|
Lightning Strike
We had a rather bad storm the other day, lightning striking everywhere.
As I left work, it hadn't started in that area yet, but I could see it off in the distance. I phoned my son to ask if he could disconnect the long wire antenna from my Yaesu FRG-100, but he said that the area very near my house already had a couple of bad lightning strikes. I told him to stay away from the radio. When I got home, most of the storm had abated, though as I traveled home I could see massive lightning strikes occurring in areas around me. The storm was accompanied by tremendous downpours, and flash flooding warnings were issued. The National Weather Service (NWS) screwed up on this one, they didn't even issue the warning until after the storm had wreaked its havoc. Nice work guys, Helen Keller could have done a better job. I get home, assess the trees in the yard, everything looks normal. Problem is that there is no power to the neighborhood, a condition that remains unchanged for the next 1 ½ hours. No problem, I can use my handhelds and portable shortwave radios. My wife arrives home, and as she is walking through the yard, she talks to the neighbor. The neighbor explains that the "wire antenna" in the yard was struck by lightning. I go out into the yard to examine the antenna and find it lying on the ground. I'm convinced that very high winds somehow pulled the antenna down. I picked it up and examined it, and lo and behold, some of the insulation is melted off. As I just installed an arrestor of sorts (it's an old one that I bought on EBay, it appears unused, a ceramic block with 3 terminals, 2 outer ones for the antenna wire, and a center one for the grounding wire) about 3 weeks ago, having had the antenna for a couple of years without it. The melted insulation extended to the arrestor, and the wire after the arrestor was normal in appearance. I examined the Yaesu, it appeared normal, but there was no power in the house yet, so I couldn't tell if operated ok. Being impatient by nature, I got the correct power cord, took the radio to the car, opened the car hood, and connected directly to the battery. The radio powered up, but didn't receive. It looked like it wanted to receive, when tuning through the frequencies every once in awhile I could hear a local station pounding through, overloading the radio, but even with a makeshift antenna I could not receive anything willfully on shortwave or broadcast AM. I gave it up as toast, and I called AES in Cleveland, explaining that it was lightning damaged. They said that I could sent it back, but that they would in turn send it to Yaesu for a proper assessment. He explained that Yaesu would try this and that, and probably end up saying that it was irreparable. Eventually the power came back on, so I took the radio and began to experiment with it yet again. When I tried it at the car, I used both antenna inputs, but I had forgotten to throw the switch on the back to use the low input impedance connector, so I tried the radio again after throwing the switch, placing the antenna wire in the Low Z connector, turned the radio on, and viola, the radio worked. But why doesn't the High Z terminal work. Since the radio had been exposed to such a large transient, I decided to disassemble it to make sure that nothing else is wrong. When I began to remove the screws to open the case, I noticed that the side was discolored. I didn't remember seeing that before. Oh well, I continued with my screw removal. When I removed the top of the radio, I noticed a small point below the discolored area on the inner unpainted chassis that was about the size of a capital O. With the top off, I could not really see anything wrong with the radio, but was curious why the High Z terminals didn't work. I consulted a schematic, and the only difference between the inputs were the switch and a choke or inductor. I could see the inductor, it appeared normal. I decided to remove the circuit board and had to pull about 10 wire connectors of various sizes from the board. This is a struggle, as there wasn't always an easy way to start to pull the connector from its socket by using a screw driver to twist and pop the connector out of its locked position. I persevered and finally removed all the wires without damage. I removed the screws securing the board, the antenna connectors, and the power connector. Viola, I removed the board. Surprise, a large blacked area was found just under the High Z antenna terminal connection to the circuit board. Mostly soot, but some minor damage to the chassis metal was observed as well. I examined the bottom of the board and found that a ¼ trace that carries the High Z antenna signal to the inductor was neatly vaporized. The board was in excellent condition. The area that the trace occupied was unblemished, just the trace itself was gone. I cleaned the inside of the radio and the circuit board, soldered a wire to replace the trace, and reassembled