Follow Slashdot blog updates by subscribing to our blog RSS feed

 


Forgot your password?
Close
typodupeerror
×
Wireless Networking Hardware

New WiFi Link Distance Record 124

Posted by ScuttleMonkey from the wifi-vs-rfc-1149 dept.
Espectr0 writes "A Venezuelan professor along with his team have set a new record for the longest WiFi link. Using commodity hardware, they established a connection between a PC in El Águila, Venezuela, and one in Platillón Mountain, a distance of about 237 miles. The previous record was 193 miles. Slides [PDF] are also available."
This discussion has been archived. No new comments can be posted.

New WiFi Link Distance Record More

New WiFi Link Distance Record

Comments Filter:

  • I've come close (Score:5, Funny)

    by nolife ( 233813 ) on Wednesday June 20, 2007 @12:39PM (#19583185) Homepage Journal
    I almost get a usable signal in my bedroom which is 237 decimeters away from my access point in my basement. Oh... the article claims 237 miles. My "of the shelf" equipment must have come from the clearance shelf.

    • Re: (Score:3, Insightful)

      by Colin Stanners ( 561554 )
      Well, some so-called "top shelf" stuff sucks too (think of Linksys, who uses crappy Broadcom radios in most of their equipment).

      If you use good radios (Atheros, esp. the Ubiquity 400mw cards - wow), good antennas (these guys' dishes are 27dbi? Standard routers and cards are *2*dbi) and have great/incredible LOS, the distance you can go is essentially limited only by earth curvature.

    • You live in an 8 floor* house?

      * Assuming 3 meters per floor. Also including basement.

  • LOS (Score:5, Insightful)

    by Moby Cock ( 771358 ) on Wednesday June 20, 2007 @12:39PM (#19583197) Homepage
    The Line of Sight caveat is a rather significant point ommitted from the summary. This is still quite an achievement.

    • Re: (Score:3, Insightful)

      by Red Flayer ( 890720 )
      I don't understand, what caveat are you talking about?

      That this connection did have LOS? That LOS (and radio interference, etc) is obviously a problem in more populated areas, and I should expect to make this work in New Jersey?

      As far as I'm concerned, anyone who doesn't RTFA, AND somehow lacks the basic understanding of wireless communications to figure out that they must have had LOS, doesn't deserve the extra effort it takes to put in a caveat like that.

      Seriously... if someone thought that they were

    • Re:LOS (Score:5, Insightful)

      by Jeff DeMaagd ( 2015 ) on Wednesday June 20, 2007 @02:09PM (#19584631) Homepage Journal
      I think the fact that a mountain was involved should be an indicator.

    • Re: (Score:2)

      by Kjella ( 173770 )
      Gee, a record that was set under extremely optimal conditions. Like, that's revolutionary man...

    • Re: (Score:3, Insightful)

      by mollymoo ( 202721 )

      You mean they didn't have anything in the way of the signal? Damn, I was thinking when they mentioned a mountain they were going through it, not using the top of it. Not only that but the damn cheats didn't even wait till it rained!

      I've done some digging and apparently this kind of flagrant dishonesty is pretty widespread. Here are some more significant points omitted from stories elsewhere in the media:

      • Miss World was wearing her makeup.
      • The lap record at Indy wasn't set in the rain.
      • Asafa Powell didn'
  • I can't even get a good enough signal to steal wireless Internet from my neighbor.

  • What the? (Score:1, Insightful)

    by Dr. Smoove ( 1099425 )
    Yea, one of those 75 foot off the shelf antennas. I am also wondering, what kind of impact does outputting a signal that strong have on living things? I don't know much about that sort of thing.

    • Re:What the? (Score:5, Interesting)

      by drinkypoo ( 153816 ) <drink@hyperlogos.org> on Wednesday June 20, 2007 @12:44PM (#19583273) Homepage Journal

      I am also wondering, what kind of impact does outputting a signal that strong have on living things? I don't know much about that sort of thing.

      One of my ex-housemates was a Sonar tech in the Navy. The Sonar and Radar guys apparently hang out together on those ships and one of their favorite games was to paint the guys coming up the desk with an armload of flourescent tubes with the radar, illuminating the lamps. Hilarity ensues. They never killed anyone doing it. But at close range and high power, I'm told you can throw hot dogs up into the path of the radar and they come down cooked.

      Moral of the story is that it's directional and as long as you don't stand in front of it there's not likely to be any significant effect. At the other end, the signal has been scattered substantially and it's only coming in at a whisper of the original signal.

      • In cold climes, it's been a convention to stand in front
        of microwave radar if possible to warm up.

      • Re:What the? (Score:5, Funny)

        by jonnythan ( 79727 ) on Wednesday June 20, 2007 @12:59PM (#19583567)
        Joke's on you.

