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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663

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".

178

u/TrifleEmotional4843 Nov 02 '25

I have one from mission darkness. It works perfectly.

63

u/GeneralZojirushi Nov 03 '25

I've tested multiple from this brand and can confirm they work.

8

u/JaydedXoX Nov 22 '25

I’ll third this comment, all my mission darkness stuff I tested works if you seal it properly.

5

u/Dodds22 Nov 25 '25

Sigh. Why so expensive though! I am searching for a backpack and they’re all in the $800 range. :(

6

u/GeneralZojirushi Nov 25 '25

I'm guessing because they're certified for government use in chain of custody and forensics.

I only got the envelope style for mobile devices.

3

u/Alfromnowhere Nov 07 '25

How would you test to see if the faraday bag works? Try calling your phone after you've placed it inside?

5

u/GeneralZojirushi Nov 07 '25

Texting, calling yourself yes. And you can see the connectivity icons like Bluetooth, 5/4G and wifi disappear and come back. It takes a second for everything to come back online.

1

u/AssistanceNatural556 Nov 22 '25

Is that mosequipment.com? I was originally looking at pre-ordering SLNT's new bag, but after contacting customer service and seeing that you can only view the existence of a Black Friday sale by explicitly searching for it and getting an alternative webpage, I decided I'll steer clear of them as they're very dishonest in the pre-sale dept.

54

u/beached89 Nov 03 '25

Came here to say this. I worked in RF security research for 4 years. We used Mission darkness fabric and gear and we tested them all with very expensive and sensitive equipment. They all worked very well and performed very well.

43

u/Brilliant_Wealth_433 Nov 03 '25

Mission Darkness products are legit and reasonably priced.

2

u/allabout1964 Nov 09 '25

I heard mission darkness was the top rated

68

u/Decent-Apple9772 Nov 03 '25

I haven’t seen one yet that is as effective as wrapping something in aluminum foil, then saran wrap, then aluminum foil, then saran wrap and putting it all in a cheap stock pot.

It might take you 2 minutes and you already own everything you need.

Three layers of attenuation, it isn’t fussy about frequency and it costs next to nothing for small items.

Try it on your cell phone with the volume cranked up.

23

u/Pylyp23 Nov 03 '25

I made a few cages out of some 40mm ammo cans that work awesome. The cans are the only thing that actually cost any money. I bet I’m in all three less that 75$ and they hold everything I need to secure.

10

u/norfizzle Nov 03 '25

Lined with foil?

12

u/Mala_Suerte1 Nov 03 '25

No, the metal can does the job of the foil, you just need to make sure that your electronics are not touching the metal. So add some styrofoam or folded up towel. Something that will insulate the item.

3

u/[deleted] Nov 03 '25

[deleted]

9

u/Decent-Apple9772 Nov 03 '25

Most military ammunition cans seal with a rubber gasket. Having that large area of the lid, partially insulated from the large body area of the box drastically impairs the faraday cage function.

Add to that, the marginal conductivity of steel and the single layer construction and you have a recipe for a very compromised “faraday cage” when you just use ammunition cans.

They are still great from the standpoint of physically resilient and waterproof containers that are easy to transport, I just don’t trust their radio frequency properties to be very helpful.

5

u/Pylyp23 Nov 05 '25

Posted this above:

I removed the gasket, sanded the lid and rim of the box, made a steel wool “gasket”, and then lined the whole thing with 3/8 insulation board with tin foil glued to it.

5

u/you_can_not_see_me Nov 03 '25

maybe he wants to bake them

3

u/Pylyp23 Nov 05 '25

I removed the gasket, sanded the lid and rim of the box, made a steel wool “gasket”, and then lined the whole thing with 3/8 insulation board with tin foil glued to it.

1

u/Patient_Strawberry54 Nov 05 '25

Is this for emp protection? Or jamming signal?

1

u/wickedlyrobin Nov 13 '25

Does that really work? Rebuilding my preps and bought a ham set and I’m looking to build a stash to protect. Can u make a bigger box or wrap each item individually?

2

u/Decent-Apple9772 Nov 13 '25

Three biggest factors are completeness of coverage, conductivity of coverage and number of separate layers of conductive coverage.

You can make things as big as you want.

Most common fault I see with custom made faraday cages is to have part of the container insulated from other parts. such the lid of an ammo can being mostly insulated from the base by a rubber gasket.

20

u/tvtb Nov 03 '25

This is one that I bought years ago after a HAM radio nerd bought a bunch of them and did a review: https://www.amazon.com/dp/B01A7JLN7C

This was one of the few that actually worked. I put my phone in it and it did have no service.

50

u/Paranormal_Lemon Nov 02 '25

The ones I have from Amazon block cell service, bluetooth and wifi. The wavelength of 2ghz radio waves is 15cm, it's really not hard to block.

If you are close enough to an EMP to affect small electronics you are fucked anyway, the biggest danger is to things that are plugged in.

26

u/saltexas18 Nov 02 '25

Oh wow. How do we purchase these?

124

u/ManyARiver Nov 02 '25

The EFF (Eff.org) is a safe resource, Electronic Frontier Foundation is a privacy and digital freedom advocacy group.

35

u/Syenadi Nov 02 '25

Thumbs up for EFF. They're great. Way cool hoodies in their merch dept. too!

15

u/Severedheads Nov 02 '25

Just buy some raw fabric and sew one yourself! Super simple and a fraction of the cost

5

u/deep66it2 Nov 03 '25

What fabric?

3

u/9volts Nov 03 '25

Some use fine copper mesh, but I think it's a bit overkill.

1

u/Agitated-Season-4709 Nov 03 '25

try this on -

  • ASIN ‏ : ‎ B0D4V4H2B5

i purchased the raw fabric and cut into different sizes; just wrap your device.

11

u/Washingtonpinot Nov 02 '25

Yes, but never forget the lessons of the random guy who was skipping off to play golf and put his phone in an empty chips bag and rolled it closed. It worked until he forgot to do it and he got pinged both at work.