the radio. Viola, the High Z terminal worked. The voltage path and its destruction seems to be as follows. The lightning strike was largely shunted to ground by the arrestor, but a surge continued on into the radio. Entering the radio, it jumped to the chassis just under the connector, the surge exited the radio on the side near the front panel close to the headphone jack. It jumped to my metal cased DVD player that was so close to the radio that it just about touched it, ruining that, somehow killed the clock radio that sat atop the DVD player, altered the TV nearby, which still works by no longer works by remote control. The surge entered the power system, and on another floor of the house, killed my cable modem, my wireless router, tripped the circuit breaker that fed the modem and router, blew 2 light bulbs in the house, and tripped 2 GFI receptacles. Questions: 1. The router and cable modem were on a different circuit from the power for the radio and DVD player. The Radio, the DVD player, and the clock radio were plugged into a spike suppressor strip. My house itself has whole house spike suppression at the power meter. I took the spike suppression strip apart to examine for damage, none was visible. If the surge entered the power system, making it to the lighting panel, why wasn't it shunted to ground by the power strip and the whole house suppression which was only about 3 feet from the panel? 2. Could it have been electromagnetic forces that destroyed the cable modem and router? 3. My equipment was not grounded or bonded. Surprisingly, the items that were destroyed near my Yaesu were items that had internal power supplies, so that a direct connection to the neutral was available. The items that were powered by transformers, including the Yaesu itself, were unaffected. I have a Uniden metal case scanner atop my Yaesu that was plugged in, and off with a mechanical switch (part of the volume control), this radio was unaffected. I also have a speaker system for my DVD and TV in the bedroom, this was also off by a mechanical switch and is transformer fed, this was also unaffected. Though the Cable Modem and Router, as described above, were always on, so is a great deal of other equipment in the house, including my main TV, DVD Player, AV Receiver, and so on. Why the preference for some equipment and not the other? 4. Lastly, how can I have an outdoor antenna and survive a strike without damaging equipment? I know that I should disconnect the wire when before a storm, which I always do, but this day was not supposed to have storms, and I couldn't get to the radio in time. Was the wire more likely to be struck since it had been grounded? Unfortunately, the strike came down my tree in the backyard, obliterating a limb at the top, (a very tall tree), and traveling down the outside, casting off bark as it traveled. The line in the bark comes right to the end of my wire antenna and no lower. Could a "leader" have been initiated by the antenna grounding system that actually led to the strike? The antenna itself was several feet from the tree, tied to the tree trunk with a rubber tube. If the wire had previously been removed from the radio and simply tossed onto the floor, what may have happened with the surge? Thanks for your comments, and be safe when lightning becomes an issue. Dr. Artaud |
You might as well give up trying to figure out lightning's
unpredictable ability to damage things. I had a direct hit on my longwire years ago and the antenna was indirectly grounded to the ham transceiver chassis. It still took out the output RF amp but did not damage the receiver at all. The antenna was totally vaporized and what was left of the ceramic insulators had the most beautiful copper plating around the holes! The same strike opened up a buried AC cable that controlled the yard lighting. That never did work correctly again and I was too lazy to dig it up for repair. I'm glad your FRG was not damaged any more than it was. I worked in high voltage physics years ago and it was facinating. Frank Tucson |
Dr Artaud wrote about his recent lightning strike, sorry for your damage
there Dr. I too, took a lightning strike a couple of years ago. Thankfully, because I took some precautions, my radio gear didn't get any damage but I can't say the same for the televisions, the cable modems, phones, etc. Questions: 1. The router and cable modem were on a different circuit from the power for the radio and DVD player. The Radio, the DVD player, and the clock radio were plugged into a spike suppressor strip. My house itself has whole house spike suppression at the power meter. I took the spike suppression strip apart to examine for damage, none was visible. If the surge entered the power system, making it to the lighting panel, why wasn't it shunted to ground by the power strip and the whole house suppression which was only about 3 feet from the panel? It may not have entered that way. Nearby strikes can induce a current into the power lines running through the house. At a distant point from the lighting panel the induced voltage could have started. As it courses its way through the house wiring looking for a ground point it will work through your appliances, etc. until it finds ground. Meanwhile, it may never make it back to the panel. 