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Lightning
In another thread some mentioned lightning protection. There seem to
b e several schools of thought on the topic ranging from preventing a strike to dissipating it when it happens. I really do not think there is much you can do to prevent a strike on a sailboat except to be in proximity to other tall objects. When you consider the voltages involved, everything becomes a conductor which is why a tall tree gets hit as often as a tower of the same height. I also do not think that lightning dissipators work. In fact, they may make you more susceptible to a strike by increasing the E field in its vicinity. Given that the water is so murky on the subject of protection,, I favor getting rid of it after a strike and attaching a small conductor to your hull isnt the best way. You may end up with a hole in your hull. Instead, I have a 2'X2' copper plate soldered and bolted to 00 gage tinned battery cable 20' long with an eyelet on the other end. When in a storm, I throw the plate over the side and attach the eyelet to the mast up high so as to minimize bends in the cable. I want to have the current go through the cable while having the shrouds help protect us inside them. I once did a calculation on the probability of a lone sailboat getting hit if out in a storm and came up with a number that seemed too high yet when compared with insurance statistics turned out to be reasonable. Basically, you should avoid being the only tall thing under such a storm. Being one of many tall things is ok |
Lightning
wrote in message ... I am always curious about how a boat takes a hit but I do have some experience with a lightning rod. I put a 3' copper rod over my weather station with a pointy stainless steel tip, connected to 2ga copper wire and terminated in a ground rod (connected to my extensive house grounding system) It has been hit twice that I know of and I was about 30' away during one of them. A mexican laborer was pretty much under it, plastered against my garage door. Other than the poop reflex we were totally unaffected.. The steel garage door he was plastered to is bonded to the same grounding system as the lightning rod as is the wet concrete driveway I was standing on. We were fine. The weather station ... not so much ... either time. Our house has a copper clad cupula, grounded to two metal rods located near the house power panels. It's been hit at least three times. Once, the driveway (near the metal rods) snapped, crackled and popped for about 5 seconds following the hit as the energy was absorbed by the ground plane. Originally, it also had a big, copper weather vane. That has long since been vaporized. Fine for a house .... not so fine for a boat. Eisboch |
Lightning
On Wed, 20 Aug 2008 19:38:50 -0400, "Eisboch"
wrote: wrote in message .. . I am always curious about how a boat takes a hit but I do have some experience with a lightning rod. I put a 3' copper rod over my weather station with a pointy stainless steel tip, connected to 2ga copper wire and terminated in a ground rod (connected to my extensive house grounding system) It has been hit twice that I know of and I was about 30' away during one of them. A mexican laborer was pretty much under it, plastered against my garage door. Other than the poop reflex we were totally unaffected.. The steel garage door he was plastered to is bonded to the same grounding system as the lightning rod as is the wet concrete driveway I was standing on. We were fine. The weather station ... not so much ... either time. Our house has a copper clad cupula, grounded to two metal rods located near the house power panels. It's been hit at least three times. Once, the driveway (near the metal rods) snapped, crackled and popped for about 5 seconds following the hit as the energy was absorbed by the ground plane. Originally, it also had a big, copper weather vane. That has long since been vaporized. Fine for a house .... not so fine for a boat. Eisboch This is the best thing I've seen on lightning, and think it pretty well hits the mark on what you can do on a boat. It's geared toward sailboats, but the principles are there. For electronics gear, I would do the same as I do at home with my computer and other electronic gear if I anticipate lightning: unplug it. An insulated non-conducting case might be appropriate for a radio when at sea. http://edis.ifas.ufl.edu/pdffiles/SG/SG07100.pdf --Vic |
Lightning
On Aug 20, 7:57 pm, Vic Smith wrote:
On Wed, 20 Aug 2008 19:38:50 -0400, "Eisboch" wrote: wrote in message .. . I am always curious about how a boat takes a hit but I do have some experience with a lightning rod. I put a 3' copper rod over my weather station with a pointy stainless steel tip, connected to 2ga copper wire and terminated in a ground rod (connected to my extensive house grounding system) It has been hit twice that I know of and I was about 30' away during one of them. A mexican laborer was pretty much under it, plastered against my garage door. Other than the poop reflex we were totally unaffected.. The steel garage door he was plastered to is bonded to the same grounding system as the lightning rod as is the wet concrete driveway I was standing on. We were fine. The weather station ... not so much ... either time. Our house has a copper clad cupula, grounded to two metal rods located near the house power panels. It's been hit at least three times. Once, the driveway (near the metal rods) snapped, crackled and popped for about 5 seconds following the hit as the energy was absorbed by the ground plane. Originally, it also had a big, copper weather vane. That has long since been vaporized. Fine for a house .... not so fine for a boat. Eisboch This is the best thing I've seen on lightning, and think it pretty well hits the mark on what you can do on a boat. It's geared toward sailboats, but the principles are there. For electronics gear, I would do the same as I do at home with my computer and other electronic gear if I anticipate lightning: unplug it. An insulated non-conducting case might be appropriate for a radio when at sea.http://edis.ifas.ufl.edu/pdffiles/SG/SG07100.pdf --Vic That is a good article. Thanks |
Lightning
wrote in message ... On Aug 20, 7:57 pm, Vic Smith wrote: This is the best thing I've seen on lightning, and think it pretty well hits the mark on what you can do on a boat. It's geared toward sailboats, but the principles are there. For electronics gear, I would do the same as I do at home with my computer and other electronic gear if I anticipate lightning: unplug it. An insulated non-conducting case might be appropriate for a radio when at sea.http://edis.ifas.ufl.edu/pdffiles/SG/SG07100.pdf --Vic That is a good article. Thanks It is a good article in terms of what happens when you get hit and how to design for a hit. The other school of thought is a design to minimize your chances of getting hit in the first place. Both approaches are not fool proof, as the effects of a hit are not 100% predictable, nor is a system designed to minimize the chances of a hit 100% effective. Personally, having many years of experience in designing vacuum processing equipment that contain controlled plasma discharges, (basically the same as lightning, except it is a sustained and controlled electrical discharge through ionized gas), I am more of a believer in the concept of minimizing the conditions that would lead to a strike in the first place. Ironically, the approach is almost the opposite of trying to design a system to capture the energy of a strike and safely transfer it to ground. Eisboch |
