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125-Mile WiFi Connection

Posted by timothy on from the beats-out-chinese-cookware dept.

Jason Striegel writes "Team iFibre Redwire smashed the WiFi distance record, successfully linking a distance of over 125 miles at this year's DefCon WiFi Shootout. They maintained a full 11Mbit unamplified connection for 3 hours using Z-com 300mw PCMCIA cards, surplus satellite dishes, Linux, and a great deal of hacker ingenuity. The best part: yesterday afternoon they said that they expect this rig would work at distances of over 300 miles. Here's additional team info, a couple pictures of one of their rigs, and some more technical details." I still wish I could find truly out-of-the-box Linux-friendly USB adapters, so I could get some tiny fraction of this distance, cheap.

29 of 222 comments (clear)

  1. The distance is... by hayalci · · Score: 4, Funny

    201.16800 km for us metric guys :)

    --
    hayalci
  2. The real question is... by Laivincolmo · · Score: 5, Funny

    .. were they allowed to use those illegal cantennas? :)

    1. Re:The real question is... by Irongeek_ADC · · Score: 3, Informative

      I think he is referring to Lt. Bob Lozito of the Sacramento County Sheriff's Department's Hi-Tech Crimes Task Force comment in this article:

      http://www.insidebayarea.com/businessnews/ci_28868 79

      ""They're unsophisticated but reliable, and it's illegal to possess them," said Lozito of the Hi-Tech Crimes Task Force."

      --
      Irongeek's Hacking Videos / Security Videos and Articles
    2. Re:The real question is... by Eccles · · Score: 2, Informative

      Note that other reports claim that Lozito claims he was misquoted there.

      --
      Ooh, a sarcasm detector. Oh, that's a real useful invention.
    3. Re:The real question is... by Chanc_Gorkon · · Score: 3, Informative

      Depends. If your a LICENSED Amateur Radio Operator, cantennas and this dish used for the record are legal. Anyone else, like 90 percent of us who use WiFI, it's not legal. Only the antenna that comes with your equipment or is designed for use with that equipment (like DESIGNED to work with it)can guarantee that you stay udner the FCC's regulated ERP rules. Will the FCC do a enforcement action? Not likely. Does podunk Police officers have the right to confiscate your equipment? NO. In the US, the FCC is the ruling body responsible for regulating RF. The local law has no jurisdiction on it. It would be called a Federal Premption.

      --

      Gorkman

    4. Re:The real question is... by dougmc · · Score: 2, Funny
      Note that other reports claim that Lozito claims he was misquoted there.
      Well, any time I say something stupid or incriminating, well, I was misquoted there too.

      This includes cases where I'm quoting myself, like this one. If this is stupid, I was misquoted.

    5. Re:The real question is... by dougmc · · Score: 2, Informative
      If your a LICENSED Amateur Radio Operator, cantennas and this dish used for the record are legal.
      Of course, it's legal for anybody to use antennas like that for receiving as well. It's not the antenna that's illegal ... it's the possible use that might be illegal.

      And while hams can use any antenna they want, they can only do this on the ham bands while following ham rules. In the US, this means IDing yourself every 10 minutes, no encryption, no pecuniary interest, third party traffic restrictions, etc.

      Only the antenna that comes with your equipment or is designed for use with that equipment (like DESIGNED to work with it)can guarantee that you stay udner the FCC's regulated ERP rules.
      Hate to burst your bubble, but 1) no antenna can guarantee this (after all, things do malfunction), and 2) there is some room for a hobbiest to legally make his own transmitters, antennas and such without a ham license and without FCC certification. Using this antenna with a standard WiFi card probably won't qualify, but it can be done.
      Does podunk Police officers have the right to confiscate your equipment? NO.
      Not if you're trying to break some world record like this. But they probably can if you're using your cantenna to leech off your neighbor's WiFi connection and you get caught.

      (Nice use of the word `podunk' in there. It's totally irrelevant (as large police departments don't have the right either), and yet it's a nice jab at Lozito.)

    6. Re:The real question is... by LordHunter317 · · Score: 2, Informative

      Power requirements are MORE then just the transmitter power. FCC ALWAYS uses ERP or Effective Radiated Power for measurement.
      No shit, and my statements aren't contradictory with this fact.
      And actually, no, they don't, always use ERP in all bands under all different parts. Part 97 isn't ERP restricted, but rather transmitter PEP restricted. Had you said 'Part 15', you'd be correct, of course.

      Only way to tell is to measure it.
      Or you know, take the manufacturer's numbers and add them together, and compare them to the rules. The FCC will not fine if you, in good faith, designed your system by the numbers and they found that something performed better than specified. Especially given the fact that numbers are most likely to be high, not low.