2. Could it have been electromagnetic forces that destroyed the cable modem and router? Absolutely. Every cable wire, every phone wire, printer cable, etc acts just like an antenna...picks up a voltage and carries it to the device. That nearby strike packs plenty of power to place a huge voltage on a wire. Most of these devices are low voltage and sucuumb to transients easily. 3. My equipment was not grounded or bonded. Surprisingly, the items that were destroyed near my Yaesu were items that had internal power supplies, so that a direct connection to the neutral was available. The items that were powered by transformers, including the Yaesu itself, were unaffected. I have a Uniden metal case scanner atop my Yaesu that was plugged in, and off with a mechanical switch (part of the volume control), this radio was unaffected. I also have a speaker system for my DVD and TV in the bedroom, this was also off by a mechanical switch and is transformer fed, this was also unaffected. Though the Cable Modem and Router, as described above, were always on, so is a great deal of other equipment in the house, including my main TV, DVD Player, AV Receiver, and so on. Why the preference for some equipment and not the other? Precisely what I had happen at my strike. The televisions were unplugged, but I neglected to unplug the cable tv channel boxes and when the strike entered via the cable it was all that was necessary to destroy 2 TV's, and 3 cable tv boxes, as well as the cable modem boxes. Oddly, the computers survived although one modem on a laptop could no longer be used. I plugged in a modem card and was able to work around that damage. Sometimes there's no rhyme or reason as to why some pieces of equipment survive while others don't. 4. Lastly, how can I have an outdoor antenna and survive a strike without damaging equipment? I know that I should disconnect the wire when before a storm, which I always do, but this day was not supposed to have storms, and I couldn't get to the radio in time. Was the wire more likely to be struck since it had been grounded? Unfortunately, the strike came down my tree in the backyard, obliterating a limb at the top, (a very tall tree), and traveling down the outside, casting off bark as it traveled. The line in the bark comes right to the end of my wire antenna and no lower. Could a "leader" have been initiated by the antenna grounding system that actually led to the strike? The antenna itself was several feet from the tree, tied to the tree trunk with a rubber tube. If the wire had previously been removed from the radio and simply tossed onto the floor, what may have happened with the surge? You need a SINGLE POINT GROUND SYSTEM, I'm not shouting there..just for emphasis. One and only one common ground system to which all equipment, and the entrance panel ground share. This way, if a voltage makes it onto your system, all points rise and fall at the same potential. It is a potential difference between points that allows current to flow. If all points rise and fall the same...no current flow, no damage supposedly. After my strike (which was strong enough to blow ceramic tiles to dust, and blow a 2 inch deep by 2 inch wide by 6 foot canyon in my concrete housepad under those tiles!) I contacted PolyPhaser and several other lightning companies, was invited to a 3 day lightning damage symposium by Florida Power to learn more and see the various company displays. I learned a lot. The results of which I have put up on a web site showing what I did to install more safeguards to my system. It is at http://www.knology.net/~res0958z/ I'm a bit to excess on this subject, once you've been hit you realize the vulnerabilities. And with a 65 foot tower out back, a mere 15 feet from the house, a bit more sensitive to the possibilities. Good luck with upgrading your system. Bill KC9CS Thanks for your comments, and be safe when lightning becomes an issue. Dr. Artaud |
On Sat, 02 Jul 2005 09:08:36 -0500, "Dr. Artaud"
wrote: The National Weather Service (NWS) screwed up on this one, they didn't even issue the warning until after the storm had wreaked its havoc. Nice work guys, Helen Keller could have done a better job. http://www.davisnet.com/productpics/big/7400dsk.jpg |
Surge suppressors that use the AC wall outlet for ground are essentially
