Please create an account to participate in the Slashdot moderation system

 


Forgot your password?
Close
typodupeerror
×
Hardware

New Phased-Array AP Boosts 802.11b Range 204

Posted by timothy from the bring-it-on-quickly dept.
ttul writes "Vivato, a well-funded wireless startup, today came out of stealth mode to announce its "WiFi" switch product, a super high performance 802.11b access point that uses an array of hundreds of antennas to provide wide-area coverage to standard 802.11b clients. See stories at Wired, and The New York Times. Vivato's new AP completely changes the economics of WiFi especially for providers such as FatPort and WayPort, who now have the technology to deliver 11Mbps to your laptop even if you're miles from a location -- it's the Jetson's, folks!"
This discussion has been archived. No new comments can be posted.

New Phased-Array AP Boosts 802.11b Range More

New Phased-Array AP Boosts 802.11b Range

Comments Filter:

  • Why? (Score:1, Insightful)

    by Anonymous Coward
    um, why is it the jetson's? I'm sure it is obvious to everyone but me.

  • Repost ? (Score:2, Informative)

    by Merkins ( 224523 )
    Umm, didn't this already get posted today ??
    Timothy, do you not not read Slashdot ?
    • They are testing one of these new access point to distribute stories. Slashdot had the antenna's pointed to the east coast when the first story was posted. Now they are aimed at the west coast. While the range of coverage for slashdot is much greater now, folks in the midwest will have to deal with the resulting duplicate packets^H^H^H^H^H^H^H^Hstories

    • Why should they? (Score:5, Funny)

      by Perianwyr Stormcrow ( 157913 ) on Monday November 04, 2002 @09:50PM (#4597132) Homepage
      Hell, even I don't read it anymore. I just go into meta-moderation and reply at random to whatever comments come up.

  • Do the editors read there own site? (Score:4, Funny)

    by DAldredge ( 2353 ) <SlashdotEmail@GMail.Com> on Monday November 04, 2002 @08:55PM (#4596879) Journal
    This appears to be a dup of a story that is still on the main page... And to think, they get paid for this.

  • Vivato (Score:1, Funny)

    by Anonymous Coward
    I suppose something radically changed since this morning [slashdot.org]. Folks at Vivato must be amazed, getting two front page stories in a single day.
  • over n'yah [slashdot.org]
  • The tech is a phased array antenna, there was a good article about using it with 802.11 (notice there is no b) in the IEEE spectrum [ieee.org] a while ago.

    Consider it a sort of software antenna, you have a series of antenna that you can bias towards a particular direction. You then listen for incoming signals and use a processor to calculate environmental multipath (RF signals bouncing off buildings, etc.) and then fire off your signal so that the main signal and multipath reflections arrive at the reciever at the same time. Instant gain.

    I'm skeptical on the reported max range but they should get a good amount. If you're sitting in the middle of a parabolic dish and so is your target, sure I expect that kind of increase in range, but in the real world...

    • Re:Phased Array Antennas (Score:2, Informative)

      by dtg ( 561145 )
      I'm skeptical on the reported max range but they should get a good amount. If you're sitting in the middle of a parabolic dish and so is your target, sure I expect that kind of increase in range, but in the real world...

      This doesn't make any sense. The purpose of a phased array is to provide gain in a given direction. Generally, this kind of technique isn't used as a feed for a parabolic dish because it's a whole hell of a lot cheaper to turn the dish than to build a phased array.

      As for users, higher gain at the receiver will help even if they're using the same antenna as always.

    • From what the articles said, I'd reckon that the antenna should be good for about 20 dB gain over a dipole. Figure that with the inverse square law, you'd be getting 10 dB in range (a factor of 10). 4 miles in free space sounds like a reasonable figure IF the laptop on the other end is in a reasonably quiet area.

      The big advantage of this system is to be able to generate multiple beams - something that is a bit difficult to do with parabolic reflector antennas.

