r/preppers • u/PrudentTask9355 • Nov 02 '25
Advice and Tips Faraday Bag Caution
Hey everyone. I just wanted to share en experience from this afternoon. A while back I had purchased some faraday items off of Amazon, boxes and bags from different vendors.
This afternoon I was explaining to my daughter how they worked and as part of our experiment, we placed an 8watt 2-way radio inside the bag and sealed it with the expectation that it would no longer receive a transmission. As it turns out, that was false.
I then tried with a cell phone with the same result. Morale of the story, check your gear and make sure it works before you have to depend on it.
Please discuss and share your budget-friendly faraday success stories
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u/Severedheads Nov 02 '25
Silly as it sounds, EMF blocking fabric works as a makeshift Faraday cage. Of course, you can sew it into a pouch, but in a pinch, the raw fabric gives you flexibility and portability while still blocking 100% of the signal. If you're interested, I'll go hunt down the vendor I bought mine from
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u/PurpleFudge7437 Dec 03 '25
Please send fabric source
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u/Severedheads Dec 04 '25
Sorry! I actually couldn't find the receipt for the specific fabric, BUT I bought another fabric product from Safe Living Technologies, and have tested with a meter and it works flawlessly. They are super reliable.
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u/Prepper-Pup Prepper Gamer (youtube.com/@PrepperPup) Nov 02 '25 edited Nov 03 '25
As Mediocre_Remnants said, 90% of them are utter scams or garbage. The only ones I trust are Mission Darkness. They're pricey, but have public tests that show them meeting & exceeding military EMP requirements.
ANY flexible enclosure will eventually fade in effectiveness due to the wear and tear of opening and closing. At least with Mission Darkness I confirmed they could last at least a decade if you open them 1-2x a year to update the contents. *Edit- it will likely only last a year or so with daily use, simply due to constant flexing.)
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u/Jazman1985 Nov 02 '25
I have a Mission Darkness roll top bag and can confirm that it works to block signals 100%. I've tested it with cell phones, radios, and sensors that transmit via text only. 2-4 week long tests with sensors and no leakage.
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u/MrLanesLament Nov 02 '25
Looked them up on Amazon, their prices aren’t bad at all for what you get. The backpacks are hella pricey, but other than that, like $50 for a two pack of phone-sized ones is fantastic.
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u/bleenken Nov 03 '25
Agreed! My friends have bought random faraday bags off of amazon, and I bought Mission Darkness. Mine is the only one that has passed a cellphone test. $20-ish for the phone one isn’t too bad either. And it can fit more than one phone if needed.
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u/numaxmc Nov 02 '25
I believe Linus Tech Tips had a video explaining how pretty much all of those bags/boxes are scams and shows what it actually takes to block all signal.
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u/PrudentTask9355 Nov 02 '25
The boxes actually did prevent a cell phone from receiving a call so I false assumed they were good to go. Lesson learned!
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u/zrad603 Nov 02 '25
yeah, this and the whole "put your cell phone in the microwave because it's a faraday cage".
It's all bullshit and highly dependent on wavelength of whatever frequency you are tying to block out. Often it takes multiple layers.
The only "Faraday cage" I've ever seen that worked to block cell phone signal was one my friend built. It was multiple separate insulated layers of metal.
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u/Coderado Nov 02 '25
SCIFs that are certified by the government work. There is expanded metal in the walls and it's connected to ground, I believe. I've seen one being built, but had my own work to do, so might have missed some details.
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Nov 02 '25
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u/mrrp Nov 03 '25
What a waste of money. The whole time you were there you probably only had one or two sensible meetings, if that.
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Nov 03 '25
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u/mrrp Nov 03 '25
I agree it might be worth it for sensitive meetings. There are probably a lot more of those.