useless against nearby lightning strikes since the distance and relatively small diameter wire conductor (16/18ga) to the main power panel earth ground rod looks like infinite resistance to a large current surge. Relatively smaller spikes on the AC line caused by appliance motors etc... can be shunted, but not a huge current induced by a nearby lightning strike. There is much good technical information at Polyphasor's web site which will keep you busy with your research for some time. "Dr. Artaud" wrote in message . 97.142... We had a rather bad storm the other day, lightning striking everywhere. As I left work, it hadn't started in that area yet, but I could see it off in the distance. I phoned my son to ask if he could disconnect the long wire antenna from my Yaesu FRG-100, but he said that the area very near my house already had a couple of bad lightning strikes. I told him to stay away from the radio. When I got home, most of the storm had abated, though as I traveled home I could see massive lightning strikes occurring in areas around me. The storm was accompanied by tremendous downpours, and flash flooding warnings were issued. The National Weather Service (NWS) screwed up on this one, they didn't even issue the warning until after the storm had wreaked its havoc. Nice work guys, Helen Keller could have done a better job. I get home, assess the trees in the yard, everything looks normal. Problem is that there is no power to the neighborhood, a condition that remains unchanged for the next 1 ½ hours. No problem, I can use my handhelds and portable shortwave radios. My wife arrives home, and as she is walking through the yard, she talks to the neighbor. The neighbor explains that the "wire antenna" in the yard was struck by lightning. I go out into the yard to examine the antenna and find it lying on the ground. I'm convinced that very high winds somehow pulled the antenna down. I picked it up and examined it, and lo and behold, some of the insulation is melted off. As I just installed an arrestor of sorts (it's an old one that I bought on EBay, it appears unused, a ceramic block with 3 terminals, 2 outer ones for the antenna wire, and a center one for the grounding wire) about 3 weeks ago, having had the antenna for a couple of years without it. The melted insulation extended to the arrestor, and the wire after the arrestor was normal in appearance. I examined the Yaesu, it appeared normal, but there was no power in the house yet, so I couldn't tell if operated ok. Being impatient by nature, I got the correct power cord, took the radio to the car, opened the car hood, and connected directly to the battery. The radio powered up, but didn't receive. It looked like it wanted to receive, when tuning through the frequencies every once in awhile I could hear a local station pounding through, overloading the radio, but even with a makeshift antenna I could not receive anything willfully on shortwave or broadcast AM. I gave it up as toast, and I called AES in Cleveland, explaining that it was lightning damaged. They said that I could sent it back, but that they would in turn send it to Yaesu for a proper assessment. He explained that Yaesu would try this and that, and probably end up saying that it was irreparable. Eventually the power came back on, so I took the radio and began to experiment with it yet again. When I tried it at the car, I used both antenna inputs, but I had forgotten to throw the switch on the back to use the low input impedance connector, so I tried the radio again after throwing the switch, placing the antenna wire in the Low Z connector, turned the radio on, and viola, the radio worked. But why doesn't the High Z terminal work. Since the radio had been exposed to such a large transient, I decided to disassemble it to make sure that nothing else is wrong. When I began to remove the screws to open the case, I noticed that the side was discolored. I didn't remember seeing that before. Oh well, I continued with my screw removal. When I removed the top of the radio, I noticed a small point below the discolored area on the inner unpainted chassis that was about the size of a capital O. With the top off, I could not really see anything wrong with the radio, but was curious why the High Z terminals didn't work. I consulted a schematic, and the only difference between the inputs were the switch and a choke or inductor. I could see the inductor, it appeared normal. I decided to remove the circuit board and had to pull about 10 wire connectors of various sizes from the board. This is a struggle, as there wasn't always an easy way to start to pull the connector from its socket by using a screw driver to twist and pop the connector out of its locked position. I persevered and finally removed all the wires without damage. I removed the screws securing the board, the antenna connectors, and the power connector. Viola, I removed the board. Surprise, a large blacked area was found just under the High Z antenna terminal connection to the circuit board. Mostly soot, but some minor damage to the chassis metal was observed as well. I examined the bottom of the board and found that a ¼ trace that carries the High Z antenna signal to the inductor was neatly vaporized. The board was in excellent