        Hot dogs are already cooked when you buy them ;)

        • OT: your sig (Score:3, Insightful)

          by TeknoHog ( 164938 )

          *BSD is for People who Love *nix; Linux is for People who Hate Windows

          I just wanted to point out that I use Linux because I like Linux. I wonder if it's possible for people in general to prefer X solely for the properties of X, instead of how it is related to Y.

          • Re: (Score:1)

            by cafucu ( 918264 )

            *BSD is for People who Love *nix; Linux is for People who Hate Windows

            I just wanted to point out that I use Linux because I like Linux. I wonder if it's possible for people in general to prefer X solely for the properties of X, instead of how it is related to Y.

            Apparently it is possible, but only if you're elite and run *BSD. I've never heard of that BSD distro.


            (I said "BSD distro"...stand back and duck for cover)

            • you're elite and run *BSD
              Oh yeah, 4ssh0l3 BSD. I've heard really good things about it, but the only guy I know who runs it just gave me a photocopy of the CD when I asked for a copy of the installation disk...

              • Re: (Score:1)

                by redcane ( 604255 )
                Yes, indeed, you should have asked for the installation disc, unless you really wanted a hard drive, or floppies.
          • I think operating systems are evolving too fast. I mean, I would have killed to have Windows XP in the 90s. Mac OS X is a completely different beast than earlier Mac OS versions. Once we get down to plain old preference things might change, but for now I need there are actual quality differences going on. As in, X solves this vastly superior to Y for almost everyone. For example, x.org are doing some major changes to support input/output hotplugging etc. in the next release which I look forward to. To me it
      • It's commonly known in the Navy, that if you're a going to be a Radar tech, you should not expect to have male children. I don't know that there are conclusive studies, but there is a visibly large disparity in the number of Radar tech offspring which are female, compared to offspring which are male. While it doesn't kill, is it possible that radar changes or destroys some kind of protein or what-have-you of Y-chromosone in the nads? Any biochemists with physics degrees (or inverse) in the house?
        • If it would just stop me from having to worry about having any children, I'd go become one today. But anyway, there are many species in which we have positively correlated temperature to gender of offspring, maybe there's a similar effect at work in us. Or maybe sperm can pick up radio waves and they get confused :)

      • Roast Seagull... (Score:3, Interesting)

        by jpellino ( 202698 )
        A colleague of mine was a submariner who had this story. They were down for an extended dive, and when they surfaced, they would send a short, dense burst of communications and data on a very powerful microwave uplink - get up, send fast, get back down. It was a very powerful signal - and they would surface to a depth that would get the periscope and the antenna above water, do a quick scan for surface vessels, send the burst and dive. One day they did this and saw thru the periscope there was a gull on
      • I'm currently still in the navy. because of the effect that our powerful equipment would have on our bodies we have designated areas and precautions taken to eliminate the chances of having a mishap due to this. It drives me crazy when they announce that shit on the 1mc.
      • You've also heard of the Darwin award winner for 1999 (could be a hoax, I don't have time to check). He apparently was using a relay dish on a tower to keep warm:

        Thompson, Manitoba, Canada Telephone relay company night watchman Edward Baker, 31, was killed early Christmas morning by excessive microwave radiation exposure. He was apparently attempting to keep warm next to a telecommunications feed-horn. Baker had been suspended on a safety violation once last year, according to Northern Manitoba Signal

        • Re: (Score:1, Informative)

          by Anonymous Coward
          I have the Darwin Awards book right here, and it lists that story as a hoax.

        • Re: (Score:1)

          by redcane ( 604255 )
          I call bs at this scentence:"Baker had not been told about a tenfold boost in microwave power planned that night to handle the anticipated increase in holiday long-distance calling traffic". Boosting power won't increase bandwidth, it'll increase transmission distance....
          • If it were a digital duplex signal, boosting power could indeed reduce the amount of error correcting data, I would imagine, leaving more of the stream available. Hence this increases the "bandwidth." Your FiOS connection, for example, can get more data through at a higher power, even though the distance from house to amplifier remains the same.

            I also doubt the story is true, but maybe not for that reason. Who the hell hires a transmission tower night watchman?
      • A buddy of mine said that they used to fire up the radar in port sometimes and it would cook seagulls right out of the air.

    • Re:What the? (Score:5, Interesting)

      by aktzin ( 882293 ) on Wednesday June 20, 2007 @12:54PM (#19583467)
      A friend of mine who's a military history buff told me a story about Soviet fighter aircraft in the 70s and 80s. Seems they had very powerful look-down, shoot-down radars and pilots were instructed to turn them off during take off and landing. Apparently sometimes they forgot, and runway maintenance crews had to regularly pick up the carcasses of rabbits, birds and other unlucky critters that were in the area when those MiGs went on missions.
      • That would be the MIG-25. Ridiculously overpowered interceptor radar combined with gloriously short combat radius.
      • Several years ago an ex soldier successfully sued the German Bundeswehr due to infertility after a radar maintenance accident.

