DIANNA COWERN (VOICEOVER): This episode
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Putting my phone in the microwave.
Do not turn it on.
Dianna Cowern.
All right.
It's in there.
[GASPS]
It's ringing.
Oh, definitely ringing.
Oh, look at that.
This was surprising to me.
The microwave let through a cellular signal.
My thinking before I did any research on the subject
is that a microwave should act like a Faraday cage.
The basic idea of a Faraday cage is
that, when an electric field or some electromagnetic waves
like those from a cell phone hit the enclosure,
they cause electrons in the metal to move and create
an electric field to exactly oppose and to cancel out
the external field.
So whatever's inside feels nothing.
I thought that microwave should act like Faraday cages,
keeping signals out and microwave radiation in when
you're cooking your food.
But this one obviously leaks.
So I had to try more microwaves.
Do you think it's going to rain?
OK, [INAUDIBLE].
I think it will.
DIANNA COWERN: You think it will?
And you're going to call me?
[RINGING]
Mm.
It's not ringing.
It's ringing.
Yeah, so it's not ringing.
Oh my gosh.
It's ringing!
How this is happening?
Now we have to figure out why this is.
It depends on the microwave.
I wanted to know why, but I was also really curious
what part of the microwave is leaking.
DIANNA COWERN (VOICEOVER): So we first
tested what I was sure would be a good Faraday cage.
DIANNA COWERN: Nothing?
KYLE: Two rings and voicemail, so I
don't think it went through.
DIANNA COWERN (VOICEOVER): Then we covered the whole microwave
door in aluminum foil.
DIANNA COWERN: This is what happens
to my friends' microwaves when they ask me to dogsit.
[CHUCKLES]
It's not ringing.
So it's leaking somewhere around the microwave door.
So microwave-- not a good radio wave cage.
DIANNA COWERN: Microwave.
Right.
DIANNA COWERN: Right?
Those are receiving microwaves.
Are they?
OK.
Time to figure out what frequency
of electromagnetic radiation cell phones and microwaves
are using.
That's what Kyle and I weren't sure about.
Because if microwaves are getting in at my phone,
is microwave radiation getting out while I'm cooking my food?
That's what we all want to know, right?
I'm Samy Kamkar.
In general, I call myself a hacker.
So you-- so this receives radio frequency signals.
This receives and transmits.
This device is awesome.
It measures and emits radio frequency signals
between 1 megahertz and 6 gigahertz.
Our cell phone and microwave radiation
should be in that range.
And we're using the gqrx software,
which is a spectrum analyzer, to look at a range of frequencies.
Samy first demonstrated the device to me with a car
key fob, which also emits radio frequency signals.
When I actually hold this down, we can actually see a signal.
We see two frequencies.
DIANNA COWERN (VOICEOVER): The numbers
show the range of frequencies you're looking at.
Above that is a live view of the signals in that range,
like these two peaks from the key fobs.
And down below, it records when you detected signals.
DIANNA COWERN: I don't know why it's so cool to see it
in graph form, but it is.
SAMY KAMKAR: It is so cool, because, yeah, you
know you can finally visibly see it, right?
So you just change it to 700, which
is one of the cellular frequencies.
So we have a phone call going on.
SAMY KAMKAR: Hello, hello, hello.
DIANNA COWERN: And every time we talk, you
can see some of the signals coming up.
Now, what happens to that signal when
we put my phone and the HackRF detector in a Faraday cage?
This is, like, legit.
Yeah, yeah, this is like a legit Faraday cage.
There is a match.
So if you look closely, that's a metal mesh.
DIANNA COWERN: All right, I'm going to put my phone in here,
and then I want to close it and see what happens to the data.
So--
SAMY KAMKAR: It's already way less.
DIANNA COWERN: Yeah, nothing.
My phone is still on, but it's not transmitting anything--
SAMY KAMKAR: Oh, interesting.
DIANNA COWERN: --with is interesting.