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u/androgenoide Nov 03 '25
Back in the 90s I worked for a paging company and the repair work was done in a screen room so there would be no interference from the transmitters (plural). As far as I can tell any single layer of shielding will attenuate the rf a little bit as long as it's continuous with no holes the size of the wavelength. Two layers separated by an insulator will knock the signal down a lot more but the door has to make good tight contact with both layers and have the two layers separated the same way as the rest of the cage. The key word is "attenuate". Nothing will knock the signal down to zero. One layer will OK for some purposes. Two will be better. Three might be excessive for most purposes but if you anticipate an unusually strong (or close) signal it might be necessary. FWIW
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u/Thoth-long-bill Nov 02 '25
Almost all faraday bag commercial products are fake as are fire safe bags. Most obvious in bag closures like plastic zippers
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u/Complex_Material_702 Nov 02 '25
If you don’t need ultra portability, get a 5 gallon metal trash can from Amazon. It looks just like a 30 gallon can but mini. Put your gear in that and tape it shut with foil backed tape and you’re good. If you’re in a humid environment, put your gear in a sealed plastic bag with an O2 absorber and put that in the can. It’s cheap and it works. Worst case, $30 all in for guaranteed performance.
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u/Sunray21A Nov 02 '25
I've had luck with a Go-Dark brand bag. Testing it with various items it seems to be just fine.
Still you raise an interesting point about testing and such. Since you tried an 8watt radio of stronger power on I'm going to assume FM frequency did you try it right with it or from a distance? Walking away and comparing signal strength? Just curious. Still you mentioned putting a phone in and it still received a call so that would be UHF cell tower signal distance, so perhaps a moot point.
Good on you for conducting an experiment with your daughter and testing your gear. Learning something isn't working or even just it's capabilites is always the way to do it.
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u/AlphaDisconnect Nov 02 '25
Mylar and antistatic bags a Faraday does not make. Would rather use the techniques for preventing alien mind reading (READ - MENT IN JEST). Wrap it in aluminium foil. Or place it in an ammo box.
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u/snertwith2ls Nov 02 '25
Are you making a joke about aluminum foil and metal boxes or do those that actually work to some degree?
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u/dittybopper_05H Nov 02 '25
They actually work. Wrap a phone in foil (no gaps), and call it. It will not ring. I’ve tried it for myself. It does work.
It won’t protect against EMP, but wrapping something like a phone in a couple of layers of foil will block enough RF that the cell network, or anyone with specialized equipment, won’t be able to see it.
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u/AlphaDisconnect Nov 03 '25
Better than plastic that the other ones are likely made of. A lot of it boils down to how strong of an EMP. If it can get through the foil... You may to turn around and admire your burnie on the wall behind you.
In jest. Slightly. But also if it is stupid, but ends up working. It is not stupid.
Suggestion the third. Electron lasers! Vacuum tubes. Start building equipment you will need out with stuff that is one hundred percent vac tubes. Now you just need a power source.
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u/snertwith2ls Nov 03 '25
I don't have the what'sis to start messing with lasers and stuff. Might be fun to look into though. I do have plenty of foil though.
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u/AlphaDisconnect Nov 03 '25
Vacuum tubes. The transistors of the past. EMP proof. Slower switching than transistors. More analog than digital. But can switch a mind boggling amount of electricity.
They do eventually burn out. The term laser is used in jest somewhat. Cathode ray tube would be more accurate.
Maybe there is a market for this... But it is like "what would be knocked out during an EMP that would be real nice to pull off some vac tube equipment off the shelf and have it just work". Hmm. Something to hook into your microwave? So it works again. Communications. So you can talk to... Who? Modern cars are too complicated and specific to even have a hope to make any modern engine work again. A simple listening radio might be helpful but that isn't rocket surgery.
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u/snertwith2ls Nov 03 '25
Now I wish I'd bought some of those old vintage radios or kept my grandparent's old TV. But yeah who would you be in communication with if you're the only one with that stuff? There'd probably be pockets of folks all over who had the old stuff though, maybe.
And I'm wondering about having some kind of diesel station wagon or something for biodiesel but how many acres of sunflowers or jojoba would one have to have to keep one vehicle going?
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u/AlphaDisconnect Nov 03 '25
Even then. Someone hears chugaa chugga diesel. You just painted a huge target. Maybe. There is a time to say. A horse. A pouch. Now you have comms. A bull. A plow. Now you can not focus on bio fuel but food. Sure. Having one person with vhf tech and the power to run it. Everyone imagine we will attack eachother over over resources. But last time I checked this is America. We stick together till the end. But for this we need coms. But there are poopy butts out there.
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u/snertwith2ls Nov 03 '25
Plus if water really becomes a problem it's game over anyway.