      Of course there are third party antennas that will work. Otherwise, they would not be able to SELL them.

      Not quite true. You don't need a ham radio license to buy a ham radio transmitter, necessarily, nor is the sale illegal. The operation would be, but for many devices, including antennas, the onus isn't on the seller to ensure legal operation.

      The ducks Linksys makes usually do not provide ANY gain. In fact, they usually cause a power loss.
      Nope, they're usually 2dBi or so, which is a small gain. It's pretty hard to build an antenna that causes loss, if you're even remotely competent.

      If the AP you have is UNDER the required wattage, then you MAY be able to get away with a higher gain antenna.
      Seeing as the ERP requirement for omni-directional systems is 1W (30 dBm), and most consumer units have output in the 15 mW range (11.7 dBm), you have a lot of room. And the rules are different for fixed, point-to-point systems, allowing for almost 100W (50 dBm).

  3. Working at 300 miles? by MichaelSmith · · Score: 4, Insightful

    How are they going to wrap their wifi signal around the Earth, assuming that they don't have their own satellite?

    I don't think ionospheric propogation is going to work at wifi frequencies. And you won't get 11 Mb/s at 27Mhz.

    --
    http://michaelsmith.id.au
    1. Re:Working at 300 miles? by Nerftoe · · Score: 2, Informative

      Very tall towers. :) I'll let someone else do the math.

    2. Re:Working at 300 miles? by strider44 · · Score: 4, Informative

      Going from the top of one mountain to the top of another.

  4. And by a.different.perspect · · Score: 5, Funny

    2.12639285 x 10^-11 light years for us space-faring people. But we already have Wi-Fi anyway. Surrender your planet!

    1. Re:And by Mudcathi · · Score: 3, Funny

      Thank you, Google calculator:
      36.2073434 leagues
      440,000 cubits
      1,980,000 hand
      1,000 furlongs
      40,000 rods
      1,000 stadia

      --

      "He who throws mud, loses ground." - proverb

  5. 300 Miles? Not gonna happen by Bad_Feeling · · Score: 5, Informative

    There is just no way they can maintain 300 miles/480km without using relay stations. Multi megawatt FM stations cannot get that range simply because the curvature of the earth causes the signal to disappear into space before reaching its destination. 125/200km is about the maximum range that is possible on frequencies much higher than HF, even with captain picard's private satellite link to france they are not going to get 480km out of it.

    --
    Disclaimer: On the other hand, I am kind of a psycho...
    1. Re:300 Miles? Not gonna happen by megla · · Score: 3, Interesting

      Multi-megawatt FM stations are omni-directional. A uni-directional signal requires only a fraction of the strength to be heard over the same distance.

    2. Re:300 Miles? Not gonna happen by dougmc · · Score: 3, Informative
      There is just no way they can maintain 300 miles/480km without using relay stations.
      Well, obviously they did it, though the site is down so I can't actually read their article.
      Multi megawatt FM stations
      You're probably thinking of UHF TV stations. FM stations don't get that much power.
      125/200km is about the maximum range that is possible on frequencies much higher than HF,
      Under normal conditions (i.e. not much altitude), maybe. But if you can put your two antennas on top of mountains, you can get further.

      This page may help you determine how far the horizon is given a certain height. (And don't forget that a nautical mile is 1.15 miles.)

      If we assume that each antenna is on top of a 5,000 foot mountain, with nothing in between this gives a line of sight distance of 190 miles. If we raise the mountains to 15,000 feet, the distance becomes 320 miles (though I'm not sure that sutiable mountains even exist that are that tall, that close, and have nothing inbetween to interfere. You could use an airplane or balloon instead of a mountain, but then aiming the antenna (and even getting it up there) becomes very difficult.)

      This is certainly possible, and in fact if you could find the proper location (i.e. two tall mountains with nothing in between) and even bigger antennas, you might be able to go even further.

      even with captain picard's private satellite link to france they are not going to get 480km out of it.
      Ok, if you're talking to a satellite this all goes out the window, because it's all line of site. In that case, it's only a matter of how good your antennas are. But yes, you can get a signal to a satellite with only a watt of power or so -- hams do it all the time. And this doesn't even require really fancy antennas if the satellite is low, like the ISS is.
  6. I can just see the spam now by Anonymous Coward · · Score: 5, Funny

    inCREASe your WIFI distance NOW!

    Over-the-counter WIFI enhancers!

    Make it go FARTHER!

