Does anyone know if the EMP device on jhonbus' site works? It dosent specify the voltage. I have tried to contact him but cant. Any thoughts would be appreciated. Thanks.
Here is the URL:
<a href="http://www.geocities.com/jhon_bus/" target="_blank">www.geocities.com/jhon_bus/</a>

The HV source is actually a big capacitor bank. The diagram on the site has appeared in New Scientist before now. No details were given in the article about exact specifications, but it did mention that around 2Kg of TNT is used as the explosive. I've read in another article (no, I don't remember where) that it could be put together by a terrorist for around �400. This sounds about right to me.

If you do decide to build one, and in case it actually works, don't set it off in a populated area or you WILL be in a world of shit. Doing it near a hospital could kill a lot of people.

I upploaded a file named EMP.pdf to the forum-ftp some time ago.

Thanks guys, I am assuming that one would take out an alarm system, but for how long? Would it be around 30 seconds?

Thats just a guess....

It would take out all the electronics within a 500m radius, permanently.

</font><blockquote><font size="1" face="Verdana, Arial, Helvetica">quote:</font><hr /><font size="2" face="Verdana, Arial, Helvetica">A Poor Man's E-Bomb
An FCG(Flux Compression Generator)is an astoundingly simple weapon. It consists of an explosives-packed tube placed inside a slightly larger copper coil, as shown below. The instant before the chemical explosive is detonated, the coil is energized by a bank of capacitors, creating a magnetic field. The explosive charge detonates from the rear forward. As the tube flares outward it touches the edge of the coil, thereby creating a moving short circuit. "The propagating short has the effect of compressing the magnetic field while reducing the inductance of the stator [coil]," says Kopp. "The result is that FCGs will produce a ramping current pulse, which breaks before the final disintegration of the device. Published results suggest ramp times of tens of hundreds of microseconds and peak currents of tens of millions of amps." The pulse that emerges makes a lightning bolt seem like a flashbulb by comparison.</font><hr /></blockquote><font size="2" face="Verdana, Arial, Helvetica"><img src="http://popularmechanics.com/science/military/2001/9/e-bomb/images/5.jpg" alt="" />

To ignite an E-bomb, a starter current energizes the stator coil, creating a magnetic field. The explosion (A) expands the tube, short-circuiting the coil and compressing the magnetic field forward (B). The pulse is emitted (C) at high frequencies that defeat protective devices like Faraday Cages

You may wish to check out the links I provided in this topic as it relates to EMP.

<a href="http://www.roguesci.org/cgi-bin/ewforum/ultimatebb.cgi?ubb=get_topic;f=4;t=000274" target="_blank">http://www.roguesci.org/cgi-bin/ewforum/ultimatebb.cgi?ubb=get_topic;f=4;t=000274</a>

<a href="http://www.powerlabs.org/uwavexp.htm" target="_blank">microwave gun</a>
I think i've posted this before. Get an old microwave and you can turn it into a deadly EMP weapon.

Take em' out permanently.......shit.
Thanks heaps guys the info is very informative.

Just wondering, what types of damage could an EMP device cause to you (besides the explosion)? I would think that you would need to set it off remotly. Also, is it possible to make some kind of smaller version to take out something like an alarm system? There must be some way to down size the range of it, right? I'm assuming this would also effect flashights and other portible electronics, right?

it will destroy anything with wires, circuits and electrical components inside. would batteries themselves be affected?

I should imagine that the EMP would do screwy things to your brain http://www.roguesci.org/ubb/icons/icon22.gif

EMP only affects integrated circuits. If it has it chip, it dies. Simple electrical (flashlight for instance) or vacuum tubed circuits are immune to EMP from anything less than a multi-megaton nuke exploded in space.

As for people, we're unaffected by it since it's just a magnetic field. But microwave or HERF weapons....that's another story.

I'm going to do some research on smaller EMP devices, one that has a 50meter range would be good for taking out alarm systems.

Also, that microwave gun, how far away from it should I be to have total safety from the magnetron?

And, when pulling apart a microwave, can I be injured if it is not switched on? I was told that they have uranium diodes in them, can they irradiate me?

