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I amplified my home's Wi-Fi with aluminum foil

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Re: I amplified my home's Wi-Fi with aluminum foil

#71

Post by ars »

logicallee wrote: post #67

theoretically, are there any regulatory issues on a piece of aluminum sold (and marketed) for this purpose? if not, why aren't there cheap and effective such designs on alibaba - why have to DIY?

No regulatory issues. The aluminum acts to increase the antenna gain (i.e. concentrate the signal in a particular direction). The total power does not increase instead you take some from one place and add it to another.

There are tons of products for sale. You can get a replacement antenna that is a directional dish for example, instead of the typical omnidirectional dipole (stick).

Re: I amplified my home's Wi-Fi with aluminum foil

#72

Post by arghwhat »

Aloha wrote: post #62
arghwhat wrote: post #57

Earlier quoted context omitted.

It is unconnected, so it will not dissipate anything (shield). Depending on whether or not it is positioned on a wave node, it will either be a passive reflector or director. It won't be a satellite dish as the comment thread on the page mentions, though, which is both a passive reflector and a focusing device, whose curvature requires at least some level of precision to be of any help. For something much more helpfu…

It need not be grounded to be an semi-effective shield, we're talking about frequencies that drywall will attenuate here. Think about it this way, if it can reflect TX, it can also reflect other cochannel signals from that direction. It may very well be working in more than one mode - but I strongly suspect its a far better shield, than it is a forward power reflector. It also may strongly effect the VSWR of the exis…

A signal from the "correct" direction will have ~half its energy reflected towards the antenna, resulting in gain. A signal from the "wrong" direction will have ~half its energy reflected away from the antenna, resulting in attenuation. It won't shield, though. That requires that you dissipate the signal somewhere.

But to be fair, it's a wild guess. It's a semi-flat piece of foil placed at an angle, at a random distance from 3 individual antennas. That's why I linked to the nice and simple, easy-to-calculate yagi-uda for if you want to hack with antenna gain.

Re: I amplified my home's Wi-Fi with aluminum foil

#73

Post by girishso »

hallz wrote: post #38

This kind of hack was really popular when wifi was first being adopted. These reflectors work best when they are spaced according to the wavelength. Here is a template I remember seeing years ago: http://www.freeantennas.com/projects/template2/

Yes, I was using this freeantennas antenna few years back. Worked pretty well to extend the range.

Re: I amplified my home's Wi-Fi with aluminum foil

#74

Post by beokop »

komali2 wrote: post #55
B1FF_PSUVM wrote: post #53

Earlier quoted context omitted.

> If you made your house/apartment a Faraday cage Might put a crimp on your cell phone reception ...

Is there a way to build your Faraday cage to block out wifi wavelengths but not cell phone ones? How far apart are they?

This is usually done with a femtocell.

[0] https://www.att.com/att/microcell/

Re: I amplified my home's Wi-Fi with aluminum foil

#77

Post by cesarb »

ars wrote: post #71
logicallee wrote: post #67

theoretically, are there any regulatory issues on a piece of aluminum sold (and marketed) for this purpose? if not, why aren't there cheap and effective such designs on alibaba - why have to DIY?

No regulatory issues. The aluminum acts to increase the antenna gain (i.e. concentrate the signal in a particular direction). The total power does not increase instead you take some from one place and add it to another. There are tons of products for sale. You can get a replacement antenna that is a directional dish for example, instead of the typical omnidirectional dipole (stick).

> No regulatory issues. The aluminum acts to increase the antenna gain (i.e. concentrate the signal in a particular direction).

AFAIK, many countries limit the EIRP, which increases with the antenna gain.

Re: I amplified my home's Wi-Fi with aluminum foil

#78

Post by gerdesj »

ohazi wrote: post #11
sarreph wrote: post #8

I was thinking of doing something similar a few days ago but came to the conclusion — perhaps wrongly — that the inevitable creases in a DIY aluminium foil sheet would render it ineffective as a dish, due to the scatter created. Anyone more knowledgeable able to chime-in on the effect of creases here? I couldn’t find any mention of it in the article...

speed of light / 5 GHz / 4 ~= 1.5 cm. If you can keep the size of the largest crease/feature/defect in your foil smaller than this, you should be okay.

Could you tell me where the /4 comes from, please?

Re: I amplified my home's Wi-Fi with aluminum foil

#79

Post by Aloha »

arghwhat wrote: post #72
Aloha wrote: post #62

Earlier quoted context omitted.

It need not be grounded to be an semi-effective shield, we're talking about frequencies that drywall will attenuate here. Think about it this way, if it can reflect TX, it can also reflect other cochannel signals from that direction. It may very well be working in more than one mode - but I strongly suspect its a far better shield, than it is a forward power reflector. It also may strongly effect the VSWR of the exis…

A signal from the "correct" direction will have ~half its energy reflected towards the antenna, resulting in gain. A signal from the "wrong" direction will have ~half its energy reflected away from the antenna, resulting in attenuation. It won't shield , though. That requires that you dissipate the signal somewhere. But to be fair, it's a wild guess. It's a semi-flat piece of foil placed at an angle, at a random dist…

You'd effectively creating a multipath generator with this setup, which means you have the primary signal, then a couple microseconds later, a reflection that is probably 20db under the main signal.

No disagreement that the yagi thing you pointed out would work better.

That said, this is a MIMO router, so that may change the modulus on the multipath problem.

Re: I amplified my home's Wi-Fi with aluminum foil

#80

Post by negativ0 »

nhebb wrote: post #45
sarreph wrote: post #8

I was thinking of doing something similar a few days ago but came to the conclusion — perhaps wrongly — that the inevitable creases in a DIY aluminium foil sheet would render it ineffective as a dish, due to the scatter created. Anyone more knowledgeable able to chime-in on the effect of creases here? I couldn’t find any mention of it in the article...

Most of the DIY's I've seen on this use aluminum cans. You could try that.

Pringles cans were really effective for me
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