A DIYer's Quick Guide To Cheap Wireless Extension

An anonymous reader writes "This piece is described in one of the comments on it as 'a little piece of genius'... and I have to agree! Although Peter Cochrane seems a bit of a crack pot, the ways that he comes up with to get connected when he's out of range in the sticks are pure genius and he makes them appear really simple! Think old satellite dishes, USB dongles and plastic bags and you'd be on the right tracks to upping wi-fi signal by 4 bars." A perfect excuse to link to one of my favorite sites, if you want more details and photos on similar jury-rigged long-distance connections. However, your meterage may vary — I've found USB Wi-Fi devices to be pretty fickle under Linux, with some distros working way better than others.

Comments

Citywide Wireless

[billy901]

Wouldn't it be nice if this technology was used to make a free citywide wireless internet? We just need a bunch of people with this ambition and it could be done. I once read a book, called When A Strange Comes To Town, in which some people had the same ambition. You can get the book from Project Gutenberg if you look around. It's a newer book that has never been copyrighted.

Re:Citywide Wireless

[Nos.]

Jury-rigged wifi extenders typically aren't the most reliable things in the world. They also tend to be unidirectional, though omni-direction is possible, you don't get as much gain. You also need to power them, as well as connect them back to the Internet at some point. In the end it all costs money, and someone needs to pay for it.

Re:Citywide Wireless

[Anonymous Coward]

It would be much more helpful to protect people from litigation when they open up their wireless networks to strangers. The only thing preventing me from providing free wifi is the tremendous risk of being sued and eventually having to pay for someone else's crimes.

If you've been wardriving lately, you know that we don't need more access points, we need existing access points to be opened.

Re:Citywide Wireless

[Anonymous Coward]

I have absolutely no problem with that. Also, if you don't have the know-how to secure your network while allowing strangers to use the internet connection, don't open it.

But there are people who want to provide free wireless internet and know how to do it safely. As long as these people have to risk their livelihood providing a free service, it's not going to happen.

Re:Citywide Wireless

[Endo13]

It's nice in sentiment. In reality though, it doesn't work. See, ISPs do need to be profitable to stay in business. The way they do that is by making money on the bandwidth they sell. At the price bandwidth goes for these days, they really cannot stay profitable if every single person were to use every mbit of their bandwidth all the time. People who torrent a lot or keep their bandwidth use maxed otherwise generally cost the ISP more than the monthly payment. It's those other low-use customers who simply don't want to wait on dialup for eBay or Yahoo to load that make them money. If every user were allowed to open their wireless and allow everyone to use their connection for free instead of paying for it, ISPs would have no choice but to raise prices to stay afloat. Personally, I'm happy with the current situation where those low-use customers pay for some of my bandwidth.

Re:Citywide Wireless

[a_real_bast...]

on sailing ships a jury rig is a replacement mast and yards improvised in case of damage or loss of the original mast.

From Wikipedia. Used in the 1800's, at least. Would you like to reconsider your previous statement?

Re:Citywide Wireless

[Medievalist]

The description you and the author are looking for is NOT "jury-rigged" - rigging a jury is a completely different thing!

The phrase you are looking for is "jerry-rigging", a racist term that comes from the even more racist "nigger-rigging" - just so you know.

Epic Fail.

Re:Citywide Wireless

[Nos.]

No, its jury rigged http://en.wikipedia.org/wiki/Jury_rigged

Re:Citywide Wireless

[Xeger]

Actually, jerry-rigging comes from the closing days of WWII when the Allies were advancing through western Europe. They would often find vehicles, structures and equipment that had been hastily repaired or assembled, or used in a way that differed from its original purpose. "Jerry" was a very common nickname for the collective German forces, hence any equipment found in this condition was "jerry-rigged."

Re:Citywide Wireless

[dontmakemethink]

Saskatoon Saskatchewan Canada has free citywide internet. It's slow as a dog during the day but quite usable at night for basic browsing/emailing etc. Great for us touring musicians!

Here is another smaller scale hack using a metal strainer/steamer as a collector.

But a satellite dish will only help the reception, not the access point on a city-wide basis, so it's benefits are limited. However, it might give hope to cottagers where wifi is close but not quite.

What the article describes as going from zero bars to five, sounds like range extension by a factor of at least five, so let's use 100m as an unmodified standard range, that's about 1/16th of a mile.

It would also help by almost as great a margin to have a small reflective dish in front of the transceivers to direct forward signals back into the larger dish (a forward collector), or else most of the transmission will travel away from the intended target. That strainer hack would be about the right size for the job, perhaps too big, but imagine that facing back into the satellite dish, directing emissions out the larger dish in a straight line. That should boost the signal strength up by at least another 80%, so call it 9x range extension.

