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Hardware Hacking Wireless Networking Build

Boost a Weak 3G Modem Signal, With a Saucepan 146

Posted by timothy from the raid-the-kitchen dept.
modeca writes "Using only commonly available kitchen equipment this guy demonstrates the amazing powers of an ordinary metal pan to boost the 3G reception of his USB modem. It really seems to work, check the right hand side of the graph in the video." It's not that crazy: cheap antenna boosting (for USB WiFi dongles, Bluetooth, and more) has been elevated to a fine art in New Zealand.
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Boost a Weak 3G Modem Signal, With a Saucepan More

Boost a Weak 3G Modem Signal, With a Saucepan

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  • isn't it?

  • Who knew? (Score:5, Funny)

    by bobdotorg ( 598873 ) on Wednesday December 30, 2009 @06:23PM (#30600854)

    Who knew that tinfoil hats actually _boosted_ reception. It's a government conspiracy I tell you.

    • Re: (Score:3, Funny)

      by w0mprat ( 1317953 )
      The solution is to cover your entire body in tin foil, faraday cage!

    • Re:Who knew? (Score:5, Informative)

      by drinkypoo ( 153816 ) <drink@hyperlogos.org> on Wednesday December 30, 2009 @06:45PM (#30601036) Homepage Journal

      Who knew that tinfoil hats actually _boosted_ reception.

      everyone but you [mit.edu]

      • Re: (Score:2)

        by Belial6 ( 794905 )
        They tested aluminum hats. Everyone knows that the reason you can only find aluminum foil in stores and tin foil is nowhere to be found is because aluminum magnifies the signal where as tin foil blocks it. So, these guys at MIT clearly are right that the aluminum foil hat 'craze' is propagated by the government. What they didn't realize was that they confirmed that the government's conspiracy is working since they obviously didn't even realize that the mind reader blocking tin foil was replaced with alum

  • oh, nice. (Score:5, Funny)

    by gandhi_2 ( 1108023 ) on Wednesday December 30, 2009 @06:24PM (#30600856) Homepage

    a pantenna.

  • Easily done (Score:5, Informative)

    by earnest murderer ( 888716 ) on Wednesday December 30, 2009 @06:24PM (#30600866)

    You can find plans for aluminum foil and cardboard reflectors in many places as well. Here's one now!

    http://www.freeantennas.com/projects/template/ [freeantennas.com]

    They work great.

  • New Zeland (Score:5, Funny)

    by Jbcarpen ( 883850 ) on Wednesday December 30, 2009 @06:31PM (#30600922)
    New Zeland appears to have been Slashdotted.

  • Moola! (Score:5, Funny)

    by Tablizer ( 95088 ) on Wednesday December 30, 2009 @06:35PM (#30600958) Journal

    I'm gonna buy up 10,000 of those pans and sell them on Ebay as a "Hi-tech USB modem booster" for $69.95. That is until IBM patents the pan.

  • Now I am torn (Score:5, Funny)

    by MichaelSmith ( 789609 ) on Wednesday December 30, 2009 @06:40PM (#30600996) Homepage Journal

    Between my liking for my wife's prawn crackers and my need for a good 3G signal.

  • Hats off too (Score:4, Funny)

    by Tablizer ( 95088 ) on Wednesday December 30, 2009 @06:41PM (#30601006) Journal

    It works so well that now I can get all the MacGyver episodes.

  • Hijacking advantage (Score:3, Interesting)

    by macraig ( 621737 ) <mark.a.craig@gmail . c om> on Wednesday December 30, 2009 @06:43PM (#30601018)

    Isn't the real value here for wifi hijackers? Why park suspiciously outside the house/cafe with an open wifi node when you can snag it from out of sight?

    • Re:Hijacking advantage (Score:4, Informative)

      by ShooterNeo ( 555040 ) on Wednesday December 30, 2009 @07:13PM (#30601266)
      Welcome to the club. People have been doing this since wi fi was first publicly available. There are special antennas available that are much better than improvised ones, as well as special wireless radios that are hacked to give a stronger signal. For a long time, everyone was using WEP for security so that basically anyone with the right equipment also had access.