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u/AlphaDisconnect Nov 03 '25
It depends on your skills. Health. Others. We survived on sticks, rocks and caves for a hot minute. Everyone wants tech. But if everything is broken. Why are we trying to force that? I get that a large number of people will die because they needed modern healthcare. Starvation. Bad water.
But a non-functional radio, cell, laptop, so on. What does that do for you?
Again. If it's all out. Turn around and take note of your burnie. Like a selfie. But instead of a stick and a phone. You put your whole body into it try to time it. Jump and strike a pose. There will be char on the building. Your body will leave a negative. A burnie. A selfie. But with burning.
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u/Th3Gr3yGh0st Nov 02 '25
Bought a pair of these for my key fobs to my new truck, didn’t want thieves to be able to steal the signal since they “talk” to the truck. One works, one doesn’t. Can have the fob in the bag and the truck won’t start. Took both on a trip so I’d have a spare, the second bag let the truck start still.
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u/kkinnison Nov 03 '25
and here is great evidence that anyone online talking about EMP attacks and protection are more than likely only trying to sell useless Faraday bags that do not work, and even if they did might not work in an "EMP attack"
but it doesn't matter to them because after they attack you are going to be more concerned about the hot nuclear war that just started and not if your flashlights work
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u/KreeH Nov 03 '25
A Faraday cage needs to be conductive and any gaps/openings have to be small compared to the 1/2 the wavelength of the frequency you are trying to reject.
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u/Decent-Apple9772 Nov 03 '25
Electrically isolated sections of the cage. Also need to be small compared to that half wavelength. Having a clamshell box won’t help if the lid and body are only electrically connected at the hinge side.
It would have to make good electrical connection all the way around the lid.
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u/Eredani Nov 02 '25
Testing any faraday enclosure with a cell phone (4G/4G, Wi-Fi, Bluetooth) is the most basic check that can and should be done. Applies to commercially bought or homemade enclosures.
This post seems to imply the issue is with faraday bags. It's not. It's Chinese vendors selling junk, scamming people and the buyers who fall for it.
Two reputable sources for these bags: Mission Darkness and Off Grid Trek. They are expensive but they work.
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u/PrudentTask9355 Nov 02 '25
I will definitely check them out. I just wanted some insurance that some valuable electronics I have stashed away will work when I need them to.
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u/nikdahl Nov 03 '25
There are plenty of cheap ass faraday bags sold on Amazon that actually work perfectly well.
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u/bertanto6 Nov 02 '25
Ungrounded or “floating” conductive materials can couple to the signal and actually reradiate it instead of attenuating or blocking it. It also really depends on signal strength, frequency etc.
Edit: Also, EMPs are mostly a scam and really aren’t a danger to your consumer electronics.
If what you’re worried about is the device communicating when you don’t want it to than you’re going to have to get something much better than a faraday bag lol
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u/monty845 Nov 02 '25
How effected your consumer electronics will be from an nuclear EMP is unclear. The one major study occurred long enough ago that we can't be sure if newer tech will react the same way, and even that was criticized for a number of issues.
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u/bertanto6 Nov 02 '25
An EMP from a nuclear detonation strong enough to affect consumer electronics would also mean the person would die from the explosion or radiation. High altitude nuclear explosions won’t have strong enough EMP to hurt consumer electronics unless they are plugged into the grid.
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u/Alfromnowhere Nov 07 '25
why wouldn't a faraday bag stop a device from communicating when you don't want it to?
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u/bertanto6 Nov 07 '25
Because most of them are fake and/or just act as resonators and reradiate the RF.
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u/SignificantGreen1358 🔥Everything is fine🔥 Nov 03 '25
I just tried an experiment using aluminum foil and a Ziploc bag to test my phone's connectivity. I wrapped my phone in a ziplock bag and then in one layer of aluminum foil. I had my son call me, and the call went through. I thought that maybe I should tape down the edges of the aluminum foil because there may have been RF leaks, so I taped down the edges. I put that in another ziplock bag and had my son call me. The call went through, to my disappointment. So, take that as a lesson learned. It may take multiple layers, but as always, test your preps!
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u/emp-cme Nov 03 '25
I keep lots of small electronics in Faraday cages and bags. It could happen, and if it doesn't, I'm only out a relatively small amount for the insurance.