      • Re: (Score:3, Informative)

        by CrossChris ( 806549 )
        A friend of mine who's a military history buff told me a story about Soviet fighter aircraft in the 70s and 80s. Seems they had very powerful look-down, shoot-down radars and pilots were instructed to turn them off during take off and landing. Apparently sometimes they forgot, and runway maintenance crews had to regularly pick up the carcasses of rabbits, birds and other unlucky critters that were in the area when those MiGs went on missions.

        That's what we engineers would call "complete cobblers". The pow
    • That's a lot of Pringles cans and many rolls of duct tape.
      And good luck keeping it from bending.

    • Re: (Score:2, Interesting)

      by KillerCow ( 213458 )

      Yea, one of those 75 foot off the shelf antennas.


      and a parabolic, and various amplifiers... and this:

      MAC of WiFi designed for up to 100 m, extending the range two orders of magnitude requires modifications


      They never said how they accomplished that, but it was presumably done by hacking the firmware to change the collision detection and the back-off settings.
    • Well being at 2.4ghz I'd think it would cook a turkey if you were standing next to, though I might be wrong :).

      • Re: (Score:1)

        by cafucu ( 918264 )

        Well being at 2.4ghz I'd think it would cook a turkey if you were standing next to, though I might be wrong :).
        Why would it cook a turkey if I were standing next to it? Might you be wrong?

    • Re: (Score:2)

      by jgs ( 245596 )
      TFA and the presentation don't provide that much information, but it looks like they used a Linksys WRT54 (check out the photo on slide 13). IIRC, the WRT54 Tx power tops out at 100mW (the presentation also mentions 100mW on one of the "background" slides).

      Based on that, I'd say the answer to your question is "none whatsoever".

      • (the presentation also mentions 100mW on one of the "background" slides).
        Based on that, I'd say the answer to your question is "none whatsoever".

        Exactly.

        What people are not understanding is that there is a BIG difference between peak envelope power (PEP) and effective radiated power (ERP). Bigger antennas and stacked arrays allow you get uber amounts of gain in signal. Instead of cranking the power output up, you focus it instead. Basically it's like adding more lenses and mirrors to an optical system to get an ever increasing focused beam of light from an incoherent light source (i.e. light bulb).

        So, instead of spraying 100mW in an essen

    • Let's just say that even looking at the open end of an SMA connector can be hazardous ;)

    • Re: (Score:2)

      by hjf ( 703092 )
      Not much, I guess, since it's like, in the middle of nowhere. But if you wanna get picky, I'd guess that's a 30dB antenna, and they must be using a 100mW rig. So it turns out to about 100W output on the antenna. 400km away that is a 152dB attenuation.

      A microwave oven puts 900 to 1100W at about 1 foot of the food, and you need several seconds to warm something up. So, unless a stupid bird happens to sit right at the antenna beam for a few hours, I don't think it will affect living things more than some 10kW

    • Yea, one of those 75 foot off the shelf antennas. I am also wondering, what kind of impact does outputting a signal that strong have on living things? I don't know much about that sort of thing.

      I wasn't able to find any information on how much power they were using, but with a few caveats, the answer to "what impact does the outputting a signal that strong have on living things?" is "about the same or less impact than using the same power with a less efficient antenna."

      It's certainly true that by standing d

  • Nice work but... (Score:5, Funny)

    by Aqua_boy17 ( 962670 ) on Wednesday June 20, 2007 @12:41PM (#19583245)
    Good for them. But since WiFi is line of sight, the only way they can do this is by using mountainous regions. I guess us flatlanders will have to resort to bouncing our signals off of blimps or flying pigs (coated in foil, of course).

  • These guys are in BIG trouble with the FCC! (Score:4, Funny)

    by gc8005 ( 733938 ) on Wednesday June 20, 2007 @12:49PM (#19583385)
    Just wait until the FCC hears about this! These guys are in big, big trouble.

  • No Chavez? (Score:1, Funny)

    by Anonymous Coward
    A Venezuelan article in /. that is NOT related to Chavez at all and it's actually science and technology?
    I'm shocked!
    • A Venezuelan article in /. that is NOT related to Chavez at all and it's actually science and technology?
      I'm shocked!

      Heh, i was actually going to put something like "See? We aren't all About Chavez down here!" but got chicken and decided to be mature.
  • OK, we get it. You can transmit WIFI as far as you have line of sight. If you have 2 mountains that can see each other 500 miles apart you can probably send WIFI communications between them.