condition. The area that the trace occupied was unblemished, just the trace itself was gone. I cleaned the inside of the radio and the circuit board, soldered a wire to replace the trace, and reassembled the radio. Viola, the High Z terminal worked. The voltage path and its destruction seems to be as follows. The lightning strike was largely shunted to ground by the arrestor, but a surge continued on into the radio. Entering the radio, it jumped to the chassis just under the connector, the surge exited the radio on the side near the front panel close to the headphone jack. It jumped to my metal cased DVD player that was so close to the radio that it just about touched it, ruining that, somehow killed the clock radio that sat atop the DVD player, altered the TV nearby, which still works by no longer works by remote control. The surge entered the power system, and on another floor of the house, killed my cable modem, my wireless router, tripped the circuit breaker that fed the modem and router, blew 2 light bulbs in the house, and tripped 2 GFI receptacles. Questions: 1. The router and cable modem were on a different circuit from the power for the radio and DVD player. The Radio, the DVD player, and the clock radio were plugged into a spike suppressor strip. My house itself has whole house spike suppression at the power meter. I took the spike suppression strip apart to examine for damage, none was visible. If the surge entered the power system, making it to the lighting panel, why wasn't it shunted to ground by the power strip and the whole house suppression which was only about 3 feet from the panel? 2. Could it have been electromagnetic forces that destroyed the cable modem and router? 3. My equipment was not grounded or bonded. Surprisingly, the items that were destroyed near my Yaesu were items that had internal power supplies, so that a direct connection to the neutral was available. The items that were powered by transformers, including the Yaesu itself, were unaffected. I have a Uniden metal case scanner atop my Yaesu that was plugged in, and off with a mechanical switch (part of the volume control), this radio was unaffected. I also have a speaker system for my DVD and TV in the bedroom, this was also off by a mechanical switch and is transformer fed, this was also unaffected. Though the Cable Modem and Router, as described above, were always on, so is a great deal of other equipment in the house, including my main TV, DVD Player, AV Receiver, and so on. Why the preference for some equipment and not the other? 4. Lastly, how can I have an outdoor antenna and survive a strike without damaging equipment? I know that I should disconnect the wire when before a storm, which I always do, but this day was not supposed to have storms, and I couldn't get to the radio in time. Was the wire more likely to be struck since it had been grounded? Unfortunately, the strike came down my tree in the backyard, obliterating a limb at the top, (a very tall tree), and traveling down the outside, casting off bark as it traveled. The line in the bark comes right to the end of my wire antenna and no lower. Could a "leader" have been initiated by the antenna grounding system that actually led to the strike? The antenna itself was several feet from the tree, tied to the tree trunk with a rubber tube. If the wire had previously been removed from the radio and simply tossed onto the floor, what may have happened with the surge? Thanks for your comments, and be safe when lightning becomes an issue. Dr. Artaud |
smoke wrote: Surge suppressors that use the AC wall outlet for ground are essentially useless against nearby lightning strikes since the distance and relatively small diameter wire conductor (16/18ga) to the main power panel earth ground rod looks like infinite resistance to a large current surge. Relatively smaller spikes on the AC line caused by appliance motors etc... can be shunted, but not a huge current induced by a nearby lightning strike. There is much good technical information at Polyphasor's web site which will keep you busy with your research for some time. "Polyphasor" You might want to spell their name correctly when recommending them. It is: http://www.polyphaser.com/kommerce_products.aspx Good products, we use them exclusively where I work, and their products work superbly. We get a lot of lightning strikes in the Gulf of Mexico area. They have saved us and the taxpayers many hundred's of thousands of dollars. Les Locklear Monitoring since ' 57 Located on the Gulf of Mexico http://www.hammarlund.info/homepage.html |
smoke wrote:
