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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

#161

Post by walshemj »

jacquesm wrote: post #84
agoodthrowaway wrote: post #69

Slight nit there's no amplification here just focusing to make the field more directional.

Gain is effectively the same as amplification, any kind of gain achieved in a passive manner indicates some kind of directional compromise. It also should work equally well when receiving and transmitting, whereas an amplifier would work for only one direction (so you'd need two, one to output more power, another to amplify the received signal).

But technically there are legal maximum emitted powers unless you are "a professional"

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

#162

Post by walshemj »

niwde wrote: post #6
godelmachine wrote: post #4

I am using my neighbors WiFi, which I can only catch in my balcony. He stays above me, but diagonally opposite, so the source is quite away. Any way I can amplify the WiFi strength? So I need the source to be around in order to amplify?

I think the source needs to be strong. I'm currently using a wifi extender and noticed the speed isn't good when I move the extender to a room further from the source.

That is because range extenders just rebroadcast so you cut your bandwidth in half with every hop

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

#163

Post by walshemj »

kbenson wrote: post #47
myrandomcomment wrote: post #39

The geek in me loves stuff like this. The old and jaded techie in me says just get something designed to solve the issue like: https://eero.com or the UniFi Mesh :)

The consumer and frugal shopper in me sees the $400 price point, and doesn't think it compares favorable with a few dollars worth of aluminum foil.

Beware cheaping out on wifi kit I have bitter experiance of trying to use POS dlink kit to provide wifi in our new office.

But for home use multiple AP's with powerline to connect them is actualy a simpler solution than mesh as using wifi for the DS (distribution system ) is always going to be slower than a wired.

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

#164

Post by walshemj »

tzs wrote: post #102
cesarb wrote: post #77

Earlier quoted context omitted.

> 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.

Correct. In the US, for example, for 2.4 GHz point-to-multipoint, EIRP is limited to 4 watts, and maximum power to the antenna is limited to 1 watt. So, if your router does 1 watt, you are limited to a maximum 6 dBi antenna gain. Lower the router power, and you can use higher gain antennas. It's more complicated for 2.4 GHz point-to-point. At 1 watt transmitter power you are allowed a 6 dBi antenna. But for every 1 d…

I think 4W that is for professional ptp use only.

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

#165

Post by Raphmedia »

Sir_Cmpwn wrote: post #156
Raphmedia wrote: post #155

Earlier quoted context omitted.

> There's no reason for this content to use JavaScript at all. How else would you add live comments without JS? This page is effectively a big chatroom. You can write at the bottom of the page and the website fetches the new messages async. Don't tell me you would have a big http refresh every 5 seconds to load in the new chat messages, that's even worst than using JS.

>How else would you add live comments without JS? This page is effectively a big chatroom. You can write at the bottom of the page and the website fetches the new messages async. Why on Earth does it need to be some kind of live chatroom? Just render them server-side and add live updates as a nice-to-have if JavaScript is enabled.

> Why on Earth does it need to be some kind of live chatroom?

Well, the website is called jiffchat.com and is a collection of chatrooms.

That being said, I turned off JavaScript and you are right. The page gets stuck on a lazyload placeholder. The initial content should be loaded and only the chat part be should added by JS.

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

#166

Post by arghwhat »

Aloha wrote: post #79
arghwhat wrote: post #72

Earlier quoted context omitted.

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.

A reflection with just 1 microsecond delay would require a 300 meter reflection path (e.g. 150 meter to/from the reflector). I think you might be thinking of multi-path propagation within the context of long-distance communication (e.g., a HAM QSO).

A regular home Wi-Fi network is already a complex multi-path system, as the primary propagation mode is reflections from walls and ceilings, leading to plenty of self-interference with many hot- and cold-spots from constructive and destructive inteference. We are at most introducing a few stronger reflections in an already extremely reflection-heavy environment. The big question is whether it does any good, either through attenuation or gain.

As for MIMO, I must admit to not knowing much about it—I know it utilizes spacial separation to increase bandwidth, but I do not know much of its actual implementation, and thereby weaknesses.

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

#167

Post by arghwhat »

topspin wrote: post #106
arghwhat wrote: post #56

If you want to to do this "properly", see http://ham-radio.com/k6sti/wifiyagi.htm When messing with antennas, things like distance needs to be thoroughly calculated. Foil can help in many ways, but it can also make things worse—antenna calculations are tricky.

Done wrong this will increase reflected energy at the feed point and make the transceiver run hotter than it is supposed to, possibly leading to an early failure. Measuring SWR at 2.4/5 GHz requires some expensive instruments; note that the link you provided has only "calculated" SWR, not measured. Wifi doesn't involve much power, but these low cost Wifi transceivers are engineered with rather limited headroom for re…

As long as you're not running a high-power transceiver (i.e. not consumer gear or consumer gear out of legal spec), I would not be worrying about SWR problems. Consumer Wi-Fi chipsets are designed to be fairly rugged. They normally operate nowhere near their limits.

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

#168

Post by arghwhat »

alinspired wrote: post #110
arghwhat wrote: post #56

If you want to to do this "properly", see http://ham-radio.com/k6sti/wifiyagi.htm When messing with antennas, things like distance needs to be thoroughly calculated. Foil can help in many ways, but it can also make things worse—antenna calculations are tricky.

This particular example of yagi for wifi - what's the logic to customize it for my router ? In short, I'm looking for logic to repeat this for my router's dipole antenna and possibly with custom wires (not #14 or paperclips of unknown thickness mentioned there)

As you already have a working dipole (which you have in this case), the primary thing to consider is the element lengths and spacings. If you don't have one of those routers with massive (and empty!) plastic antennas, there's probably a good chance that you can use the authors design parameters.

Otherwise, there's plenty of 3-element Yagi-Uda calculators online where you can stuff in various amounts of parameters and get the unknowns—the author used fancy antenna simulation software, but you don't need that.

A few links:

http://www.rfwireless-world.com/calculators/3-element-Yagi-A...

http://www.changpuak.ch/electronics/yagi_uda_antenna_DL6WU.p...

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

#169

Post by laresistance »

pimlottc wrote: post #31

A bit off topic, but what is this page doing, loading almost 500K in 2 XHR calls for approximately 9K of text... Egads, all the images are inlined data URIs! I was staring at a blank page with a single image for over 10 seconds before the article text loaded. No loading indicator or anything.

This is why I uploaded this as an image: https://i.imgur.com/gSLrqPl.jpg

I hate sites that require JS and are not viewable on archive.is or Wayback Machine.

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

#170

Post by Obi_Juan_Kenobi »

pjc50 wrote: post #128
aylons wrote: post #94

Earlier quoted context omitted.

It's not needed to do it in both ends. Naturally, improving both antennas is better than doing in only one, but every improvement in sending is completely equivalent in receiving for a system that uses the same antennas for both directions of communication. So, if a new antenna in client side improves signal reception by 3dB, it also improves transmitted power by 3dB. If you used the same antenna on the other side, t…

I don't know why people are arguing so much with this when it's straight out of textbook antenna theory. Evidently it's very HN to work things out inaccurately from first principles. Edit: http://www.cv.nrao.edu/course/astr534/AntennaTheory.html "An antenna can be treated either as a receiving device, gathering the incoming radiation field and conducting electrical signals to the output terminals, or as a transmittin…

> Evidently it's very HN to work things out inaccurately from first principles.

I find this quite common among people that consider themselves technically minded. One of the key indicators I have for truly 'smart' people is an inclination toward curiosity with new things, and perhaps a degree of humility.

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