Now, I can see wifi signals.

February 16, 2015 5:44 PM

Most of us are surrounded by a myriad of radio signals. Some inspired people have taken the opportunity to enable us to see them. Often seemingly random but with a semblance of pattern, the Rayleigh fading model describes much of what you see. via Hacker News
posted by escher (13 comments total)

So that's what the Bessel functions are for.
posted by PMdixon at 6:05 PM on February 16, 2015

For some reason, giving the answer "Rayleigh fading" when our business development guys ask me "Why can't I figure out how far something is based on the strength of its RF signal?" doesn't get me very far.
posted by doomsey at 6:19 PM on February 16, 2015 [5 favorites]

Nice post. I've always wondered what it would look like if I could see the radio waves around me. That imgur link helps.
posted by double block and bleed at 6:35 PM on February 16, 2015

Heh, as a physicist, I learned that Bessel functions are for quantum.

This is a neat visualization, thanks!
posted by sgranade at 6:41 PM on February 16, 2015 [1 favorite]

This is not particularly groundbreaking, this is straight out of a textbook. I remember doing something like this in my high school physics class, plotting signal strengths, and ultimately the interference pattern of two microwave emitters. Except we didn't have digital stuff, we had a sheet of graph paper, a pencil, and a microwave receiver connected to an oscilloscope. I just slid the receiver along the graph paper lines and drew dots where the amplitude maxed out. And yes I did correctly complete the assignment, calculating the unknown frequency of the emitters, using a slide rule. Now get off my lawn.

I was curious about this bit..

But PhD student Luis Hernan has changed that by designing a system..

Okay.. a PhD in what exactly?

..an interaction paradigm based on the emergent architectonic network created in physical research spaces. His current research endeavours concentrate in adaptive architecture, digital thickening of space and hertzian waves.

Hertzian waves? Perhaps you mean Radio? Or did you mean Retroencabulation?
posted by charlie don't surf at 6:55 PM on February 16, 2015 [7 favorites]

I bought a $20 software defined radio and now I can walk around with my phone and see what the spectrum looks like in real time. Although it doesn't go up to wifi ranges, the aviation bands are interesting to explore.
posted by miyabo at 7:05 PM on February 16, 2015

wifi light stick
posted by BungaDunga at 7:50 PM on February 16, 2015

The Luis Hernan pics were kind of bugging me and I just do not believe those colors in the pics represent any real phenomenon. But someone check it out for me, he wrote an Android app called Kirlian Device mobile, it's mentioned in his video (no it obviously has nothing to do with Kirlian photography). I don't have an Android phone to test it, supposedly it changes colors in response to your wifi signal strength. Sure it makes pretty pictures with a device that apparently changes color nearly at random in response to a wifi signal. But I don't see how the long exposure "light painting" is connected to any real physical phenomenon.

This all reminds me of a friend who told me she didn't want to go into the back of a cafe because it was too close to their wifi router, and too many people with too many laptops in the back room gave her a headache. She said she was wifi sensitive. And then we sat down in the front room near the street, she fired up her laptop, and connected to their wifi.
posted by charlie don't surf at 9:07 PM on February 16, 2015 [1 favorite]

These pictures are neat, but I wish I had never seen them. I would have been much happier going through life not knowing how we are bombarded by radio waves. I mean I knew it, but I just never thought much about it. I doubt there is anything wrong with it, but it bothers me that the more bars on my wifi, the more I am enmeshed in radio waves. I know I am coming from a place of ignorance, but ignorance can actually be bliss.

charlie don't surf has a funny story about not going to the back of the restaurant. However, I too don't want to go back there but for a different reason but similar to my feelings above. I don't want to see the sausage being made. I come to this restaurant because I like the food. THere is no upside to me seeing it being prepared. Well, I like the wif a lot, but I don't want to see it.
posted by 724A at 10:42 PM on February 16, 2015

There are some interesting parallels with this project: Christina Kubisch's Electric Walks.
posted by dubitable at 6:34 AM on February 17, 2015

Here is a pretty fascinating hi resolution analysis of wi fi signals,.
posted by Just this guy, y'know at 7:36 AM on February 17, 2015

charlie don't surf: Okay.. a PhD in what exactly?

..an interaction paradigm based on the emergent architectonic network created in physical research spaces. His current research endeavours concentrate in adaptive architecture, digital thickening of space and hertzian waves.

Gack. This guy is a weapons-grade bullshitter. Good catch, charlie.
posted by IAmBroom at 8:51 AM on February 17, 2015

724A, if it makes you feel any better humans have been surrounded by perpetual radio waves since the very beginning, since before we were human! In a nutshell, radio wave pulses from lighting cause the gap between Earth's surface and ionosphere to ring like a bell with radio energy. Granted that's at very low frequencies, and weaker than something like wi-fi, but it does change the story a little to know we've always been living in a radio cloud of some sort.
posted by traveler_ at 8:43 PM on February 17, 2015