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What Wi-Fi Would Look Like If We Could See It

samzenpus posted about 9 months ago | from the looking-behind-the-curtain dept.

Wireless Networking 120

Daniel_Stuckey writes "Artist Nickolay Lamm, a blogger for MyDeals.com, decided to shed some light on the subject. He created visualizations that imagine the size, shape, and color of wi-fi signals were they visible to the human eye. 'I feel that by showing what wi-fi would look like if we could see it, we'd appreciate the technology that we use everyday,' Lamm told me in an email. 'A lot of us use technology without appreciating the complexity behind making it work.'"

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120 comments

Huh? (5, Funny)

Laxori666 (748529) | about 9 months ago | (#44354767)

I could always see it that way. I thought it looked that way to everyone? I always wondered why when I took a photo I wouldn't see the waves in the photo.

Re:Huh? (3, Insightful)

gl4ss (559668) | about 9 months ago | (#44354831)

I could always see it that way. I thought it looked that way to everyone? I always wondered why when I took a photo I wouldn't see the waves in the photo.

I think it's just your dope supplier playing pranks on you.

anyway the picture is cheesimusmaximus. bullshit scifi drawing - the waves would go so fast that it would color just everything in rainbow hues if it worked like that. in the pics it's also quite projected.. along flat wavy planes.

Re:Huh? (2)

Em Adespoton (792954) | about 9 months ago | (#44355533)

I have to admit, I was hoping for coloured 3-D clouds -- where it actually mapped the signal strength curve of each channel including reflections from each AP.

I was also hoping that someone had developed a CCD that responded in the WiFi wavelengths instead of visible spectrum. Oh well.... maybe someone will visualize it as flying pigs next.

Re:Huh? (0)

Anonymous Coward | about 9 months ago | (#44358989)

Actually it's not. This has been done in the telecom technical field for years. Antennae can be placed in arrays to create a specific "shape" for the beam to focus on the area where you want to provide coverage, and there are several models that help techs calculate signal propagation in each specific terrain and conditions.

An example [cst.com]

I'd venture to say that good wireless networking techs always do their calculations for these things and place antennae and shape the signal accordingly, but the harsh truth is, there are too many situation where this is not the case and we end up with a mess that increases noise and lowers the data rate.

Re:Huh? (0)

Anonymous Coward | about 9 months ago | (#44360151)

The article itself is undiluted horseshit. The author misunderstands light, color, radio waves, and digital signal processing.

Wifi waves are about 3 to 5 inches from crest to crest. The crests of waves is translated to a 1 by a computer, and the the troughs equal a 0.

Wrong. The waves are just like light or radio waves, they're just a different frequency. The waves are radio waves, the ones and zeros are pulses in these waves, like a blinking light. Think "morse code".

Typical wifi waves decrease in amplitude as they travel further from the source which is why the waves are larger to the right and smaller to the left, assuming the source is somewhere near the right of the image.

He seems not to know the difference between frequency and amplitude. The waves don't get smaller as they travel, they get weaker, just as a light bulb is dimmer farther away, but the color doesn't change; the color of light is determined by its frequency.

Anybody who has taken a general studies undergrad entrance level physics course knows this. I'm surprised this sorry story made slashdot, apparently the firehose voters either didn't RTFA (it does sound interesting until you read the bullshit article) or slept through their physics classes (or skipped them and took something easier).

Re:Huh? (5, Funny)

hawguy (1600213) | about 9 months ago | (#44355717)

I could always see it that way. I thought it looked that way to everyone? I always wondered why when I took a photo I wouldn't see the waves in the photo.

Nice one Geordi. Stop going on about how superior your VISOR is. You're blind. We get it.

As a tinfoil hat-smith (3, Funny)

Bill, Shooter of Bul (629286) | about 9 months ago | (#44354791)

I wish they were visible...

Re:As a tinfoil hat-smith (1)

ericloewe (2129490) | about 9 months ago | (#44355105)

I thought tinfoil-hatters made their own to avoid being trapped in a government conspiracy to sabotage tinfoil hats? How's the business?

Re:As a tinfoil hat-smith (2)

AK Marc (707885) | about 9 months ago | (#44355165)

Just make some glasses that can "see" in the RF spectrum used by WiFi and translate it to visual spectrum. Repeat for all other radiations, and compress it all to the visual spectrum. Make the wrap-around goggles into a visor. Possibly tunable and also able to pick up particles (see alpha and beta radiation, or see smells). I'm sure they'd sell. At $1000 each, you'd sell billions. Be a trillionaire. I'm just missing the sensor technology, and test subjects, LeVar Burton keeps turning me down.