The same improvements would apply at both ends, so by my math, a well-configured line-of-sight array with dishes and forward collectors at both ends should achieve at least 18x range extension, definitely over a mile.

Rhombic Antennas

[hardburn]

Does anyone know of any attempts to use Rhombic Antennas with WiFi? They're very simple and provide huge gain. Their typical downside is that the length of one leg needs to be 8-12 wavelengths, which means they're the size of a football field when you're dealing with most radio frequencies, but 2 GHz has a 0.15m wavelength. A point-to-point rhombic should easily fit on the roof of a house.

Re:Rhombic Antennas

[elgatozorbas]

I suspect these antennas are typically aimed at much lower frequencies (say HF/VHF), and require a ground plane. The reason why I think so is that for (super) high frequencies, antennas are mostly self-contained (one piece you can attach to a pole) and don't require a large garden and poles and the like.This is not the kind of structure you use for pleasure, but because you have to (at low frequencies).

Re:Rhombic Antennas

[Born2bwire]

I suspect these antennas are typically aimed at much lower frequencies (say HF/VHF), and require a ground plane. The reason why I think so is that for (super) high frequencies, antennas are mostly self-contained (one piece you can attach to a pole) and don't require a large garden and poles and the like.This is not the kind of structure you use for pleasure, but because you have to (at low frequencies).

There wouldn't be any reason why this would be worse at high frequencies than low frequencies. I could envision making a printed version of this on a very thick PCB and using the bottom copper cladding as your ground plane. Heck, a sheet of aluminum foil could probably do it in a pinch. The ground plane size at Wifi frequencies is not very large. I would guess the main reason that people haven't done this is why bother? The short wavelength of 2.4 GHz compared to everyday length scales means that it is easy and space efficient to build simple antenna arrays. In addition, you can easily create the antenna array as a printed antenna further simplifying the build process. With the rhombus though, you're talking about an antenna footprint of several wavelengths, like 8-12 as the OP stated. Why bother having such a large footprint when you could easily make a simple printed antenna array with spacings of sub-wavelength between elements? Or, if you are just a garage enthusiast, a waveguide or reflector antenna provides excellent gain. A parabolic dish requires minimal assembly and gives you 10's of dBi in gain.

!news

[Thelasko]

everybody knows that old satellite dishes and Asian parabolic cookware can be used to boost wifi signals.

Re:!news

[jellomizer]

Dont forget Pringles cans.

Re:!news

[maxume]

Dude, what carrier is offering a temporal calling plan?

Re:!news

[emag]

Dude, what carrier is offering a temporal calling plan?

TARDIS Telecom, for one...

if you have a few bucks to spend

[dickens]

Check out.

Free... Really?

[gamanimatron]

I get nervous when folks start talking about "free" services. Seems that more often than not, "free" actually means that I end up paying for power, bandwidth, and the army of bureaucrats that makes sure those bills get paid on time, and that their uncle's brother's company wins next year's bid.

So, please, count me out. I'll rig my own parabolic signal booster if and when I feel like it.

Re:Free... Really?

[stranger_to_himself]

...I'll rig my own parabolic signal booster if and when I feel like it.

That's my new sig sorted out then.

Re:Free... Really?

[Attila Dimedici]

He doesn't get nervous around "free" services, he gets nervous when people talk about "free" services. You see, he understands that all those "free" services you mention are paid for by somebody. I wonder where you live that get the fire engines for free. The last time the fire company near me was talking about getting a new fire truck, the cost was a couple hundred thousand dollars.
You see the poster you were replying to was a productive member of society and therefore he pays taxes. That means that all of those "free" services you were talking about are paid for out of his pocket.

Re:Free... Really?

[gamanimatron]

Allow me to clarify, then: Discussion of novel "free" services makes me nervous.

Every "free" (meaning, of course, tax-supported in one way or another) service I could possibly want, and a great many more I believe should not be "free", are already provided by my current city.

Re:Free... Really?

[Mr. Slippery]

You do realize, of course, that fire fighting services are, in fact, not free, right? Most (if not all) fire fighting services bill you for their services when they respond to a fire.

Where do you live that this is the case? That's a tremendously stupid way to run things: "Ah, my kitchen is on fire, but it'll cost money for my insurance deductable if I call it in. I'll put it out myself with the garden hose...Whoops! It was a grease fire! It's spreading! Now the whole block will burn down."

Out in the middle of the country, where houses are isolated, maybe they could get away with that, but in the city (the topic of discussion here) such a policy would get people dead. You never want to provide a disincentive for an honest activation of an emergency service, because delays can make the emergency worse. Therefore they must be tax-funded public or common goods.

