Lightning

[SCPD]

I remember'd I had these photo's-- not that they add much to the discussion-- though I was at this site during an electrical 'event' and that "Antenna" was hit several times...
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No one need tell me what lightning can do ! Scared the Beegeezus out of us all !
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...........CF
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[AK9R]

I'm reminded of some projects I worked on at a U.S. Navy weapons development center. Some of their buildings had extensive lighting protection that amounted to four masts, one at each corner of the building. These masts were simpler that the one in C-F's photos--just tapered poles taller than the building. At the bottom of each mast was a buried mesh of wires and each mast was connected together under the soil. Additionally, there were wires strung in a criss-cross fashion between the masts. These wires formed an X over the building. Given that they were working on live ordnance in that building, they were a bit nervous about lightning.

 

[prcguy]

Many years ago I watched a fascinating program about lightning on PBS. It was done at a lab in New Mexico if I remember and they would attract lightning to towers, long cables stretched between hills and they also launched barrages of rockets into the air with wire attached during lightning storms.

The program had all kinds of footage of things being struck by lightning and showed how the lab measured the strength of the strikes, etc.

A couple of years later I was working at a customers site in the aerospace industry where I was sent about once a month to do maintenance on some equipment we built and I got to know some of the people there very well. I don't know how the conversation of lightning came up but it turns out one of the guys there had worked at the lightning lab and he was in the PBS program I watched. Talk about a coincidence.

One of the better stories he told me about the lab was the 2.75" rocket engines they had for launching probes into the lightning storms. They were surplus from the Viet Nam war and they literally had a blast using and playing with them. They were also completely illegal and nobody there had the needed ATF license to receive or possess them.

Anyway, I learned quite a bit about how lightning works from the guy and I think I'll do a search on Youtube to see if the program is available.
prcguy

 

[KC4RAF]

That was a great program PBS had about lightning. I saw it about 8 or 9 years ago, though I never saw the whole thing; and have never been able to find it on any of the PBS stations' listings. Good luck finding it.

 

[kayn1n32008]

I thought they did lightning research in northern florida.

 

[prcguy]

I found this which looks like some of the video from the program I saw in the late 80s, early 90s mixed with some new. https://www.youtube.com/watch?v=csEaixmsnno

The scenes of the raised test tower and rockets looks very familiar. The original I saw also had some aircraft footage where they flew into a storm and lightning hit the small plane with wirey things sticking out of the wings for the lightning it hit. If I see video of the big cable stretched across a valley and the guys running away just in time before the lightning hits, I'll know I've got the original.
prcguy

That was a great program PBS had about lightning. I saw it about 8 or 9 years ago, though I never saw the whole thing; and have never been able to find it on any of the PBS stations' listings. Good luck finding it.

 

[RFI-EMI-GUY]

I found this which looks like some of the video from the program I saw in the late 80s, early 90s mixed with some new. https://www.youtube.com/watch?v=csEaixmsnno

The scenes of the raised test tower and rockets looks very familiar. The original I saw also had some aircraft footage where they flew into a storm and lightning hit the small plane with wirey things sticking out of the wings for the lightning it hit. If I see video of the big cable stretched across a valley and the guys running away just in time before the lightning hits, I'll know I've got the original.
prcguy

University of Florida Gainesville I believe. Is the audio broken or is it just me?

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[SpugEddy]

I am, by no stretch of any imagination, an expert on
neither lightning nor electronics. This subject has been
argued by techies for many years and it opens the air for
many arguments, theories, and questions.
One such theory came from an instructor at a class I took back
in the 90's. It goes like this: You will never see an electrician working
on an electrical box in bare feet standing on concrete. Why? Because
he would be "grounded". If he were to touch a hot line he would obviously
be electrocuted. However, if he were wearing rubber soled shoes he would
be fine. Why? Because he was "isolated" from ground.
So the question is: Should we ground or should we isolate from ground?
Good question. In "theory" if you don't ground then lightning can't strike
because it needs positive AND negative. It would simply look for the next nearest
ground point. I personally don't trust that theory.

If we believe in what the government tells us then we
also believe that all electricity flows from negative to positive. That means
lightning starts from a ground reference and goes up. What we see is an
optical illusion. That lightning comes from the sky and to the ground.

I'm a parent and grandparent so "reverse psychology" is 2nd nature to me.
I'm not so sure that I buy into that instructor's "reverse theory". I feel much
better having a good ground in place. Grounding my equipment and my antennas
is NOT going to necessarily stop lightning from hitting, but if it is to be hit, then
grounding is just a way of directing that nasty traffic into the ground and not into
my house / shack and equipment. Not only that, but I often rely on the two 500'
towers for a local radio station (that are located about 400 yards from my house)
to take the strike rather than me.

I think that the bulk of your money is better spent in surge protection combined
with grounding. Just opinion.

 

[RFI-EMI-GUY]

You need to add "bonding" to any discussion of surge protection and grounding. Bonding is the practice of ensuring that all elements of the system are kept to the same voltage potential. It is the difference in potential which causes damage.



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[KC4RAF]

RFI-EMI-GUY, the audio is fine. Hopefully it isn't a problem with your equipment.
Yeah, that has part of the show that I saw. The best I can remember is the first 5 -10 minutes.
Thanks for finding that link, much appreciated.