Re:As a tinfoil hat-smith (5, Insightful)

rullywowr (1831632) | about 9 months ago | (#44355279)

As an RF Field Support Engineer, I deal with this on a daily basis. The truth is that there is always some kind of noise floor, therefore if you could "see" RF energy it would be a lot different than light (visible) energy as there is ALWAYS some energy around and it would most likely obscure your "vision" of the spectrum. Completely. The question is where is the noise floor and where would you set your "squelch" to be? Also, where are the RF reflections off of solid objects? Where is the phase cancellation from competing waves?

On a side note, we already have technology that can "see" RF...it's called a Spectrum Analyzer. Many are available in many forms. Or you could simply download one of the many Wi-Fi software tools available and visualize what is happening in those (Wi-Fi) regions of the RF spectrum right from your very own computer or tablet. I suppose if you wanted to get downright stupid you could tape a directional RF antenna on your head and pipe the output from your analyzer into a pair of LCD goggles. Woo-hoo.

In other words, this article is downright shit and has zero credibility other than some asshat that was getting fruity on the ol' rainbow gaussian blur in Photoshop over some stock pictures.

Re:As a tinfoil hat-smith (3, Insightful)

Stumbles (602007) | about 9 months ago | (#44355365)

Yes spectrum analyzers are used as you suggest but they show you a side view of a three dimensional wave.

Still though I agree, this artist is nothing more than an asshat.

Re:As a tinfoil hat-smith (2)

BrokenHalo (565198) | about 9 months ago | (#44356589)

My bullshitometer went into the red when I saw how he seems to imagine the radio waves go around a pond, rather than across...

Re:As a tinfoil hat-smith (2)

matrim99 (123693) | about 9 months ago | (#44355385)

Agreed; I RTFA in order to learn something about the patterns for broadcasting, reflecting, and cancelling out of these waves. Instead, the images were created by someone who has less of a clue about radio waves than even I do, and they didn't even try to visualize anything even remotely close to reality.

TLDR: Ooh, pretty colors.

Re:As a tinfoil hat-smith (4, Funny)

the_other_chewey (1119125) | about 9 months ago | (#44357047)

Yup, this is worthless.

in TFA, the person creating the pretty images is cited:
"Wifi waves are about 3 to 5 inches from crest to crest.
The crests of waves is translated to a 1 by a computer,
and the the troughs equal a 0.
"

I laughed out loud and closed the tab.

Re:As a tinfoil hat-smith (0)

Anonymous Coward | about 9 months ago | (#44357633)

I'm sure they mean crests are 1.0 and troughs are 0.0 (as in floats/doubles). But yea, totally idiotic and a lot of people are going to be misinformed based on the comments so far.

Re:As a tinfoil hat-smith (2)

JakartaDean (834076) | about 9 months ago | (#44359213)

Yup, this is worthless. in TFA, the person creating the pretty images is cited: "Wifi waves are about 3 to 5 inches from crest to crest. The crests of waves is translated to a 1 by a computer, and the the troughs equal a 0." I laughed out loud and closed the tab.

I had exactly the same reaction. WTF??? He had an expert astrobiologist advisor too... I guess he calls a baker when he wants his hair cut.

Re:As a tinfoil hat-smith (1)

AK Marc (707885) | about 9 months ago | (#44356389)

I used to do what you do. A spectrum analyzer "sees" RF the way a sound meter "sees" sound. Play music for it, and you might be able to guess the work based on beat, peaks, and such, but it doesn't "see" it in any manner that's intuitive to a person, like a frequency conversion to visible light. That would be the real trick. And yes, people would just not get it. A high noise floor would have the world in a bright white haze, trying to pick out flashes of color. Like picking out an airplane diving out of the sun. There'd have to be some noise cancellation, like the noise cancellation headphones to make such a view of any use to a human.

Re:As a tinfoil hat-smith (0)

Anonymous Coward | about 9 months ago | (#44357687)

If you want to get real stupid tape two Directional RF antennas to your head and pipe the outputs to the oculus rift. RF in 3D!

Radar (2)

lobiusmoop (305328) | about 9 months ago | (#44354801)

Wifi is just microwave radiation. We already 'see' microwave radiation, it is called 'radar'.

Pictures entirely wrong (4, Interesting)

Roger W Moore (538166) | about 9 months ago | (#44356301)

We already 'see' microwave radiation, it is called 'radar'.

No we do not see it - our eyes are not sensitive to that region of the EM spectrum. We can detect it but that requires a device which detects the waves and then displays the information to us in a human accessible form like radar, radio or TV. If we could see WiFi then it would look nothing like the artist's rendition. For a start we would not see the crests and troughs of the wave anymore than we see the crests and troughs of light waves or hear the crests and troughs of sound waves. Then there is the problem that the artist seems to have drawn the waves and lines or planes from which light is emitted. Again this is wrong. Unless something is scattering the EM waves you will not see them unless they are aimed at you. This is a classic mistake made by artists. Think of a laser pointer - unless there is dust in the air to scatter some of the beam in your direction you only see the spot on the projection screen not a beam between the pointer and the screen.

