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Lightning EMP and other effects on electronics..?

S

spinjector

Hi all,

I was curious about the hidden effects of lightning on electronic devices near a lightning strike.

Obviously, if a bolt of lightning passes through the Orban, the Burk, or a PC, we're completely......perhaps "bolted" is a better term to use than "screwed"... har har =-)

However, I was wondering about electronics in/near the ATU buildings. Or - in some cases there are studios with antenna towers right on top of the building.

What effects do phenomena like EMP have? Is it possible to shield from this with simple metal enclosures without having them made of the substance known as "Mu Metal"..? (http://en.wikipedia.org/wiki/Mu-metal) Or is EMP not really an issue..?

I ask this in light of possible putting some electronic gadgets in one of our doghouses, and I was wondering if a strike at that tower would fry them, from simply being 20 feet away from the strike...

Thanks.
 
You can put your equipment in a Faraday Cage to protect it, but it's the connection(s) to the outside world that'll nail it.

Lightning strikes many miles away can induce EMP in power and telco lines.

EMP from direct strikes results from the current in conductors like coax lines and ground straps.

Not too long ago a direct strike on a studio building that was constructed of steel beams magnitized the structure. All the CRT monitors were totally whacked. Nearly every piece of equipment hooked to wire exiting/entering the building was damaged or destroyed.

If you've used good engineering & grounding practices you have a better chance of survival.

Start here:
http://www.nautel.com/Resources/Docs/Whitepapers/lightningprotection.pdf
 
Does a Faraday cage (or for that matter, just a metal box/chassis) protect against EMP, or just direct bolts/leaders/discharges..?
 
The big truth is. if you can predict what lightning will do, then your a prophet.
The cage would be a nice place to store electronics but hook them to the outside world, get hit by a positive strike (they say 10 times more power than a negative one) all bets are off.

Google Faraday Cage and read up on it.
 
I used to work for WBEN in Buffalo and Tower 1 once got hit by a positive strike. The thunderclap was so loud that residents in the area called 911 to tell them someone from the fire department might want to go check the radio station buildings down the road. One of them even called the station the next day to tell us. The DOE went out to check, and everything seemed ok, but the top beacon was out.

We called in our tower climber and he went up the following week to fix it. Well... The top beacon wasn't just out, it was gone. And I don't mean merely burned out, but GONE. All of the red glass was gone, the middle ring was gone. The socket & bulb was gone. EVERYTHING was gone. All that was left was the bottom mounting bracket and the melted ends of the wires. We walked around in the grass around the tower base (which is difficult because it's kinda swampy), but we couldn't find any trace of red glass anywhere. Not even on the roof of the doghouse.
 
Yow!

About 2 weeks ago I was in the basement, and during a particularly electrical storm, I heard a distinct, almost loud SNAP
of a current discharge, and within maybe half a second, the flash and crash of nearby lightning.

I have witnessed this more than once. Is this collector current in advance of a discharge?

Or is this actually simultaneous with the real discharge event and I only perceive it to be in advance?
Any others seen/heard this?


A few days after, we were walking by the river (250 ft away) and found a gigantic sheet of bark blown off a tree where the ligtning current turned the water under the bark to steam.
 
boiseengineer said:
You can put your equipment in a Faraday Cage to protect it, but it's the connection(s) to the outside world that'll nail it.
Click to expand...

I am a ham radio operator and was part of a group once invited to a government communications facility for a tour. We were shown the radio room that was like a compartment in a submarine. All metal with serious filters on every wire or connection that exited or entered that room. Was supposedly lightning, EMP (nuclear type) and just about everything else proof. Very impressive, and that was before we got to see the radio goodies on the wall! DC to Daylight!
 
Tom Wells said:
Yow!

About 2 weeks ago I was in the basement, and during a particularly electrical storm, I heard a distinct, almost loud SNAP
of a current discharge, and within maybe half a second, the flash and crash of nearby lightning.

I have witnessed this more than once. Is this collector current in advance of a discharge?

Or is this actually simultaneous with the real discharge event and I only perceive it to be in advance?
Any others seen/heard this?


A few days after, we were walking by the river (250 ft away) and found a gigantic sheet of bark blown off a tree where the ligtning current turned the water under the bark to steam.
Click to expand...

Tom I can'r remember where I saw it, but there was a shot on TV or some web site (old, sorry) that clearly showed a ground based event preceding a strike. It was like something rising off the ground where a lightning strike hit, or hit nearby. Lightning is nasty, unpredictable stuff, but you know that.
 
I guess we should store our spares, a portable radio and some walkie-talkies in an old galvanized trash can just in case. At least my old R-390A should still work if I can get enough power to run it.
 
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