Surge suppressors that use the AC wall outlet for ground are essentially useless against nearby lightning strikes since the distance and relatively small diameter wire conductor (16/18ga) to the main power panel earth ground rod looks like infinite resistance to a large current surge. Relatively smaller spikes on the AC line caused by appliance motors etc... can be shunted, but not a huge current induced by a nearby lightning strike. There is much good technical information at Polyphasor's web site which will keep you busy with your research for some time. ---------------------- They can and do offer protection to the devices pluged into that outlet, if said device doens't have any other connection. By clamping the differential volatage they can really help. Not a cure all, but one more tool. Terry |
A station my father and I shared came to an end by lightning strike,
when I was no longer interested enough to repair it, just from a nearby strike, using a tri-bander beam with no particular ground path, just from general reception of fields, and it was enough to blow out a collins 75a4 and a kw linear final at the end of about 100' of coax, almost all of it indoors through conduits. That is to say, the antenna was not hit, but just the rf load was enough to damage things. I had outgrown ham radio, or whatever happens when you're 17, and moved on to other things; and my father was more of a swl than a ham at heart. He just bought another receiver and used its whip antenna. Well it was interesting at age 12 for a few years anyway. Lightning may be nature's way of telling you it's time for another hobby. -- Ron Hardin On the internet, nobody knows you're a jerk. |
Hello Dr Artaud,
You are very lucky. The damage could have been far worse. Your house could have burned down! As you have found out, the National Weather Service, while far better than in the past, is not as reliable as we should like. I personally have my shortwave antenna mounted in my attic so I am somewhat protected from a lightning strike to the antenna itself, but I ALWAYS make it a point to UNPLUG from the AC every piece of electronic equipment I own when I am not actually using it. It would be wise for you to do the same and, in your case, to disconnect your antenna(s). I know it's a pain, especially with computer routers, cable TV connections, etc., but, as you've found out, surge protectors do not afford 100% protection. I have whole-house surge protection as well as individual surge protectors - sometimes more than one - protecting my electronic components, but there is no substitute for unplugging. Many years ago my parents lost three televisions to a nearby (50 feet) lightning bolt; none of those TV's were operating at the time, just plugged in. Since then I have been almost "religious" in my care of my equipment, not so much for the equipment itself, but for the possibility of a fire as a result of a lightning strike entering my house and damaging electronic components. I must mention that there is absolutely no protection against a "bolt from the blue." (In other words, a lightning bolt while you are actually using your radio, computer, etc., when there was absolutely no warning.) You just have to have luck in that case. I NEVER use any electronic equipment when there is any weather threat whatsoever (determined by looking out the window - not depending in the NWS). Generally a thunderstorm lasts no more than a half-hour or so. During the storm I don't even use battery-powered radios; their circuits (especially the front end) can be damaged by a nearby lightning strike. But I hope you'll consider my "mantra:" UNPLUG, UNPLUG, UNPLUG! Best, Joe |
- You'll drive yourself batty trying to figure out why lightning does
what it does. - Might there have been *two* strikes? The one that hit your antenna & damaged the Hi-Z input, and *another* one that hit the power lines & damaged the other equipment? - Even if there was only one, that strike on the antenna would have induced some pretty high voltages on the AC line, which could have caused the damage to the other gear. - Around here you can pretty much assume there will be at least one thunderstorm within 100 miles of Nashville on any given summer day. From about early April through about late September, I leave my antennas disconnected when not in use. -- Doug Smith W9WI Pleasant View (Nashville), TN EM66 http://www.w9wi.com |
Doug Smith W9WI wrote:
- You'll drive yourself batty trying to figure out why lightning does what it does. - Might there have been *two* strikes? The one that hit your antenna & damaged the Hi-Z input, and *another* one that hit the power lines & damaged the other equipment? - Even if there was only one, that strike on the antenna would have induced some pretty high voltages on the AC line, which could have caused the damage to the other gear. - Around here you can pretty much assume there will be at least one thunderstorm within 100 miles of Nashville on any given summer day. From about early April through about late September, I leave my antennas disconnected when not in use. Hey Doug, I checked out your web site. Fascinating stuff especially the F2 skip recording from 1938 of the BBC, captured in N.Y. I managed a signal while in N.C. (near Cherokee) from a station in Kitchener, Ontario back in the 70's. This is a good time of year for that stuff too. Bill KC9CS |
