Ways to achieve EMP - Page 1
Forum section: electronics / projects

author: Mazo
author_rank: Regular Contributor
timestamp: February 06, 2022, 04:44:33 pm
content: Hello,I have thought about ways to achieve high enough levels of EM radiaton in any form to test devices for electromagnetic immunity and potentially crash(or even destroy) them(so it needs to be variable in some way).I am well aware of the standard setups in chambers with all the antennas,RF power amps and such,but I am talking about something far simpler,cheaper,and DIY.I wish to see some effect on devices placed some 0.5~1m away from this contraption.So far I thought about 2 possible "easy" ways to achieve that:a)Magnetron from a microwave with a as directional antenna design as possible with the HV supply made variable by dimming the transformer primary voltage(would have to think about the heater supply as I suppose I shouldn't interfere with it and they are typically derived from the same transformer?)b)High voltage generator that pumps energy into a cap,a spark gap as a switch to discharge the energy into a coil.How do I go about designing the coil though?As far as I understand the theory magnetic field disperses rapidly outside the coil,and to achieve a high enough remaining field @few tens of cm to a m would require either some unrealistic currents or coil size.Using any type of core material seems out of the question.Am I missing something?Would like to hear opinions on the matter.

author: jonpaul
author_rank: Super Contributor
timestamp: February 06, 2022, 05:27:31 pm
content: 1/ Nuclear device, exoatmospheric (Starfish Prime, 1952)2/ Low ser L, high current HV cap for pulsed use eg 0.1 mF 100 kV, triggered spark gap, hydrogen thyratron, etc.Microwave devices may be continous or pulsed byt will not create an EMP.Jon

author: doktor pyta
author_rank: Frequent Contributor
timestamp: February 06, 2022, 05:33:40 pm
content: Search for:-Vircator-Pulse Compression Generator

author: PartialDischarge
author_rank: Super Contributor
timestamp: February 06, 2022, 05:52:45 pm
content: Here's one I read long time ago: if you pass a current thru an inductor the energy in it is 0.5*L*I^2 right?So what happens to this energy if you blow the inductor with a firecracker inside it?And the power is going to be E/t, very high

author: jmelson
author_rank: Super Contributor
timestamp: February 06, 2022, 06:14:01 pm
content: There are commercial EMC testers that use a spark gap, a small dipole amd a reflector behind it. You can try looking one of these up, there might be some document with pictures online. The device is actually quite simple. I saw one used by IBM to check an IBM370 install for suseptibilty.Jon

author: Vovk_Z
author_rank: Super Contributor
timestamp: February 07, 2022, 04:50:14 am
content: The cheapest EMP-generator is an electric ignition lighter (battery or mains powered).

author: T3sl4co1l
author_rank: Super Contributor
timestamp: February 07, 2022, 04:56:42 am
content: Jamming devices are illegal in most (all?) countries.Although given the location, one might (profitably) employ the defense "it's only illegal if you get caught"...Tim

author: I wanted a rude username
author_rank: Frequent Contributor
timestamp: February 07, 2022, 07:28:31 am
content: Quote from: MasterTech on February 06, 2022, 05:52:45 pmThat's anexplosively pumped flux compression generator, as mentioned by doktor pyta above.It's a cute ideal, but doesn't seem to satisfy the criterion of being "easy" in any way aside from "easily" getting you on a government list.

author: Mazo
author_rank: Regular Contributor
timestamp: February 07, 2022, 09:33:31 am
content: Hi,I am aware of explosively pumped generators,nuclear bombs and other ways of electronic extremism,but I just wanted a device that I can just place infront of my old TV(or some other thing that is going to the trash bin) and turn some knob to potentially see some artifacts on the screen/influence on the DUT's operation,maybe a spark or 2,just some cheap fun and maybe learn a thing or two in the process.I will not operate this thing to jam anybody,or destroy property which is not mine and I don't need it to be able to do it(so generating a field and not radiating energy as such is ok,I think?).Pulsed operation with low repetition rates is absolutely acceptable I am not in a hurry.Regarding T3sl4co1l's concerns,real GSM/Wi-Fi/GPS jammers are freely sold atleast in Bulgaria,and the control here about such things is <0,but I don't plan on operating this thing for nefarious purposes anyway.Maybe my use of "EMP" steered the discussion to explosive compressors and nuclear bombsThe Vircator thing is really interesting,but I think I lack the skills and certainly lack the will to build such a thing.Quote from: jmelson on February 06, 2022, 06:14:01 pmThat seems to be like what I am searching for,but I tried searching around for some information and I couldn't get anything.Maybe someone can help with the right words to google?

author: Haenk
author_rank: Super Contributor
timestamp: February 07, 2022, 10:20:16 am
content: https://www.eevblog.com/forum/chat/mini-handheld-emp-generator!/

author: jonpaul
author_rank: Super Contributor
timestamp: February 07, 2022, 10:56:40 am
content: RebonjourSeems like the terminologie is confusingEMP is very different from EMI or ESD!It is a single powerful short duration and fast rise time pulse, capable of damages to area's many kmEMI is electromagnetic interferenceESD is the pulsed electromagnetic due to static charges.All solide state electronics are susceptible to all three.Seems like the OP is concerned with ESD, or EMI, and not true EMP.Beware that an EMP attack will be a plausible strategy by our enemies....JonAn optimist in the nuclear age....

author: Haenk
author_rank: Super Contributor
timestamp: February 07, 2022, 11:01:53 am
content: Quote from: jonpaul on February 07, 2022, 10:56:40 amI assumed OP did not want to ignite one of those old nuclear missiles forgotten by russian troops back then

author: jonpaul
author_rank: Super Contributor
timestamp: February 07, 2022, 11:36:05 am
content: EMP was a US invention, see 1962 Starfish Prime.https://en.wikipedia.org/wiki/Starfish_Primehttps://www.smithsonianmag.com/history/going-nuclear-over-the-pacific-24428997/EMP definition includes both nuclear and non-nuclear generation.https://en.wikipedia.org/wiki/Electromagnetic_pulseJon

author: Vovk_Z
author_rank: Super Contributor
timestamp: February 07, 2022, 01:16:28 pm
content: Quote from: jonpaul on February 07, 2022, 11:36:05 amThanks god. It is a bit easier now. Possibly, we'll survive

author: jonpaul
author_rank: Super Contributor
timestamp: February 07, 2022, 07:01:04 pm
content: Rebonjour, dont worry!An EMP Nuclear is a 1..10 MT burst at exoatmospheric height, 50..250 kM altitude, thus NO blast, thermal or radiation is detected at the surface.The only emission is the EMP electromagnetic wave and a bomb casing residue in the ionosphere.DONT LOOK UP!All your electronics are destroyed, as well as all telecoms, internet, and electrical power transmission and distribution.Back to 1870!However vacuum tube (valve) equipment is immune.Bon Courage,Jon