Lightning
On Wed, 20 Aug 2008 23:09:52 -0400, "Eisboch"
wrote: wrote in message ... On Aug 20, 7:57 pm, Vic Smith wrote: This is the best thing I've seen on lightning, and think it pretty well hits the mark on what you can do on a boat. It's geared toward sailboats, but the principles are there. For electronics gear, I would do the same as I do at home with my computer and other electronic gear if I anticipate lightning: unplug it. An insulated non-conducting case might be appropriate for a radio when at sea.http://edis.ifas.ufl.edu/pdffiles/SG/SG07100.pdf --Vic That is a good article. Thanks It is a good article in terms of what happens when you get hit and how to design for a hit. The other school of thought is a design to minimize your chances of getting hit in the first place. Both approaches are not fool proof, as the effects of a hit are not 100% predictable, nor is a system designed to minimize the chances of a hit 100% effective. Personally, having many years of experience in designing vacuum processing equipment that contain controlled plasma discharges, (basically the same as lightning, except it is a sustained and controlled electrical discharge through ionized gas), I am more of a believer in the concept of minimizing the conditions that would lead to a strike in the first place. Ironically, the approach is almost the opposite of trying to design a system to capture the energy of a strike and safely transfer it to ground. Biggest trouble with avoidance is that any boat is the tallest thing around, and will attract any lightning that would have struck anywhere near there without it. You get a choice of the mast or the lightning rod. No strikes on boats just isn't doable. They even put masts on powerboats to get the radar and VHF antennae higher for more range. The only counter measure that really works is radar and a very big engine. Hiding under a bridge works, if there is room. A powerboat in a marina next to sailboats won't be hit. Someone checked statistics on one make and model of powerboat and found that more than ten percent had been hit in the last five years. Casady |
Lightning
On Aug 21, 1:47 am, (Richard Casady)
wrote: On Wed, 20 Aug 2008 23:09:52 -0400, "Eisboch" wrote: wrote in message ... On Aug 20, 7:57 pm, Vic Smith wrote: This is the best thing I've seen on lightning, and think it pretty well hits the mark on what you can do on a boat. It's geared toward sailboats, but the principles are there. For electronics gear, I would do the same as I do at home with my computer and other electronic gear if I anticipate lightning: unplug it. An insulated non-conducting case might be appropriate for a radio when at sea.http://edis.ifas.ufl.edu/pdffiles/SG/SG07100.pdf --Vic That is a good article. Thanks It is a good article in terms of what happens when you get hit and how to design for a hit. The other school of thought is a design to minimize your chances of getting hit in the first place. Both approaches are not fool proof, as the effects of a hit are not 100% predictable, nor is a system designed to minimize the chances of a hit 100% effective. Personally, having many years of experience in designing vacuum processing equipment that contain controlled plasma discharges, (basically the same as lightning, except it is a sustained and controlled electrical discharge through ionized gas), I am more of a believer in the concept of minimizing the conditions that would lead to a strike in the first place. Ironically, the approach is almost the opposite of trying to design a system to capture the energy of a strike and safely transfer it to ground. Biggest trouble with avoidance is that any boat is the tallest thing around, and will attract any lightning that would have struck anywhere near there without it. You get a choice of the mast or the lightning rod. No strikes on boats just isn't doable. They even put masts on powerboats to get the radar and VHF antennae higher for more range. The only counter measure that really works is radar and a very big engine. Hiding under a bridge works, if there is room. A powerboat in a marina next to sailboats won't be hit. Someone checked statistics on one make and model of powerboat and found that more than ten percent had been hit in the last five years. Casady Eisboch: C'mon down and you can help build a big sputtering system for us. |
Lightning
wrote in message ... Eisboch: C'mon down and you can help build a big sputtering system for us. It's funny. The bulk of the systems we designed and built were conventional batch type box coaters for optics, utilizing thermal and electron beam evaporation, often with an ion source for controlling the packing density. Mostly for high energy laser stuff, but we also built several systems over the years for ophthalmic coatings. "Neutral Green" :-) We also built many sputter deposition systems for everything from optics, diamond-like coatings, to razor blades. Plasma processing systems was my personal favorite and interest. It combines so many technical disciplines that it was never boring. Eisboch |
Lightning
On Aug 21, 9:01 am, "Eisboch" wrote:
wrote in message ... Eisboch: C'mon down and you can help build a big sputtering system for us. It's funny. The bulk of the systems we designed and built were conventional batch type box coaters for optics, utilizing thermal and electron beam evaporation, often with an ion source for controlling the packing density. Mostly for high energy laser stuff, but we also built several systems over the years for ophthalmic coatings. "Neutral Green" :-) We also built many sputter deposition systems for everything from optics, diamond-like coatings, to razor blades. Plasma processing systems was my personal favorite and interest. It combines so many technical disciplines that it was never boring. Eisboch We need to make a sputter system to deposit thin multilayers on small diameter parabolic mandrels. The mandrels are highly polished and we need coatings with surface and interfacial roughness of less than 10 angstroms. These are for x-ray mirrors. See our web site at www.parallax-x-ray.com |
Lightning
On Wed, 20 Aug 2008 19:38:50 -0400, "Eisboch"
