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I wouldn't waste my money one of those. it might restart your computer but for 200$ you can buy 2000 feet of coaxial cable and make a real emp generator.
I wouldn't waste my money one of those. it might restart your computer but for 200$ you can buy 2000 feet of coaxial cable and make a real emp generator.
Typical coax capacitance is 30 pF per foot, so 2000' is about .06μf. It has a dielectric strength around 1kV. So the energy storage (.5*C*V^2) = 0.03 watt-seconds.
the thing with these "mini emp" devices and even the explosively pumped military EMP devices is they are subject to the inverse square law, i.e. field strength drops off at a rate of the inverse square of the distance. a "real" EMP is generated over a large portion of the earth's magnetic field, so essentially the distance within the peak effective area is close to zero. the little handheld "EMP" generators are great for magnetizing screwdrivers, and shooting screwdriver bits and nails across a room, but not much else. i know, i've played with the idea (several hundred thousand microfarads at 40V dumped through a coil of 12ga wire using a motor contactor to be precise) .
i'm more worried about my own government violating it's constitution and running amok, than i am about some foreign government EMP'ing us back to the iron age....
Typical coax capacitance is 30 pF per foot, so 2000' is about .06μf. It has a dielectric strength around 1kV. So the energy storage (.5*C*V^2) = 0.03 watt-seconds.
another source says
RG-8 with the hard polyethylene is used in commercial 40Kv supplies.
I personally have used cheap 75 ohm cable tv coax (aluminum wrapped foam, stainless steel braid, copper plated steel conductor) (i forget the number)
at 10Kv, I don't know what it breaks down at.
it also looks like everyone thinks it breaks down at just 2kv so they don't use it near that.
one poster says except for defective batches it doesn't break down below 15kv.
ethernet cable will handle 6 KV across the insulation btw.
This is a "DC Link" cap, designed for high voltage (1kV) and high discharge current. It has low-inductance: .04μH. That's less than what just one foot of the coax has. Low inductance is very important for the super fast rise-time an EMP generator has to have. It's also low-esr: .0013Ω, which at the 1kV rating could give you a crazy high peak current and wattage (with the appropriate switch and coil).
well, i'm sure you can run the numbers and tell me what the current will be 10 nano seconds after you short that capacitor out through a 200 ohm antenna
and then compare it to 5x 40 pieces of 10 foot long coaxial cables configured as a marx generator to deliver ~200kv
i've messed around with a 2500 joule capacitor bank that has no problem dumping all of its energy in all of 20 uS, but it is 3 orders of magnitude too slow to be of much interest for an emp gun.
it could be used to precharge an explosively pumped flux concentrator though, which could be diy'd.. however what do you do with the output? most of them feed black boxes that make gigawatts of microwaves... and that technology is classified, and will be for sometime.
*they* are still using big klystrons for things like particle accelerators and such.
one topic i have been looking into is building a traveling wave tube amplifier for household microwave oven magnetrons, which can be pulsed at several times their ratings.
The problem with EMP's is they're designed to destroy infrastructure not people, this is not what an invading army wants to do, they want to destroy people not infrastructure, I'd be far more worried about chemical weapons which are far more practical to this ends.
during the cold war, the first objective was to cripple any retaliation. so an EMP would have been used as part of a first strike since it's primary purpose would have been to wipe out communications, command and control. the accompanying targeted weapons would then strike missile silos, hardened command locations, and airbases, etc... (quite possibly ALL military installations and governmental buildings). some of the experiments conducted with nuclear weapons during the 50's and early 60's were to study the effects of detonations on delivery systems (missiles and aircraft mostly), as well as tracking systems and communication systems. some of the side benefits of these experiments were the discoveries about how the ionosphere works. the Starfish Prime shot not only created an EMP that knocked out power in Hawaii, but also created an artificial aurora as high speed electrons got trapped along magnetic field lines, which were detectable up to 6 months afterward. there's an interesting series of declassified training films from that time period which is up on youtube. just do a search for "declassified nuclear test films".
The thing with an emp esp a smaller one is that it lends itself to diy, the sort of thing terrorists could use to give us headaches, you could shut an airport for a day quite easily with an effective device, and not killing anyone would make more willing to do it.
Yep chemic weapons worry me more, a dose of sarin is less pleasant than a kw of rf.
I don't think an airport would be easy to shut down, and "not killing anyone" in the process would be even more difficult. You would be lucky to fit an EMP generator like that inside a semi tractor-trailer, it would cost a butt-ton of money, and it would make a big damn explosion when it went off. Planes would crash. Cars would crash. Fires would start. People near the truck would die from the explosion. There would be no communications to direct rescue workers and firefighters. People would die.
Conventional explosives (and a distant possibility of chemical or biological agents) are the weapons terrorists will seriously consider. By the time you engineer, build, and pay for an EMP generator big enough to shut down an airport, you could have had a couple hundred car bombs, maybe more.
the goal of a terrorist is to overturn our nation's Costitution and replace it with their own totalitarian version of government (whatever that may be... in the case of the 9/11 hijackers, a religious oligarchy). everytime terrorists instigate a knee-jerk reaction from our government, we lose some of our freedom, and in the process, our government becomes more totalitarian.
the goal of a terrorist is to overturn our nation's Costitution and replace it with their own totalitarian version of government (whatever that may be... in the case of the 9/11 hijackers, a religious oligarchy). everytime terrorists instigate a knee-jerk reaction from our government, we lose some of our freedom, and in the process, our government becomes more totalitarian.
Well maybe your right I hadnt considered it that much.
I spose a bent electronics enthusiast could make a device that would cause more headaches than airport closures.
I can't abhor the concept duffy. Early science fiction mixed political and social anxieties together in a bottle and delivered some of the best early fictional productions known to writing history.
Remix history with myth shake and you could pour out a really good movie that has pertinent moral and historical references well blended, the directors/production is really top notch. I hope to see it's fruition.
Yes you might be right.
These days there are more and more people that want to do silly things, which is a little worrying when you think that technology is advacing to the point where its possible to make effective weapons in ones garage.
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