
ignoring good conducting copper wires 3 feet away. The only damage to the
ham gear was a burn mark and heat distortion on the rear panel of the tuner.
It's operation was unaffected.



"chuck" wrote in message
ink.net...
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