    Can we now please stop trying to set ridiculous "records" concerning WIFI connections?

    • Re: (Score:3, Funny)

      by sammy baby ( 14909 )

      Can we now please stop trying to set ridiculous "records" concerning WIFI connections?


      No.

      We thank you for your interest.
  • I'm working with a group of people to setup an emergency wifi network grid around the county. It has hit a barrier due to technical issues mostly dealing with distance. So this can be very useful as long as they give real info rather than a "we just used a WRT54GS and a directional antennae and pumped up the wattage"
    • There's not much tech info needed... if you use good radios/ants (see my post above; also, amplifiers other than those on the card are usually a bad idea) and have great LOS and no interference and you're set for hundreds of miles. You'll notice they used radio mobile to compute the signal stength; it's not entire accurate but it helps.

      • Re: (Score:2)

        by LarsG ( 31008 )
        Not really. The 802.11 MAC was originally designed for short range / indoor use. For long links to work properly, some timeouts need to be relaxed. (if you follow the standard strictly, 802.11a/g runs into problems past 3KM)

  • In unrelated news... (Score:5, Funny)

    by Anonymous Coward on Wednesday June 20, 2007 @12:57PM (#19583517)
    In other news...

    Cuban government officials have begun a new, lucrative service where they have established a WiFi base and are charging $10/day to residents of southern Florida for unfettered Internet access. "We have very good download rates for Sicko and, of course, for all your favorite music artists," Castro's spokesperson is quoted as saying. In the background this reporter could hear maniacal laughter and intermittent shouts of "See what the RIAA thinks of that!" and other such obscenities.

  • They used 1 meter dishes. Of course it works. (Score:5, Insightful)

    by Animats ( 122034 ) on Wednesday June 20, 2007 @01:15PM (#19583843) Homepage

    The technology is straightforward. They had line of sight, used 1 meter dishes at each end, and aligned them with telescopes. Point to point microwave links have been doing that since the 1950s. After all, you can get a signal to and from geosync orbit with a dish of that size.

    The most interesting thing about this is that they found two points on the earth's surface 273 miles apart with a clear line of sight between them.

    • Re: (Score:2, Informative)

      by lostguru ( 987112 )
      you can get a signal to and from orbit without using a dish, but thats putting out 5W, and the same with point to point microwave links of the 1950's, a lot higher power than off the shelf wireless gear and no amp

    • Re: (Score:2)

      by NateTech ( 50881 )
      There's lots of places where you can do this. Pikes Peak on the Front Range of the Rocky Mountains in Colorado can see Kansas on a clear day... it gets real flat out there, real quick going East.
  • Now there is a record that will last til the beginning of August. (Think Vegas)

    • Re: (Score:2, Informative)

      by SMS_Design ( 879582 )
      As one of the crew that ran the Wifi Shootout in Vegas a couple of years ago, I can say that there won't be another Defcon Wi-Fi Shootout any time soon. We simply ran out of Line-of-Sight locations. I'll tell you right now that the iFiber Redwire team could have established that link were they to have the LoS.
  • I'm suprised they are sticking to the 100mW provided by the Linksys unit. There are a LOT of signal amplifiers for 802.11 and I bet pumping that signal up to 1W would allow them something closer to the 11mb with less noise.

    Since it's Venezuela I bet they don't have any regulations on transmission power either.

    I have setup systems using the same hardware they are using for an old neighbor of mine who wanted to link his horse barn to his home network so he could install security cameras. I set him up with a s

  • 193 miles = 310.603392 kilometers :)
  • I really don't see what all the fuss is about. It's nothing compared to my router. My signal goes around the world twice before reaching my laptop.

  • 295 km in Italy (Score:3, Interesting)

    by mennucc1 ( 568756 ) <d9slash@mennucc1.debian.net> on Thursday June 21, 2007 @04:43AM (#19591961) Homepage Journal
    let me also share this record [polito.it] (announced also 24 may in in this Italian newspaper [repubblica.it]): the Ixem team [polito.it] of "Politecnico" in Torino has set up a 20megabit connection from "Capanna Margherita" (Mount Blanc, 4556m of altitude) with "Pian Cavallaro" (a point on the mountain range that divides Tuscany from Emilia-Romagna); the two points were 295km apart; the hw used was a 386 CPU running Linux; the network is Hiperlan type 2 and Wi-Max 802.16 (EIRP regulatory requirements limited to 30 dBm is satisfied). They have also set a webcam in Capanna Margherita [polito.it], that is accessed thru the link

Slashdot Top Deals

You are always doing something marginal when the boss drops by your desk.

Close