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Worse Case Scenario - Lightning Strike?

BOOTY MONSTER said:
CK i didnt mean to imply that i thought it would help with a actual lightning strike , im %100 it wouldnt i was wondering if it might help to reduce a static charge to reduce the likely hood of a lightning strike .

dont little pointy thinks on antennas attract and cause noise ?
Click to expand...


Booty, those arrestors will not bleed off like you think they will and certainly not fast enough when the time comes for them to work. Those are either a spark gap or gas discharge type that simple sit there allowing static to build up, often to a couple hundred volts which admittedly is small beans compared to lightning. When the voltage builds up to the point where they arc they then dump that static to ground in a flash, literally. The question I have is do you really want a few hundred volts building up on your coax connector connected to your radio? Are they better than nothing? Yes, but do not get too confident in using them. Good lightning protection comes from using multiple techniques from solid bonding to offer a low impedance path to ground to preventing static buildup that leads to a strike.

Here is an idea what the broadcast business does. In fact this is from the Nautel website. Nautel makes commercial broadcast transmitters, both AM and FM as well as navigation beacons. They have a plant right here in Nova Scotia and I serviced several Nautels as well as toured their plant. They know what they are talking about. The article below is much more involved than a simple home station but it gives some good insight into what is required to have good confidence in your ground system.


http://www.nautel.com/Resources/Docs/Whitepapers/lightningprotection.pdf


Some more technical stuff but good info on grounding and site preparation for transmitter sites. It's a lot more then we need but it has good background info as to why we need what we need.

http://www.nautel.com/Resources/Docs/Site Recommendation Book - Issue 3 (2004).pdf
 
It is the opposite voltage that randomly builds up in particular spots of the Earths surface that attracts the opposite charged cloud discharge in a lightning strike. The antenna is incidental in this, and is not the cause of the discharge from the cloud. It might become a link; but that isn't always the case.

While storm chasing near Elgin NE a couple years ago, I had a lighting strike less that 20 yards away - right in front of me. Had three antennas on my roof: CB/10m, cell phone antenna, and a 2m/440 antenna. None were hit. Why? Because the static potential opposite charge was strongest at that point some 60 ft away. Not because I had antennas up.

That doesn't mean that you shouldn't make your station safe by proper grounding. My vehicle was somewhat insulated because of the tires. It was a poor path of electrical flow is all. But a house is grounded; and a strike will go thru the wiring and the plumbing. And ALL things that are hooked up to it at the time of the lightning multi-discharge strike. Giving it the clearest, least resistive path possible -and away from the house- is best. If it finds resistance; things will get hot and start fires instantly.
 
I simply wanted to know how to safely/correctly ground a hobbyist antenna in a residential setting...not how to ground a multi-million dollar commercial broadcast station. I don't have the resources to do that kind of protection (and I doubt that few actually do), so the next best alternative is to avoid the issue completely by not installing an antenna.

So my equipment will be up for sale soon as I don't have the resources or time to invest in the grounding systems presented.

Thanks for the insight.
 
Nobody suggested you try and do what the commercial stations do. I posted those links because on the first page of this thread it was asked what commercial broadcasts stations do and so people could get an idea of the reasons WHY grounding is important and to what extent you must go to have reasonable confidence that your station can take a direct strike and be undamaged.

Take at least a 6 gauge copper wire,preferably heavier, and connect it to the antenna mount. Run it in a straight line to a ground rod driven at least 8 feet into the ground and use a GOOD clamp to connect the wire to the rod. Use multiple ground rods if the soil is dry or sandy. Space ground rods a minimum of their length from each other. Bond the coax shield to the ground rod at the same point the ground wire is connected too. Also connect these ground rods to the main electrical entrance ground using heavy wire.When not using the radio disconnect the coax and preferably throw the end of the cable outside the house. That will take care of about 90% of your protection.If you want 99.9% protection you will have to spend some money, time, and effort. Nothing comes free when talking about lightning protection.
 
packrat said:
Thats great Booty, but they are man made hits or setups. You can do anything with a camera. Never heard of a REAL, Natural lightening strike to a car
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And why wouldn't lightning strike a car? It hits airplanes. Cars are no longer insulated from the ground when they are rolling on wet pavement in a rainstorm. Just because you have never heard of a real, yet unusual event, does not mean it has never happened. We had a truck driver pull into work a year or two ago with a large piece of the aluminum roof of his trailer peeled back in the front corner. Closer inspection also revealed blown out plywood pieces and melted metal. He said he had the crap scared out of him earlier in the day by a "close" strike. Apparently the strike was closer than he thought.


More proof. http://video97.com/lUUOdO6eEZA/Minivan-Struck-By-Lightning.watch
 
Let me restate the original question...( and it was a question, not a challenge)

Has anyone here heard of an antenna on a car, or the car itself being hit by a lightening strike, first hand. I never said it doesnt happen, just that the fact is, IF it does happen, the odds are so tremendously low as to be a non issue.

(I am sure we could prove the existance of little green men if we search youtube long enough, too.):eek:
 
packrat said:
Let me restate the original question...( and it was a question, not a challenge)

Has anyone here heard of an antenna on a car, or the car itself being hit by a lightening strike, first hand. I never said it doesnt happen, just that the fact is, IF it does happen, the odds are so tremendously low as to be a non issue.

(I am sure we could prove the existance of little green men if we search youtube long enough, too.):eek:
Click to expand...

Well you may have never said it has never happened but that certainly is the tone of your posts. Why do you find it so hard to believe that it happens albeit rarely? You must have missed it the first time so I present it to you again. I saw the damage myself and it was NOT from overhead wires. They would not do that kind of damage and there were thunderstorms in the area that day.

Captain Kilowatt said:
And why wouldn't lightning strike a car? It hits airplanes. Cars are no longer insulated from the ground when they are rolling on wet pavement in a rainstorm. Just because you have never heard of a real, yet unusual event, does not mean it has never happened. We had a truck driver pull into work a year or two ago with a large piece of the aluminum roof of his trailer peeled back in the front corner. Closer inspection also revealed blown out plywood pieces and melted metal. He said he had the crap scared out of him earlier in the day by a "close" strike. Apparently the strike was closer than he thought.


More proof. Minivan Struck By Lightning
Click to expand...
 
packrat said:
Let me restate the original question...( and it was a question, not a challenge)

Has anyone here heard of an antenna on a car, or the car itself being hit by a lightening strike, first hand. I never said it doesnt happen, just that the fact is, IF it does happen, the odds are so tremendously low as to be a non issue.

(I am sure we could prove the existance of little green men if we search youtube long enough, too.):eek:
Click to expand...

Yes, there was a storm chaser I knew of that had a 2m radio and mag mount obliterated by a direct strike (it was a borrowed radio - at that!). There was a YouTube video of it a couple of years ago. The lightning strike also flattened two of his tires, as they were wet and provided the ground path.

It DOES happen - unlike little green men.
Lighting is an equal opportunity killer...he survived an indirect strike...
 

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