Try this.. the strainer WiFi.. cheap too!

[i_want_you_to_throw_]

I found this great instruction on Instructables (pops new) on how to create a usb wifi out of a 2.00 strainer from WalMart. Works like a champ!

My friend lives across the Ohio River and we're able to send the signal across the river that way.

Old news anyone?

[b96miata]

I'm too lazy to search for how many times the satellite dish wifi setup has been posted on slashdot, but suffice to say I had one on my roof 5 years ago after getting the idea from a web page that was itself a couple of years old. (even the actual useful link added on by the editor is from 2004)

It's not even a good writeup of the concept. Here's a summary of the "Genius":
-Stick it on the end of the arm.
-Electronics don't like water.
-The sun is hot.

There's nothing genius about this. It's a rehash of something people have done for years, sans details.

Nobody wants it!

[drewzhrodague]

I am one of those long-time WiFi zealots, and it is clear to me that people just don't want free ubiquitous wireless internet -- or they just don't care.

Here in Pittsburgh, there is occasional talk of some group trying to do this. There have been some people who have received funding, but they waste it, and their project evaporates. Between ten and twenty (or more) companies start off here, and either fade away, or move to some other city. telerama, hobnob are the two that stick out (for which I remember URLs to).

Largest public network here is run by ONE GUY who just went and built it himself, Shadyside WiFi.

Otherwise, there is chatter on some of the local lists, but by and large, nobody wants free city-wide wireless Internet. Just me.

Can I draw your attention to...

[Gordonjcp]

... my own comment, yesterday?

Not new

[drewzhrodague]

This isn't really new, there have been people doing this kind of thing for years. Check Seattle Wireless dot net for their experiences. I'm sure there are others.

How to get long distance WiFi to work with ease

[viking80]

10 years ago you might have had to improvise, but today you can get cheap high quality antennas and amplifiers that is a lot better than a USB dongle in an old satellite dish.

My favorite source is http://www.hyperlinktech.com/
and you can do your link analysis here:
http://cgi.gbppr.org/wireless.main.cgi

If you really need big distances, you can use an old 12' sattelite dish, but otherwise stick to the formula above. It will save you a lot of time and trouble.

I have reliable links over 10km with 10mW running at 50Mb/s

It's not that easy

[Puls4r]

It's not that easy - and you might be better off just buying a cheap unidirectional antennae I live in a rural community and a 3G USB dongle several months ago. The low signal strength meant I was on the slow end of the speed for 3G. I tried the exact thing he did, but tried some other options as well. First, I purchased a $50 unidirectional antennae. That improved my signal strength by 10db. That was enough to get me to the range of 1300 down and 400 up consistently, with full "bars". So then I unplugged the antennae, added a couple of active USB cables, and put the dongle on the roof (1 story up). That improved my signal 5 db without the antennae, and 3 db with the antennae. So now I had improved about 13db. Finally, I grabbed my old dish, and aimed it at the cell tower. Then I put the dongle in place of the amp unit. Please note that most dishes have offset amp units, so you dish looks like it's aimed "below" the tower. It helped several decibles. I replaced the unidirection antennae and put in the dishes sweet spot, and it got me nothing more. Short version - I was better off elevating the dongle and attaching a cheap unidirectional antenna than I was playing with the dish. I suspect that will be true of most who play around with this. Final note - I have experience making other antennas - AM, FM, etc. I can assure you it wasn't lack of knowledge that prevented any huge increase in signal when using the dish.

Re:It's not that easy

[Anonymous Coward]

Why use a unidirectional antenna with a dish? The dish focuses a wide beam (eg 45 deg) at the amp to a narrow beam (eg 1 deg) at a distance. The unidirectional antenna is already radiating at a narrow beam, so the dish will basically be a flat mirror for the signal, which will not help at all (as you noticed).

You should try with one or the other, not both.

Access more than one network?

[Bombula]

Every year or so I hunt for a simple utility to allow me to connect to more than one wifi network simultaneously and boost bandwidth that way. Never had any luck. Anyone know if this is feasible or not? The apartment complex where I currently live has multiple secure wifi networks set up specifically for residents, plus a bunch of folks have unsecured ones based on local cable broadband they don't mind sharing. If there was a way to connect to all of them at once ... awesome.

Re: Another source

[Bovius]

A link to an old writeup from one of my favorite professors: http://people.wallawalla.edu/~Rob.Frohne/Airport/Primestar/Primestar.html

Also, ditto on the !news.

What about sending?????

[Caspan]

Humm so how you you send when your 500 M out of range. That's fine to receive any signals but screwed if you want to send. good idea but FAIL

Re:What about sending?????