What you would actually see if you could see WiFi would be a glow of a fixed 'colour' emanating from the router and visible through walls and other radio-transparent objects. Metal objects would reflect this light so really what you would see is one bright spot that might appear in the middle of a wall or a floor etc plus several other less-bright spots due to reflections off metal.

Now you might argue that this is overly nitpicking on an artistic work but if an artist comes up with a clever idea like this is it really too much for them to actually put a little thought into it and read up some simple physics to figure out what it might actually look like? Afterall if they decided to draw an elephant without ever having seen one wouldn't they take the time to read up about them and either find a picture of one or visit one in a zoo. It would be insane to try to draw one without this and I doubt anyone would recognize it as an elephant if they tried. Well guess what - the same applies if you are trying to draw something physics related!

Er.... wifi IS radio... (5, Insightful)

jerel (112066) | about 9 months ago | (#44354819)

This quote is a little off: "The distance between wifi waves is shorter than that of radio waves...". It is radio, at 2.4 GHz. (first post?)

Re:Er.... wifi IS radio... (5, Insightful)

black3d (1648913) | about 9 months ago | (#44355017)

Yeah, there's a lot of technical errors in the article. All we know for sure, is that he can photoshop rainbows onto photographs. I'd take anything else stated there with a grain of salt.. Most of the "technical" information about wifi in the article is incorrect.

Re:Er.... wifi IS radio... (1)

Russ1642 (1087959) | about 9 months ago | (#44355745)

I wasn't going to read the article after I saw how stupid the pictures were. Apparently WiFi has all the characteristics of colourful soap bubbles.

Re:Er.... wifi IS radio... (0)

Anonymous Coward | about 9 months ago | (#44355045)

This quote is a little off: "The distance between wifi waves is shorter than that of radio waves...". It is radio, at 2.4 GHz. (first post?)

A bunch of things are off. WiFi is a type of microwave radio. I'm guessing by radio he means FM radio, still this quote:

The distance between wifi waves is shorter than that of radio waves and longer than that of microwaves

is just wrong. WiFi is the same wavelength as microwave ovens. Newer 5 GHz WiFi is even shorter than microwave ovens.

Wifi fields are usually spherical (like the one here) or ellipsoidal and extend about 20-30 meters, assuming a typical off the shelf wifi box.

This seems to confuse the spherical expansion of radio waves with the always non-spherical antenna pattern. The differences in frequency between channels is very small compared to the carrier frequency. These visualizations exaggerate that greatly. I could list more, but that's enough.

All in all, it was a good try, but he should have consulted with someone, say a HAM at some point. I've tried to represent radio waves myself (for academic papers) and it's an almost impossible task.

Re:Er.... wifi IS radio... (0)

Anonymous Coward | about 9 months ago | (#44355819)

. WiFi is the same wavelength as microwave ovens. Newer 5 GHz WiFi is even shorter than microwave ovens.

Or even older WiFi is shorter than some microwave ovens. A lot of commerical ovens use 900 MHz.

Re:Er.... wifi IS radio... (1)

Trogre (513942) | about 9 months ago | (#44358255)

Kindly wipe the aspergers from your mouth and note that further down the page he states, "Wifi occupies the radio frequency band of the electromagnetic spectrum between actual radio waves and microwaves".

He is clearly using the term "radio waves" to describe waves in the portion of the RF spectrum reserved for wireless audio receivers, normally modulated either by amplitude or frequency, commonly known as radio.

It would look like light (4, Insightful)

tom17 (659054) | about 9 months ago | (#44354823)

Surely it would just look like light (with a different 'colour'). Things that block it would not appear to give off light, things that allow it to pass would appear to glow, and things that reflect it would just be visible if there is already some ambient wifi 'light' to reflect.

Is this actually how things work at these lower frequencies? Or would it work completely differently in regards to how it refracts/reflects etc?

Re:It would look like light (1)

Anonymous Coward | about 9 months ago | (#44354937)

As best I can figure, you have it exactly right. A wifi antenna would look much like a light-bulb.

Re:It would look like light (0)

Anonymous Coward | about 9 months ago | (#44355029)

Exactly, this guy is an artist, an this is just an artistic representation. It's not what we'd see in reality; in addition to your list we'd see a flickering/color-changing light coming from the transmitters, like we'd see like from a light bulb. Not waves traveling through the air.