Any assistance would be very helpful as I want to learn alot about microwaves before I even think about fucking around with them.

Say this "Microwave gun" was to work what would the effective range on electrical equipment be and would it be destroyed as soon as I switched the weapon on?

I dont want to end up like the message icon above!

Microwaves have at least one large capacitor, which will easily kill you if charged up. It will be on the high voltage (2kv+) side of the transformer. Short it out with a well insulated screwdriver. Other than that, there's no need to worry about radiation etc.

If you're serious about microwaves, you should read an introductory book about them because it's a very large subject. I have one which I'd reccomend if I could find it! I'll try and dig it out later. I warn you though, there's a lot of theory about waves that you'll need to know about already.

Just look at <a href="http://www.powerlabs.org," target="_blank">www.powerlabs.org,</a> that's the site the gun is on. They have extensive info on high voltage and EMP.

</font><blockquote><font size="1" face="Verdana, Arial, Helvetica">quote:</font><hr /><font size="2" face="Verdana, Arial, Helvetica">but it did mention that around 2Kg of TNT is used as the explosive.</font><hr /></blockquote><font size="2" face="Verdana, Arial, Helvetica"> </font><blockquote><font size="1" face="Verdana, Arial, Helvetica">quote:</font><hr /><font size="2" face="Verdana, Arial, Helvetica">It would take out all the electronics within a 500m radius, permanently.</font><hr /></blockquote><font size="2" face="Verdana, Arial, Helvetica">I think an explosive like RDX or PETN would be extremely suited for this type of use.One could use about 500 grams of PETN/RDX to almost have the same effect however the actual device would be a great deal smaller and lighter,also easier to conceal. :D
Im sure if you knew what you were doing one could be produced for alot less than $800 Australian dollars,depending on the prices of your chemicals. :p

It's not the chemicals that would be expensive, it's the capacitor bank. Since a very fast rise time is required to get maximum effect, high voltage pulse caps must be used. These are expensive, and generally not available through the average electronics supplier. I don't think electrolytic caps would do the job, but I may be wrong.

Testing would also be required to get the timings right.

Electrolytic capacitors are much too slow for a priming pulse in a FCG, you need caps with a very low ESR and short pulse length

You'd also be looking at a pretty hefty amount of electrical engineering work.

<small>[ July 18, 2002, 01:36 AM: Message edited by: Zambosan ]</small>

if you wanted, say, a 5m radius one, could you use photoflash capacitors from disposable cameras? and how small do you think you could get this down to? hand held, lob-it-through a window size? burgler alarms are going to be a pretty pathetic barrier if these ever get into general circulation. And there could be a big price for one of these on the black market. If one of us does get a reliable one, they could be a millionaire in 6 months selling it to burglers!

Burglar alarm = loud alert to the police. EMP device = very loud alert to police, + additional (and far more serious) laws being broken.

I don't see why it couldn't be scaled down though. But photo flash caps are electrolytic, so they wouldn't be any use. I highly doubt a grenade sized device would be possible, at least to the amateur with poor funding.

<small>[ April 29, 2002, 07:57 AM: Message edited by: J ]</small>

You can forget about making one without housands of dollars in test equipment let alone alot more for a small one that is not likely to work. the caps in photoflash cameraa are electrolytic but that isn't the reason why they won't work, the capacitors need to discharge very fast and while they are discharging the detonation wave needs to travel down the conductor and the pulse of electricity needs to be millions of amps and happen during the discharge, so your capacitor bank needs to discharge fast and drain very quickly witch means very little resistance, and high precision in the timing of the detonation. nothing short of a 250 pound pulse cap and a half million dollars worth of equipment. (double that if you want it to survive)

The Irony with an FCG is; that you would need a computer for the theory, yet an FCG is designed to destroy computers.

anyway
how big would an FCG be if it was designed to take out any device within a 200m radius, would it be small enough to mount in the back of a van?
I was thinking about where you would place an FCG if you wanted to set one off.

