Posted: 12/12/2008 6:01:11 PM EDT
| So say a person wanted a spare Aipoint in their BOB in the truck and have it be protected from an EMP. How would you do it as efficiently as possible? |
|
Quoted:
So say a person wanted a spare Aipoint in their BOB in the truck and have it be protected from an EMP. How would you do it as efficiently as possible? IIRC an EMP blast or charge will drain any device made for storing energy or electricity. Maybe some type of heavy rubber coated metal case burried, or stored below ground. Not sure, but tagged for an answer. |
|
Any box that completely contains the device you wish to protect and is made of a material that will block RF will do. The box should be lined with a non conductive material like foam. Any metallic strongbox lined with foam will protect the vast majority of electric devices from an EMP surge unless you are extremely close to the surge.
Most devices that suffer will be attached in some fashion to an length of metal that can act as an antenna. Power lines can do this as can other metallic wires of more than a few feet in length. Discrete objects like an Aimpoint optice etc. would require you to be quite close to the burst for it to have enough power to affect it. Your PC however being plugged in to a power source plus the internet is much more vulnerable. |
|
The best protection for any electronic device is a Faraday cage, which is a continuous metal enclosure. Any discontinuities in the surface (seams) will act as a slot antenna, and overlapping edges will act as what is known in EE parlance as a waveguide cutoff.
In all honesty, I would not expect an Aimpoint to be particularly susceptible, as it has no external wiring to act as a(n) (receiving) antenna for the incoming EM Pulse. If you're still concerned, get an ACOG or BUIS. (I'm not particularly concerned) |
|
Quoted:
Any box that completely contains the device you wish to protect and is made of a material that will block RF will do. The box should be lined with a non conductive material like foam. Any metallic strongbox lined with foam will protect the vast majority of electric devices from an EMP surge unless you are extremely close to the surge. Most devices that suffer will be attached in some fashion to an length of metal that can act as an antenna. Power lines can do this as can other metallic wires of more than a few feet in length. Discrete objects like an Aimpoint optice etc. would require you to be quite close to the burst for it to have enough power to affect it. Your PC however being plugged in to a power source plus the internet is much more vulnerable. Please read the above links. |
|
The subject of EMP comes up a lot, so here's the canned response:
The amount of damage that can be produced by HEMP (EMP produced by a high-altitude nuke detonation - the only kind of EMP that is likely to be encountered by anyone living more than a few miles from a high-value target) has been GREATLY exaggerated on the internet. EMP does its damage by inducing a very brief, high-voltage spike in electrical devices. This spike can be strong enough to burn out wiring, "punch through" the thin semiconductor layers in transistors, diodes and computer chips, or cause the software in computer-controlled devices to go haywire. However, the strength of the electrical spike induced in any electrical device by a HEMP burst is dependent on the length and physical orientation of any conductors connected to the device. Long conductors (i.e., AC power lines, phone lines, big antennas, etc.) receive a significant amount of the EM pulse; short conductors do not. In devices that aren't connected to any long conductors, almost no electrical spike is generated due to EMP, and thus the device is unlikely to be damaged. Most small electronic devices (i.e., cell phones, portable radios, PDAs, laptop computers, digital wristwatches, flashlights, electronic combination locks on safes, red dot sights, etc.) would fall into this category - The few inches (or fractions of an inch) of conductors present in these devices is simply too short to intercept any significant amount of the EM pulse, and thus no damaging voltage spike is generated within them. Similarly, the short length of the wires present in most vehicles (automobiles, motorcycles, ATVs, etc.) also intercepts very little of the EM pulse - and thus, is unlikely to be damaged. Also the wiring in most vehicles is partially shielded by the vehicle's metal body (thereby further reducing the strength of a voltage spike induced), and all vehicle electrical systems are designed to deal with the high voltage spikes normally produced by the ignition system, motor brushes, relay and solenoid coils, etc. Several practical examples: 1. During the Starfish Prime high-altitude nuclear test conducted on July 9, 1962, it was reported that EMP effects caused damage to streetlights in Hawaii (some 930 miles away), and yet portable radios located on Johnson Island (located immediately under the nuclear burst) were undamaged. Explanation: The portable radios lacked any large antennas or other connections to long conductors, and thus didn't receive enough of a spike to be damaged. 2. The American Radio Relay League (ARRL) re-printed a series of articles (originally published for the National Institute of Standards) that described the effects of EMP on various communication equipment: Intro to EMP EMP Protection Devices EMP Implications for Communications EMP Protection for Communications These tests demonstrated that even very sensitive equipment is unlikely to be damaged by EMP, provided that the equipment doesn't have any connections to long conductors. BOTTOM LINE: Most portable electronic devices (including Aimpoints) stand a good chance of being usable after a HEMP burst, even without taking any special precautions beforehand - and ditto for motor vehicles. The electric, telephone and cable utilities will probably sustain major damage (as will many devices that happen to be connected to them when the EMP occurs). However, protecting these utilities from EMP is beyond the abilities of any one person. For further reading on the subject: Report of the Commission to Assess the Threat to the United States from Electromagnetic Pulse (EMP) Attack (in PDF file format). |
|
Quoted:
It wouldn't matter. An EMP the magnitude necessary to disable electronics on a massive scale would probably come from a nuclear device, which would make us all very dead. Unless they set one off in the atmosphere, you don't get as much radiation, but you get the EMP. Some consider it the ethical way to nuke a country. |
|
Quoted:
Quoted:
It wouldn't matter. An EMP the magnitude necessary to disable electronics on a massive scale would probably come from a nuclear device, which would make us all very dead. Unless they set one off in the atmosphere, you don't get as much radiation, but you get the EMP. Some consider it the ethical way to nuke a country. Wasn't there a discussion about the Tesla therory and EMP on this subject? I will try and find it. |
|
Quoted:
Quoted:
It wouldn't matter. An EMP the magnitude necessary to disable electronics on a massive scale would probably come from a nuclear device, which would make us all very dead. Unless they set one off in the atmosphere, you don't get as much radiation, but you get the EMP. Some consider it the ethical way to nuke a country. A high-altitude nuke burst doesn't produce any radioactivity that reaches the ground. The sole purpose of detonating it is to generate EMP - which only damages electrical devices - not people. 