"Dr. Artaud" wrote in
. 97.142: One huge collective thanks for all those that responded to this thread. I have read all the responses, and I appreciate the time that each of you have taken to respond. For the time being, I am going to use a white wire antenna draped around the very edge of wall where it meets the ceiling, tucked into the crevice, so that in the future it mat be painted over and lost in the confusion of all the other imperfections of our 100 year old house (believe me, it's old in the poor sense, not the classic "drink with your pinky in the air" sense). That should provide about 45 feet of wire, going, of course, in different directions. Will the orientation of the wire be an issue, or is it, in the Freudian sense, better for the antenna to be longer? ************************* * X * * * * * * * * * * * ***** ***** * Window * ***************** If by any chance this comes through correctly, the X = the radio. I will start there, go towards the window, and loop back eventually almost to the radio again just above it. The window protrudes over the roof slightly, that is why it is drawn offset. Any suggestions on why or why not this will work or not would be appreciated. Thanks again all! Dr. Artaud |
Dr. Artaud wrote:
"Dr. Artaud" wrote in . 97.142: One huge collective thanks for all those that responded to this thread. I have read all the responses, and I appreciate the time that each of you have taken to respond. For the time being, I am going to use a white wire antenna draped around the very edge of wall where it meets the ceiling, tucked into the crevice, so that in the future it mat be painted over and lost in the confusion of all the other imperfections of our 100 year old house (believe me, it's old in the poor sense, not the classic "drink with your pinky in the air" sense). That should provide about 45 feet of wire, going, of course, in different directions. Will the orientation of the wire be an issue, or is it, in the Freudian sense, better for the antenna to be longer? ************************* * X * * * * * * * * * * * ***** ***** * Window * ***************** If by any chance this comes through correctly, the X = the radio. I will start there, go towards the window, and loop back eventually almost to the radio again just above it. The window protrudes over the roof slightly, that is why it is drawn offset. Any suggestions on why or why not this will work or not would be appreciated. Thanks again all! Dr. Artaud In your drawing, it looks as if the wire will nearly loop around the entire room. Not a "loop" antenna in the strictest terms, but a random length wire in all directions. It should favor no particular direction, but you'll have at least a sizeable piece of wire up. It should work okay. If you've a very old house and it happens to have steam radiators you could make a connection to the pipe as well...more metal to collect signal. Bill KC9CS |
A few days ago,I read on the internet where lightning zapped a 9 year
old girl's mattress and set it on fire in Kansas.There was some metal things on the wall in her bedroom and the lightning was hunting for the metal.It can do the same thing to antenna wire in a room too. cuhulin |
|
"B. Otten" wrote in
: That is correct, that is what concerned me, that fact that it will have orientation in all directions. The radio works quite well with the 15 ft. stub that remains of the original antenna, it has been cut off outside the window. I would like to return to the outdoor wire antenna, but only after I can ground my equipment properly. I also need to redo the ground rod and connections, and purchase an arrestor that may be more successful in shedding the voltage of the strike/near strike successfully. I will also run the antenna on the other side of the yard, and terminate it well short of the tree, as the strike rode down the outside of the tree to the wire. I still don't know if it was a coincidence that I just put the arrestor on the wire 3 weeks ago, and that it may have saved my house, or if the presence of the arrestor is responsible for a "leader" climbing the tree and connecting with the bolt of lightning, encouraging it to the arrestor's ground. Regards, Dr. Artaud In your drawing, it looks as if the wire will nearly loop around the entire room. Not a "loop" antenna in the strictest terms, but a random length wire in all directions. It should favor no particular direction, but you'll have at least a sizeable piece of wire up. It should work okay. If you've a very old house and it happens to have steam radiators you could make a connection to the pipe as well...more metal to collect signal. Bill KC9CS |
Michael A. Terrell wrote:
there is one device which can be used on, at least, a receiving antenna with possibly the best protection which can be had, it is called a "coherer" google with coherer and "lightning protection" (yes, include the quotes) and you will see it has been deployed as such however, using it with a transmitter would probably NOT work, since the xmit signal would "set" the coherer and cause a direct short to ground a homemade coherer can be made with a couple of electrodes, metal filings and a plastic or glass tube and stoppers at the ends for the electrodes to enter through and both be within the medium of the metal filings, again, a web search should provide you with a visual diagram to construct one with ------------------ Thanks for the interesting search topic. I had no idea that""coherer" had any modern useage. I think I will stick with my PolyPhaser but I love finding out about new (or old) technologies. Terry |
wrote:
Michael A. Terrell wrote: there is one device which can be used on, at least, a receiving antenna with possibly the best protection which can be had, it is called a "coherer" google with coherer and "lightning protection" (yes, include the quotes) and you will see it has been deployed as such however, using it with a transmitter would probably NOT work, since the xmit signal would "set" the coherer and cause a direct short to ground a homemade coherer can be made with a couple of electrodes, metal filings and a plastic or glass tube and stoppers at the ends for the electrodes to enter through and both be within the medium of the metal filings, again, a web search should provide you with a visual diagram to construct one with ------------------ Thanks for the interesting search topic. I had no idea that""coherer" had any modern useage. I think I will stick with my PolyPhaser but I love finding out about new (or old) technologies. Terry You replied to a faked messge, written by a complete idiot. Check the headers. -- http://home.earthlink.net/~computersforvets/ Michael A. Terrell Central Florida |
Michael A. Terrell
You replied to a faked messge, written by a complete idiot. Check the headers. -- http://home.earthlink.net/~computersforvets/ Michael A. Terrell Central Florida ------------------------------- Sorry I didn't bother the check the header, I didn't know the children were acting up again. Some of the links sure appear to be interesing at first glance. Terry |
On 2 Jul 2005 16:35:48 -0700, "Joe Analssandrini"
wrote: Hello Dr Artaud, You are very lucky. The damage could have been far worse. Your house could have burned down! As you have found out, the National Weather Service, while far better than in the past, is not as reliable as we should like. We generaly don't have as much worry about lightning along the coast of Calfornia. But we do have the local power utility. Some years back, a worker dropped a multi-KV line across the local 110V line. It took out almost all electronics on at least one block, as well as burning out the motors on some refrigerators and blowing a lot of light bulbs which were not even turned on at the time. |
wrote:
On 2 Jul 2005 16:35:48 -0700, "Joe Analssandrini" wrote: Hello Dr Artaud, You are very lucky. The damage could have been far worse. Your house could have burned down! As you have found out, the National Weather Service, while far better than in the past, is not as reliable as we should like. We generaly don't have as much worry about lightning along the coast of Calfornia. But we do have the local power utility. Some years back, a worker dropped a multi-KV line across the local 110V line. It took out almost all electronics on at least one block, as well as burning out the motors on some refrigerators and blowing a lot of light bulbs which were not even turned on at the time. I wonder when some idiot power company employee, bored out of his gourd, will hook up a KV line to 110V and watch the houses blow up. Of course, he'd probably spend a few years in prison, possibly the rest of his life if he kills somebody, but at least he'll have fun doing it. I doubt that the people whose lives he destroys won't be laughing, and the judge won't like his explanation of "I was bored, Your Honor, so I decided to have a little fun". Several times when my grandparents lived out in the country, lightning hit their power pole and literally sent flames shooting out of the electrical sockets. Somehow, their house never burned down, although everything electronic was ruined and so was their wiring. My grandfather estimated that the lightning bolt must have been hundreds of GIGAVOLTS, if not teravolts. ----== Posted via Newsfeeds.Com - Unlimited-Uncensored-Secure Usenet News==---- http://www.newsfeeds.com The #1 Newsgroup Service in the World! 120,000+ Newsgroups ----= East and West-Coast Server Farms - Total Privacy via Encryption =---- |
I once saw some electric wires up there along them poles in
Harvey,Louisiana (N'Awlins area) that had got fried by lightning,it wasen't a pretty sight either. www.lightningstorm.com cuhulin |
| All times are GMT +1. The time now is 07:36 PM. |
Powered by vBulletin® Copyright ©2000 - 2024, Jelsoft Enterprises Ltd.
RadioBanter.com