SAMY KAMKAR: So we're not seeing it trying to communicate.
DIANNA COWERN: Yeah.
SAMY KAMKAR: Right?
Just radio silence.
DIANNA COWERN: Yep, Faraday cage works.
So let's go up to 2.4, where we know
there's a bunch of [INAUDIBLE].
DIANNA COWERN: Yeah.
So we see-- we see blips.
DIANNA COWERN (VOICEOVER): And that's
where Wi-Fi is on the spectrum.
A common Wi-Fi frequency is 2.4 gigahertz.
So now we've seen what happens to the cell phone signal
when you put it in a real Faraday cage,
and we've gotten great measurements of that.
It's time to figure out what frequency microwave oven
radiation is.
But first--
The phone's in your microwave.
I think the phone call will not go through, because I believe
my microwave is awesome.
DIANNA COWERN: Let's see.
Moment of truth.
It's still not ringing.
AUTOMATED VOICE: Your call has been forwarded--
SAMY KAMKAR: Yes!
DIANNA COWERN: Can we try one more thing?
Because I actually haven't tried this yet.
On this experiment, I turned cellular frequencies off,
I turned Wi-Fi on, and I had Samy
call me through the Wi-Fi network on FaceTime
to see whether Wi-Fi signals get through.
FaceTiming now.
[PHONE RINGING]
Oh, look at that.
Wow, so 2.4 is still reaching through my microwave.
DIANNA COWERN: Which is interesting,
because Wi-Fi is closer to microwaves
that you use to cook your food.
Hmm.
Did you hear that?
One of the most surprising things about all of this for me
was that Wi-Fi uses 2.4 gigahertz,
and most microwave ovens use 2.45 gigahertz.
In fact, your microwave oven probably
says 2450 megahertz on it.
On older microwaves that leaked a lot more, and we don't have,
I think--
DIANNA COWERN: The regulations?
Yeah, as many regulations on that.
You would actually find that, let's say, older Wi-Fi would--
your Wi-Fi would just go out when
you would microwave something.
DIANNA COWERN: No way.
Checks out.
So there's just one more thing to try.
We're going to keep the spectrum on the same 2.4 gigahertz range
and see whether we can detect any microwave oven radiation
from outside the microwave.
SAMY KAMKAR: Three, two, one, start.
So now I'm going to stop.
Stopped.
DIANNA COWERN: Yep.
SAMY KAMKAR: Definitely.
DIANNA COWERN: Definitely leaking.
You can see it right there.
Well, there it is.
At least this microwave oven leaks a small amount.
So should you be worried?
Well, the FDA regulates microwaves.
And they even allow for a small bit of leakage.
And remember, microwave radiation is not ionizing.
So it couldn't damage your DNA directly.
The risk is of heating up your tissues,
but that's only with super-concentrated amounts
of microwave radiation.
You're in more danger of burning yourself
on the water you heat it up in the microwave.
So I have some last thoughts on this whole experience, which
was that the result of the experiment
depended on the microwave.
But there were some things I didn't keep constant,
like the age of the microwave, where
the microwave was in the house, how close it
was to a cellular tower.
So these things might have affected
the results of the experiment.
The other thing that was interesting
is that, with Samy's microwave, the cellular frequencies
did not get through.
But the microwave frequencies did.
Now, this might be demonstrating a property
of Faraday cages, which is that there can be holes in the cage.
But they should be much smaller than the wavelength
of the frequencies you're trying to block.
So since cellular frequencies have a longer wavelength
than Wi-Fi frequencies, it's possible
that we were seeing a hole that was somewhere
between the wavelength of those two signals.
Physics works.
Happy physics-ing, and thank you for watching.
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Thanks again to Samy Kamkar, who let me use all of his toys.
You can check out his YouTube challenge.
It's called Applied Hacking.
I'll put the link in the description.
And thank you to ArcAttack for letting
me use the lightning Faraday cage footage.