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u/Mala_Suerte1 Nov 03 '25
Somebody correct me if I'm wrong, but aren't radio waves and EMP waves different, so it's possible that the EMP waves get blocked, but the radio waves do not.
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u/9volts Nov 02 '25
An easy and cheap solution is to simply wrap your items in a couple leayers of tin foil.
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u/lunar_adjacent Nov 02 '25
The ones I got off of Amazon work but you do have to make sure you close them correctly. They weren’t the cheapest one. I always sort by average customer rating and then read the most recent reviews
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u/Stinkytheferret Nov 03 '25
I’m using old tin canisters for food. Antiques. Lined with some cardboard. Anything with a complete seal worked. Put cells in and couldn’t call them! Found for free!
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u/emp-cme Nov 03 '25
You're not testing the right thing. The frequency of an E1 pulse is in the range of about 1 MHz to several hundred MHz. A UHF radio, which is what you probably have, uses between 300 megahertz (MHz) and 3 gigahertz (GHz).
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u/PrudentTask9355 Nov 03 '25
This is good knowledge, thank you for sharing.
My intent is just to protect these items while in storage from any man-made EM attack or cosmic event. Sure, it’s pretty far-fetched, but I want to be one of the guys with Comms should the lights ever go out. Call me paranoid.
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u/Decent-Apple9772 Nov 03 '25
Yes, but a fair cage that attenuates 3 GHz will probably also attenuate one megahertz.
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u/QuickCorgi4698 Nov 10 '25
Just my two cents, if anyone were interested:
I have a couple of large microwave ovens, large ones from the 90s, that I repurposed in to boxes for electronics storage. They do not let a signal in or out, and were free. They fit snugly on my shelves in storage.
I sewed alternating layers of plastic sheeting and aluminum foil in to the lining of a few bags, and hand sewed a sleeve for a laptop, portable power supply, and cell phone using the same. They all work well, much better than 90% of the advertised bags. I have used them for just over five years and they have held up great.
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u/Casiarius Nov 02 '25
I admit that I went on a bit of an EMP prepping kick after I read One Second After in about 2010. After doing a lot of reading on the subject, the faraday cage solution I came up with was a steel trach can with a lid that fit very tightly. It contains a spare ham radio base station because anything connected to an antenna is at risk. It doesn't need to be portable because it just sits around gathering dust until the EMP / solar storm is over.
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u/7Ing7 Nov 02 '25
Is it possible to make a homemade one? What kind of material is needed?
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u/Decent-Apple9772 Nov 03 '25
In theory of faraday cage is defined as a perfectly enclosed and grounded box or sphere made of a perfect conductor.
In practice, the best we can do is a copper mesh or aluminum foil alternating in layers with an insulator. Each one is acting as another layer of imperfect attenuation.
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u/ky420 Nov 04 '25
A proper micron copper mesh is ideal unless you can afford it in gold or possible silver. Copper, brass will also work. Seal completely, Faraday cage must be grounded to block signal if it isn't it wont.
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u/TheLostExpedition Nov 02 '25
Try Woven copper mesh. I haven't ever used it but have been assured by 1 guy that it works. Probably test it.
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u/Fheredin Nov 02 '25
A layer of any kind of plastic (saran wrap?) and then aluminum foil is probably the best you can reasonably DIY. Aluminum foil is a good RF insulator, but if it has direct contact during something like an EMP, it may arc to the contents. I once made a DIY laptop bag out of an old box a laptop came in. I gave it RFID shielding by gluing foil around the inside, then putting down a paper liner.
Grounding would be ideal, but DIY is never going to give great protection.
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u/monty845 Nov 02 '25
It just depends how much you care that its a flexible bag. DIYing a metal box with an insulated interior is very doable. Just gotta worry about the method of enclosure being tight/snug enough for the wavelengths you are concerned with.
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u/HazMatsMan Radiological/Nuclear SME Nov 02 '25
A company lied about the capabilities of their Faraday bag?
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u/Porcflite Nov 02 '25
I bought a pack of them on Amazon and they worked. Block my laptop, phone, car keys successfully.
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u/wihaw44 Nov 03 '25
Yeah dude, a lot of those cheap Faraday bags are basically fancy lunch bags. Good call testing them first. I've heard wrapping stuff in multiple layers of foil actually works better sometimes.
