There are good privacy and security reasons that you might want a personal
sized Faraday shield. New hacking tools are emerging every day and your ID, your
car, and even your wallet could be at risk. But, in an industry that is a wash
with pseudo-science and weapons grade blog damn, are any of these personal
shields any good? That's the question that this user posed on the LTT [music]
subreddit. And to answer them correctly, we're going to need a couple of things.
First, a whole assortment of RF shields.
Second, this RF meter. And third, a
controlled environment so that we can ensure that any fluctuations in our
measurements are due to the actual shield itself and not, say, someone in
the lab over there downloading a file over the Wi-Fi. That is where our EMC
chamber from Raymond EMC comes in. This
bad boy gets us down to functionally zero RF, meaning that, yes, I'm going to
test Faraday cages inside of an even bigger Faraday cage. We've got several
popular cages from Amazon and one of our new writers, Danny, also MacGyvered one
out of common household objects. Now,
it's time for me to MacGyver this segway out of this cable and these twist ties
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A quick search online will yield a veritable buffet of Faraday shields,
many of which appear to be quite similar looking and make similar claims. So,
rather than ordering all of them, we chose a few different types to measure
their effectiveness with a cell phone as a transmitter and our EMF strength meter
as a receiver. Let's take a look at our candidates here. This bag here from
Hadufi is pretty small and kind of flimsy
feeling, but it's only 10 bucks. Meanwhile, Sam Folk makes this $25 box
that comes with a free IQ test and also these
pouches. One is the size for your keys and then the other is the size for your
phone. So, I guess it's meant to live by the front door of a house where all of
the calls come in via the landline. Anyway, the Mission Darkness bag is
double the price of the Sam Folk, but also includes
two layers of shielding cloth, so it must be twice as good then. Then,
finally, we've got this RFID blocking wallet from our partners over at Ridge.
We'll have links to all of the stuff down below. Finally, finally, we picked
up some bulk shielding fabric from Amradield Amradield Amradield I'm
rattled by my inability to pronounce this [music] word. The point is this
will let you make an RFID blocking whatever you want and we will make one
of those. But, before we do that, we're going to do a basic test on the fabric
by itself. While we do have a handful of different tools for measuring electric
fields, we're going to keep things really simple today with our Extech EMF
meter. You can see that here inside the chamber with the door closed, we're
sitting at virtually zero. Just
1917 [music] mV per meter. That is orders of
magnitude less than just outside these walls. [music] Now, all we got to do is
position this about 40 cm from our test platform and grab a phone to put on the
pedestal. We left all our phones outside. Oops. One moment, please.
First up is the Hadufi bag. Let's start
by getting a baseline though. Immediately upon bringing a phone in
here, you can see it's just searching for network, sending [music] out pings
for other Bluetooth devices, Wi-Fi devices. We're sitting at anywhere from
around 1 to 2 and 1/2 volts per meter. A
lot more. However, now that it's kind of gone to sleep, it looks like we're
closer to around 700 millivolts to 1.2
up and it spiked up to two again. What is your logic? Pro logic?
Realistically, anywhere from around 650
millivolts to [music] 2 and 1/2 volts per meter. Pretty broad,
but compared to what we saw when the room didn't have an iPhone in it, I
think we should be able to tell if this is doing anything. First up is the ha
dufy.
They were very specific about folding it twice and that actually makes a ton of
sense because just one fold could leave gaps where the dangerous RF could leak
out. I'm going to aim [music] to put it in the same spot on the pedestal here
and let's see what our measurements look like.
Oh, wow. I don't know exactly what I was
expecting, but that wasn't it.
High five ha dufy.
Left me hanging, but it didn't leave me hanging in terms of performance. This is
functionally identical to what we had before we brought the iPhone in here.
Next up Wait, hold on. Before we move on, the ha dufy also claims that it can
withstand temperatures of up to 1,000°
F. I assume you like your phone not broken though, so what kind of a claim is that?
What is this bag for? You never know if in the apocalypse you might need to very
specifically withstand 1,000° F. Next
up, we've got our Sam folk box. Oh,
leaking a little. And good. You really got to close it
though.