Re:It would look like light (1)

Qzukk (229616) | about 9 months ago | (#44355135)

It seems like the obvious thing to do would be to scale the signal to visible light range then show us the result, but I'm guessing that's not artistique enough for the artist.

Though now I'm kind of curious as to what wifi would look like when it's scaled to visible light range.

Re:It would look like light (1)

tibit (1762298) | about 9 months ago | (#44359551)

This guy is an artist and this is nothing but an excuse for being a dumb fool, that's all. You know how artsy-fartsy people snicker when a non-artistic nerd doesn't know basics of art history and style? Well, that's the same reason that the nerd snickers when an artsy-fartist has no clue about basics of electromagnetics at a freshman introductory level. Both artsy-fartists and nerds should be reminded that while not everyone is interested in the same thing, neither is everyone to be expected to be a complete ignorant of other things. General education and all that jazz, what happened to it?

Re:It would look like light (4, Informative)

chuckinator (2409512) | about 9 months ago | (#44355173)

The graphic shows 2 perpendicular waves centered on the transmission axis. I understand he's trying to depict the I and Q components of a signal, but it's just a singular, corkscrew waveform in real life that we cannot easily map from 3D to 2D in most educational graphics on the subject. Some of the fancier radio chains compute the jQ component because the Nyquist frequency of the ADC in the baseband receiver only has to equal the frequency of your baseband instead of 2x the baseband frequency when you're only sampling the I component.

This is just nitpicking, but the wavelengths are HUGE. I understand that it's impossible to depict a wavelength in nanometers without resorting to showing a fuzzy cloud and saying that there's not enough pixels to show the discreet waveforms. tom17 is dead right when he says it would look like light, because all the scattering and reflection and refraction occurs with visible EMF as well as radio.

Re:It would look like light (1)

tibit (1762298) | about 9 months ago | (#44359577)

The perpendicular waves on an axis got zero to do with I/Q components, sorry. The I and Q components are a way of re-representing the phase and amplitude in a way that's more convenient to further process. There's no such thing as I and Q components once you're outside of your transceiver box, similarly to there being no prime factorization magically appearing on the blackboard every time you write down an integer. Just as prime factorization is a way of representing integers, the I and Q decomposition is a way of representing signals given a certain reference source of some frequency and phase.

Re:It would look like light (2)

hyperquantization (804651) | about 9 months ago | (#44355425)

This is exactly how it works. The only difference is, at longer wavelength/lower frequencies, the size/density of objects that are considered opaque is higher (a person is roughly large/dense enough to block RF, a toothbrush is not), while each photon is less easily scattered or refracted.

You could even go so far as to say the perceived color also depends upon the channel within the Wi-Fi spectrum, much like the false-colored images of non-visible astronomical imagery (e.g.: Cosmic Microwave Background radiation [wikimedia.org] ).

Re: It would look like light (1)

Anonymous Coward | about 9 months ago | (#44355673)

Seems like ray tracing a falsw-color scene with WiFi antennae as the light sources might make for a more useful (though maybe not entirely interesting) visualization...

Re:It would look like light (1)

X0563511 (793323) | about 9 months ago | (#44355577)

Rather, it would look much like the world does now, but lots of things would be translucent/transparent and the IORs for things would be completely different.

You'd also see some phenomena [wikipedia.org] which is much harder to see with the naked eye and visual light.

Re:It would look like light (1)

sjames (1099) | about 9 months ago | (#44357861)

There would be a few differences due to the wavelength involved, such as radio shadows having fuzzier edges than light shadows, but you have the basic idea.

Re:It would look like light (1)

tibit (1762298) | about 9 months ago | (#44359537)

You're spot on. It'd work exactly like light, just much longer wavelength. Speaking in orders of magnitude, 2.4GHz is a 10cm wave, visible light is a 1um wave. The difference is 5 orders of magnitude (100,000).

If we were to see radio waves of such a length, Wi-Fi would be a particularly uninteresting kind of a signal. A Wi-Fi node would look to us like an equivalent of a rather low power indicator lightbulb with some tint applied to the glass. It'd flicker, too. Why incandescent? Because it's broadband, not narrowband ("monochromatic") like an LED. Why tinted? Because a Wi-Fi channel can be centered on one of a couple of different frequencies, so it's an equivalent of a tinted light bulb. Why flicker? Because Wi-Fi is half-duplex.

Of course, if we'd put ourselves in a dark room (otherwise known as a Faraday cage), things would be more interesting as could see standing nodes and zeroes around objects. You could also focus Wi-Fi with a plastic lens, but it'd need to be the size of a large serving plate.

Wi-Fi, compared to any other signal, would be very much drowned out if we had similar receiver sensitivity compared to our eyes. It'd also be a pain in the butt to get a room dark enough to sleep in - a Faraday cage would be a must, with shielding screens over the air ducts lest those act as waveguides.