In each of the experiments, a Russian (VNIIEF) designed and built imploding MC-1 flux compression generator was used to explosively compress the magnetic field into a smaller volume. Thus, generating an energy density of approximately 60 times that of the detonating high explosives on their own.

this could be useful in detirmining the amount of explosive needed to create an FCG.
i got some info from <a href="http://www.lanl.gov/projects/dirac/index.html" target="_blank">this website </a>

Actually, you can create a small emp device in your garage rather easily. You just need a HV/High Current transformer, a capacitor banks, and a electromagnet. Depending on the size of your transformer you can either use a standard throw switch or, if it's a large transformer, a spark gap. You connect the caps in parralel and put the switch/spark gap anywhere that allows the caps to charge when closed. When the caps have fully charged, you flip the switch and all the current rushed through the elecromagent and creates an emp or if you're using a spark gap, it reaches the breakdown point, the air ionizes and the circuit is completed creating the same effect. MOT's will probably work as the transformer, and you want high capacitance caps. More joules = more emp in my understanding. The caps at <a href="http://www.thegeekgroup.org" target="_blank">www.thegeekgroup.org</a> might work but i think their capacitance is too low. If I'm wrong about any of this, correct me.

I forgot to mention that if there's too much resitance in the wire, it will explode.

<small>[ May 19, 2002, 04:48 PM: Message edited by: photonic ]</small>

It's high current which creates high level emp isn't it? If so, why the use of HV?

Also, isn't most electromagnetic flux/radiation created when a field collapses? If so, what about a car battery in parrel with one or more 1Farrad audio booster caps connected to a coil with a fast breaking solenoid/relay, nice thick, short cables all round. Or am I just making a bad arse electromagnet here and no emi? :)

You're right about high current making a stronger emf I think. It's just most transformers that aren't current limited(i.e. Microwave Oven Transformers) also produce a decent amount of voltage. Also, HV allows you to use a spark gap triggered emp device. Low voltage won't ionize the air. With a sg you can control at what point the caps trigger by widening the gap. As for batteries in parrael, that will just speed up the charge time. The caps are in parralel to increase the capacitance. I think we use HV because we're using caps instead of straight from the tranny.
Because j = .5(v^2c) where j is joules, v is voltage, and c is capacitance in farads, the higher the voltage, the more energy and the more emf. That's why we want HV/High Capacitance caps. Most audio caps are high capacitance but only like 25 volts i think.
If anybody has the formula for the em strength(gauss i think) in relation to voltage and current that would answer my/anthony's question. All the formula's i'm finding so far indicate voltage is of no consequence, but all the emp devices I've seen use HV. So I'm not sure.

Forget the MOT, I think the power supply needs to be DC. It will be difficult to find a hv dc power supply so I'm going to assume that hv is not a requirement. It will just decrease the time it takes for the caps to charge.

<small>[ May 19, 2002, 11:58 PM: Message edited by: photonic ]</small>

You want high voltages beacuse a capacitor's energy is lineraly increased by it's capacitance, but if you plot the voltage you get an exponential curve witch means that the more energy from the voltage the faster the discharge and the high voltage travels better through conductors. As for microwave oven transformers, They are current limited, their current is just very high, ex> PRI: 120V 8.3A SEC: 2000V .5A this is a typical 1Kw microwave oven transformer. Their are several types of electronic weapons some mentioned before are TED herfs, these are usually of the spark gap type that use a waveguide to guide the RF from the spark (usually from a cap bank discharge) there also is the HERF or HPM that is usually from a magnetron with wave guide or MASER attached to colimate the microwaves and I will mention this now: DO NOT USE SWITCHES WITH HIGH ENERGY CAPACITOR DISCHARGES! A capacitor of a suitabe size will probably cause your switch to explode on closing, I recomend using a very high power scr.

Hey, thanks for the explanation. Although it would not be portable I suppose you could wire a line transformer backwards to a cap bank and ballast it at whatever current you wanted. If you could afford to create the capacitor bank for it, I imagine you could have a pretty sizable emp. Most SCR's for high voltage are expensive and hard to come by aren't they? Since this thing not firing very quickly I think a standard adjustable spark gap would probably work well. You mentioned energy "weapons" that use a waveguide on the spark gap. I read something about magnetically quenched spark gaps that use neodymium magnets to guide the spark. Is this what you're talking about?