  • Headline news? (Score:5, Funny)

    by cmeans ( 81143 ) <chris...a...means@@@gmail...com> on Monday November 04, 2002 @08:56PM (#4596888) Journal
    What is this, CNN's Headline news?..all the news, the same news, every half hour!
  • I can't believe how fast this technology just keeps advancing. I am so glad to be alive in this day and age, instead of 200 years in either direction. Just think about it for a second, if you were alive in 1802 you'd be getting some amazing technological advances at a rate of ... well pretty slow. And in 2202 we'd just be used to it all, and completely unphased. (i.e. How excited does turning your light bulb on make you today?)

    I can't wait to get my hands on one of these new toys!

    • Re:We're on a roll folks (Score:4, Insightful)

      by gozar ( 39392 ) on Monday November 04, 2002 @09:30PM (#4597059) Homepage

      Actually, the late 1800's was when technology affected human lives (at least in America) the most.Before that time it wasn't unusual to go for years without communication to your family that was only a few hundred miles away. Then the telegraph, steam engine, mass production, the industrial revolution began to really change things.

      It is an exciting time now, but don't kid ourselves that this is the golden age of advances. We're still doing the same thing, just slightly faster. Give me a call when we have anti-gravity devices, holodecks, and transporters.

      • Anti-gravity [slashdot.org], holodecks [slashdot.org], and transporters [slashdot.org].
      • It is an exciting time now, but don't kid ourselves that this is the golden age of advances. We're still doing the same thing, just slightly faster. Give me a call when we have anti-gravity devices, holodecks, and transporters.

        There's something ironic in that sentence, but I can't put my finger on what. I'll give you a call when I figure it out.
      • It's a common fallacy to assume that we live in unique times. Everyone has lived in unique times, throughout prehistory and beyond.

        It's all now with a few memories and some hope for the future. And before we geeks crow about how wonderful our portion of the world is--and it is technologically exciting--remember there is a big world of human suffering out there. Or are we living in the 1939 NYC World Fair's vision of the world. Or is it Metropolis? Then there was WWII. That drove technology too, didn't it?

        I love my Zaurus running the Crow ROM.

        • However, it was technological developments in the second half of the 19th Century that really changed the world.

          Three developments that became widely used at this time--the telegraph, railroads with steam-powered trains, and steam-powered ships--literally changed the face of the developed world almost overnight.

          Just the telegraph allowed news and other information to be spread over thousands of miles in from the originating point in a matter of hours. The rapid growth of trains made it possible for people and goods to travel hundreds of miles on land in a matter of a few days; and steam-powered ships made it possible to traverse the world's oceans and wider rivers without worrying (generally) about wind and water currents.

          Most of the cities in the midwestern USA could not have developed rapidly without the developments I mentioned.
      • Actually, the late 1800's was when technology affected human lives (at least in America) the most.

        Even discounting the effects of the automobile, airplane, and computer, the 20th century brought us widespread vaccination and antibiotics. I think those are at least as important to most people as the railroad and telegraph were.

        -Isaac

  • Is this a good thing? (Score:5, Insightful)

    by JohnA ( 131062 ) <johnanderson.gmail@com> on Monday November 04, 2002 @08:59PM (#4596905) Homepage
    What if I don't want this super-array to interfere with my local WLAN? It appears that this technology has the potential to create a "mine is bigger than yours" arms race among WiFi users.
    • I totally agree! I don't want someone beaming hi-power out-of-spec 2.4Ghz radiation. The point of WLAN is that you get a local area ~100ft around the AP. If these guys are successful it will increase the SN ratio on any channel they are on. When the baseband in your client tries to get the medium it will be filled with crap far away from you away. Thus your local performance will suffer.

      No more than 18db-20db output power, these guys better have that output power or we will all have a problem. Kinda like the old adage: The squeaky wheel gets the oil.

      Hedley
    • Miles of omni-directional range in a unlicensed, uncontrolled band of spectrum with only three non-overlapping channels??

      No thanks, get your own spectrum from the FCC if your going to pull this . . . .

    • Re:Is this a good thing? (Score:5, Informative)

      by Merkins ( 224523 ) on Monday November 04, 2002 @09:31PM (#4597064) Homepage
      Did you read the articles ?