[Anonymous Coward]

There are EIRP limits. Basically you can't legally use a directional antenna to improve the signal on the sender side if you're already at the EIRP limit. The only benefit of the directional antenna in that case is that you can lower the emitter power and don't pollute the unused directions with your signal. To establish long-haul wifi connections legally, you need directional antennas on both sides to boost signal reception, not emission.

You need load-balancing

[GameboyRMH]

I've been looking into a similar setup. You need multiple wireless adapters and a load-balancing utility.

http://forums.remote-exploit.org/archive/index.php/t-7419.html

A quick and dirty way to do it with Linux iptables:

http://tetro.net/misc/multilink.html

My goal is to create a monster wardriving setup for constant on-the-road connectivity.

Also works with WiMax

[aharth]

Just tried on my balcony: WiMax box in front of old sat dish = ~ 30% higher transfer rate!

Re:Nothing to See Here

[brechin]

It's jerry-rigged, not "jury-rigged," dammit!

Actually, it is "jury-rigged".

MOD THIS UP!

[Iron Condor]

I rarely do this, but this AC is making the only point that needs to be made here. My own home router could comfortably serve a block of my neighborhood including the nearby park (I tried) but I'm not going to open it up because under US law I will go to jail if someone uses my open WiFi to download childporn or some such.

The cost to me would be minimal and I'd set the QOs such that the freeloaders wouldn't interfere with my own activities -- and if everybody did that, we'd already have free ubiquitous wifi in all cities in the US. Because there's always some server around somewhere -- it's been forever since I truly got a "NO networks found". They're just all locked down like crazy because of the absurd US laws that hold a communications provider (me!) responsible for what clients do with the services they provide for free out of the goodness of their hearts...

Re:MOD THIS UP!

[Firehed]

If the RIAA is able to successfully sue/prosecute people based off of IP logs, you can be damn sure the CP police can. At least when you're in control of the router, you may be able to trawl through logs and find the MAC associated with the illegal download and hunt down the right person, but don't count on it.

Re:Nothing to See Here

[Arthur Grumbine]

It could be both. Here it's not particularly "jerry-rigged", as the focus with that phrase is on the quality of the construction, instead of the make-shift nature of it.

Linux use of Wi-Fire

[cmacdona101]

It's getting easier to use USB WiFi adapter with linux lately. Linuxwireless.org has done some great work with the re-written modules, which are included in the recent kernel version. And some companies are paying attention. I've been using the Wi-Fire for long range wifi for a while, and hField Technologies just released a Linux Version, which I've had no problem with on my Suse or Fedora machines.

Re:how many bars?

[arbitraryaardvark]

NASA uses spacebars.

I did that, and found the MAC address, but...

[Medievalist]

apparently DE:AD:BE:EF:DE:AD:BE:EF is some guy named Peter Shipley, and he just laughed at me when I called him up and asked him about it.

Not news...

[jemenake]

Sorry, but this really isn't news. Hell... even *I* have done this, which means that it can't be anywhere near the cutting edge. :P The concept of putting a cantenna or bi-quad at the focal point of the dish has been out there on web pages for years. I fitted *my* dish so that I could interchange a cantenna or a USB dongle as the need arose.

The advantage of the USB dongle is that you don't incur the line losses of the antenna cable if your laptop/PC is a long way from the dish. You can get around the problem of USB cable-length limitations by using some nifty USB "extension cords" which are basically a long USB cable with a 1-port hub at the end.

I will add one thing that I haven't seen on any pages, however. Most satellite dishes have the arm positioned away from the centerline axis of the dish... usually below it, which must be accounted for when aiming. For example, if the arm holding your dongle/cantenna is 10 degrees below the centerline of the dish, then you'll be receiving signals from whatever is 10 degrees above the centerline. It's the same concept as flat mirrors... angle of reflection equals angle of incidence.

Why does this matter? Well, if you are trying to communicate with a station that's at relatively the same elevation as you, then you're going to have to point the dish down toward the ground a bit. This can be very conspicuous... especially if, ahem, the other station's owner doesn't know you're communicating with them (cough, cough). The best solution that I've come across is to turn the dish upside-down so that the arm holding the dongle is on top, which allows you to point the centerline of the dish skyward again, so that it looks more like the other dishes in the neighborhood. Almost nobody will notice that the arm is affixed to the top of the dish rather than the bottom... and even fewer will grasp the ramifications of it.

mod that down

[el americano]

"...under US law I will go to jail if someone uses my open WiFi to download childporn or some such.

No, you won't go to jail, but you might get investigated and have some equipment confiscated, which is still enough reason for most people not to do it.