      • "special antennas available that are much better"

        What are the cost of these antennas? If they are much more then some tin foil or an already purchased pot like the guy is using then their antenna is MUCH more cost effective.

        • Re: (Score:2)

          by adolf ( 21054 )

          Being more inexpensive does not always entail being more cost effective.

        • If you can afford a laptop computer, and have the time to be doing a little long range hacking via wifi, you probably can afford a $100 antenna that gives you 10-100 times the range of a saucepan.

    • Wi-fi hijackers know perfectly well how to make a high-gain antenna. This is not rocket science.

      rj

      • Re: (Score:2)

        by macraig ( 621737 )

        Wasn't suggesting it was... although using a rocket to put a giant one 'o these in a low geosync orbit might qualify as such.

    • Isn't the real value here for wifi hijackers? Why park suspiciously outside the house/cafe with an open wifi node when you can snag it from out of sight?

      I'm not an electrical / electronic / radio engineer, but I think I can take a stab at that: Because it's a 3G dongle. You might want to RTFA next time, or even just RTFS.

      • Re: (Score:2)

        by macraig ( 621737 )

        The FS linked to a site that had everything to do with WiFi and nothing to do with 3G, so I was just mirroring their own confusion.

  • I think I'll start keeping a frypan in my backpack (Score:4, Funny)

    by syousef ( 465911 ) on Wednesday December 30, 2009 @06:47PM (#30601048) Journal

    Why not? I already have a GPS, mini binoculars, a radio scanner, a flash light, an external hard drive, a 20x zoom camera, multiple cables, a AAA/AA battery fast charger, batteries, a USB r/c flight sim controller (Realflight), a Logitec gamepad, a graphics tablet and a laptop in my backpack. I figure if I ever get into trouble and get searched the authorities will already think I'm some sort of hyper-nerd spy anyway. Heck if I didn't have to face the consequences it would be a laugh to catch a plane and cross into the US with my backpack just to see the look on TSA drone's face. Why not add a frypan to the mix? Now if only I could work out a way to fit a kitchen sink in my backpack.

  • can someone explain what the pot is doing? Is it acting as a focusing/collimating device? Because if that were the case, I would expect the signal to be focused in the up direction, which I doubt is where the average wireless signal is coming from. Or is it somehow providing a larger surface area for signal collection in all directions, and focusing it internally to the modem? But I don't understand how that would work. Would love to hear a cogent explanation.

    • Most likely (Score:5, Interesting)

      by Tehrasha ( 624164 ) on Wednesday December 30, 2009 @06:59PM (#30601154) Homepage

      He is probably located in a wifi-dead spot where singals bouncing off various buildings/objects causes some of them to arrive out of phase and cancel out. By placing the antenna in a pan, the signals are only arriving (mostly) from one direction and the out-of-phase signals are being blocked.

      No magic. Just math. He certainly isnt using the pan as a reflector which then would more accurately 'boost' the signal.

      • Re: (Score:2)

        by instarx ( 615765 )

        Actually it isn't math, it's logic.

        • Re: (Score:3, Insightful)

          by Mister Transistor ( 259842 )

          Actually it isn't logic, it's physics.

          • Re:Most likely (Score:4, Informative)

            by GrpA ( 691294 ) on Thursday December 31, 2009 @12:38AM (#30603160)

            And fairly simple physics at that... The pot attenuates some signals and may even amplify others... The end result is a better S/N ratio and less lost packets due to errors.

            I do the same, except I use a mesh spagetti strainer ( a big sieve ) and I've mounted a USB cable extender just below the focal point... Add my 3G dongle and away I go... up from 1 bar to 4 bars reception and my download speed doubles.

            My neighbor now uses one for his mobile phone and then he uses bluetooth to take the call so he can leave his handset in there.

            They are kind of directional though, but it's very repeatable.

            GrpA

            • Re: (Score:2)

              by Plunky ( 929104 )

              My neighbor now uses one for his mobile phone and then he uses bluetooth to take the call so he can leave his handset in there.

              I was just thinking about this, as I have a friend who lives in a valley with terrible signal (and no landline). Doesn't the sieve (or wok) block the bluetooth signals from the other direction though?

