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Posted: 5/17/2006 2:28:39 PM EDT
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I have been purchasing a lot of LED lights or upgrade kits to replace my old maglites, mostly AA minimags. I just purchased a Surefire X200A Weaponlight to use with a new pistol we bought for my wife. It uses an LED instead of a conventional bulb. Many (all?) LEDs use a small microcircuit to control battery drain to keep the light level uniform for as long as possible. Out of curiousity I sent an email inquiry to Surefire, hoping that, because they sell to the military, they would have hardened their circuitry. Here is the exchange: I just purchased an X200A weapon light. Has Surefire tested its LED lights to see if they are EMP proof? I know many LED lights now use a microprocessor of some kind to regulate light output - does the X200A? This would make them vulnerable to failure if they were exposed to EMP, either in a tactical scenario or via an upper atmosphere nuclear explosion. Thanks, (Me) Reply: Sir, The model X200 lights are nor EMP proof. If you have any further questions please call us at 800-828-8809. SureFire strives to provide World class customer service to all of our customers. SureFire technical support 1-800-828-8809 1-714-545-9444 1-714-545-9537(FAX) I assume this applies to all LED lights. This is a problem in my mind, because I look at a high altitude nuclear blast/EMP attack as one of the three likeliest high casualty/affect lifestyle SHTF scenarios, along with man made and naturally occurring disease pandemics. Edit/Delete Message |
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I have been of the understanding that electronic devices connected to internal or external powersupplies are most at risk from an EMP event and that in most cases those electronics isolated from electric charge will often survive. PCBs get 'fried' by their own power supplies as a result of the EMP event. To achieve this your electronic equipment would have to be within about 30 miles of the blast. If the blast was at high altitude electronic equipment needs to be connected to fairly long unprotected exposed conductors in order for enough voltage to be induced to cause breakdown. An EMP event is like a lightning strike - good surge protection is sufficient in most cases for mains powered electronic equipment. That includes surge protection for aerials and data lines. Regarding flashlights - it is likely that only flashlights which are switched on, and extremely close to the EMP event are at risk of being damaged. If this is not correct please let me know! Al :) |
That's fine, that's the choice most make. However, in evaluating threats to our country, it is the one way that an egomaniac ruler running a country say, like, North Korea or Iran could, in one stroke, cripple the most powerful country in the world, a country that is directly opposed to them. They could accomplish this without directly killing any Americans or touching American soil. And the wrong kind President would hesitate to make an appropriate response, which would be to incinerate their entire country. Ever notice how the Bush administration has pushed to get some kind of missile defense system in place, against a lot of skepticism and oppostion from the Democrats and the chattering classes? technology is a wonderful thing, but it serves to make us vulnerable down to the very basics, like a flashlight. |
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I'm so sure AL is a high priority target for EMP too I’m sure Osama Bin-sandy is sitting there saying you know what, lets launch a tactical EMP strike to bring doom to ElmerFudd and his puny little flashlight. Seriously though this might be a little too tinfoil hat |
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A nuclear weapon exploded 300 miles above the U.S. would cover the entire country line of sight and subject all electronics to possible EMP damage, even in AL. BTW, a good rule of thumb is to actually know something about the subject at hand before commenting. My thread was posted as a consideration for those who might buy gear with an eye toward the worst case scenario. If your among the great mass of folks who believe Wal-Mart will always be there for you and the kids and the lights will always turn on when you flip the switch, then this is a not a consideration you would bother thinking about. |
If this is so then my information is incorrect. It would be useful to have clarification on this. Al |
| The literature I have read has a wide variation of opinion on the susceptibility of modern electronics. Part of the problem is the lack of actual test data with modern electronics with an atmospheric explosion. Some predict catastrophe and some say it is all hype to extract more research $ from the federal milk cow. My readings have also suggested that devices plugged in to power lines or antennas would be more likely to be damaged than unplugged devices. |
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This is a strange question, and between it and the EmerFudd a little flame is not suprising. But I do have a ansewer. When I first got in the service back when it was called the cold war the drill for electronics (radios, NVG's and the like) and EMP was to bury it at leat a meter if you could. The dirt would act as a crude but effective shield. If that is really someting you are looking at cache with back up LED heads along with what ever electronics you can aford to put in. Then dig up when SHTF. As for my self (pause as I reach for my tin foil hat), I have considered this option for electronics in general and acted, but will not post on a open forum.hug.gif |
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The information on hi altitude EMP is correct. An explosion in the outer atmosphere generates more emp, and the whole CONUS could be line of site from the blast. EMP is just a super broadband pulse of energy, and has the same propagation issues as cb, AM or VHF radio. Having said that, the length of the antanna proportional to the surge (up to a point, at some point (in the mile range) losses from propagation along the antenna can be as great as the increased energy. So for a surefire light, you are talking about a manimum antenna length of 6-8 inches. This doesn't allow for much of a surge, and the lack of a ground connection or conterpoise means the return path is through the batteries. If the light is off that is blocked. were it on, I wouldn't worry about the LED, but the internal power supply some lights use to maintain LED output. I think it's pretty much a non issue. It is expected that handheld radios would surive, and they have far more delicate imput circuitry. |
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So my understanding is correct? - EMP creates a surge in powerlines and antenna which could damage unprotected electronics sensitive to power supply surges. Portable electronic devices, especially those which are not powered at the time of the EMP are unlikely to be damaged. Al |
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A simlear thread pop up on the night vision forum. They listed this website with some intresting info: www.aussurivialist.com/nuclear/empprotection.htm So it looks like a padded ammo can and no battaries in whatever electronics might work. I was being serious about the buring stuff. A FTX when I was a PFC we wraped up some radios and other electronics in plastic and burried them. Then I came across it in BNCO in 1999 in a FM (do not remeamber which one) durring the NBC portion of the course to bury electronics (that is you get a warning of a nuclear attack WTF?). Of course in the same section they talk about once you get yourself in to cover to grab your nuts as you get nuked (from what the over presure?, when I got hit by IED,rockets and mortars the overpresure never affected the nuts). Early on in the military I came to the conclusion that all the military manuels were writen for people with a 8th grade education by people with a little less education. But given that a suprising amount of it has proved to work. |
This is standard procedure for me in any SHTF situation, especially one involving nukes. |
That's my SOP for Friday nights! 