Ad supported post... (0)

Anonymous Coward | about 9 months ago | (#44354839)

So what's the use of the 'a blogger for MyDeals.com'-line? I thought I actually ticked the 'i don't want to see ads'-option on Slashdot...

Re:Ad supported post... (3, Funny)

pspahn (1175617) | about 9 months ago | (#44354899)

The bloggers at MyDeals.com are some of the most forward thinking RF engineers on the planet, though, be sure not to confuse them with the exceptional Geo engineers often found blogging for FreeCreditReportOnline.com... those guys are genius.

TFS should have read... (0)

Anonymous Coward | about 9 months ago | (#44354847)

"Artist Nickolay Lamm, a blogger for MyDeals.com and Barbie photoshopping enthusiast"

Some people (1)

mstefanro (1965558) | about 9 months ago | (#44354851)

also wonder what the waves in the visible spectrum look like.

So where's the smartphone app? (1)

Animats (122034) | about 9 months ago | (#44354875)

There should be an app for this. You walk around in an area to gather data, and then you can look at where the WiFi signals are. Maybe share this with other phones nearby, so you can crowdsource a view of the WiFi landscape.

Re:So where's the smartphone app? (0)

Anonymous Coward | about 9 months ago | (#44355007)

Not an app on a smartphone, but pretty cool:

http://vimeo.com/20412632

Not So Much WiFi (0)

Anonymous Coward | about 9 months ago | (#44354889)

This is what it would look like for all radio frequency(RF) devices.

Television is a Radio Frequency device. Mind asplode.

Yawnnnnnnnnnnnnnnnnnnnnnnnnn

Is the article confused? (4, Insightful)

black3d (1648913) | about 9 months ago | (#44354923)

>The crests of waves is translated to a 1 by a computer, and the the troughs equal a 0.

So, every Wifi signal is "10101010101010101010101010101010..."?

Re:Is the article confused? (0)

Anonymous Coward | about 9 months ago | (#44355027)

>The crests of waves is translated to a 1 by a computer, and the the troughs equal a 0.

So, every Wifi signal is "10101010101010101010101010101010..."?

Is the article confused? Let's see -- an artist and a third-rate blogger attempts to visually portray a scientific phenomenon... Nah, he probably got every detail exactly accurate!

Re:Is the article confused? (2)

kamakazi (74641) | about 9 months ago | (#44355109)

Yeah, I looked at those troughs and crests and said
"Wait, that isn't wifi, I don't see any Orthogonal frequency-division multiplexing there, he must have accidentally visualized the NSA scanner waves protecting Washington DC from any stray intelligence"

And then I realized the NSA scanner waves must really work.

Re:Is the article confused? (1)

Anonymous Coward | about 9 months ago | (#44355223)

>The crests of waves is translated to a 1 by a computer, and the the troughs equal a 0.

So, every Wifi signal is "10101010101010101010101010101010..."?

One or two readers might not have the physics or communication theory background to get that. The data is encoded in slight variations in the wave, not in the peaks and troughs of the wave. You can make them closer together or further apart, or change the phase or amplitude, but for every trough there will be a peak and they will always alternate. All the peaks and troughs do is set the frequency band we're operating in (ie 2.4 GHz for wi-fi).

Re:Is the article confused? (1)

jones_supa (887896) | about 9 months ago | (#44355311)

There's probably also an extra modulation scheme to make the signal more suitable to air transport which also shuffles the bits around. Just like when you use copper, you don't want long strings of 1s and 0s but rather to keep the wire alive.

Re:Is the article confused? (2)

Pinhedd (1661735) | about 9 months ago | (#44355361)

Yes, the article is very confused. Wifi standards do not measure just the amplitude of one stream to separate ones from zeroes. It has to measure the amplitude of two separate streams as well as their phase angle. The exact method of coding depends on the data rate but in general most methods boil down to Binary Phase-Shift Keying (1 bit per symbol), and Quadrature Amplitude Modulation (2, 4, or 6 bits per symbol for 4-QAM, 16-QAM, and 64-QAM respectively).

can't be interrupted by other signals? (1)

sl4shd0rk (755837) | about 9 months ago | (#44354955)

Bah.. Decided entire TFA was trash once I read that line.

Re:can't be interrupted by other signals? (1)

AK Marc (707885) | about 9 months ago | (#44356209)

A wave itself isn't interrupted, but the ability to extract data from it can be. Like two intersecting waves in the water cross without greatly affecting the other. Like saying you can't see the green in white light. It's not that green isn't there, it's that you just can't pick it out of white light.