      The actual output of this thing is on 30mw. It just increases range by locking on to it's clients and adjusting itself to aim more directly at them. because of this, it will actually cause less general interferance than a standard garden variety AP

      • Re:Is this a good thing? (Score:5, Interesting)

        by Beryllium Sphere(tm) ( 193358 ) on Monday November 04, 2002 @09:59PM (#4597154) Journal
        Sometimes the FCC regulates how directional you're allowed to be.

        The magic word here is EIRP, Effective Isotropic Radiated Power. It's how bright you look to someone who's in line with your RF beam. Even if your total power is low, and you're avoiding interference with people who aren't in line with your directional beam, high EIRP can cause problems for innocent bystanders anywhere on the line between you and your intended recipient.

        EIRP increases with transmitter power and with antenna gain (== directionality).

        This is why it's technically illegal to put a better antenna on your cordless phone, and why the phones don't come with easily replaceable antennas.

        Now, if these people are really smart, they could set their beamforming code to plant a null on any 802.11 network that's not a customer, in which case they'll avoid interference.

        Fred KC7YRN
        • Technically illegal?
          As you said, it depends on the EIRP.
          It may or may not be illegal.

          And eirp regulations for the 2.4Ghz ISM band, especially in the US, are quite reasonable. I don't have the numbers in front of me....

        • Sometimes the FCC regulates how directional you're allowed to be.
          They may be getting around this using multipath. (I.e., using reflections from large metal objects to provide more signal. Do a web search for rake receiver [google.com].) That way they can use multiple weak beams, keep the peak brightness in any direction to a reasonable level, but deliver more coherent power to the receiver. You can do it in reverse to make more coherent power available during reception. CDMA does this to great effect.
        • Given that the base station is only running 30 mW, it's almost impossible for them to be out of FCC spec.

          (Come on, they wouldn't bother releasing a product that didn't meet FCC regulations...)

          30 mW = approx. 15 dBm
          The maximum power you may run into an isotropic antenna under FCC regs is 1 watt. 1 watt = 30 dBm.

          This means that they have a MINIMUM of 15 dB of antenna gain headroom. That's a lot.

          But it doesn't stop there - The FCC allows (somewhat) higher EIRPs. I don't remember the exact guideline, but it's something on the order of reducting peak transmit power by 1 dB for every 3 dB of antenna gain. (Not sure of the exact numbers, but you do get an increased EIRP ceiling as you narrow the beamwidth.)

          So if you put on a 3 dBi antenna, your peak transmit power isn't 27 dBm (For 30 dBm EIRP), but it's 29 dBm (For 32 dBm EIRP).

          Do a Google search for N9ZIA, you should reach the site of a guy that has done a LOT of WLAN hacking (not all of it legal, while he is very knowledgeable of regulations, he often chooses to ignore them...) He has some good info on the exact FCC regs in the band.

  • Wi-Fi all hype no action? (Score:1, Interesting)

    by Anonymous Coward
    What does everyone think of Wi-Fi really? I mean we have a Wi-Fi connection at my school, but why would I really want to use it? What use is it to have a connection "anywhere", when most conference rooms and what have you have a cord connection nearby which is infinitly more secure.

    Personally I think This story [yahoo.com] makes several good points about the so called "Decline of Wi-Fi". Is Wi-Fi quickly becoming Why-Fi? Simply an expensive gadget which in general doesn't aid the modern human at all?

    Sidenote: Perhaps this would be a good idea on airplanes...
    • What use is it to have a connection "anywhere", when most conference rooms and what have you have a cord connection nearby which is infinitly more secure

      First off convenience, you don't need to mess with wires. Secondly if you have the system configured right ie using the revised scheme done by the A team after the B team messed, then wireless can be more secure than ethernet. Network access can be restricted to NIC cards that are authorized to access that LAN. The basic technology was originally designed for ethernet but came out for wireless first after their 'difficulties'.

      Sidenote: Perhaps this would be a good idea on airplanes...

      Actually that is in the works. They are already required to be robust against microwave radiation from onboard kitchens so WiFi is not far out.

      However your other comments about WiFi being on its way out suggest to me that either you have never used the technology or you are a troll.
      • Actually it is quite easy to spoof a MAC which is the ONLY way you can filter by card.

