Hacker News Board Hacker News, browsed like a classic message board
Live data from Hacker News

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

jiffchat.com

Post reply on HN
Print view View original

111–120 of 181 posts

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

#111

Post by Redoubts »

pishpash wrote: post #50
Aloha wrote: post #49

I don't think this is working the way he thinks it does. What he's likely do is shielding the wifi receiver from co-channel interference, which is likely reducing the noise floor at the AP - which is giving him effectively more range, because now the AP can hear stations that are further away with greater ease. I don't think this is giving expanded tx coverage lobes as his diagram indicates, its likely a function of…

Yeah, something so imprecise isn't likely to work as he thinks. Proper shielding can do a lot more. If you made your house/apartment a Faraday cage and eliminated neighbors' AP's that would already solve most problems.

I've always wondered what it would be like to have paint like this as an exterior primer

https://www.lessemf.com/paint.html (Warning: this site gets a little silly)

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

#112

Post by tinytim69 »

joniels wrote: post #14

What´s the 'household shelter' for?

Mandatory in Singapore houses. Practically used for live-in maid or general storage. But effectively involves a massive metal box in the middle of your house. Given the information (a.o. Sunlight as a electrical contractor) in the blog the OP is living in Singapore.

The red circle in his first image will like be much more distorted in practice by the bomb shelter, meaning his home WiFi will have a lot of trouble reaching whats behind the shelter (i.e. the bathroom and the Mr Bedroom in particular). Basically he got a pretty horrible spot for his router. Study/bedroom3 would have been substantial better.

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

#113

Post by TeMPOraL »

throwaway613834 wrote: post #96
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…

> 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. Does this actually make sense to you? Gain is a factor; it needs to be multiplied by something. Here's the obvious thought-experiment: consider an (ideal) parab…

The trick here (in this Wi-Fi example) is that the end you control is the end with parabolic antenna - if you can make it to collect enough energy for RX from an omnidirectional source, you can also make it send enough energy towards that source for its antenna to pick it up.

But you're right that "every improvement in sending is completely equivalent in receiving for a system that uses the same antennas for both directions of communication" is wrong; there are different ways of improving TX and RX, even though some overlap a bit, to some extent.

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

#114

Post by drewmol »

ce4 wrote: post #12
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?

You could buy a cheap TP-Link Router with a USB-Port and LEDE/OpenWRT support, add a second wifi interface (usb dongle) and then use your neighbors wifi as WAN connection. Good usb dongles are: 1. Alfa AWUS036NHA – $28.97 2. TP-LINK TP-WN722N OR TP-WN722NC $15.99 Benefits: have "your" wifi on a separate channel, you have your own subnet, firewalled (nat) from your neighbor's net.

I second ce4's suggestion. LEDE/OpenWRT are open source projects of linux based firmwares that run on embedded devices. Tangentally, I've used OpenWRT in combination with: a cheap router, a USB dongle as a second wifi interface, a 4G/LTE hotspot and a package called MWAN3 (previously MultiWAN) to configure a cheap and reliable setup for automated WAN failover (backup internet) and for circumventing restrictions of 4G/LTE hotspot devices.

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

#115

Post by kijin »

tqdm wrote: post #91
mrtksn wrote: post #37

It can work surprisingly well, I made a "dish" with an aluminum foil that was able to connect to a Romanian Wi-Fi hotspot from Bulgaria, according to Google Maps it should be something like 20KM distance. I should note that I had direct view of the town as I had significantly higher altitude. The hotspot was some kind of public service provided by the Romanian town as it's name suggested. The ip WhoIs also confirmed…

I've also achieved substantial improvement with simple parabolic shaped, ~40 cm wide aluminum foil constructions, but there always seemed a bit luck involved and it needed some tweaking. Not sure whether the foil mainly acted as shielding that reduces the noise floor from other directions. I've read in other forums that fiddling with aluminum foil is mostly luck because additional reflective surfaces also introduce i…

A wok (Chinese stir-fry pan) works surprisingly well for this purpose. It's roughly parabolic, and has a smooth surface that helps you avoid irregularities in the shape of your foil.

It gets even better if you drill a hole in the center and stick an antenna vertically in there. Now you've got a wi-fi antenna with all the advantages of a satellite dish! The Chinese call it wok-fi.

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

#116

Post by jpalomaki »

mrtksn wrote: post #37

It can work surprisingly well, I made a "dish" with an aluminum foil that was able to connect to a Romanian Wi-Fi hotspot from Bulgaria, according to Google Maps it should be something like 20KM distance. I should note that I had direct view of the town as I had significantly higher altitude. The hotspot was some kind of public service provided by the Romanian town as it's name suggested. The ip WhoIs also confirmed…

Old trick is to use Pringles (or other) can as directional antenna: https://www.makeuseof.com/tag/how-to-make-a-wifi-antenna-out...

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

#117

Post by rconti »

throwanem wrote: post #34
markvdb wrote: post #33

Earlier quoted context omitted.

Use a Ubiquiti Nanostation directional antenna. These things are quite powerful and relatively cheap. Have used them before to link two sites ~20m apart.

Seconding the Ubiquiti rec, just in general. Their equipment is better in difficult radio environments than anything else I've ever used.

Thirded. I had some Meraki (MR32 and MR18) equipment in my house and spent years mucking with the settings and always felt like something was wrong. My AP-AC-PRO Ubiquiti APs that replaced them have astoundingly better range and throughput. IMO the Meraki APs are worse than consumer gear in terms of range.

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

#118

Post by friendzis »

throwaway613834 wrote: post #96
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…

> 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. Does this actually make sense to you? Gain is a factor; it needs to be multiplied by something. Here's the obvious thought-experiment: consider an (ideal) parab…

Yes, it does make sense to me. I think conclusions drawn from this thought experiment are not entirely correct. Under your experiment when sending you spatially create a beam - there is this beam as wide as parabolic dish and no light anywhere else. With zero interference (using the word quite freely) this beam "will be just as strong no matter how far away the receiver is". With roles reversed, you do not necessarily get directional transmitter. For the sake of argument consider omnidirectional light bulb (the same bulb without parabolic dish) as sender. Classical intro/ELI5 description of transmit power is fixed number of spatially evenly distributed omnidirectional "rays". The larger the distance, the lower number of "rays" you receive per unit of area (receive power scales with surface area of transmit profile, usually r^2). By adding a parabolic dish you effectively increase receive area to size of dish instead of sensor size. When sending, the area over which power is dissipated is constant instead of scaling with distance.

> You're claiming it won't matter how far away the sender is from the focus, which makes no sense.

You are correct in that it makes no sense, but the claim was "every improvement in sending is completely equivalent in receiving for a system that uses the same antennas for both directions", key word improvement. While this is not entirely correct, this approximation (that antenna improvement works both ways equally) is pretty close to reality in practical far field applications.

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

#119

Post by logicallee »

vvanders wrote: post #109
tzs wrote: post #102

Earlier quoted context omitted.

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…

Or if you get your ham license you have a limit of 1500W PEP[1], just plug your callsign into the router ID and away you go. However that means you're also subject to no encryption or business related traffic. [1] http://www.qsl.net/kb9mwr/projects/wireless/allocations.html

>However that means you're also subject to no encryption or business related traffic.

how does that work? isn't all wifi traffic encrypted by something between devices and AP?

(I skimmed your link and did a find for encry on it but saw nothing.)

Post reply on HN