What is electricity? (1)

binkless (131541) | about 9 months ago | (#44355041)

This reminds me:

I once heard an explanation - geared towards children - of what electricity is. It went somewhat like this - "Don't ever ever ever do this, but, if you were to cut open an electric wire and look inside it, you would see a blue spark. That is electricity"

Re:What is electricity? (4, Funny)

Obfuscant (592200) | about 9 months ago | (#44355071)

And don't ever ever do this, but this is what electricity tastes like...

Re:What is electricity? (0)

Anonymous Coward | about 9 months ago | (#44355417)

Just like Chicken!

Wouldn't it leave the antenna in spheres of waves? (1)

DickBreath (207180) | about 9 months ago | (#44355107)

Wouldn't the signal leave the antenna structure as a waves of spheres? Not lines? The spheres would be strongest at the top of the "sine wave" and absent at the bottom of the wave. Sort of like sound is spheres of compression of denser and less dense.

Think of the crest of each sine wave as an expanding sphere, followed by more and more spheres all expanding from the antenna.

As a particular wave crest (eg sphere) expands from the center point, which is the transmitting antenna, the energy at any point on the surface of the sphere is decreased as the square of the number of furlongs it has traveled from the antenna.

Being an electromagnetic wave the magnetic wave and electrical charge wave are out of phase with each other. Wouldn't spheres of magnetism be strongest at the point where the spheres of electrical charge disappear -- and vice versa -- spheres of electrical charge are strongest at the places where magnetism goes to zero?

Or am I imagining or understanding this wrong? (I mean, I have little more than basic general science level understanding of electromagnetic waves.)

If we 'see' it, like we see light, then would we see the waves (spheres) at all? Wouldn't we just see bright spots where antennas seem like sources of illumination? And some materials are opaque and cast 'shadows' and other materials are transparent to WiFi? (eg, a black plastic garbage bag might be 'transparent')

Re:Wouldn't it leave the antenna in spheres of wav (2)

Media_Scumbag (217725) | about 9 months ago | (#44355349)

More like a donut than a sphere, commonly, but it all comes down to the type of antennae alignment of antennae, and the frequency and amplitude of the waves.

More PhD plagerism (0)

Anonymous Coward | about 9 months ago | (#44355137)

This is just copying what Richard Hammond did a few years ago.

Light vs Light (4, Interesting)

elistan (578864) | about 9 months ago | (#44355139)

There are fourteen WiFi channels, each corresponding to electromagnetic radiation ranging from 2412 MHz (12.43 cm) to 2484 MHz (12.07 cm.) The visible light we see with is also electromagnetic radiation, but ranges from 700 to 390 nm wavelength. I'm not sure what materials reflect, absorb and transmit 12.43 to 12.07 cm wavelength light, but once that's accounted for wouldn't "seeing" WiFi essentially be the same as seeing a rapidly flashing, single colored (assuming it was operating on a single channel,) omnidirectional light bulb? The rainbow emanations in TFA strike me as pretty artistic interpretations, which is apparently the point in order to drum up "appreciation" for WiFi, but my IANAP (I Am Not A Physicist) understanding suggests there's little to do with reality here.

Re:Light vs Light (1)

Anonymous Coward | about 9 months ago | (#44356053)

First of all, we would see very little of the "volume", because air doesn't scatter 2.4GHz that much. Maybe the environment would look very lightly foggy. Secondly, we would see objects illuminated by Wifi if they reflect the signal in our direction. Absorbing surfaces would be dark, like a green surface illuminated by a red light. Most non-metal objects would be more or less translucent, but glas would not be as transparent as we know it. Someone should run a detailed model of a park, a house, etc. through a lightmap renderer, but with 2.4GHz radio propagation rules instead of visible light propagation rules. It would not be sufficient to change the translucency and reflective properties of the materials, because radio waves don't propagate along straight lines like light does.

Re:Light vs Light (0)

Anonymous Coward | about 9 months ago | (#44357123)

Radio waves don't propagate in straight lines? Does it propagate in curved lines? Unless my understanding of electromagnetism is fundamentally flawed, radio waves, like all other electromagnetic waves, propagate in straight lines as either photons or waves depending on how you look at them. (ignoring effects of gravity, refraction and that kind of thing)

Re:Light vs Light (0)

Anonymous Coward | about 9 months ago | (#44356765)

especially when the first image appears to show the waves increasing in amplitude the further they get from the source ... I always thought that EMR followed an inverse square law ... just saying

Immaterials = better (0)

Anonymous Coward | about 9 months ago | (#44355145)

Already done, much better elsewhere,...
http://www.nearfield.org/2011/02/wifi-light-painting ...though since it was not in the US, the slashdot community will ignore it.
a Coward.

