What you need to know about EMP weapons

Post by accoil » Sat, Jun 07, 2025, 6:58 AM UTC

lostlogin wrote: post #150

Workaccount2 wrote: post #41

Earlier quoted context omitted.

Let me tell you something from first hand field experience with faraday cages... They attenuate signals, they do not block them. The common verbiage is to say "faraday cages block EM radiation", so people naturally assume that it blocks EM radiation. But I learned the hard way while doing compliance testing that no, they do not block EM radiation, they just weaken it (and it's highly frequency dependent on top of tha…

From messing about with MR scanners: An MR Faraday cage attenuates the RF signal about 100db (according to the engineer who built it). Phones work as long as the door is open 1mm or so. Blue tooth works through the cage just fine. Wifi doesn't work very well anywhere near the cage. MR scanners get nice pictures with the scan door open, but the if the scanner next door has its door open (so 2x scanners running with do…

Post by Animats » Sat, Jun 07, 2025, 7:18 AM UTC

timewizard wrote: post #162

Animats wrote: post #152

Earlier quoted context omitted.

There's plenty of unclassified info available. Start here.[1] This is an overview document from Defense Acquisition University, a unit of DoD. It's a painful PowerPoint. You have to plow through a lot of really boring military documents to get the details. EMP doesn't address small devices much. Small devices with no wires connected are not very vulnerable, because the energy is mostly at somewhat longer wavelengths,…

> Worry about cell towers, not cell phones. The grounding is usually required to meet a standard and is tested during the towers installation. There are also coaxial surge arrestors and isolators that get used along the span. Some of the site to site communications equipment has no ground component other than a PoE switch. The ethernet interface, radio, and antenna are all in a single packaged unit installed at heigh…

Post by acidburnNSA » Sat, Jun 07, 2025, 9:48 AM UTC

ufmace wrote: post #113

I'm not sure about most of this. The great majority of the articles and stories about this I've read trace back to layman speculation and disaster porn fiction written by people who have never claimed to actually be informed about how these things work. There's damn little stuff out there that traces back to actual experiments with real hardware. Probably most of the serious experiments are by various militaries and…

Post by cesarb » Sat, Jun 07, 2025, 10:35 AM UTC

Calwestjobs wrote: post #60

bollybobthoeton wrote: post #22

Can't I just chuck it in the microwave and hope no one presses start?

chuck what? your desktop pc already is inside of metal enclosure designed to minimize EM emissions, per UL/CE requirements for electronic devices. also Voltage is difference between two levels, "potential". so that means 5Volt dc device will work if "GND"/minus pole is 3000volts "above real earth" and positive pole is 3005Volt "above real earth" difference between + and - is voltage, so 3000 V - 3005 V is 5 V. youtub…

Post by milkshakes » Sat, Jun 07, 2025, 11:37 AM UTC

Workaccount2 wrote: post #41

tomxor wrote: post #15

> wrap that in aluminium foil, making sure that the ends are folded over and pressed down hard to provide good inter-layer contact I've tried this many times, it's impossible to prevent gaps without welding it shut. Obviously I wasn't testing with an EMP or nuke, but trying to block 2.4GHz WiFi... But that is well within the E1 range the author states. I think the problem with folding is it's too uniform, it's still…

Let me tell you something from first hand field experience with faraday cages... They attenuate signals, they do not block them. The common verbiage is to say "faraday cages block EM radiation", so people naturally assume that it blocks EM radiation. But I learned the hard way while doing compliance testing that no, they do not block EM radiation, they just weaken it (and it's highly frequency dependent on top of tha…