wrote: wrote in message .. . I am always curious about how a boat takes a hit but I do have some experience with a lightning rod. I put a 3' copper rod over my weather station with a pointy stainless steel tip, connected to 2ga copper wire and terminated in a ground rod (connected to my extensive house grounding system) It has been hit twice that I know of and I was about 30' away during one of them. A mexican laborer was pretty much under it, plastered against my garage door. Other than the poop reflex we were totally unaffected.. The steel garage door he was plastered to is bonded to the same grounding system as the lightning rod as is the wet concrete driveway I was standing on. We were fine. The weather station ... not so much ... either time. Our house has a copper clad cupula, grounded to two metal rods located near the house power panels. It's been hit at least three times. Once, the driveway (near the metal rods) snapped, crackled and popped for about 5 seconds following the hit as the energy was absorbed by the ground plane. Originally, it also had a big, copper weather vane. That has long since been vaporized. Fine for a house .... not so fine for a boat. You evidently think a lightning rod will somehow increase the danger, but such has been proven by long experience not to be the case. BS in other words. The lightning rod doesn't know or care what is under it. It prevents strikes in a 90 degree cone under it. Works equally well for buildings, boats, and powerlines. Casady |
Lightning
On Wed, 20 Aug 2008 19:38:50 -0400, "Eisboch"
wrote: wrote in message .. . I am always curious about how a boat takes a hit but I do have some experience with a lightning rod. I put a 3' copper rod over my weather station with a pointy stainless steel tip, connected to 2ga copper wire and terminated in a ground rod (connected to my extensive house grounding system) It has been hit twice that I know of and I was about 30' away during one of them. A mexican laborer was pretty much under it, plastered against my garage door. Other than the poop reflex we were totally unaffected.. The steel garage door he was plastered to is bonded to the same grounding system as the lightning rod as is the wet concrete driveway I was standing on. We were fine. The weather station ... not so much ... either time. Our house has a copper clad cupula, grounded to two metal rods located near the house power panels. It's been hit at least three times. Once, the driveway (near the metal rods) snapped, crackled and popped for about 5 seconds following the hit as the energy was absorbed by the ground plane. Originally, it also had a big, copper weather vane. That has long since been vaporized. Fine for a house .... not so fine for a boat. Did the cupola have a 000 wire and a ten foot long grounding rod, the practice with lightning rods? Casady |
Lightning
wrote in message ... On Aug 21, 9:01 am, "Eisboch" wrote: wrote in message We need to make a sputter system to deposit thin multilayers on small diameter parabolic mandrels. The mandrels are highly polished and we need coatings with surface and interfacial roughness of less than 10 angstroms. These are for x-ray mirrors. See our web site at www.parallax-x-ray.com Your process requirements are a bit out of my league, (primary concern is surface roughness 10 angstroms). I have access to a small sputter deposition system that was originally built for MEMs type research and small scale production. It is basically new, very little use and would probably be cheaper than designing and building your own system, assuming the configuration, instrumentation and metrology is suitable for your purposes. http://www.vptec.com/New_Pages/VPT_Products.htm The system I am referring to is similar to the "SP-2000" Click on "Sputter Systems", then SP-2000. My company was recently sold, however this piece of equipment was not part of the sale. I was going to hold on to it for my own purposes, or find someone that can use it. If you are interested, I can get the details of the configuration, power supplies, cathodes, instrumentation, etc. and forward them to your company's address. Eisboch |
Lightning
"Richard Casady" wrote in message ... You evidently think a lightning rod will somehow increase the danger, but such has been proven by long experience not to be the case. BS in other words. The lightning rod doesn't know or care what is under it. It prevents strikes in a 90 degree cone under it. Works equally well for buildings, boats, and powerlines. Casady I think we are talking two different concepts here. A lightning rod is designed to be "the" point of strike, should one occur and equipped with sufficiently sized conductors to discharge the strike to ground. .. I am talking about making the building, boat, or whatever less favorable to the strike. It has to do with the positive column .... based on the static charge that builds on the ground point. Eisboch |
Lightning
On Aug 21, 10:09 am, "Eisboch" wrote:
"Richard Casady" wrote in message ... You evidently think a lightning rod will somehow increase the danger, but such has been proven by long experience not to be the case. BS in other words. The lightning rod doesn't know or care what is under it. It prevents strikes in a 90 degree cone under it. Works equally well for buildings, boats, and powerlines. Casady I think we are talking two different concepts here. A lightning rod is designed to be "the" point of strike, should one occur and equipped with sufficiently sized conductors to discharge the strike to ground. . I am talking about making the building, boat, or whatever less favorable to the strike. It has to do with the positive column .... based on the static charge that builds on the ground point. Eisboch Wiki has a good discussion of Lightning rods and basically the theory of preventing a strike by dissipating charge from the ground is very controversial. Like Eisboch, I have some familiarity with HV and large electrical sparks, My graduate work was on electrical particle charging by very high electric fields to improve electrostatic precipitators. My experience with this is that things like so-called lightning dissipators tend to increase the likelyhood of attracting a spark. I am not certain this experience can be generalized to lightning but such dissipators do not seem to work well in practice any better than conventional lightning rods. The safe approach would seem to be to have a very good conducting path with few bends going to a large grounded conductor. I do not think that those sintered metal plates used to ground radios will work to replace a large area conductor for lightning. The electric fields inside the pores of those plates will essentially be zero so that the actual area for the purpose of dissipating a lightning strike will basicall be the outside surface area that is fairly small. |
Lightning
On Aug 21, 10:30 am, wrote:
On Aug 21, 10:09 am, "Eisboch" wrote: "Richard Casady" wrote in message .. . You evidently think a lightning rod will somehow increase the danger, but such has been proven by long experience not to be the case. BS in other words. The lightning rod doesn't know or care what is under it. It prevents strikes in a 90 degree cone under it. Works equally well for buildings, boats, and powerlines. Casady I think we are talking two different concepts here. A lightning rod is designed to be "the" point of strike, should one occur and equipped with sufficiently sized conductors to discharge the strike to ground. . I am talking about making the building, boat, or whatever less favorable to the strike. It has to do with the positive column .... based on the static charge that builds on the ground point. Eisboch Wiki has a good discussion of Lightning rods and basically the theory of preventing a strike by dissipating charge from the ground is very controversial. Like Eisboch, I have some familiarity with HV and large electrical sparks, My graduate work was on electrical particle charging by very high electric fields to improve electrostatic precipitators. My experience with this is that things like so-called lightning dissipators tend to increase the likelyhood of attracting a spark. I am not certain this experience can be generalized to lightning but such dissipators do not seem to work well in practice any better than conventional lightning rods. The safe approach would seem to be to have a very good conducting path with few bends going to a large grounded conductor. I do not think that those sintered metal plates used to ground radios will work to replace a large area conductor for lightning. The electric fields inside the pores of those plates will essentially be zero so that the actual area for the purpose of dissipating a lightning strike will basicall be the outside surface area that is fairly small. My reasoning on why the so-called dissipators do not work (these things often look like a brush atop a mast) is that the actual static charge that would need to be dissipated is enormous. Basically, you are trying to dissipate a charge from many meters around your boat (or other object) and in these kinds of E fields, everything conducts. So, if you do end up dissipating this charge, you ionize the air above the dissipator causing a strike. In general, these systems are well grounded so they then act like a conventional lightning rod. |
Lightning
On Thu, 21 Aug 2008 10:09:55 -0400, "Eisboch" wrote:
I think we are talking two different concepts here. A lightning rod is designed to be "the" point of strike, should one occur and equipped with sufficiently sized conductors to discharge the strike to ground. . I am talking about making the building, boat, or whatever less favorable to the strike. It has to do with the positive column .... based on the static charge that builds on the ground point. I am not sure what you have in mind, but lightning rods work, and are about as complicated as a pool ball, hence reliable. However, the 000 wire is not cheap. Every powerline has lightning protection, a grounded wire above the power conductors. What does every electric utility know? None the less lightning does hit powerlines. A long wire lacks sharp points, if that makes a lot of difference. Casady |
Lightning
wrote in message ... On Aug 21, 10:30 am, wrote: On Aug 21, 10:09 am, "Eisboch" wrote: "Richard Casady" wrote in message .. . You evidently think a lightning rod will somehow increase the danger, but such has been proven by long experience not to be the case. BS in other words. The lightning rod doesn't know or care what is under it. It prevents strikes in a 90 degree cone under it. Works equally well for buildings, boats, and powerlines. Casady I think we are talking two different concepts here. A lightning rod is designed to be "the" point of strike, should one occur and equipped with sufficiently sized conductors to discharge the strike to ground. . I am talking about making the building, boat, or whatever less favorable to the strike. It has to do with the positive column .... based on the static charge that builds on the ground point. Eisboch Wiki has a good discussion of Lightning rods and basically the theory of preventing a strike by dissipating charge from the ground is very controversial. Like Eisboch, I have some familiarity with HV and large electrical sparks, My graduate work was on electrical particle charging by very high electric fields to improve electrostatic precipitators. My experience with this is that things like so-called lightning dissipators tend to increase the likelyhood of attracting a spark. I am not certain this experience can be generalized to lightning but such dissipators do not seem to work well in practice any better than conventional lightning rods. The safe approach would seem to be to have a very good conducting path with few bends going to a large grounded conductor. I do not think that those sintered metal plates used to ground radios will work to replace a large area conductor for lightning. The electric fields inside the pores of those plates will essentially be zero so that the actual area for the purpose of dissipating a lightning strike will basicall be the outside surface area that is fairly small. My reasoning on why the so-called dissipators do not work (these things often look like a brush atop a mast) is that the actual static charge that would need to be dissipated is enormous. Basically, you are trying to dissipate a charge from many meters around your boat (or other object) and in these kinds of E fields, everything conducts. So, if you do end up dissipating this charge, you ionize the air above the dissipator causing a strike. In general, these systems are well grounded so they then act like a conventional lightning rod. Indeed, they are controversial, but the theory is supported by many in the "field" so to speak. My understanding is that they act in a similar manner to a dark space shield around the back side and edges of a sputtering target. When the target or cathode is energize with enough voltage to ionize the partial pressure within the vacuum chamber, the small space (1/4 inch or so, depending on pressure and voltage) between the cathode and the grounded dark space shield does not have sufficient ions to sustain current flow, so there is no plasma. Move the dark space shield *away* from the cathode (increasing the space) and a discharge current will start. I am sure you are familiar with the Faraday Column and the voltage division nature of a plasma (or lightning) discharge. One explanation of the workings of the static charge dissipaters is similar. There simply are not enough ions around each of the thousands of points so sustain current flow. In the case of my boat that has one .... I figure it can't do any harm, even if the theory is wrong. Eisboch |
Lightning
"Richard Casady" wrote in message ... On Thu, 21 Aug 2008 10:09:55 -0400, "Eisboch" wrote: I think we are talking two different concepts here. A lightning rod is designed to be "the" point of strike, should one occur and equipped with sufficiently sized conductors to discharge the strike to ground. . I am talking about making the building, boat, or whatever less favorable to the strike. It has to do with the positive column .... based on the static charge that builds on the ground point. I am not sure what you have in mind, but lightning rods work, and are about as complicated as a pool ball, hence reliable. However, the 000 wire is not cheap. Every powerline has lightning protection, a grounded wire above the power conductors. What does every electric utility know? None the less lightning does hit powerlines. A long wire lacks sharp points, if that makes a lot of difference. Casady We still aren't connecting here, Richard. I agree with everything you are saying, if you *want* to design something that is more likely to take the strike instead of another nearby object or surface. I am talking about trying to make the strike less likely in that area. I sorta agree with the point ohara made .... they are probably too small to have a significant affect. But .... here's one type that is marketed: http://www.lpsnet.com/ALS.asp Ok .... we've beat it to death. Eisboch |
Lightning
Slightly OT, slightly...
