Stupid netbook tricks: DIY microwave shield testing
By Joseph L. Flatley 
posted May 16th 2009 7:42AM
posted May 16th 2009 7:42AM
So, we're guessing that at some point in your life you've wondered whether or not your microwave oven has sufficient shielding. Well, we certainly haven't -- but maybe we're the fools for trusting the United States Consumer Product Safety Commission. Then again, in Russia they don't even have a "United States Consumer Product Safety Commission" (for obvious reasons). Clearly, someone over there was nagged by the thought that this appliance was scattering radiation where it didn't belong, so he got this bright idea: as microwave ovens operate at 2.45 MHz, and 802.11d WiFi operates on a 2.4 GHz frequency, any netbook placed in a closed microwave should be woefully un-pingable. And you know what? When he placed his netbook in a closed microwave, it couldn't be pinged. Clearly relieved that his microwave oven was amply shielded, the author has one final piece of advice for any of you who might be thinking about conducting this test for yourself: "Don't try to turn your microwave on, while experiment." Action photos after the break.
Should have used kismet to scan for networks, a ping requires higher level connectivity
Funny that this is in Russia ......
Up until the fall of the communist regime, and the mad plunge into the free market and 'shock therapy', microwave ovens were banned.
They were briefly available, as trinkets for party workers, decades back. However, after considerable research being conducted, it was decided that food subjected to microwave radiation was too dangerous for people to eat. Of course, once the regime fell, palms were crossed with silver and the statutes fell to commercial pressure.
If you can read Russian, or do sufficient digging on Google in English, one can see some of their findings ...... scary stuff. You're mad if you eat microwaved food.
In Soviet Russia, netbooks nuke you!
So actually, my all-American deep-fried diet is the _healthy_ option? I knew it was, just waiting for science to catch up and prove it...
True. Access points can have minimum signal strength cutoffs so that a weak signal won't be allowed to connect (and therefore ping). It would be more useful to see the signal strength in dB via a full scan
It's called a Faraday Cage.
http://en.wikipedia.org/wiki/Faraday_cage
are u sure it's not a Nicholas Cage?
no, this is the page for Nicholas Cage
http://en.wikipedia.org/wiki/Tool
Yahr, I heard that microwaves can act as Faraday cages.
That's why I hide my netbooks inside my microwave in case of an EMP attack.
Bastards killed Faraday, I like him.
My guess is, after the nuke, Faraday will be alive again.
I liked Faraday mom better (1970 mom of course).
Exactly what I thought when i read the article. the microwave is acting as a faraday cage
Nah, the writers already confirmed that he's gone for good. I'm still pretty angry they killed him off, as he was easily one of my favorite characters on the show.
Those bastards making us wait till next year to see the last 17 episodes. People better come back to life because right now there are only 2 survivors in the present.
That's why I go to sleep every night in my microwave...
Just 25% packet loss with my iPod.
run.
turning it on should result in 100% packet loss.
i was kinda hoping for the pictures after the break to be ones where the microwave had been turned on. sadly they are slightly less exciting.
Umm isn't there like a few errors in that article? i.e. MHz, instead of GHz and 'd' instead of 802.11g/b/?
umm. no. on both questions
umm. yes. on both questions
After unplugging the microwave, I can confirm my cellphone can be called, just loses two of four antenna signal strength bars. Frequency is close but not the same (850 MHz). So much for Faraday's cage,
When the oven is plugged in, however, there is no leakage detectable. Checker would indicate below 0.1 mW per square cm at 600W micowave power blasting behind the closed door. Safety is maintained, according to current state of science and regulation. What kind of radiation is it then that keeps the connection working as it obviously goes through the faraday cage, losing little strenght?
850mHz is no where near 2.4gHz
A Faraday cage should be connected to ground, if you unplug the microwave it's not a Faraday cage as such, the housing will pick up EM radiation and guide it and some will bounce around inside, or if the radiation is inside some will be transferred out, in fact the waveguide would become a pickup antenna tuned to roughly the right frequency when you think about it, although I'm not sure how it would then travel further down the circuitry.
if you unplug it, the microwave is no longer grounded, so the shielding doesn't work as well. it needs to be plugged in so that the radio waves are redirected to the ground.
Or he could simply have put his cellphone in and called it :/
did you even READ the article?
did you just skip the part with numbers in it?
the 2.4 reasoning GHz just flew past your head, woosh?
SERIOUSLY MAN. there's even a comment above you that debuks the same thing.
The shielding for higher frequencies must consist of a denser mesh (spacing no larger than the wavelength), so if it's shielded for 2.4GHz it should most certainly also shield 800MHz.
I say mesh since the door and lightbulb and airvents are obviously where the leakage would most likely occur.
