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/diy/ - Do-It-Yourself

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Anonymous 05/15/14(Thu)12:21 UTC+1 No.638614 Report

hello /diy/

i want to build a shielded tent for an art project. basically what i want it to do is to block wifi and cell reception. i'm currently looking into different shielding materials.

can anyone of you suggest a certain material or can tell me if this is even possible?
Anonymous 05/15/14(Thu)12:27 UTC+1 No.638616 Report

it's called a Faraday cage
Anonymous 05/15/14(Thu)12:27 UTC+1 No.638617 Report

Tinfoil will work against alot of signals and it's light. Not 100%sure about it. I'll look into it and get back to you
Anonymous 05/15/14(Thu)13:16 UTC+1 No.638626 Report

Purchase a jammer?
Anonymous 05/15/14(Thu)13:22 UTC+1 No.638631 Report

does the tinfoil need to be wrapped tightly around the mobilephone? and how perfect would it need to be sealed?

they are illegal. so not an option
Anonymous 05/15/14(Thu)15:08 UTC+1 No.638654 Report

I'd say implement some sort of Faraday cage design in between two layers of whatever fabric you want to use. you'd have to make your own tent cover as well as the zipper door out of the stuff.


its what I got after a quick Google for "Faraday fabric"

best of luck
Anonymous 05/15/14(Thu)15:13 UTC+1 No.638656 Report

>for an art project
That's the stupidest excuse I've ever heard. How about you stop insulting everyone's intelligence and tell us the real reason?
Anonymous 05/15/14(Thu)15:26 UTC+1 No.638660 Report

It needs to create a sealed cage around the phone.
It's got to be tight in order to block the radio signals.
Anonymous 05/15/14(Thu)15:47 UTC+1 No.638667 Report

if the whole tent is made out of this fabric then any device inside the tent would not be able to send or receive external signals.
Anonymous 05/15/14(Thu)17:39 UTC+1 No.638687 Report

Anonymous 05/15/14(Thu)17:44 UTC+1 No.638690 Report

the faraday cage also needs to be grounded to work properly. You could probably just do ot with a wire wrapped around a metal tent peg.

tinfoil is probably too delicate to work with. Check YouTube for mythbisters faraday cage. They used a copper screen mesh or something. Probably expensive as fuck. You could probably get a steel one cheaper that would still work.
Anonymous 05/15/14(Thu)20:03 UTC+1 No.638753 Report

If you have a ton of money you could buy a electronic jammer. It would block cell and wifi signals. The problem is that it is very expensive and most consumer modals have very short ranges.

I don't know how one would DIY a jammer so I can help in that way. I also do not think that a Faraday cage would work in a conventional tent form but if you are creative enough I guess you could make a faraday cage that kind of looks like a tent.

If this is really for a art project, any chance you could give the details/reasoning you are going into this? It is obviously conceptual in nature.
Anonymous 05/15/14(Thu)21:26 UTC+1 No.638778 Report

A wire mesh, grounded into the earth
Aluminum foil

Each work
Anonymous 05/16/14(Fri)10:59 UTC+1 No.639053 Report

op here

i looked into the faraday cage a bit and watched diy projects on youtube. they all seem to be solid – do you guys think that it would even be possible to build a faraday cage that is soft (like a tent)
Anonymous 05/16/14(Fri)14:50 UTC+1 No.639116 Report


Are you stupid? Read your own damn thread >>638654
Anonymous 05/16/14(Fri)18:44 UTC+1 No.639146 Report

Aluminum foil, or metal screen for windows is probably your best option, honestly I would just use aluminum foil. Yeah, it is fragile, but so what, just fix it with more, and you could just line the inside of a tent with it, not sure if it needs to be grounded or not, look it up
Anonymous 05/17/14(Sat)11:07 UTC+1 No.639434 Report

but wouldn't that hinder the faraday cage effect? i mean it needs to be constructed perfectly to work.

i don't need windows or anything – it's good enough if it resembles a camping tent.

i can't think of a construction that would seal the tent 100% since the slightest slit keeps the faraday cage from working
Anonymous 05/17/14(Sat)11:24 UTC+1 No.639436 Report

just make sure any holes are less than 1/10th wavelength in diameter.
what frequency are you blocking?
Anonymous 05/17/14(Sat)11:50 UTC+1 No.639439 Report

>wifi and cell reception
So... 850, 900, 1800, 1900, 2100, 2400, 2600, 5000, (MHz) and anything else I've missed
Anonymous 05/17/14(Sat)15:01 UTC+1 No.639474 Report

does that imply that i won't be able to cover them all?
Anonymous 05/17/14(Sat)15:13 UTC+1 No.639477 Report