And we found the same thing in our next couple of tests, meaning that everything
from the boxes to the bags to the loose
fabric performed pretty much identically.
The question now is why though? For wallets and key fobs, the answer is
pretty [music] obvious to keep your cards from being skimmed and to keep
your car from being stolen. But so many of these companies market these products
for cell phone use. They do understand how cell phones work,
right? Here's a Linus Tech Tip, free of charge. If you're ever tempted to put
your phone into one of these shields for any extended period of time, just put it
in airplane mode instead. It offers up the same security benefits, that is to
say little to none, but it comes with none of the downsides of putting your
phone inside a Faraday cage. Like people, your phone gets lonely without a
connection and it will just keep swiping desperately for a wireless hookup until
finally its social battery is drained and it
doesn't want to do anything anymore. The Ridge Wallet claims to offer defense
against RFID card skimmers, but this raises some questions. How can it do so
if it doesn't even form a complete enclosure around your cards? To find
out, we're going to need a different test methodology. Because those RFID
chips are passive, [music] being powered on by the reader through induction
before they actually transmit any data, we can't just
poke an EMF meter at it. We're going to have to power up the card first. That
is where the Flipper Zero comes in. In theory, it's as simple as putting the
Flipper against the back of the card and it'll power up that chip and grab a
reading. Just like that. Now, the Flipper is scrambled because it
doesn't actually try to be a device for theft. But, this is enough to find out
if the Ridge Wallet will block us.
It works, which is nice because as a long-time partner, it would have been
awkward if we had to be the ones to expose that the Ridge Wallet doesn't
work cuz it doesn't enclose the card. Uh presumably that doesn't matter thanks to
the extremely low range and low power
operation of RFID. Now that we validated it, that totally makes sense. I just
hadn't really thought about it before. So, now my only remaining question is
do I need any of these off-the-shelf solutions or could I just as easily put
something together myself? YouTube is chock-full of DIY RF blocking solutions
with the most common being the old CIA classic, the wrap it before they wiretap
it with aluminum foil, of course. It's um
not exactly a durable material, though, is it? That's where this solution comes
in. >> [music] >> This is a cheap resealable Ziploc bag
with some metal foil tape in an overlapping pattern. Theoretically, by
following the same installation process that we did with our other bags, that is
to say, folding it over and over and
then putting a little clamp on it, we should
be able to block any signals in or out.
While we're at it, I also want to try this cookie tin and how does this hat
figure into it? Are you just Are you just trying to protect me or what's the
idea here? Of course. Thanks, Danny.
This one's not available at lttstore.com, but we do have hats. You
can check them out at the link below.
And as we've confirmed before on this channel, tinfoil works, but
it's not exactly convenient.
Why don't we try our reusable bag?
And like the tin foil, it works. Now, let's try something that
you might already have in your house sitting in your garbage or recycling
bin. This metal cookie tin should make a perfect shield now that it's empty.
>> [laughter] >> Anyhow, let's go ahead and put that in there.
And voila, perfect. You might think, but
we actually found that the orientation mattered a little bit and the seam,
well, the seam did have some leakage, but apparently now it doesn't. Since we're
at it, one final thing we wanted to test was these ESD safe bags that many
electronics ship in. There are rumors on Reddit that, depending on the type, it
can block signals for devices inside them.
I don't actually expect this to work.
Huh. [laughter] Totally works. It's maybe not quite as
low as some of the stuff we've seen, but it's pretty much there.
With that said, I fully expected this kind to do nothing.
Yeah. That's [music] pretty rough. It might do something, but not much. All of
which leaves only one thing to test, the bulk fabric. Now, I'm not saying that 5G
signals are dangerous for your junk. I'm just saying that um
if you believed that, this underwear might do something.
You want to check it? There's nothing there. Oh, come now.
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squarespace.com/LTT. If you guys enjoyed this video and you
want to learn more about RF and how this EMC chamber works, check out the
unboxing we did. It was very generous of Raymond EMC to provide this chamber so
that we could bring you guys important tech tips like
whether this fabric protects your junk from the 5G.