I am talking about waveguides that direct and focus the EM radiation, they usually have a fed horn to further increase gain in one direction, as for a triggered spark gap they are very loud and can cause metals to explode and shoot out hot liquid metal. I have seen big scr's on ebay for a fair price but I recently got 2 18KA hockey puck scr's for 5$ each at a surplus store.

for those thinking of trying to make an emp with pulse capacitors alone... it isnt worth the effort. Some time ago I collected 70kj worth of capacitors from old pulsed ruby lasers. me and a few friends tried discharging the cap bank through all manner of coils and were not able to produce any signifigant emp (a cheap 5$ walmart timex was used as an emp 'detector') we were sucesfull in making straight wire out of alot of coils, or more to the point, bits of straight wire as the coils exploded (the magnetic flux from a high curent discharge tends to turn a coil into a line), but not much emp.... and that was with a pile of capacitors that weighed about a ton!!!!!

alright, sorry to bring this topic alive again, But i was thinking, Could you use a battery,magnet,copper wire and the bomb.

Could you set it up like this
battery (+) to the mag's negative, then from there to the copper wire loop around the explosives then back the the (-) on the battery, when it would go off, would that produce and EMP/EMF, I was thinking this because the magnet ,would magnatise the copper wire, so when it explodes the pipe touches the copper wire, but would this create the short as if not using the magnet? it might seem stupid, dumb ass, what not.. i had this idea, and was not sure if it was a good idea, or a wrong one since. thanks

That makes no logical sense whatsoever, wrapping a magnet in wire and running current through it and blowing it up will result in shreded wire for a flux compression generator to work you need a huge capacitor bank and a precision density HE that will travel at the instant the coil is energised. Not really something that the ametuer can hope to build. As for a 70KJ capacitor bank, that is absolutely huge in fact unless the capacitors were slow electrolytic or very huge HV caps I don't see how you could have gotten them, let alone switched them safely to fire this device. I could use a couple of big capacitors myself they are very hard to come by. with 70KJ of energy I'd build a rail gun. With 70 KJ though you should have been able to destroy more than a watch.

Not wrapping the magnet in wire, but adding power (+) to the magents (-) side, then from the magnets (+) side, run a wire around the explosives , then that wire runs back to the (-) on the battery, which would complete the circut, i was thinking this because magnets have magnetic field , so i just thought that making the copper wire hooked up to the magnet could produce the same effect but maybe of a smaller size

Well possibly you could destroy the electronics controlling your 9 v EMP, by blast effect. :p
I belive they use an explosive lense in a linear EMP device to to get a planar(is that the word?) shockwave.

That idea makes absolutely no sense whatsoever, just beacuse you blow up a coil of wire wrapped around a battery doesn't mean it'll make an emp.

I *think* he means run a current through a permanent magnet...

pyro500,
the caps were 10kv, and a mix of 100 and 60 uf... the whole array weighed in at over a ton.... as far as how i safely switched this??? well a high power ignitron would probably have handled the curent if there was some inductance in the circuit to keep the pulse length long... however we did it the old fashoned way... hardshorting the caps... each short would vaporize maybe half a foot of the ground electrode (doubled up 0000 guage copper wire) since tnt puts out about a kcal per gram, 70kj was the explosive equivalance of about half an ouce of tnt... to say the least the hardshorts were pretty damn loud!!!! i have video somewhere of setting this bitch up, if i find it I'll post to the media section later....

we destroyed plenty of stuff, but couldnt generate any signifigant amount of emp... we tried quarter crushing, and at low powers had some luck, but once we got into the tens of kj range, we didnt crush the quarters much, just propelled them at high speed... guess our coild had too many nonuniformities...

my ftp client keeps crashing my damn puter.... is there any way to post pics directly to the forum???

<small>[ July 14, 2002, 11:10 PM: Message edited by: pyromaniac_guy ]</small>