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Sorry to say I did not follow SOP and in all SHTF situations I've been in, not once did I grab my nuts (I did check them once, after things had calmed down, when I was checking if I had picked up any extra orifices). Should fix that hole in my trianing before the North Koreans let loose on us. By the way my 3 sure fires(including 1 LED) that went through various SHTF situations from over presure just fine. While I did approach this subject a bit tounge in chech. For some people (and not all of them wearing tinfoil hats) EMP is on their threat board. And to prepare for that you can put your LED flash lights or other electronics in metal ammo cans with padding so your electronics do no touch the metal of the can. Or for the tin foil hat crowd (or those setting up caches any way) bury them 3 feet as the by the book from a old Army FM. I suspect most people have read this thread for laughs rather than knowlegde. |
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If you feel strongly about EMP, store your electronics in one of these. faraday cage |
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Does this mean that I have to worry about my incandescent light filaments acting like an antennae and flashing???? LED lights are better protected electrically than incandescent, at least all the ones I've taken apart. Most LED lights are made to handle a couple amps of current. I'd wager that most lights are more likely to die due to parts other than the processor from dying. It is unlikely that an EMP would generate that much umph to an electically isolated system. Most of the Surefire LED's I've taken apart were dumber lights, which means more robust. They all also have a nice metal body that acts as a ground. It would take a very powerful EMP to knock out your flashlight. If it came from a nuke, you probably look like a potato chip and lights wouldn't be a concern. |
Ok, I see. You've been watching too much TV. Futureweapons perhaps? I saw that episode and I won't watch another- EVER!! I like how they tried to scare people into fearing EMPs with that ACTOR who pretended to be some expert for congress. That's the fucker that told you that an EMP blast 300 miles above the earth could cover the entire US of A. Do you know how high 300 miles is? Did you know the edge of space is at 62 miles? Iran might develop nukes but I don't think they will get them 300 miles up over the USA. no offense to you, of course... Besides, LEDs themselves don't use electronics- not all of them anyway. |
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If you are truly and honestly worried about EMP damaging things you'd like to have around in your BOB/SHTF collection, there's a pretty simple solution. Build a Faraday Cage and put your SHTF stuff inside it. You can build a small one (closet sized) cheaper than you might thing, and if you ground it properly, that's all the EMP protection you need. When electronics are "EMP Hardened" that's all they do with them anyway -- they put them inside miniature faraday cages. Grounding isn't a requirement for operation, but unless you have some linesmans gloves, you aren't going to want to open an ungrounded FC after a reasonably powerful EMP. |
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A serious answer to a somewhat humorous question, but... If you keep your pistol & light in a metallic gun safe, then it's already inside a rudimentary Faraday Cage. As far as the linesmans gloves, my understanding of EMP was that it worked similarly to an AC generator... changing magnetic flux induces a current (which creates a new magnetic field, inducing current in nearby objects... etc, etc). In other words, you're not building a charge on the cage, just moving the charge that's already there. Once the magnetic flux was stable, there wouldn't be any more current, therefore no danger. EDIT: Although it might be a little toasty to the touch, which may have been what you were implying. h.gif I could certainly be wrong, though... E&M was not my strong point. |
No, it's really an electric charge much higher than what is normally present. EMP is the result of gamma rays from the nuclear blast knocking electrons off the different molecules present in air. The free electrons flying through the air are the EMP. Conductors will of course conduct these electrons and build up an electrostatic charge very quickly. If the conductor isn't grounded, the static charge will remain until it is. You don't want to be the ground wire, so either ground it properly, wear the gloves, or hope you can wait a few days for it to dissipate. Cool to see a level of intelligent discussion on a rather "far out" edge case in the SHTF playbook though. ;) |
Ah, I see. Learn something new every day and all that. Thanks for the explanation! |
Probably, yeah.. good idea with the combination lock, but ground the whole thing anyway because it can still pick up a rather impressive static charge. A lot more than you get shuffling your feet over the carpet, and the shock would be equally impressive. ;) |
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