http://www.youtube.com/watch?v=HcalasGr_uk Video: "Bird on a wire" Faraday cage footage... I know it's been posted before, but it is still cool.. On Thu, 21 Aug 2008 10:09:55 -0400, "Eisboch" wrote: "Richard Casady" wrote in message .. . You evidently think a lightning rod will somehow increase the danger, but such has been proven by long experience not to be the case. BS in other words. The lightning rod doesn't know or care what is under it. It prevents strikes in a 90 degree cone under it. Works equally well for buildings, boats, and powerlines. Casady I think we are talking two different concepts here. A lightning rod is designed to be "the" point of strike, should one occur and equipped with sufficiently sized conductors to discharge the strike to ground. . I am talking about making the building, boat, or whatever less favorable to the strike. It has to do with the positive column .... based on the static charge that builds on the ground point. Eisboch |
Lightning
On Thu, 21 Aug 2008 10:09:55 -0400, "Eisboch" wrote:
"Richard Casady" wrote in message .. . You evidently think a lightning rod will somehow increase the danger, but such has been proven by long experience not to be the case. BS in other words. The lightning rod doesn't know or care what is under it. It prevents strikes in a 90 degree cone under it. Works equally well for buildings, boats, and powerlines. I think we are talking two different concepts here. A lightning rod is designed to be "the" point of strike, should one occur and equipped with sufficiently sized conductors to discharge the strike to ground. . I am talking about making the building, boat, or whatever less favorable to the strike. It has to do with the positive column .... based on the static charge that builds on the ground point. Having some experience with lightning after constructing and using two hundred foot and one 120 foot radio towers in the back yard, it's not always height that affects possibilities. My towers actually took fewer hits over the years than the Beverage I had running out through the woods for 5,000 feet which was seven feet off the ground and covered by tree branches. Also, something that I didn't realise until about ten years ago, the damage is done not on the air-ground strike but the ground-air return strike. - there is more power going that way. I took a trauma course back when I was still active in the vollies and I was surprized to find that with injuries, it's actually better to be closer to the actual strike rather than five/ten feet away. |
Lightning
On Aug 21, 4:13 pm, Short Wave Sportfishing
wrote: On Thu, 21 Aug 2008 10:09:55 -0400, "Eisboch" wrote: "Richard Casady" wrote in message .. . You evidently think a lightning rod will somehow increase the danger, but such has been proven by long experience not to be the case. BS in other words. The lightning rod doesn't know or care what is under it. It prevents strikes in a 90 degree cone under it. Works equally well for buildings, boats, and powerlines. I think we are talking two different concepts here. A lightning rod is designed to be "the" point of strike, should one occur and equipped with sufficiently sized conductors to discharge the strike to ground. . I am talking about making the building, boat, or whatever less favorable to the strike. It has to do with the positive column .... based on the static charge that builds on the ground point. Having some experience with lightning after constructing and using two hundred foot and one 120 foot radio towers in the back yard, it's not always height that affects possibilities. My towers actually took fewer hits over the years than the Beverage I had running out through the woods for 5,000 feet which was seven feet off the ground and covered by tree branches. Also, something that I didn't realise until about ten years ago, the damage is done not on the air-ground strike but the ground-air return strike. - there is more power going that way. I took a trauma course back when I was still active in the vollies and I was surprized to find that with injuries, it's actually better to be closer to the actual strike rather than five/ten feet away. My neighbors below surface well has been hit 3 times even though none of it protrudes above ground, it is a really good ground I guess. Mine has been hit once. |
Lightning
On Thu, 21 Aug 2008 12:48:27 -0400, wrote:
On Thu, 21 Aug 2008 13:58:54 GMT, (Richard Casady) wrote: I am always curious about how a boat takes a hit but I do have some experience with a lightning rod. I put a 3' copper rod over my weather station with a pointy stainless steel tip, connected to 2ga copper wire and terminated in a ground rod (connected to my extensive house grounding system) It has been hit twice that I know of and I was about 30' away during one of them. A mexican laborer was pretty much under it, plastered against my garage door. Other than the poop reflex we were totally unaffected.. The steel garage door he was plastered to is bonded to the same grounding system as the lightning rod as is the wet concrete driveway I was standing on. We were fine. The weather station ... not so much ... either time. 000 wire and a ten foot long grounding rod, is the customary practice with lightning rods. The 2 ga does an excellent job of routing the shot. My ground electrode system is a lot more extensive than a single rod. The proof is in the pudding as they say. The only thing I have ever lost is the serial port in the PC that hooks to the weather station and that is because the weather station signal cable runs parallel to the ground wire from the air terminal for about 20'. I am a bit embarrassed that I did that but I didn't really think this thing would attract lightning so well. It should be noted that the PC was connected to my network and nothing else was affected. In fact I am still typing on the same PC as we speak. The only thing that went was the serial port. The last time it took a hit the same thing happened. The serial port on the lap top it was connected to wasn't even totally fried. It still runs a modem, just not the weather station. Next time around I am putting the weather station on a fiberglass pole on the other corner of the house but I am keeping the air terminal where it is. If I was using the RF connection from the weather station I bet nothing would have been hurt I was working at my computer when lightning hit 6 feet away. The screen didn't even flicker. All the juice stayed with the 000 wire. Casady |
Lightning
