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anyone know what sort of protection antennas have against lightning? if the object is insulated or not? was making a jump the other night and saw some lightning around and it got me thinking

got you thinking? like what... "oh shit get oof this thing now!"

I was thinking this same thing the other night during a storm.

in florida, i dodge bolts all the time. mostly while tracking. fun stuff.

funny response i found that someone wrote responding to a simular lighning question...

Lightning protection is 30 percent applied physics, 30 percent luck (karma), 30 percent voodoo, and the disposition of the remaining 10 percent is unknown. There is no sure bet here.

From a physics standpoint, grounding metal structures bleeds off static charges that may accumulate during electrical storms. This places the metal object (tower, PV racks, or radio antennas) at the same potential as the ground. This reduces the likelihood of a direct strike. Lightning is just like any electricity, just incredibly intense, powerful, and quick. A lightning bolt looks for the path of least resistance to ground. If static charges build up on metal structures, they are at higher potential than the ground and attract lightning because they present an easier path of less potential difference.

From a physics standpoint, if an outside structure takes a direct lightning strike, the grounding conductors may or may not make a path for this strike to go to ground. Considering the amount of energy carried by a lightning bolt, the grounding conductor, all its connections, and grounding rod or plane must be capable of conducting tens of thousands of amperes in a microsecond. We’re talking copper conductors as big around as your arm... Thinking that a #8 copper wire and a 6 foot ground rod is going to do this job is a fantasy. If gear gets a direct strike, there is sure to be damage.

I spent three years operating a commercial, 100 KW TV transmitter on top of 7,500 foot tall Mount Ashland. On top of this mountain, we had a 260 foot tall metal transmitting tower. This tower was protected by multiple grounds with cables over 4 inches thick feeding six huge ground rods. The electronics were guarded by every known form of isolation and protection—cost was no object. During lightning season, we’d sometimes take up to six direct hits daily. We always lost some of the electronic gear inside the transmitter building. I’ve removed electronics with a hacksaw when they welded themselves to steel racks and conduits. I’ve watched blue fire coursing across the racks of delicate electronics while I sat on a wooden stool in the middle of the room too petrified to even consider moving or touching anything.

From a karma and voodoo standpoint, I recommend thinking good thoughts and burning copious quantities of Nepali temple incense under wind generator towers and PV racks. And avoid listening to the Grateful Dead’s “Fire on the Mountain” during electrical storms.

In the beginning of my BASE foray, Me and my Bro was climbing a 1900ftr, Packed for slider up. At about 400ft thunderstorm from nowhere("nowhere"/now here, ahhh, i get it now. And here) appeared (I am well educated on weather forecasting now). So we climbed down and My idea was to directbag a 220ftr a mile and half away. because WTF. Lightning will strike the highest object right?
As we were climbing I heard a hiss, then there was a flash.
Happened a 2nd time in the climb.
3rd Time I recognized the pattern. Hiss/lightning.
I told my bagholder the pattern. Then a very loud hiss came and our hair stood on end, there was the flash and a crack and then thunder. We were temporarily blinded/deafened. We climbed back down and my GF was asking "why did you not jump and what was that hissing noise?".
"Electrons baby" I answered. She didn't understand but I got laid anyway and jumped the 1900ftr the next morning. So all was good. But I aint been right since ;-)
I researched not only weather, ie T-storms but lightning as well.
Theoretically, if one would be standing on the top, one would be liable to die from the strike. Realistically, near the place of the strike, the blast would freak you out and you would drop your grips and plunge unless you had an ascender thingy clipped in. My advice is to know the weather patterns and don't be like that park ranger in Fla.
Take care,
space

so your saying that the tower got struck while you were on it and you didnt even feel it???

The main bolt, I doubt it, It struck in the vicinity, we got an offshoot. Cloud to ground lightning is not the Hollywood picture. It starts from the ground up from many points. As the electron stream reaches the point of whatever you call it the charge surges back down in a flash which can go to a single point but normally it retraces the major electron flows and goes that directions.Kinda like tributaries in a delta.
I would not consider hair standing on end, blinded and deafened as not feeling it.
Take care,
space

well could of been a lot worse....but fahk that must of been intense

But I still got laid, so it aint all bad.
My failures were not knowing the weather and thinking Hollywood style that lightning would only strike the highest point (1900ftr) nearby.
That hiss is embedded in my brain for ever.
Take care,
space
Check this out. http://images.google.com/imgres?imgurl=http://static.howstuffworks.com/gif/lightning-gallery-18.jpg&imgrefurl=http://science.howstuffworks.com/lightning9.htm&usg=__-aE_1sFZTG5iBDUMOoQmlwYAmuY=&h=320&w=400&sz=14&hl=en&start=2&tbnid=t_NmS3Ch2Yp5kM:&tbnh=99&tbnw=124&prev=/images%3Fq%3DLightning%26gbv%3D2%26hl%3Den%26safe%3Doff

Im not sure. All I know is that I was 500' up a very tall A when I saw a lightning storm rolling in. I downclimbed immediately. Not worth the risk.

