Wi-Fi bridge claims a range of 5 miles

Wi-Fi bridge claims a range of 5 miles

Summary: I’d love to get my paws on this one: A wireless outdoor network bridge that can connect 802.11g devices over a range of up to five miles.

TOPICS: Wi-Fi, Networking

I’d love to get my paws on this one: A wireless outdoor network bridge that can connect 802.11g devices over a range of up to five miles. Or so claims its manufacturer, HD Communications.

Wi-Fi bridge claims a range of five miles

For $318, the HD26200 includes two high-performance Ubiquiti network radios with integrated 17dBi dual-polarity antennas that are configured in wireless bridge mode. You don’t even need power cables, since both the units are powered over Ethernet.

There’s just one gotcha: the 802.11g devices need line of sight of each other in order to work. HD Communications says it plans to launch a version that doesn’t require line of sight by summer’s end.

In a press release, the company claims that the HD26200 “works every time and outperforms other manufacturers' $10,000 wireless bridge solutions.” Is there a money-back guarantee?

Topics: Wi-Fi, Networking

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  • Old news

    Come on, Rik, this technology has been around for some time. I installed my first bridge using equipment like this years ago to extend our network out to remote buildings, and have done so many times since. We recently installed SMC 2891s to bridge between buildings several blocks apart, and those units have a claimed range of over 9 miles, although at a bit higher price. Trendnet and WLANantennas are other sources for equipment of this nature at very reasonable prices. Besides the internal antennas, most also allow you to connect higher gain external antennas for increased range or for multiple bridges from a single unit.

    The only ones paying $10K for equipment like this are those who don't look past Cisco or 3Com for their network needs. Both make good equipment, but it should be gold plated at the prices they charge.
    • Cisco is less than $10K! :)

      I've installed a few Cisco 1300 and 1400 series wireless bridges, and they're far less than $10K, even for the pair and all the accessories plus SmartNet contracts. You're looking at more like $2K for a pair for 1300's. (About $800 each for the Bridge itself in the 1300 series) And about $3,5K each for the 1400 series, which offer extended range and higher throughputs. I'd recommend the 1300 series to anyone as they're reliable and can be redeployed as a WAP should your needs change. We're using ours to keep links up during construction.

      I'm sure the Cisco's carry the same limitations on line of sight, but the 1400's can reach over 8+ miles with a total throughput at 54Mbps. (Throughput is more important than negotiated speeds. A wireless device can negotiate 54 Mbps, but only have a throughput of 1 Mbps.) The one caveat with these is that they can go distances even greater pushing out in upwards of 15+ miles but the throughput starts to drop off.

      I would be excited if this news was using 802.11N specifications and 100+ Mbps throughput. Too bad it's just 802.11G - this is old news indeed. I've even read some Linksys consumer-grade WAP's that linked over a distance which would blow your mind. Put it this way, the curvature of the Earth had to be factored into their aiming calculations. Google: "Linksys WiFi Distance Record"
  • RE: Wi-Fi bridge claims a range of 5 miles

    5 miles? I have used the same gear for RELIABLE links of more than 10 miles. Shrug.
    Ex Dementio Scientia
    • Doesn't 10 miles put you below the horizon?

      Or is yours not line of sight?
      Michael Kelly
      • Not necessarily...

        The curvature of the earth is roughly 8 inches per mile, so five miles is only a 40 inch drop. If mounted on even a single story building's roof, line of site would be no problem as long as there are no obstructions.
        • That's 8 inches for the first mile

          The further you go out, the more it curves. 10 miles out gives you an ~800 inch drop, which is ~67 feet, or just a shade under 7 stories.
          Michael Kelly
          • Not on my planet?

            My home planet, Earth, is a sphere, more or less. So, each additional mile adds and additional 8 inches, 200 mm.

            Your planet may be a paraboloid, and if you are on the tip, you may want to move closer to the sides. You'll get much longer WiFi connections since the curvature is less there. It must be hell living on a place with logarithmic dimensions.

            If you want to see what it's like a spherical planet, stop by for a visit.
          • Uh... no

            [url=http://www.boatsafe.com/tools/horizon.htm]Type in 67 feet and see what you get.[/url]
            Michael Kelly
          • math is hard

            if the Earth was flat, your calculus might hold water, but we don't have a linear equation here.
            Linux Geek
          • (Not so) hard math...

            Since I always hated "and the exercise is left to the reader" type stuff, you all can do this at home and check my math:

            Draw a circle, a line tangent to the circle, a line perpendicular (at a right angle) to the tangent through the center of the circle, and another line from the center of the circle to another point on the tangent line. So, now you have a right triangle whose sides are: R (the radius from the center to the tangent line), X (the line of sight distance from where the second line intersecting the circule tangent outside the circle, to where the radius intersects the tangent), and the hypotenuse (long side of the triangle) whose length is equal to R + H, the radius of the circle, plus the height of the point of view looking out to the horizon (where the radius intersects the tangent perpendicularly).