"Richard Casady" wrote in message ... I was working at my computer when lightning hit 6 feet away. The screen didn't even flicker. All the juice stayed with the 000 wire. Casady If you could instantaneously block the vivid light of a lightning strike, you would see a large area surrounding it, the diameter of which is dependent on the voltage, of ionized atmosphere around the primary strike point. It also is conducting, although at a much lower amperage compared to the main current path. You just don't see it because the primary flash of light is so bright. Eisboch |
Lightning
On Wed, 20 Aug 2008 23:09:52 -0400, "Eisboch"
wrote: wrote in message ... On Aug 20, 7:57 pm, Vic Smith wrote: This is the best thing I've seen on lightning, and think it pretty well hits the mark on what you can do on a boat. It's geared toward sailboats, but the principles are there. For electronics gear, I would do the same as I do at home with my computer and other electronic gear if I anticipate lightning: unplug it. An insulated non-conducting case might be appropriate for a radio when at sea.http://edis.ifas.ufl.edu/pdffiles/SG/SG07100.pdf --Vic That is a good article. Thanks It is a good article in terms of what happens when you get hit and how to design for a hit. The other school of thought is a design to minimize your chances of getting hit in the first place. That isn't a school of thought in the scientific community. It's been pretty well debunked, but will live on, like Bigfoot. We could argue about it, but I have the feeling it would be endless no matter how many cites I come up with. Of course I'm not a scientist, but can google like crazy. If you have NFPA approved lightning protection the addition of devices of "the other school" will do no harm. But IMO the "other school" alone is Voodoo - and dangerous. The danger part is why I feel compelled to answer your post. --Vic |
Lightning
"Vic Smith" wrote in message ... That isn't a school of thought in the scientific community. It's been pretty well debunked, but will live on, like Bigfoot. We could argue about it, but I have the feeling it would be endless no matter how many cites I come up with. Of course I'm not a scientist, but can google like crazy. If you have NFPA approved lightning protection the addition of devices of "the other school" will do no harm. But IMO the "other school" alone is Voodoo - and dangerous. The danger part is why I feel compelled to answer your post. --Vic Hey, I never said it worked. Eisboch (in his best Harry impersonation) |
Lightning
On Aug 21, 7:45 pm, "Eisboch" wrote:
"Vic Smith" wrote in message ... That isn't a school of thought in the scientific community. It's been pretty well debunked, but will live on, like Bigfoot. We could argue about it, but I have the feeling it would be endless no matter how many cites I come up with. Of course I'm not a scientist, but can google like crazy. If you have NFPA approved lightning protection the addition of devices of "the other school" will do no harm. But IMO the "other school" alone is Voodoo - and dangerous. The danger part is why I feel compelled to answer your post. --Vic Hey, I never said it worked. Eisboch (in his best Harry impersonation) Every effin day in summer we have lightning shutting stuff down here. I come in after lunch and power surges have shut down both electron microscopes. At home during a storm I was sitting 4' from my computer and a huge spark jumped from the cable modem to the power outlet, the computer survived. Last week it was my well getting fried by lightning. I use cordless phones cuz I am terrified of a strike to the phone lines (another neighbor had that happen to him). |
Lightning
On Thu, 21 Aug 2008 19:45:04 -0400, "Eisboch" wrote:
"Vic Smith" wrote in message .. . That isn't a school of thought in the scientific community. It's been pretty well debunked, but will live on, like Bigfoot. We could argue about it, but I have the feeling it would be endless no matter how many cites I come up with. Of course I'm not a scientist, but can google like crazy. If you have NFPA approved lightning protection the addition of devices of "the other school" will do no harm. But IMO the "other school" alone is Voodoo - and dangerous. The danger part is why I feel compelled to answer your post. --Vic Hey, I never said it worked. Eisboch (in his best Harry impersonation) Works for me (-: --Vic |
Lightning
"Vic Smith" wrote in message ... That isn't a school of thought in the scientific community. It's been pretty well debunked, but will live on, like Bigfoot. We could argue about it, but I have the feeling it would be endless no matter how many cites I come up with. Of course I'm not a scientist, but can google like crazy. If you have NFPA approved lightning protection the addition of devices of "the other school" will do no harm. But IMO the "other school" alone is Voodoo - and dangerous. The danger part is why I feel compelled to answer your post. --Vic I am not a scientist either, but have an interest in this kind of stuff. From what I can tell, the operational theory of a "Lightning Dissipater" has never been scientifically proved .... or disproved. So, the controversy continues. However, those that believe it works are in good company. Nicola Tesla patented it in 1918. He is rumored to know a thing or two about electricity. Ol' Ben Franklin even muttered about it. Eisboch |
Lightning
wrote in message ... On Aug 21, 7:45 pm, "Eisboch" wrote: "Vic Smith" wrote in message ... That isn't a school of thought in the scientific community. It's been pretty well debunked, but will live on, like Bigfoot. We could argue about it, but I have the feeling it would be endless no matter how many cites I come up with. Of course I'm not a scientist, but can google like crazy. If you have NFPA approved lightning protection the addition of devices of "the other school" will do no harm. But IMO the "other school" alone is Voodoo - and dangerous. The danger part is why I feel compelled to answer your post. --Vic Hey, I never said it worked. Eisboch (in his best Harry impersonation) Every effin day in summer we have lightning shutting stuff down here. I come in after lunch and power surges have shut down both electron microscopes. At home during a storm I was sitting 4' from my computer and a huge spark jumped from the cable modem to the power outlet, the computer survived. Last week it was my well getting fried by lightning. I use cordless phones cuz I am terrified of a strike to the phone lines (another neighbor had that happen to him). Lightning storms scare the bananas out of me. Eisboch |
Lightning
On Thu, 21 Aug 2008 19:45:04 -0400, "Eisboch" wrote:
"Vic Smith" wrote in message .. . That isn't a school of thought in the scientific community. It's been pretty well debunked, but will live on, like Bigfoot. We could argue about it, but I have the feeling it would be endless no matter how many cites I come up with. Of course I'm not a scientist, but can google like crazy. If you have NFPA approved lightning protection the addition of devices of "the other school" will do no harm. But IMO the "other school" alone is Voodoo - and dangerous. The danger part is why I feel compelled to answer your post. --Vic Hey, I never said it worked. Eisboch (in his best Harry impersonation) ~~ snerk ~~ |