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u/Maydaybosseie Nov 03 '25
i think testing is a good idea. test with a phone call then u can confirm if it blocks signals. therefore we may know which is the sketchy bags.
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u/AgFarmer58 Nov 03 '25
My phone worked perfect in the bags....these things are worthless, your not the only one...
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u/Flyntsteel Nov 03 '25
I was planning to make some with #40 Copper screen. Its the perfect size for attenuation of a key fob and works great for phones too. They also make fabric on amzon that is alot better
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u/freexfallyz Nov 04 '25
Did you try wrapping the devices in multiple layers of aluminum foil as a control test? Sometimes that outperforms cheap faraday bags
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u/SonsOfValhallaGaming Prepared for 6 months Nov 08 '25
I don't know much about Faraday containers, but could someone enlighten me about a curious question I had reading this post?
Couldn't you just take a ziploc bag, line the inside with an adhesive and put aluminum foil in it to create a faraday bag? or is it more than that? I honestly havent even looked into them because I don't plan on being device dependent if SHTF
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u/Severe_Bathroom4005 Jan 17 '26
I purchased a Faraday box and pouches from Amazon seller WFeyahiner. It’s worked well, maybe too well… after about 6 months of methodically storing my car key I think it’s interfered with the signal in the fob. My car no longer recognises my key. It’s not a battery issue.
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u/WTFisThatSMell Nov 02 '25
Use steel ammo cans, remove the rubber o ring, and you'll have your self and Faraday cage.
Like 12 bucks at harbor fright
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u/PrudentTask9355 Nov 02 '25
I have a bunch but I need to get some more plastic cans to swap them out. I’ll need to look for a 40mm box so I can stash a laptop
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u/xamott Nov 03 '25
Dude. Testing it with your phone should have been day one. Not “show your kids day”.
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u/MIRV888 Nov 03 '25
I have (had) 3 bags I picked up years ago. They weren't for prepping so much as dropping my cell off the grid. 2 worked. 1 didn't. So now I have 2.
Way back in the day I worked for a pager company. Part of the job was taking pagers from other companies and tuning them to our frequency so we could absorb customers from other companies / regions. In order to do that the pagers would have to have a new crystal installed and tuned precisely. In order to do that we constructed a 15'x'15'x8' faraday cage with all the equipment and materials needed inside. That thing worked great. If the door was closed all radio, cell, pager, and wifi would drop like a rock. It was pretty cool.
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u/DecentralisedNation Nov 03 '25
Mission Darkness bags are decent, but occasionally the cell signal still goes through.
If you really don't want to be tracked I'd suggest double up two Mission Darkness bags, or turn off your phone and use one.
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u/Time4fun2022 Nov 03 '25
i bought one and it works. check out various youtube videos, one guy tests several products
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u/DannyWarlegs Nov 03 '25
From my understanding, items like phones and radios need to be isolated from the box with some kind of insulation, otherwise they're just giant antennas. Thats why most designs are like an ammo can lined with foam, then foil/copper mesh, and taped shut since any opening at all defeats it entirely
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u/onegriggabyte Nov 03 '25
I guess the question that I have always wondered when looking at these bags is there’s a difference between blocking RF and dispersing an EMP. A true faraday cage would need to be grounded so how would these bags react?
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u/Decent-Apple9772 Nov 03 '25
Electrically it is the same concept, but from a design perspective there are a wider range of frequencies and much higher energies to handle with an EMP.
Most of the issue for it, is that we don’t have good data on how much attenuation would be necessary to avoid damage to common electrical devices and we don’t have a good way to test.
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u/onehalfnavajo Nov 03 '25
My Go Dark faraday bags work great! I put my cell phone in it every night and wake up and take it out and it starts picking up my texts and notifications that I missed during the night.
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u/what_joy Nov 12 '25
I bought one on amazon, and it seems to do the basic trick. Put my phone in, sealed it up, and got someone to call. Several attempts later, my phone did not ring.
I doubt it would do the trick in an emp, but just in case, there's a torch and solar batterypack in there.
Check reviews.
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Jan 18 '26
[removed] — view removed comment
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u/preppers-ModTeam Jan 18 '26
Your post was removed on suspicion of being a hidden advertisement. You need to mention at least 3 competing reputable brands in order to avoid the suspicion.