            Thanks to Pythagoras: X^2 + R^2 = (R + H)^2
            A little bit of substitution later, this is equivalent to: X = SQRT(H^2 + 2RH) or H = (SQRT(X^2 + R^2)) - R

            Wiki being Wiki...there are as many "Earth Radius" values as there are cartographers, so I'll take Volumetric Radius (it rounds the easiest to): 6371 km or ~20.902E6 feet.

            So, if you're 8 inches tall (2/3 ft): X = 5279 feet (So yes, the earth curves 8 inches in a mile.) But as the non-linearist and others here point out: @ H = 6 feet, X = 15837 ft (3 miles) and for a range X = 5 mi (26400 ft), H = 16.672 ft (16' 8")

            Edit: I should have pointed out that since the curve goes as (approximately) a squared factor: if you drop 8 inches in a mile, you don't drop 40 inches in 5 miles, but approximately 8 * 5^2 or 200 inches (exactly 16'8") in 5 miles.
          • Not really, try it sometime........

            It's really simple geometry. It's an arc section with a 4000 mile radius. The elevation difference is the gap between the chord and the height of the arc with end points 5 miles apart.

            Wifi links will also have elevated locations on both ends. The remote end is not sitting on the ground. Clear the arc height plus some clearance for the fresnel zone and that's all you need.

            You can't solve all of the worlds problems with Google. I don't know what the parameters are for the Boatus link provided, but I'll bet Motorola and the WISPs would be disappointed by it. Boats have VHF radios which are line-of-site also. If you had a 67' mast on a boat you could communicate MUCH farther than 10 miles. We never would have won WWII in the Pacific otherwise.
          • Re: Not really, try it sometime.

            I found another calculator, and you are right, the height of the other side does make a difference. Also atmospheric reflection makes some difference too, which I also did not take into account. But it is still not a linear solution. Two ships with 67 foot masts would need to be within 24 (12 + 12) miles to communicate.


            But to answer my earlier question, it seems as if say a two story building would be within the radio horizon of another two story building that is within 12 miles. This also means your average small business can use this bridge even at 4 feet high at each side and still be able to broadcast the bridge's 5 mile maximum.
            Michael Kelly
          • Line of Sight Radio

            This is the same discussion relating to UHF radios, including the FRS and GMRS radios. The average curvature of the earth dictates an average maximum range of 6 miles - period! If you are on one end of a tropical island in your holtel room on an upper floor you can have a line of sight in the 20 to 30 mile range. Almost ANY radio will work. If you put a couple of obsticles in the way and the "range" will disapear. Add a very high gain antenna and some power, and you may see greater range do to both obsticle penetration or reflection or stronger signal on the edges of the radiation pattern. It's easy to see how the unobstructed over water signals can be reflected (water or atmosphere) for greater range. It is just as easy to see what would happen in cities or mountainous terrain, etc. Real range gain can be achieved with active relay systems. Other than that, using digital rather than analogue signals on clear frequencies could allow detection of weaker signals.
            Old Disti
  • RE: Wi-Fi bridge claims a range of 5 miles

    There is nothing new here at all; zero!
    The price point is fine but the sollution is just old hat.
  • RE: Wi-Fi bridge claims a range of 5 miles

    EtherLinx Communications Inc. has been doing 50+ mile los links (line of sight) since 1997 and nlos (non line of sight) links of 10+ miles since 2002.
    "Just Because We Care"
    "One Laptop Per Child"
    • But at what price?

      Having this at below $1000 is huge. That means small businesses will use it. Heck, at this price you might even get some individuals who will use it (which might not be a great thing).
      Michael Kelly
  • RE: Wi-Fi bridge claims a range of 5 miles

    Easily done. The key is the 17 dBi gain dishes on each end, and the height of each antenna to put you above the drop-off due to curved Earth. One gotcha I see is: even a 17 dBi antenna beam spreads out - so anybody out there can aim his dish at your antenna and read your signal
    • Dish antennas?

      Use Yaggi antennas and significantly reduce the "spread".
      Old Disti
  • Apparently 'serious' engineers don't do Cantenna tests...

    Back in 2001 with my first Linksys .11b WAP setup, I spent about $10 (including the Pringles) and a couple of hours to play with low power and antenna options. Worked like a charm, gave me an easy one mile plus range. Fast forward a few years, add in a newer .11G box plus WW-DRT, and we're up to about three miles.

    Why is this 'news'?
  • bull

    if the earth was a perfect circle this would be a discussion the math geeks are right

    but it does not matter use your gps and find both elevations then go from there forget the math until this information is found then add your measurements for the curvature usually one end will be on a hill(thats why you need the elevation stupid)