Mind you I always wondered if the connection between the shielding in the door was sufficient in many microwaves, often the rim is painted and the latch plastic so only the hinges seem to have to connect to the door's shielding, but hinges can get dirty I would think and make poor contact either already from the factory or eventually after some use.
Just stand away/to the side of them seems the best policy and advise.
oddly enough, many microwaves when turned on disrupt 2.4Ghz cordless (land-line) phones, so clearly they are not shielded as well as people think...
or just put a cellphone with wifi inside. and try ping it.
and yeah u can forget bout Verizon phones...
I was using my stove (it's one of those glass-smooth types) as a place to situate a laptop whilst transferring some files. I happened to use the microwave, which is mounted directly above, for about 10 seconds - and zap! My laptop was fried, completely. I'm assuming it would be too much of a coincidence to not link the two events. Peees me off. Obviously shielding on the underside was lacking somewhat! (laptop was running on batteries btw, so no power spike)
In soviet russia you shield microwave.
No,no,no,no,no, you got it all wrong "In Soviet Russia Microwave Nuke YOU" :D
Ehrm Microwave Oven = 1500 Watts
Wifi = 200mA
I know if the thing is fully shielded that hardly makes a difference.
But there maybe there's some other material thats stopping your wifi but is insufficiënt for your 1500 Watt Microwave rays.
My microwave is 800 watts, and it's not exactly the low-power model, I don't think they sell microwaves of over 900-1000 Watts, although they sell combi-ovens that say 1500 Watt but that's the grill being so hungry and the actual microwave part being no more than 900W.
That's AFAIK.
They use 1000W & 1500W microwaves in commerical kitchens.
you just compared watts and milliamps. did you mean 200mW?
There is a 1200W microwave in my kitchen right now.
I remain amazed at how people will put inaccurate knowledge on the internet for the world to mock.
800W, 1.5kW, it's all the same; as Gert pointed out, that's 1000 to 10000 times the power of a typical WiFi transceiver. A factor of 2 on top of that doesn't mean much. That's the answer to all the "If microwaves are shielded, how come my microwave interferes with ?"
Suppose the shielding is good enough to reduce radiated power by 99.9% -- the WiFi is down in microwatts, probably undetectable, and certainly unusable. The microwave oven, when on, is radiating on the order of 1W. Perfectly safe, but stronger than most 2.4GHz communication device, and capable of interfering with any of them.
Well there you go, buy a 900 Watt microwave and the leakage will be 30% less than a 1200 Watt one, meaning more range on your bluetooth and wifi, yay :)
Is that Alfred E. Neuman on the screen of the laptop in the first picture (the diagram)?
The one and only.
What, me worry?
Boy, should he worry now!
Why not put your phone in there and try to call it?
If im not mistaken both use microwaves so the shielding should in theory stop said microwaves from reaching telephone?
I just tried it and I got no call.
Does Joseph write his intros in another language and then run them through Google Translator to get English? He has a very stunted, unnecessarily wordy style that makes my head hurt.
Its the lack of education I think.
The enclosure is made from highly conductive metal.Microwaves generated by the netbook will bounce around inside the microwave. And since the power of the waves are miniscule, your netbook will not be damaged.
well, we had different findings. build a large panoramic scanner for wifi (spectrum) waves, just the see how pretty they are. but whenever a microwave oven is turned on, even if its several rooms away, it just washed our sensors out.
check the video
http://wificamera.propositions.org.uk/Panoramic-Wifi-Camera
forgot to say, its at 1:20.
ok.... what is the purpose of the experiment again?...... wait... does it mean that if RF can get in, microwave can get out?
Russia does have consumer protection and in the case of microwave ovens they identify the risk as being to your eyes (scientifically correct, it can cause glaucoma when youare exposed to much I understand) and they advise you to stay at least a 25cm (I think it was), or a 'foot' if you will if you live in backwater US, away from microwave ovens during operation.
I have a question regarding this test, it seems to be a microwave in some livingroom setting, so is the thing plugged into a grounded outlet? and if so is the ground of that outlet actually grounded (sometimes it's not), and also, the inside seems to not be painted so is anything touching between the netbook and the housing since that might turn the microwave housing into an antenna.
US? Backwater?
Kind sir, the microwave oven was invented in the US. http://en.wikipedia.org/wiki/Microwave_oven
Tongue in cheek ;) because the author joked about the russians not having "'United States' Products Safety Commission" and because the US although officially having adopted metric still use foot and inches and such.
Thanks for being so polite btw! :)
Incidentally, the microwave was discovered in the US, but since it's based on RADAR which was invented in britain the US can't claim full credit, also did you read how it was discovered?