Lightning
On Thu, 21 Aug 2008 20:07:31 -0400, "Eisboch" wrote:
"Vic Smith" wrote in message .. . That isn't a school of thought in the scientific community. It's been pretty well debunked, but will live on, like Bigfoot. We could argue about it, but I have the feeling it would be endless no matter how many cites I come up with. Of course I'm not a scientist, but can google like crazy. If you have NFPA approved lightning protection the addition of devices of "the other school" will do no harm. But IMO the "other school" alone is Voodoo - and dangerous. The danger part is why I feel compelled to answer your post. --Vic I am not a scientist either, but have an interest in this kind of stuff. From what I can tell, the operational theory of a "Lightning Dissipater" has never been scientifically proved .... or disproved. So, the controversy continues. However, those that believe it works are in good company. Nicola Tesla patented it in 1918. He is rumored to know a thing or two about electricity. Ol' Ben Franklin even muttered about it. Actually predates Ben. This is dense, but readable, and has good historical reference, http://www.lightningsafety.com/nlsi_lhm/Uman_Rakov.pdf --Vic |
Lightning
"Eisboch" wrote in message ... "Vic Smith" wrote in message ... That isn't a school of thought in the scientific community. It's been pretty well debunked, but will live on, like Bigfoot. We could argue about it, but I have the feeling it would be endless no matter how many cites I come up with. Of course I'm not a scientist, but can google like crazy. If you have NFPA approved lightning protection the addition of devices of "the other school" will do no harm. But IMO the "other school" alone is Voodoo - and dangerous. The danger part is why I feel compelled to answer your post. --Vic I am not a scientist either, but have an interest in this kind of stuff. From what I can tell, the operational theory of a "Lightning Dissipater" has never been scientifically proved .... or disproved. So, the controversy continues. However, those that believe it works are in good company. Nicola Tesla patented it in 1918. He is rumored to know a thing or two about electricity. Ol' Ben Franklin even muttered about it. Eisboch The University of Florida is recognized as leading, if not the leading, institution for the study of lightning. The following link may be of interest to you guys here if you haven't come across it before. http://www.powerandmotoryacht.com/co...03electronics/ |
Lightning
"Eisboch" wrote in message ... wrote in message ... On Aug 21, 7:45 pm, "Eisboch" wrote: "Vic Smith" wrote in message ... That isn't a school of thought in the scientific community. It's been pretty well debunked, but will live on, like Bigfoot. We could argue about it, but I have the feeling it would be endless no matter how many cites I come up with. Of course I'm not a scientist, but can google like crazy. If you have NFPA approved lightning protection the addition of devices of "the other school" will do no harm. But IMO the "other school" alone is Voodoo - and dangerous. The danger part is why I feel compelled to answer your post. --Vic Hey, I never said it worked. Eisboch (in his best Harry impersonation) Every effin day in summer we have lightning shutting stuff down here. I come in after lunch and power surges have shut down both electron microscopes. At home during a storm I was sitting 4' from my computer and a huge spark jumped from the cable modem to the power outlet, the computer survived. Last week it was my well getting fried by lightning. I use cordless phones cuz I am terrified of a strike to the phone lines (another neighbor had that happen to him). Lightning storms scare the bananas out of me. Eisboch Buddy worked in a small low power radio station while in college. A rip and read news report place. TTY in a closet and 5 minutes before the news, go rip the page off the TTY and read it. Said they had a lightening strike and the transmitter reset automatically and when they went to rip, opened the closed door to a melted TTY. Did not plow the 110V fuse and the resistors on the telephone pad were still intact. Nothing else harmed. |
Lightning
"Eisboch" wrote in message ... wrote in message ... On Aug 21, 7:45 pm, "Eisboch" wrote: "Vic Smith" wrote in message ... That isn't a school of thought in the scientific community. It's been pretty well debunked, but will live on, like Bigfoot. We could argue about it, but I have the feeling it would be endless no matter how many cites I come up with. Of course I'm not a scientist, but can google like crazy. If you have NFPA approved lightning protection the addition of devices of "the other school" will do no harm. But IMO the "other school" alone is Voodoo - and dangerous. The danger part is why I feel compelled to answer your post. --Vic Hey, I never said it worked. Eisboch (in his best Harry impersonation) Every effin day in summer we have lightning shutting stuff down here. I come in after lunch and power surges have shut down both electron microscopes. At home during a storm I was sitting 4' from my computer and a huge spark jumped from the cable modem to the power outlet, the computer survived. Last week it was my well getting fried by lightning. I use cordless phones cuz I am terrified of a strike to the phone lines (another neighbor had that happen to him). Lightning storms scare the bananas out of me. Eisboch Sorry. Can't help you right now. Got pineapples though. |
Lightning
"Eisboch" wrote in message ... "Vic Smith" wrote in message ... That isn't a school of thought in the scientific community. It's been pretty well debunked, but will live on, like Bigfoot. We could argue about it, but I have the feeling it would be endless no matter how many cites I come up with. Of course I'm not a scientist, but can google like crazy. If you have NFPA approved lightning protection the addition of devices of "the other school" will do no harm. But IMO the "other school" alone is Voodoo - and dangerous. The danger part is why I feel compelled to answer your post. --Vic I am not a scientist either, but have an interest in this kind of stuff. From what I can tell, the operational theory of a "Lightning Dissipater" has never been scientifically proved .... or disproved. So, the controversy continues. However, those that believe it works are in good company. Nicola Tesla patented it in 1918. He is rumored to know a thing or two about electricity. Ol' Ben Franklin even muttered about it. Eisboch The University of Florida is recognized as leading, if not the leading, institution for the study of lightning. The following link may be of interest to you guys here if you haven't come across it before. http://www.powerandmotoryacht.com/co...03electronics/ |