              • Re: (Score:2)

                by GrpA ( 691294 )

                Not entirely.. But it's not an ideal situation either... It's the sieve or missed calls due to drops in network coverage. Besides, he can always put it at the back of his house so he's always in front of it I guess... And he can probably use his bluetooth right down the road in at least one directions... We didn't experiment much past that... I made it for his 3G data dongle originally. The phone benefits were unexpected.

                GrpA

    • Re:what's going on? (Score:5, Interesting)

      by dtmos ( 447842 ) on Wednesday December 30, 2009 @07:23PM (#30601334)

      I'm suspecting that the pot is shielding the modem from a nearby source of interference. There's probably 3G signal arriving from above (e.g., from a tower), and it will certainly be scattered by various objets d'home so that some signal will be available from the vertical. Since the modems typically have rancid selectivity, the source of interference doesn't even have to be in the 3G band -- it could be a Wi-Fi access point, microwave oven, or any number of other things.

      • The other possibility is that it's working as a ground plane. It's just about the right size to be a short backfire antenna.

        ...laura

    • Maybe the signal strength shown on his computer includes signals reflected from the pan back into the wifi modem.

      • Re: (Score:3, Insightful)

        by gyrogeerloose ( 849181 )

        Maybe the signal strength shown on his computer includes signals reflected from the pan back into the wifi modem.

        Just to be sure, I watched the video again. The graph on his computer was measuring download speed in KB/s rather than actual signal strength. Although there's a correlation between the two, I'd tend to agree with the other posters who have postulated that the pot was more likely attenuating interfering signals rather than boosting the desired ones.

        • Although there's a correlation between the two, I'd tend to agree with the other posters who have postulated that the pot was more likely attenuating interfering signals rather than boosting the desired ones.

          Right. It's often better to have a weaker signal with little interference than to have a stronger signal with lots of interference.

    • Re: (Score:2)

      by cuby ( 832037 )
      What the previous posters said seems right. The saucepan seems to have a diameter compatible to the wavelength of one of the UMTS bands (~15 to ~30cm), it may resonate or focus the RF beams to a nearby tower. Obviously this may work in this particular place, maybe at that particular time but is not a general solution.

    • Actually, the way a network, cellular or similar, works is sometimes counter-intuitive. What I am guessing is happening is that he is probably getting into several sites with it out of the pan, and the fixed tower sites are, like the phone, idling back power due to a decent connection being had. With the phone in the pan he is probably only getting into one site and because the connection is more tenuous, the tower and phone both are probably kicking out more wattage.

      The bottom line is you don't want too

  • I've seen stuff about people using woks [wonderhowto.com] and TV satellite dishes [instructables.com] to boost signal power, so there's nothing surprising about saucepans doing it too. I'd be interested to see a comparison of these improvised devices with "proper" boosters. Would I be better off saving my money and just rigging up an old wok instead?

    • Re: (Score:3, Informative)

      by rantingkitten ( 938138 )
      Depends on the application, I guess. Years ago, I was out of work, and so my phone got shut off, along with my DSL, leaving me with no useful way of communicating with the world. If I put a laptop on this certain part of the kitchen counter I could get a really weak wireless signal from one of the neighbors, but not enough to be useful. So I put a wok next to the antenna of the computer, and with a little adjustment in direction here and there, got a signal that way, decent enough to actually stream vide

      • Re: (Score:2)

        by mspohr ( 589790 )
        So.. it sounds like the wok worked!

      • That's a great use of limited resources. It also gives you powerful leverage with any future ISPs.

        I mean, the next time they do something to get on your nerves, no one will doubt your sincerity when you threaten to wok.

    • Re: (Score:2)

      by plover ( 150551 ) *

      Head to http://www.usbwifi.orconhosting.net.nz/ [orconhosting.net.nz], they have a lot of similar plans for DIY parabolas. In general, the trick is to to aim a flashlight at the parabola, and mount the transceiver at the focal point of the reflected light. If you have a "spider skimmer" type tool or any other mesh basket instead of a solid pan, line the basket with reflective aluminum foil, then you can use the flashlight trick. Voila, you now have a directional antenna.

      It'll likely perform as well as a "proper booster", assu

    • You could do what I just did, and try lining three sides of a cardboard box with aluminum foil.