Spot on Lady.
T-storms are always the same. They expand and are always coming towards you. I did the downclimb (nice coinage). I didn't want the extra factor of the jump + am I gonna get struck/risk management thingy. It is totally unnerving to me to realize that I could die because I have no control over the weather that could smite me.
Kinda goes a lil bit like this:
# I am in control
# Getting scary, but still in control
# Mother Nature is scaring the hell out of me.
# OK Mother Nature, I am not in control.
# Please deliver me from this evil.
# I will pick up cig butt, trash extra.
# I don't want to jump anymore, just let me get off this mountain alive.
# "Windsucks" told to the ground crew. "downclimb".
# Arrive LZ and Mucho BASE team jumps.
# Break out excuse book
Take care,
space

I was at about 1200ft on a 1500ft'er when the lightning came. Winds were honking and it was my 9th jump, i was scared shitless.

I jumped, linetwists facing not completely 180 but almost. Kicked, landed. No more storm jumping.

That said it was beautiful watching it roll in, it seemed like it was all around us in every direction

i was on a tower when lightning went shooting past me parallel to the tower about 6 feet away with no sound to it.

i jumped immediately afterward out of terror despite being too low to safely jump given the way i packed. i was at 450 feet on a 900 foot tower.

the tower may have been hit with me on it.

you'll sometimes see rings of wire with lots of points circling the outside of the tower occasionally. you'll also sometimes see a little if you notice protrusions on the outside of the tower like a rod with lot of nails on it. these are used to attract lightning away from the waveguides.

 

One should know about the "Lifted Index" and avoid the situation in the first place.
Take care.
space

A few years ago, a group managed to capture lightning in super slow-motion, as I recall for a BBC documentary. Enjoy!

A tower I was climbing last year was struck by lightning ....it caused a few wide eyes...especially since the 'weather' came literally out of no where.

We recalled a a weird feeling of calmness followed by a loud noise and a then a blinding light.
Nothing else.

We elected to jump as we were near the top and climbing down would have put us in more trouble with approaching bad weather.

A week ago I got caught in a storm on a via ferrata route.
It was a pretty heavy one....and whilst climbing out , holding the cable...I got a shock...just enough to make me whip my hand away...followed by a flash of lightning and the thunder crack.
We dont think it hit any of the cabling...just some type of earthing or induction...as it was just a small shock....I guess we should have been more worried....but after a few nervous 'fuckin' hells' and giggles...we carried on climbing out ( a bit faster)

Lightning BASE # anyone ??

yep...

Here's some induced lightning in slow motion:

http://www.youtube.com/watch?v=buSaGIoNXu8

University of Florida lightning lab...

Got a small shock once on an antenna with Leroy.
It was my first guyed A so I was sketchy about
hopping off earlier. He exited at 300ish feet.

The storm came in and he made the smart move
to huck early, I downclimbed (Kiki ) till I got hit
with that small arc/shock and then wrapped my
arms around the ladder and slid them while my
feet moved as quick as possible for an old fat
married pipe smoking guy could.


Just got back from my local Freestander Friday
and got up in record time (10 minutes) cause
the WX was moving in. By the time I got to
the top the lightning started, got off fine.

A word of caution (not that I expect most people here need it) about jumping before the lightning gets to you... I jumped from a local cliff once about five seconds after I saw lightning strike a transformer a few kilometers away. Storm was moving in, but there was no wind, so I figured this was the time to go. The whole way down under canopy, I must have been getting a glide ratio of 1:1 or worse in full flight. My brother had the same experience. Cratered in hard on a scree slope (our out, and the softest place to land).

After the fact, I've come to associate the whole experience with what I've dubbed "microturbulence" -- the tiny puffs of air you can feel on your face when the air isn't moving in bulk (ie, no wind), but it is agitated. The kind of stuff that's not large-scale enough to make the canopy accordion or buck. I figure enough of it turns the canopy more into an aerodynamic decelerator than a wing, hence the glide ratio problem and the very hard landing.

 
I was doing some reading about this recently as we were rewireing the mast on my boat.

Most lightning is from the ground up. Part of the concept of a lightning rod is that it is pointed or has sharp corners on it the idea is that it sheds electrond into the air kind of like the carbon feathers on the back edge of an airplane wing. it provides a buffer os negatively charged air around the top of the mast that "sheild the boat from the high gradents that might start a spark from the negatively charged ocean/mast and the sky. There are some little things. Look like a pipe cleaner made of copper brissles about 8 in long and 2 in diamiter. The idea is it has hundreds of sharp points each of which sheds electrons out in to the air. I think what your seeing on the antina is the same concept.

Lee