Re:Immaterials = better (0)

Anonymous Coward | about 9 months ago | (#44355879)

Or maybe Slashdot already covered that, a timely single month after it was posted: Light Painting Wi-Fi [slashdot.org]

100% inaccurate. It's art and is not reality. (5, Insightful)

Lumpy (12016) | about 9 months ago | (#44355197)

No reflections, no lobes from the gain antennas, no blockage from green trees. It's 100% art with 5% reality.

Re:100% inaccurate. It's art and is not reality. (1)

ram.loss (151102) | about 9 months ago | (#44355595)

No reflections, no lobes from the gain antennas, no blockage from green trees.

... lame

Re:100% inaccurate. It's art and is not reality. (0)

Anonymous Coward | about 9 months ago | (#44355701)

I was about to post along these lines too...... Will add here that they're not perfect sine waves either as this is what's depicted - you require modulation to send information.

Re:100% inaccurate. It's art and is not reality. (1)

SnarfQuest (469614) | about 9 months ago | (#44355829)

No interactions with cars, power lines, interactions between other towers, geological features, buildings, peope, ....

WIFI siglans would never look so pretty.There would be great disturbances in the force.

Re:100% inaccurate. It's art and is not reality. (0)

Anonymous Coward | about 9 months ago | (#44355977)

with 5% reality.

The artist is probably not reading Slashdot, so you didn't have to be so generous with the sugar coating.

Re:100% inaccurate. It's art and is not reality. (1)

bill_mcgonigle (4333) | about 9 months ago | (#44357881)

yeah ... I've done a little bit of designing WiFi networks to work in very difficult locations, and the general thought experiment is to think of both ends of the path as the points of a football. Unless there's ground in the way, in which case the football goes through the earth, except when it doesn't. Or if there's a metal roof inside the football, except all of that is illusory and not really what it looks like, to the extent that anything exists and is not virtual. It's not like visible light in its behavior, and these get wildly different at different frequencies.

I get the impression that Tesla could visualize it, but most humans just don't have it in them.

Re:100% inaccurate. It's art and is not reality. (0)

Anonymous Coward | about 9 months ago | (#44359451)

Not to mention that proper footballs are round.

(Sorry)

Nope (0)

Anonymous Coward | about 9 months ago | (#44355219)

No, WiFi does not go in one direction. It would be more of a haze, denser in one area and less dense in another. It would be moving out from antennae, with the strength noticeably weaker behind some obstructions. You could visually see the inverse-squared law if WiFi weree visible.

The OP is full of $#!T.

the real question is... (0)

Anonymous Coward | about 9 months ago | (#44355241)

what would a cat5 cable look like if I could see it?

Re:the real question is... (0)

Anonymous Coward | about 9 months ago | (#44357715)

8 tubes with pairs twisted like a double-helix.

He might be an artist... (1)

Stumbles (602007) | about 9 months ago | (#44355305)

but he is wrong about how "wifi" would look. IOWs, he (the artist) and the OP is full of shit.

Really wanna know how they'd look in meatspace? (1)

Media_Scumbag (217725) | about 9 months ago | (#44355327)

Buy a copy of AirMagnet Surveyor or another viz tool, an AP, a supported wifi NIC, and get a hold of some blueprints for the space in question.

Basically he reinvented a heat map? (0)

Anonymous Coward | about 9 months ago | (#44355339)

In a large WiFi deployment step 1 is to do a wireless site survey and generate a heat map. A physical map of the building showing all the WiFi signals.

In many large deployments there is also technology in use to map the Wifi signal real time, for instance Cisco's Wireless LAN Controllers: http://www.cisco.com/en/US/docs/wireless/wcs/4.0/configuration/guide/wcsmaps.html

Now, this guy is doing something slightly novel in that he's mapping multiple WiFi sources in a public space. But I doubt many NOC guys would find this all that interesting, since they stare at screens of it all day long.

It's blue lines silly! (1)

wjcofkc (964165) | about 9 months ago | (#44355375)

Some odd time ago I was in a training class for a job supporting smart phones and similar devices (oh god I have fallen so far from grace!). The instructor scribbled a quick visualization of signals from a cell tower and wifi. She drew crude waves emanating from a tower and wifi device (she drew them in blue)--of course we all got it, right? There was one student in the class who stopped everything to mention that he lived very close to a tower and never saw these blue waves emanating from it or his wifi router, and wanted to know why. With the exception of those chuckling, the class was otherwise stunned into silence. The individual was asked to not return the next day.