"He was working on an active radar set when he noticed that a peanut chocolate bar he had in his pocket started to melt. The radar had melted his candy bar with microwaves. "
Hate to know what that did to his private parts if he's basically standing in a microwave.
Also inventing something that way does sound a bit.. backwater, doesn't it? But that's coincidence in this case.
Haven't you seen MIB? The microwave was handed to us by aliens of course!
Hmmm... I wonder if my *blender* is properly shielded...
Stupid netbook tricks: DIY microwave shield testing = Slow news day, technically uninformed writer.
Scanning for signal is what he wanted to do not pinging, D'OH!
Doesn't seem like a great test - relative power of Microwave vs consumer WiFi anyone?
What is stupid about this? It's a sweet idea.
Except he didn't have the results twittered automatically, tisk tisk.
Or he could have bought one of those little $5 testers you hold around the seams when you are cooking something to see if it's leaking.
I was going to mention that but you beat me to it. I have one of these:
http://www.maplin.co.uk/Module.aspx?ModuleNo=222028
Of course, there's no way to tell if the thing is working unless you actually have a broken microwave - it doesn't react to my phone at all, but it does blip a little if you hold it near a dent in the microwave door when it is running.
We used to have a low tech detector which was some sort of bulb in a plastic case. Microwave doesn't make it light up but a plasma ball does.
Nice. About 15-20 years ago we used these little strips that changed color in the presence of it. Tested them in a radiation lab to make sure they were for real.
If microwaves are so shielded why is it that my old 2.4ghz cordless phone used to sound like crap if the microwave was on (the reciever sat on top of the microwave.
Chances are that had to do with the electromagnetic radiation from an unshielded/badly shielded power cord. The things draw a crapload of power compared to other other kitchen appliances (fridge excluded). It's possible that the current gave off enough of a magnetic field to disrupt the receiver.
Actually... Has anybody tried using a bluetooth earpiece near a running microwave? Something is bugging up my 2.4GHz range... and only when the microwave is on... so...
Yeah... what Mark said...
stop spamming us with your crappy blog
The operating frequency of a microwave is 2.45 Ghz (not the quoted 2.45 Mhz). Wifi, Cordless phones, Bluetooth, etc all use the 2.4+ Ghz range, Wifi channel 9 has a center freq of 2.452Ghz!. It's always nice to know why your head gets warm while using a Wifi/Cordless phone ;-)
Just stay away from hypnotists, you I fear are very susceptible.
Microwaves operate at 2.45Ghz and so do cordless phones (most of them anyway). So it makes sense why you can't use a cordless phone near an operating microwave without either being disconnected or having extreme static. A lot of the wireless singals (namely /b/g) are around 2.45Ghz as well but will vary depending on the channel that it's on. So it only makes sense why microwaves, cordless phones, laptops, and baby monitors are all bad for each other if used at the same time.
Also, put your face near a microwave, you'll feel dizzy, I know I do -- then again I might just be weird or a mutant. Also don't put your face near a microwave, it might cause cancer. =P
Aha, sorry for repeating you Richard, I wrote this before your post (or this page for the matter) was even up. Guess we have hiveminds!
My remark to richard could be mirrored here.
We have 2 microwaves- an old one that got gross and no one wanted to clean, and a new one that my new roommate brought. We switched them out, and I wanted to know which had better shielding.
So I tested this with my iPhone as I have AFP installed (
What the hell is wrong with the comment system?
From above...
AFP is an awesome addon.
So..
On the newer microwave (which was plugged in), I was still able to access my iPhone via wifi and take files off, and actually watch a vid from the folder of my cycorder videos.
When I put it in the considerably older microwave (not plugged in) any connection attempts would time out, and I was unable to make phone calls to it.
Really makes me uncomfortable, looks like I'll be washing the old one and putting it back into use. And putting some kind of extra shielding junk just to be be overly paranoid...
Hmm, you know I also had a feeling for some time now that in the west the government doesn't do any effort any more to safeguard people, dirty restaurants that don't get fined, firetraps that get no citations, USB cables that clearly have no shielding, and now it seems we are finding out microwave ovens aren't shielded anymore, I wonder if you can still sue about that stuff.
well i made a test with microwave, in fact i used 2 new microwaves and they both leaked
and here is the link to my youtube video
http://www.youtube.com/watch?v=ovfviS6rZIQ&feature=channel_page
http://www.youtube.com/watch?v=YZ7tbP6futE&feature=channel_page
http://www.youtube.com/watch?v=sGuoGtLitck&feature=channel_page
from my exoerience all microwaves leak, that is a sad story, and small children often look inside the oven and lean their head close to the source of HF field
if you need to contact me admin@altermedicine.org.