      My wifi host lives in the basement; I recently moved into a second story room. I have reasonable throughput after a connection is established, and the authorization handshake happens quickly without failures. But things frequently hang while negotiating the IP address, and often fail after a lengthy delay. The article got me to thinking about interference... My host's signal is often being reported at 30% - 50%,

  • Dim-sum scoop works on modem antennas too (Score:4, Informative)

    by stimpleton ( 732392 ) on Wednesday December 30, 2009 @07:31PM (#30601396)
    I came accross the USB Wifi site [orconhosting.net.nz] by accident a couple years back. I recalled seeing the dim-sum scoops in the local chinese mini-mart up the road, so I went up and bought one (NZ$4.50), and leaned it behind my modem's wireless antenna, then went to my garage sleepout for guests, which previously was out of range. Using NetStumbler, I watched the graph while a friend adjusted the scoop in the house. It went up to a usable "Good/Excellant" signal.

    I havent investigated why, but a wire mesh scoop seems better than a sold dish(Engineers will know I am sure).

  • Works well for WiMax (Score:2, Informative)

    by Coert ( 1710558 )
    The approach works equally well with WiMax (clear.com). I am 5 miles from a tower, but get plenty of signal using a simple Al foil reflector. Boost was about 6 dBm.
  • Coming up next, make a peppercorn sauce with a 3G Modem Antenna.

    • Re: (Score:2)

      by GTRacer ( 234395 )
      (OT warning)

      Halcyon, I can't find a way to contact you (no email nor active journal) and I wanted to ask you about your book rec in your sig, "Give Up The Ghost".

      I read it this week and liked it. Just curious what about it was enough to get you to sig it. If you want to discuss, please reply here or to my email (on my profile). If not, no worries. I still enjoyed the book, though it ended about 5 pages sooner than I thought it would...

      Also, you mention in your "Annoying" journal how you dislike obfus

      • Odd, I had my email set to "just display it". Thanks, Slashcode. Reset, should be displaying now. Feel free to drop me a line at halcyon1234@hotmail.com

  • This just in! (Score:3, Funny)

    by jd2112 ( 1535857 ) on Wednesday December 30, 2009 @08:12PM (#30601676)
    In response to Verizon's "Map" ads, All AT&T 3G phones now come with a skillet. A new iPhone ad states: "Frying bacon and eggs for breakfast? There's an app for that"

  • Well that worked.... (Score:5, Interesting)

    by skimitar ( 730902 ) on Wednesday December 30, 2009 @08:18PM (#30601728)

    ...against all expectations on my USB modem using a metal bowl I had lying around (think of a paraboloid with a flat bottom). Boosted download speeds on 3 consecutive tests by 50% (with bowl over without). Also, 3 tests in a row with no bowl showed some variation, but didn't peak at the same speed as with the bowl. Whod've thunk it.

  • Protip (Score:5, Funny)

    by ThatsNotPudding ( 1045640 ) on Wednesday December 30, 2009 @08:24PM (#30601770)
    Spraying it down with Pam prevents the radio waves from sticking; worth at least 10 extra Mbps.

    • Spraying it down with Pam prevents the radio waves from sticking; worth at least 10 extra Mbps.

      That's only a problem if you have an uneven distribution of ones and zeroes. If you use encryption, which evens them out, you don't need to spray it with anything.

  • it may be shielding it from an interference source and not necessarily "boosting" the signal, it might be lowering the noise - there is lots of crap at 2.4 GHz, cordless phones, microwave ovens, etc.. strong interferes will look like poor signal strength since the signal to noise ratio is low... just a thought...

  • Old time ham radio guys (Score:3, Informative)

    by nurb432 ( 527695 ) on Wednesday December 30, 2009 @08:55PM (#30601978) Homepage Journal

    Already knew about this sort of stuff.. Kids these days ..

  • http://www.tennatron.co.nz/cellphone/ [tennatron.co.nz] get the stats.
    Then build own.

  • My guess is that the pot is filtering out other sources of RF noise and so the link data speed can increase. His graph does not show RF gain, only data speed, so it's a bit hard to tell what is actually going on.

  • Hello this is not newsworthy at all, anyone remember "Cantenaes" when wifi first rolled out? Or my personal fave, the spageti strainer parabolic for a wifi usb stick.

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