Do Faraday pouches work? Testing a faraday bag is important because all brands are different. There’s a lot of misinformation about what a Faraday pouch, bag, or cage protects against. The basic belief is that Faraday bags are designed to block radio wave transmissions, act as an insulator to protect against electronic currents, blocks tracking, and hacking.
Federal agencies and local law enforcement officers use them to protect information and evidence (cell phones or laptops) from being hacked and tampered with. Preppers use them as a precaution against an electromagnetic pulse (EMP) from a bomb or astrological event. Nonetheless, are all Faraday cages and bags created equal and how protected are we really?
What Are Faraday Pouches Made Out Of?
Mylar bags and Faraday pouches look the same so how are they different and what are faraday bags made out of?
Mylar bags are made of a transparent polyester resin and coated with aluminum. The thickness of the Mylar bag is 3.5 mils.
A Faraday Defense bag has five layers made up of static dissipative polyethylene (plastic), aluminum, polyester, aluminum, and the final coat dissipative polyethylene polyester. The thickness of it is 7 mils.
The thickness and protection from light is apparent in the picture above.
Do Faraday Pouches Work? The Test
I decided to try testing faraday bags before securing valuables in them then stashing them away and I am so glad I did. The outcome of these tests were surprising! It definitely changed how I’ll be protecting my electronic devices. Supplies used to conduct the tests: tinfoil, cell phones, walkie talkies, a radio, and two Faraday Defense bags. Watch the following video to see if the Faraday bags work.
What Are Faraday Bags Used For?
Not all Faraday bags offer the same protection. The most basic Faraday bags are used to block electromagnetic interference (EMI). Electromagnetic currents can damage electronics. Attenuation or dB is what you’re looking for when shopping for Faraday bags. Attenuation is the measurement of how effective the shielding is. Anything above 60dB is considered very good protection.
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Since the bags failed two out of the three tests, it raised the question: why didn’t they block the radio frequency better?
RESPONSE FROM SELLER:
I would like to address your concerns if possible to help clear up questions:
1. Our listing does not claim to block cell phones or walkie talkies – these are EMP bags for protecting items from EMP frequencies causing damage to electronics (they are not bags blocking cell signals – we do carry a full line of privacy bags if this is what you’re after)
2. Much like lightning will pass on the outside of a car (faraday cage) but not harm inhabitants, so an EMP bag acts as a path of least resistance for EMP frequencies to reach the ground.
3. A car will still easily allow a cell phone call or radio signal, but the car itself can block an inhabitant from a direct lightning strike.
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The bags you see above DO NOT block radio-frequency interference (RFI), RFID, GPS, WiFi, or cell phone signals. They are not an RF shield bag! They are just designed to block electromagnetic interference. There are Faraday bags and RF shield bags that provide more protection. Sometimes, they are called privacy bags or signal blocking bags. These bags are designed to protect devices from hacking and tracking by adding more protection.
After researching and testing the Faraday bags, I’ll be adding extra protection to each electronic device. Each item will be wrapped in plastic to act as an insulator, then wrapped in two layers of tin foil, and lastly placed in the Faraday bags for anti-static shielding.
There are a couple of things I liked about the Faraday bags. First, I like that the bags seal completely. The zip-locking seal also protects the contents from moisture. Second, it’s easily accessible and compact, unlike most Faraday cages.
These did not provide the level of protection that I wanted in a Faraday pouch. However, after more research, I found a bag that shielded my electronic devices. Check out a Faraday bag that really works. Faraday Bags that really work!
Do Faraday Pouches Work
Ideas on What to Store in a Faraday Bag
- laptop
- cell phone
- solar charger
- solar light
- tablet
- walkie-talkies
- radio (NOAA emergency weather radio, AM/FM, shortwave radio, ham)
- external memory devices
- calculator
- alarm clock
- small DVD player with monitor
- glucose tester
- Smart car key
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Nice article. Though I’ve tried these bags and they don’t really seem to work that well. I used the md faraday bags tester app and they didn’t block wifi or cell signals. Just FYI as I recently got other bags and they do the trick. I know that EMI protection relates to radio frequency blocking, they are similar in effect. If the bag blocks radio frequencies it will likely block emi. Thanks for the info, you did a nice and thorough job. I am a big fan of this site and we take a lot of tips from here. Thanks!
Thanks Christina for the app recommendation. Here’s a link to the app: https://play.google.com/store/apps/details?id=com.mos.tester
I like this group
I’m interested in the Faraday duffel bags to hold all my electronic gear. Have you tested any of those?
No I haven’t tested a Faraday duffel bag yet. If you test one please let us know what you think of it.
