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1KM 802.11b @ 2MB

Posted by Hemos on from the if-you-build-it,-your-costs-will-fall dept.

OffTheRack writes "Check out this web site to see how a guy in Egypt built his own line-of-site (H:Get? It's Punny.) 1KM broadband connection. Plenty of nice pictures." Pretty cool set-up.

5 of 271 comments (clear)

  1. Interference by gpinzone · · Score: 5, Interesting

    Although I live in a small-ish town with presumably little electromagnetic interference, it is worth mentioning that this high-gain, 3 meter tall GSM network monstrosity is located about 7 meters away from my AP antenna, on the same roof. I really can't tell whether or not it is affecting my antenna.

    I think the more important question would be, "Is your unlicensed amplified antenna affecting their transmissions"

  2. He should try this by t0qer · · Score: 5, Interesting

    http://trevormarshall.com/biquad.htm

    I read direct TV dishes are a lot easier to build and go alot further.

    1. Re:He should try this by Lumpy · · Score: 4, Interesting

      direct TV dishes do not work well... they are not designed for the right gain that you are looking for and are more expensive than the correct dish...

      Get a set of primestar dishes... they re larger and the feedhorn on them can easily be modified for this use. I use primestar dishes only and they work awesome for my hub links.

      Primestar dishes are free, cince TCI abandoned it back in 1996 there are still many of them floating in yards or at hamfests with the reciever for $5.00

      Otherwise if you really want a good solution that is ready to go, ramsey electronics sells turnley 802.11b point to point 22dbi dishes... plug it in and you are working... no building anything.

      --
      Do not look at laser with remaining good eye.
  3. 1km? No biggie. by 4ginandtonics · · Score: 5, Interesting

    Linksys outputs 50mw. If you were to go to the FCC regulation maximum of 100mw (1 watt), you would do better.

    If you use Cisco's Wireless Calculator Excel spreadsheet, you will see that a 21 dbi parabolic dish (as seen here could grant you 76.1 kilometers.

    Now you have problems with this distance. Line of sight, for one.

    The common calculation calls for a cone shaped space from each antenna meeting at the middle. This is called the Fresnel Zone The calculator says that this zone, for 76km is 28.2 meters (92 feet). So, you have to have 92 feet of clearance. No trees. No buildings. Nothing.

    At this distance (44.5 miles) The earth curvature is 90 feet, somehow your signal must peak over that!

    So, you are going to need antenna heights of over 150 meters to set up a 802.11b wireless like of this long.

    Most engineers say this is simply not feasable. Other issues, such as antenna alighment, water (nasty multipath bounce), WiFi hotspot interferance, and the actual time it takes for a signal to travel that far are issues as well.

    So just remember line of sight. If you have clean line of sight to the other endpoint, and clarity through the Fresenel Zone, you might just have a chance for point-point 802.11b wireless.

    Cheers!

  4. 128 bit encryption internationally? by i22y · · Score: 4, Interesting

    I may be way off base here...but I was under the impression that 128 bit encrypted products couldn't be exported without a permit of some kind. The author mentions that a friend in California brought the products to Egypt. Wouldn't that be illegal to export such a product?

    And yes, I do find it cool what he did... just curious about the legality by US laws.

    --
    Mike