Completely wrong (1)

grumbel (592662) | about 9 months ago | (#44355383)

The idea is nice, but the actual images are completely wrong. WiFi is just electromagnetic waves and those in turn are nothing other then light at another wavelength, i.e. a different color if you will, see this infrared image [cloudfront.net] . This means being able to see WiFi signals would look fundamentally no different then just seeing ordinary light. You wouldn't see waves shooting out of your router, as you can't see waves unless they actually hit your detector, so the thing would simply glow like a light source. The thing where it gets interesting is in how different materials react to the WiFi, materials that are obaque to regular light would be transparent for WiFi signals, while others that are transparent for light would be opaque to WiFi. How much or how little WiFi gets reflected would also change. Being able to see how directional the signal of different antenna could also be interesting. There might also be issues with image resolution, as the wavelength determines how good you can resolve an image (not sure if that's just a practical limit of detector size or actually a physical limit).

Anyway, some simple photoshopping won't cut it, it would probably need a raytracer to simulate the wave propagation properly.

Re:Completely wrong (0)

Anonymous Coward | about 9 months ago | (#44355665)

Absolutely!! There'd be no reason PovRay couldn't be loaded up with a bunch of fresh surface data for the models. The antenna's are "light sources" and the shape of the antenna would be modelled as a light source with some fancy emission structure/shape.

The end result would be really cool. Anyone with more time on their hands want to give it a crack?

Re:Completely wrong (0)

Anonymous Coward | about 9 months ago | (#44355917)

Geometric optics might be good enough for the outdoor scenes. But if you wanted to create an image indoors of say a router sitting on a desk, you might run into diffraction and interference effects that wouldn't be captured by PovRay.

I know exactly what it would look like (1)

neminem (561346) | about 9 months ago | (#44356009)

Watch Alphas, and you can too!

"You have bad breath. Yeah, Cindy Wellin, she said she'd rather lick a toilet seat than kiss you. It got 47 retweets."

I'm not sure what is worse... (0)

Anonymous Coward | about 9 months ago | (#44357377)

The a loose artistic license visualizing a wave, or the insane amount of bullshit in this thread.
I'm seeing stuff from "a spectrum analyzer is the size view of a three dimensional wave" to "crests of waves are 1" ....

National Mall? (0)

Anonymous Coward | about 9 months ago | (#44357629)

article mentions National Mall in Washington city, not state. all this time i thought the national mall in the US was a big shopping center with department stores. i need to get out more

but seriously, the radio waves in the photos/renders look like artwork to me.

Isn't this obvious? (0)

Anonymous Coward | about 9 months ago | (#44357763)

OK, sorry, before I took computer science (BSc) I went to college and got an ASc in Electronics Engineering. Studied electromagnetic radiation. Yep, radar, cell phone signals, radio, tv, microwave, radar, police radio, fire/ambulance, air traffic, millitary, space communications, satellite tv, baby monitors, cordless phones, microwave relay, CB and Ham radio, wireless keyboards, aircraft and police radar, and every other damn thing under the sun (including wifi) are all surrounding you, right now. Some are more line of sight (higher frequencies), and some more easily scatter around objects and refract on the ionisphere and travel around the earth (lower frequencies). Yep. The different frequencies can be called channels, be they wi-fi, tv, ship to shore, cell phone or fire/ambulance. Sometimes I'm shocked about how little other people know about technology. I won't talk about superposition theory, nortons theory, thevenins theory, superheterodyne receivers, tank circuits, mixers, phase locked loops or any of that other stuff. Today we are grasping em radiation. Did you know that at even higher frequencies (even Higher than wifi) we call it ....wait for it.... light? Damn! Only there, instead of talking about lower and higher frequencies, we say "it looks red" or "it looks blue".

It's hard to see waves unless it reflects (2)

ceview (2857765) | about 9 months ago | (#44359113)

This is imagery in the article is really very misleading. What would be more meaningful to set the visible spectrum to black ( so no colour for the buildings) and then set some colours for each individual wifi transmitter. In fact it would look more like an image of Earth from space with only the lights showing, but rather than light it would be a microwave image. It would probably show only the faintest outline of buildings as the RF is absorbed creating an odd looking set of structures. But to 'see' the RF you would also need to set up a kind of 'RF reflective' fog particles in the scene to view the reflections ( a bit like the way you need dust to see a laser beam in the dark)

What? (1)

Yvanhoe (564877) | about 9 months ago | (#44359397)

These pictures are half-assed photoshops, they do not come for real measurement, they do not vizualise anything. They give an "artistic rendition", and a fake one that is. In the real world, radio waves do not cross a wall or a window the same way, they bounce back, they resonate... If you want to see a cruder yet more information-bearing representation of a wifi signal's attenuation, check this instead: http://hackaday.com/2011/03/02/how-to-find-wifi-carry-a-big-stick-and-use-long-exposures/ [hackaday.com]

Pollution! (0)

Anonymous Coward | about 9 months ago | (#44359507)

No wonder the bees have fucked off.

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