A Faraday Duffel Bag? Does anyone know how heavy that can get? My sea bag hit around 66 lbs. with just issue clothing (commercial air travel max load at the time. I can easily get 100 lbs or so of “essential” clothing into a duffel / sea bag. Electronics are denser and more fragile than any towel or coat. I have a number of transceivers that I do not co-locate do to the potential threat of loss. A bag of this size MAY be handy as I do not know what Jeannie or someone else has in mind. I would offer turning one’s garage into a Faraday Cage would be a potentially better solution.
Gunz, You really could turn a garage into a Faraday Cage? I never gave much attention to preserving electronics in the event of wide spread emp wipe out, basically because of 1) the cost of Faraday Cages 2) would need alot of them and ultimately like you state 3) bulk and weight which without a vehicle would make them immobile. 4) the chances that what ever item I want to protect, I cant afford multiple of them, to have one always protected and put away and another to use (such as laptop), it will without doubt NOT be protected cage when shtf.
Yet you raise an excellent alternative option if its doable and relatively low cost if done ourselves. Please elaborate
Excellent test. Thank you. I think I’ll get more aluminum foil to wrap my electronic things in. Along with paper towels for moisture, plastic baggies for water proofing then aluminum foil for emp’s and cme’s that should be good. 🙂
So, what you are saying is that Faraday Defense bags don’t work as advertised. I use .50 cal ammo cans and 10 gallon galvanized steel garbage cans to store sensitive items, such as radios, GPS, etc. They work!
I wrapped a ham radio in an emp bag then put that in an ammo can and the radios was still getting a signal.
Just an interesting point for everyone. Where I live, metal roofs and stucco walls are normal, stucco is usually placed on chicken wire attached to the walls of the house. This in itself can help you protect your equipment, notice I said HELP. This along with a 10 gallon steel garbage bag. My hope is that my equipment will be safe if an EMP event happens.
I use the EMP Defender bags and have tested them using both cell phone and radio. Put them in a bag, then into the garbage can. I closed the lid and tried to call the phone. No ring. I then turned on the radio very loud. Put it into the EMP bag, there was a signal decrease along with some fairly heavy static. Placed the radio in the can and it went dead with the exception of static. I’m hoping that I’m protected during such an event.
I can’t comment on the effectiveness, or ineffectiveness, of these ‘faraday bags’. But the explanation given by the seller – on how they work and why they don’t block cell & radio signals is nonsensical. To illustrate:
“Our listing does not claim to block cell phones or walkie talkies – these are EMP bags for protecting items from EMP frequencies causing damage to electronics (they are not bags blocking cell signals – we do carry a full line of privacy bags if this is what you’re after”
EMP radiation spans a very large frequency range, including and exceeding the frequencies used by common handheld transceivers (walkie talkies) and cell phones. Indeed – it’s the actual frequencies these devices are built to receive that pose the most potential in terms of damage due to EMP. The above statement either illustrates a fundamental misunderstanding of electromagnetic radiation in general, or a purposeful attempt to mislead the buyer.
“Much like lightning will pass on the outside of a car (faraday cage) but not harm inhabitants, so an EMP bag acts as a path of least resistance for EMP frequencies to reach the ground.”
How, exactly, would an EMP bag allow EMP frequencies to ‘reach ground’ when the bag itself is not grounded? This statement illustrates significant ignorance. Also – equating lightning – which consists primarily of a powerful DC component, with EMP is silliness.
“A car will still easily allow a cell phone call or radio signal, but the car itself can block an inhabitant from a direct lightning strike.”
Another insinuation that a lightning strike is similar to EMP… they’re nothing alike. And a car, btw, is not a ‘faraday cage’. The reason lighting may not harm the occupants in a car is because lightning (DC) will take the path of least resistance. This is NOT the mechanism by which a faraday cage operates. Again – whoever wrote this nonsense knows nothing of the subject at hand.
Here’s the real deal: If your cell phone or radio can still receive a signal in one of these bags – a signal that – at your device – is likely measured in milliwatts (maybe microwatts) of power, then what do you think will happen when subjected to a fast-rising pulse reaching amplitudes of up to 50,000 Volts/Meter?
These bags are snake oil. And the seller’s either a scam artist or someone who desperately needs to go back to school.
Was exactly thinking that.
it’s probly the ziplock mechanism and inside insulation layer that provides a leak to these faraday bags. The conductive sheets should meet all the way around. Your tin foil wrapping does a nice job, but it would be better to fold the edges over at least twice, all around. This should also be the case with the faraday bags.
Current is current. Whether a radio signal or electricity. I say make your own faraday bags from aluminum foil and cardboard.
I used thick construction trash bags, flexible spray contact cement, and heavy duty aluminum foil to build my own faraday bags in a bag/foil/bag/foil/bag design to custom size my own faraday bags; they passed the radio and walkie test in the video, and were big enough to protect my portable solar panels their battery packs.