It doesn't imply that, at least not directly. However, making the tent tight enough is going to be a pain in the ass.
Anonymous 05/17/14(Sat)15:29 UTC+1 No.639482 Report

using the copper fabric from the site layered with tinfoil and another cotton fabric glued together instead of sewing them was what i was thinking of. is there any other logical way of achieving the desired effect?
Anonymous 05/17/14(Sat)15:39 UTC+1 No.639484 Report

It could be a John Duncan-like art project.
Anonymous 05/17/14(Sat)15:48 UTC+1 No.639488 Report

I don't doubt this at all. There is literally no practical purpose for it IRL.
Anonymous 05/17/14(Sat)15:51 UTC+1 No.639489 Report

It can be made of anything that's conductive. Aluminium foil, Mylar, fine metal meshes (copper works best) should all be flexible enough line a tent with.
Anonymous 05/17/14(Sat)17:34 UTC+1 No.639526 Report

yea probably, but it won't be blocking cellphone signals or wifi signal.

it really is for an art project though.
Anonymous 05/17/14(Sat)17:43 UTC+1 No.639527 Report

... No, it would. A faraday cage needs to be able to ground out the voltage induced in it by the radio it's absorbed, but considering the area it's dissipated over and the strength of cell phone signals, its material is not significant so long as it's conductive and easy to work with.
Anonymous 05/17/14(Sat)17:46 UTC+1 No.639528 Report

To block a cellphone or wifi signal completely, the smallest hole in the tent needs to be half the wavelength of the target frequency.

... Which for cellphones is 900mhz or 2.4ghz, so 333mm for 900mhz.
Anonymous 05/17/14(Sat)18:02 UTC+1 No.639530 Report

you can get big rolls of steel mesh from walmart for pretty cheap, theyre for redoing screen doors like 5 of em should work to cover your tent you crazy dreamer.
Anonymous 05/17/14(Sat)18:17 UTC+1 No.639535 Report

>To block a cellphone or wifi signal completely, the smallest hole in the tent needs to be half the wavelength of the target frequency.
I'd like some backup for that. As an RF tech with decades of experience I will tell you that openings even smaller than 1/10 wavelength can cause problems if you are talking "total" blockage.

OP the tent is quite do-able if you got the time and or bux the "faraday fabric" search mentioned above should satisfy your needs.

If you are trying to make a portable "cone of silence" you are on the right track
Anonymous 05/18/14(Sun)14:45 UTC+1 No.639878 Report

yea thats pretty much what i wanted to do.

would i be able to sew the fabric or would the holes take the faradays effect?

also any ideas for a "door" mechanism that could work? the site also sells conductive hook and loop fastener.
Anonymous 05/18/14(Sun)14:53 UTC+1 No.639880 Report

You just need to seal the door with conductive Mylar tape once you're inside to ensure total coverage (making sure the tape is in contact with the cage material)...

In reality though you'd be unlikely to get a signal even without the tape.
Anonymous 05/18/14(Sun)18:52 UTC+1 No.639930 Report

using what material exactly? i can't imagine tinfoil alone to be enough. i'll try it out tomorrow but when wrapping a cellphone in tinfoil it needs to be pretty tight and no gaps at all
Anonymous 05/18/14(Sun)19:05 UTC+1 No.639933 Report

the tinfoil needs to be grounded.
Anonymous 05/18/14(Sun)19:22 UTC+1 No.639947 Report

according to videos online it doesn't. would it really make that huge of a difference?
Anonymous 05/18/14(Sun)19:53 UTC+1 No.639957 Report

yes, its not a faraday cage if its not grounded. Its just something attenuating the signal
Anonymous 05/18/14(Sun)20:36 UTC+1 No.639976 Report

what would happen if attached a Faraday cage to the positive and negative terminals of a 9V or 12 volt battery?
Anonymous 05/19/14(Mon)04:26 UTC+1 No.640168 Report

The battery would short circuit through the cage, but nothing inside the cage would be affected.
Anonymous 05/19/14(Mon)13:46 UTC+1 No.640280 Report

would there be any benefit to having electrical power flow through the cage? can you use a battery as a "ground" so to speak?
Anonymous 05/21/14(Wed)04:42 UTC+1 No.640972 Report

No, and no. Ground has to be ground. But even a non grounded cage will probably. attenuate a signal to the point that cell phones won't work.

Just connect a wire to a tent peg and drive it into the ground.
Anonymous 05/23/14(Fri)18:15 UTC+1 No.642194 Report

Holy fuck you guys are dumb.

OP, google "all weather space blanket". It's basically a tarp with an aluminum sheet embedded in it. It'll work the same as aluminum foil for blocking purposes, is pretty light, and is waterproof so it'll work just fine as tent material
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