Lightning
D.Duck wrote:
"Eisboch" wrote in message ... "Vic Smith" wrote in message ... That isn't a school of thought in the scientific community. It's been pretty well debunked, but will live on, like Bigfoot. We could argue about it, but I have the feeling it would be endless no matter how many cites I come up with. Of course I'm not a scientist, but can google like crazy. If you have NFPA approved lightning protection the addition of devices of "the other school" will do no harm. But IMO the "other school" alone is Voodoo - and dangerous. The danger part is why I feel compelled to answer your post. --Vic I am not a scientist either, but have an interest in this kind of stuff. From what I can tell, the operational theory of a "Lightning Dissipater" has never been scientifically proved .... or disproved. So, the controversy continues. However, those that believe it works are in good company. Nicola Tesla patented it in 1918. He is rumored to know a thing or two about electricity. Ol' Ben Franklin even muttered about it. Eisboch The University of Florida is recognized as leading, if not the leading, institution for the study of lightning. The following link may be of interest to you guys here if you haven't come across it before. http://www.powerandmotoryacht.com/co...03electronics/ Florida is the lighting capital of the US. It would make sense the U of Fl would study it. |
Lightning
"D.Duck" wrote in message ... "Eisboch" wrote in message ... "Vic Smith" wrote in message ... That isn't a school of thought in the scientific community. It's been pretty well debunked, but will live on, like Bigfoot. We could argue about it, but I have the feeling it would be endless no matter how many cites I come up with. Of course I'm not a scientist, but can google like crazy. If you have NFPA approved lightning protection the addition of devices of "the other school" will do no harm. But IMO the "other school" alone is Voodoo - and dangerous. The danger part is why I feel compelled to answer your post. --Vic I am not a scientist either, but have an interest in this kind of stuff. From what I can tell, the operational theory of a "Lightning Dissipater" has never been scientifically proved .... or disproved. So, the controversy continues. However, those that believe it works are in good company. Nicola Tesla patented it in 1918. He is rumored to know a thing or two about electricity. Ol' Ben Franklin even muttered about it. Eisboch The University of Florida is recognized as leading, if not the leading, institution for the study of lightning. The following link may be of interest to you guys here if you haven't come across it before. http://www.powerandmotoryacht.com/co...03electronics/ Yup, more acknowledgement that we really don't 100% understand lightning. BTW, I am curious. Did you just resend this post? It arrived on my computer marked 8/22/2008 at 8:30 am or 15 min ago. Yet, I seem to recall read the same post yesterday. With all the goofy stuff going on lately with the servers, I was just wondering. Eisboch |
Lightning
"Earl of Warwich, Duke of Cornwall, Marquies of Anglesea, Sir Reginald P. Smithers III Esq. LLC, STP. " wrote in message . .. D.Duck wrote: "Eisboch" wrote in message ... "Vic Smith" wrote in message ... That isn't a school of thought in the scientific community. It's been pretty well debunked, but will live on, like Bigfoot. We could argue about it, but I have the feeling it would be endless no matter how many cites I come up with. Of course I'm not a scientist, but can google like crazy. If you have NFPA approved lightning protection the addition of devices of "the other school" will do no harm. But IMO the "other school" alone is Voodoo - and dangerous. The danger part is why I feel compelled to answer your post. --Vic I am not a scientist either, but have an interest in this kind of stuff. From what I can tell, the operational theory of a "Lightning Dissipater" has never been scientifically proved .... or disproved. So, the controversy continues. However, those that believe it works are in good company. Nicola Tesla patented it in 1918. He is rumored to know a thing or two about electricity. Ol' Ben Franklin even muttered about it. Eisboch The University of Florida is recognized as leading, if not the leading, institution for the study of lightning. The following link may be of interest to you guys here if you haven't come across it before. http://www.powerandmotoryacht.com/co...03electronics/ Florida is the lighting capital of the US. It would make sense the U of Fl would study it. Roger that. I live 50 miles from the UF and have seen some of their open field test setups where they catch lightning in a bottle. |
Lightning
"Eisboch" wrote in message ... "D.Duck" wrote in message ... "Eisboch" wrote in message ... "Vic Smith" wrote in message ... That isn't a school of thought in the scientific community. It's been pretty well debunked, but will live on, like Bigfoot. We could argue about it, but I have the feeling it would be endless no matter how many cites I come up with. Of course I'm not a scientist, but can google like crazy. If you have NFPA approved lightning protection the addition of devices of "the other school" will do no harm. But IMO the "other school" alone is Voodoo - and dangerous. The danger part is why I feel compelled to answer your post. --Vic I am not a scientist either, but have an interest in this kind of stuff. From what I can tell, the operational theory of a "Lightning Dissipater" has never been scientifically proved .... or disproved. So, the controversy continues. However, those that believe it works are in good company. Nicola Tesla patented it in 1918. He is rumored to know a thing or two about electricity. Ol' Ben Franklin even muttered about it. Eisboch The University of Florida is recognized as leading, if not the leading, institution for the study of lightning. The following link may be of interest to you guys here if you haven't come across it before. http://www.powerandmotoryacht.com/co...03electronics/ Yup, more acknowledgement that we really don't 100% understand lightning. BTW, I am curious. Did you just resend this post? It arrived on my computer marked 8/22/2008 at 8:30 am or 15 min ago. Yet, I seem to recall read the same post yesterday. With all the goofy stuff going on lately with the servers, I was just wondering. Eisboch Yes, the double post was a glitch on my part. I saw the message still in my Outbox this morning and when trying to clear it, it was sent a second time. |
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