However, the effects of just one burst can be very wide-reaching - If it detonates at a sufficient altitude over the midwest, most of the entire continent would be feel the EMP effects. |
|
Quoted:
Making electronic optics EMP proof...is it doable? http://www.ar15.com/forums/topic.html?b=10&f=17&t=618254 http://www.ar15.com/forums/topic.html?b=10&f=17&t=613318 Take the time to read these posts, wealth of knowledge... however... "Cliff Notes" for Friday night drinkers, the lazy and those with ADD (Thanks to CWO for taking the time in posting in Survival Discussion): Quoted:
I have not posted on this subject in a long time. One reason is that ArJedi does a very good job of instilling realism and facts to these threads and second, because I have written a lot in the past and no-one ever seems to want to search the archives. There is some very good material on this subject there. I have worked in EMP application engineering and field testing before and my positions are based upon that experience. My work was in "cannot fail" applications - so my views are probably flavored somewhat by that mentality. That experience (which is by no means the final say on this subject) has taught me one basic truth: If you haven't actually tested it - you don't really know what its going to do. Generalist statement: I spent more time on the EMP test range than I ever wanted to. I came away intrigued by what systems/devices survived repetitive nominal tests (HEMP simulations of predicted real-world field strengths) - and which ones didn't. Most surprising were commercial off the shelf electronics (radios, generator sets with solid state ignition systems etc etc etc survived a LOT of hits. One day we had a little "accident" and left a tested system's door open roughly 1/4" while the EMP system charged. When the 10 second discharge horn sounded we looked over and saw the door ajar. We ran like hell to slam it shut but were about 1 second late. The damage to one electronic switch frame (roughly 25 PCBs) was absolutely catastrophic - damage was >$150,000 IIRC. (The manufacturer - a large, well known company replaced it for free - in order to get the damaged parts for engineering analysis). My pager was never affected. Ditto for car ignition systems nearby, AM/FM radio etc. The oft-repeated statement about system/components lacking long conductors are considered "safe" –– well that isn't my experience. None of what I ever damaged had ANY external conductors leading to it (all penetrations were fiber through waveguides). I have little doubt that systems WITH long conductors connected are quite susceptible to damage. I had a fair amount of experience with these applications and planning to live and operate in that hostile environment. Here is my recommendation (which you probably don't want to hear). Forget about it. Don't try to protect small consumer devices with jury-rigged measures that you have no way of knowing their succeptability or the effectiveness of the protective measure. If you want to take some crude measures - fine. But stop and ask yourself where you are going to get electricity or network connection on the 1st/4th day (or the 4th week). Who is going to be broadcasting? (within the event footprint anyway). Look at the bigger picture and ask yourself what assumptions you are making and whether they are well-founded considering the event. There would be little if anything to do with a laptop that I can think of). I used to plan for such days and I'll tell you that from a private citizen viewpoint - planning, protecting and equipping for EMP is IMO largely a waste of resources, time and thought. If there is an EMP event that is truly damaging (and IMO the chance of that is very, very, VERY tiny) - you are going to have MUCH larger things to worry about than your radio working or your car starting (where are you going to get gasoline pumped?). It is (IMO) better to concentrate on other preparations that are far more likely to be needed and USEFUL through a wide range of emergency situations - instead of doing something halfway hoping that it might be effective in the 10,000/1% chance than a HEMP event should ever occur during your lifetime. YMMV |
|
Quoted: Making electronic optics EMP proof...is it doable? http://www.ar15.com/forums/topic.html?b=10&f=17&t=618254 http://www.ar15.com/forums/topic.html?b=10&f=17&t=613318 That is about my attitude, I was just jonesing for a good arf teotwaki thread. |
| Here's a link to the TACDA Lesson on EMP's - I'll let the guys on here that know more about it then I do tell me what they think. |