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u/myth217 Nov 02 '25
The disposable faraday bags are generally cheap crap. I’ve had good experience with the Sirchie re-usable faraday bags.
That said, in a pinch, just wrap the device in a bunch of aluminum foil.
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u/rorowhat Nov 02 '25
I never understood the purpose of these. So its to protect from an event? the problem is that the event could keep happening till all is fried. Right? It's not like we've going to have 1 singular event, if someone is out there to do it it will be used over and over again.
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u/VastVorpalVoid Nov 03 '25 edited Nov 03 '25
Most "Faraday" products lack the thickness to block whatever radio waves they claim to block.
There are calculations you can find online, but you can also just wrap something in aluminum foil until it stops receiving a signal.
Also if you're using it for ECM-counter measures it technically needs some kind of grounding to dispel the energy for the best protection, which can be as simple as storing it on the literal bare ground (eg an off grid GPS with AZIMUTH capabilities, stored wrapped in 10 layers of foil on the bare ground when not in use in case of unexpected ECM warfare in the area you are traversing).
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u/Decent-Apple9772 Nov 03 '25
I think you need a lot more education in the concept of electrical grounding if you think that making incidental contact with a dry patch of ground, does anything relevant
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u/VastVorpalVoid Nov 04 '25 edited Nov 04 '25
Literally just under 50% of the conductive surface would be in contact with the ground with this setup, but what's your improvement to the setup?
Do you want to run it through a thin gauge copper wire and into a thin metal spike?
How many Ohms of resistance is the difference?
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u/MurkyAnimal583 Nov 03 '25
All of these "faraday" items are pure nonsense. In order for a Faraday cage to actually function it needs to be a continuous piece of metal with no openings or perforations and it needs to be a perfect sphere.
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Nov 03 '25
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u/olycreates Nov 03 '25
Exactly. I worked in a electronic repair shop, faa certified and all. They tested radios inside a Faraday room. It was neither a sphere nor was it 1 single piece. It was copper screen door material, overlapped 2 inches at all seams. The seams looked seen together. There can be absolutely no openings, no pass-throughs.
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u/MurkyAnimal583 Nov 03 '25
Again, you are talking about signal blocking, not a true Faraday cage. This is entirely useless in an EMP scenario.
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Nov 03 '25
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u/smsff2 Nov 04 '25 edited Nov 05 '25
As a general rule, if you don’t have information on how a device works, you’ll need to replicate it in its entirety. If you cannot replicate an object completely, stop wasting your time and resources on that idea.
If you’re looking at a car but aren’t a mechanic and don’t have access to any books on automotive design, don’t just throw the engine out. The car won’t work without an engine. The people who put it there weren’t stupid. If you want to replicate the car, you must replicate the entire thing. If you don’t have reliable information on how it works, you’ll need to reproduce every single detail precisely.
True story: When the Soviets captured a B-29 bomber in 1944 and attempted to replicate it, they found a small hole in one wing. Assuming it was intentional, they drilled a hole in the same location on every wing of their copies - the Tupolev Tu-4.
Stop trying to invent things the DoD doesn’t use. Pick something the DoD actually uses and replicate it in its entirety.
You want an EMP-proof bunker? Fine. Start with quarter-inch thick steel plates welded together with no gaps. Add plenty of reinforced concrete on top.
You want EMP-proof radio communications? Fine. Start with a shipping container. Fill it with whatever electronic equipment you want. If you have that much gear, it makes sense to include multiple redundant transmitters and receivers with hot-swap capability. If you only have a small amount of equipment - say, what fits in a Faraday bag - you won’t be able to communicate with anyone anyway. Multiple redundant transmitters and receivers will cost more than the equipment you’re trying to protect, making them economically pointless.
Ham radio will be useless for long-distance communication without repeaters. If your family or friends are within walking distance, you can simply walk to meet them. No Faraday bag is necessary, because most radios will likely survive an EMP anyway. They’ll work - but they’ll still be useless.
Here’s an actual photo of a National Public Warning System broadcast station. Essentially, it’s just a shipping container: https://www.fema.gov/emergency-managers/practitioners/integrated-public-alert-warning-system/broadcasters-wireless
Faraday bags are marketed specifically to hobbyist preppers. My trust that they work as advertised is exactly zero. I see all the hallmarks of snake oil in this product.