  7. 500 miles also done by bvdbos · · Score: 5, Interesting

    At whatthehack there was someone telling about how he managed a 500 km connection (which is 311 miles says google)...

    1. Re:500 miles also done by Ingolfke · · Score: 3, Informative

      Interesting, but the connection wasn't 11-Mbps. It was actually only 3kbs. This is an interesting project, I'm certainly not trying to bash the work their doing. Just want to point out that the goal of the original post was broadband wi-fi, and the article you linked to was just trying to pass data over a very long distance wirelessly.

      A few snippets from the article.
      Non IP data were succesfully transmitted over 350 km. Speed: 3kbs troughput.

      Their goal is to create a radiomodem that is capable of 64Kbs in a multislotted system

  8. Good for Cuba? by J.+T.+MacLeod · · Score: 4, Interesting

    Perhaps this could mean real internet connections for some Cuban citizens again. It's close enough to Florida, Mexico, and the Dominican Republic to make it feasable.

    Not many would be able to make use of it, of course, but every bit helps when you're living under a government such as that.

    1. Re:Good for Cuba? by MichaelSmith · · Score: 2, Insightful
      but every bit helps when you're living under a government such as that.

      Actually its a fantastic idea. I always thought it should have been tried in Iraq: flood the population with free communication from outside and wait for change to start from within.

      Perhaps the wifi links could be supported with covert donations of old PCs running free software, with cryto built in so that it is hard to track usage at the Cuban end.

      --
      http://michaelsmith.id.au
  9. Slashdotted by Rhoon · · Score: 2, Funny

    They maintained a full 11Mbit unamplified connection for 3 hours

    That is until the were slashdot'd

    --
    "If all the world's a stage, I want to operate the trap door." - Paul Beatty
  10. Re:The death of land lines? by cnettel · · Score: 3, Informative

    Sorry. The point is that both parties are using highly directional antennas. And, well, a single access point wouldn't be able to serve much bandwidth with that many users anyway. (As the contention management protocols are not really designed for 1000+ users, you will get even less than your theoretical slice.)

  11. Developing nations by erbmjw · · Score: 2, Interesting

    This would be useful for many developing nations. No expansive infastructure required for internet connections in remote locations. Wondering when "wired" will have the article on the competition out. Also wondering what the power requirements for the entire setup are ie -- can the whole setup be run off of micro dams, solar power, etc.

  12. 125 Miles tropospheric propagation by kalevi · · Score: 4, Informative

    All communication for longer distances than so called line of sight communication is due to tropospheric propagation.

    In summertime it is very common in areas of extreme high pressure condiftions. Today it might work just fine, tomorrowe no connection.

    Best of luck with your experments!

    Kalevi Nyman
    SM0NTE
    ---

  13. Re:The death of land lines? by morie · · Score: 2, Interesting

    the city of Leiden is doing the same by providing high points with directional antennas to form a grid and omni-antennas to connect to the users who use directional antennas to reach the omni. the whole thing was supposed to be plugged into a landline internet connection at some point, but for now it is just a networked system.

    http://www.wirelessleiden.nl/english/

    --
    Sig (appended to the end of comments I post, 54 chars)
  14. Depends on their licenses by bluelip · · Score: 2, Informative

    Hams get the neat ability to modify their equipment to pump out more power and use better/stringer/faster toys. (Legally)

    This is also true when using cantennas.

    Read up here for the commercial aspects:
    http://www.michwave.com/bbnetwork/faq/fcc.htm

    Here for the amateur side:
    http://www.qrpis.org/~k3ng/ham_wisp.html

    --

    Yep, I never spell check.
    More incorrect spellings can be found he
  15. Also at boingboing.net by amcdiarmid · · Score: 2, Informative

    They had corporate support to go to DefCon.

    They used the VCom 325hp+ PCMCIA cards running at a built-in power of 300 mw on each end of the link
    They used two antennas with 802.11b. One was 10', the other 12'.
    Yes it is fast enough to support VNC, they had a 12ms ping time.

    They are going to try to break a 1Mile bluetooth record.

    Oh yeah, for the guy wo said this was impossible due to the curviture of the earth: one team was on top of a mountain.

  16. "Truly OOTB Linux friendly adapters" by joel48 · · Score: 2, Informative
    I've recently purchased several of the RALink 2570 (USB) based adapters and they work fabulously. I personally bought the Gigabyte GN-WBKG and have been quite pleased. Good to see this hardware with full support from the manufacturer. For PCI cards they also have 2500 chipsets equally well supported.

    List of brand/model numbers with the chipset: http://ralink.rapla.net

    RALink's own GPL linux driver here.

    Further development of RALink's codebase here.