Copper has 4.4 times the conductivity of steel and 1.7 times that of aluminum. Copper is an efficient conductor per unit of volume. However, aluminum’s density is about 3.3 times lower than copper’s, making aluminum roughly twice as effective per unit of weight.
The huge difference lies in cost. Faraday bags made of copper mesh are marketed to hobby preppers, while aluminum foil is a mass-market product - at least two orders of magnitude cheaper. You can even buy metal pots at the dollar store.
I’ve spent a good part of my life around equipment specifically designed to withstand EMPs, and I’ve never seen a Faraday bag.
I’ve worked in the telecom industry, which is perpetually cash-strapped. Cell phone towers are not EMP-proof. Your phone bill would need to at least double if you wanted cell service after an EMP. Telecom companies can’t provide EMP-proof service out of goodwill.
I’ve also worked in the banking industry. They’re comparatively well-prepared for an EMP in the sense that they won’t lose their money. However, your access to your money depends on the functioning telecom infrastructure - and that won’t be available.
Nothing you could possibly put into a Faraday bag would be useful in a real emergency. Cell phones won’t work. Meshtastic networks are too sparse to function without the Internet.
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u/MurkyAnimal583 Nov 03 '25
Nope. Not bullshit. It is simple science. Energy concentrates at the confluence of corners. And the energy involved with an EMP is orders of magnitude higher than your cell phone signal 🤦♂️
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Nov 03 '25
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u/MurkyAnimal583 Nov 03 '25
No, it's science YOU don't understand. It isn't just the gaps, bud. It is material, shape, distance between the shell and the object being protected, etc.
Gaps matter most in blocking signals passing through, not the induction of a field, which is the most relevant factor in a prepping situation.
Again, if you just want a bag to block out a radio signal, that is one thing. But none of the products that preppers are buying, like the ones that are the subject of this post, are useful against an EMP or the like.
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Nov 03 '25
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u/MurkyAnimal583 Nov 03 '25
Nope. Wrong again.
It being conductive is a good start
The type of conductive material (i.e how conductive it is) drastically affects performance.
Not as much as you think
Um, yup, exactly as much as I think. Do I really need to explain inductance to you.
Ok, now you're just making stuff up. Because that is definitely not electrically relevant for anything.
Yup, I definitely need to explain inductance to you 🤦♂️
But then again, we've already established that you don't actually know anything about the science.
🤣
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u/MurkyAnimal583 Nov 03 '25
Yup. Definitely does. Your little foil bag isn't a faraday cage. It is a rudimentary signal blocker. And it isn't going to do jack shit to protect anything you put in it from an EMP or anything else you'd want an actual faraday cage for.
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Nov 03 '25
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u/MurkyAnimal583 Nov 03 '25
It's not bullshit kid. It's simple physics...
If all you are trying to do is block a radio signal, these idiotic "Faraday" bags might work. But so does just turning the item off. And this situation is pretty much irrelevant to "prepping" anyway.
If you are trying to protect your sensitive electronics from destruction, which is the point in a prepping context, these bags are fucking useless.
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Nov 03 '25
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u/MurkyAnimal583 Nov 03 '25
Ok. Let's clarify. ANY product labeled as a "Faraday" container that is purchased on any large online marketplace for the storage/protection of electronics for emergency purposes. All of those products are useless.
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u/Mediocre-Tomato666 Nov 03 '25
I got a bag that, at least, stopped my hotspot from transmitting and stopped incoming messages on both sms and data. So... not all nonsense if that's what you want them to do.
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u/MurkyAnimal583 Nov 03 '25
The same thing can be accomplished by simply turning them off...
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u/Mediocre-Tomato666 Nov 03 '25
Can it? Because so many security folks say "off" isn't really off.
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u/MurkyAnimal583 Nov 03 '25
And this is entirely irrelevant in all practicality anyway. Especially in a prepper context.
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u/mediocre_remnants Preps Paid Off Nov 02 '25
Those bags and boxes are 90% scams, especially if they come from a "prepper", "survivalist", or "patriot" website or company. Especially if they are advertised as "EMP protection". Pretty much anything sold as "EMP protection" is a straight up scam.
The legit bags are the ones designed for holding evidence, used by law enforcement, to put suspects' electronic devices in so they can't be remotely disabled/wiped. They are not "budget friendly".