        If you want a secure WiFi network, try using a Kerberos server for authentication with VPN only access to the network on the other side.

        And remember, WEP stands for worthless equivalency protocol.
        • why not both? that's what we're doing where I work...
          • If by both you mean why not use Kerberos/VPN AND MAC filtering I would say that MAC filtering adds additional administrative overhead that you don't need because MAC spoofing is not hard at all. In fact, you should expect it. Extracting the MAC from an 802.11b and a packet is not very difficult.

            Why bother with that which is not secure?
        • Actually it is quite easy to spoof a MAC which is the ONLY way you can filter by card.

          Which is why the new cards will have RSA keys embedded in them during manufacture with digital certificates to authenticate the MAC address.
    • Comment removed based on user account deletion
    • Cost is a big reason for wanting wifi. It costs a lot to wire a building and an impossible amount if you want to compete with the local cable or telco incumbent by wiring a city.

      Convenience is the other factor. The importance of this right now is relatively small, but I'd say in a year or 2, handhelds with wifi will be able to break through the chicken/egg conundrum.

      • Re:Wi-Fi all hype no action? (Score:4, Interesting)

        by Martin Blank ( 154261 ) on Monday November 04, 2002 @11:00PM (#4597381) Homepage Journal
        Cost is a big reason for wanting wifi.

        I'm generally suspicious of wireless (I have a semi-paranoid security perspective), but cost could be a huge consideration for me, as I'm trying to figure out how to get my apartment complex to set up high-speed internet. Between a Cogent 100Mbps connection for $1000 a month and this for a central antenna, the costs to the complex may well be able to drop from close to $100,000 for wiring it into every unit to perhaps $5000-$10,000, maybe less. That's far more reasonably in the eyes of the owners, as they can pay it off more quickly. With a little luck, we might actually even be able to get some pretty high speeds for maybe $20 a month -- and the complex might even make some decent profit with it.
    • > cord connection ... which is infinitly more secure.

      Just because most admins are lazy doesn't make the technology unable to secure...

      I'm writing this from a laptop in my living room, over an 802.11b connection whose only route to the network is protected by FreeS/WAN.
      And yes, I could get a wired connection here, but why deal with the hassle of a 100' cable?

      • Just because most admins are lazy doesn't make the technology unable to secure...

        OTOH, any technology which requires admins to not be `lazy' needs more work before it is ready for the real world.

        Most admins are `lazy' becase they already have enough on their plates.

    • What use is it to have a connection "anywhere", when most conference rooms and what have you have a cord connection nearby

      When you get out of school you will find that those cables don't lay themselves. They are expensive and sometimes hard work (try working when somoene is trying to drill cable runs through stone walls someday).

      Even for a simple home nettwork, I would have gone the wireless route if the technology was mature last year when I was laying a cable the length of my (then-) new flat. The difference between plugging in one wireless hub and putting in a couple of sockets in each room with all the structured wiring and hole drilling would easily pay for the extra cost.

  • Think about it: if 1 in 10 (maybe a lot less) people get one of these babies, and run a reasonable VoIP software on it...all you need is a wifi PDA and you've got "free" telephone services!

    Hmmm, I guess you'd also want IP6 running...but wow! what a thought: technology makes another middleman obsolete!
    • Wifi can't replace the telcos. Not yet anyway. And certainly not as long as the FCC keeps the unlicensed frequencies very small and limited.

      There are only 3 non-overlapping channels in the 2.4 ghz band in the US. Same goes for the 5.8 band. Combine the throughput on those and in the best case scenario you have about 180 Mbps. Actual performance would probably be half at about 90.

      Now lets assume you are going to build your network so that you can honeycomb those channels. If you do it with scalability in mind, at most you are going to have 65 Mbps throughput. Actual performance would probably be about 35 or 40.

      There isn't a very good chance that will get a good VoIP service with that espeically if people are using that for web access too.

  • I'll beleive it when..... (Score:3, Insightful)

    by Chris_Stankowitz ( 612232 ) on Monday November 04, 2002 @09:05PM (#4596947)
    it sticks around for more than a year. The old addage of I'll beleive it when I see it has fallen victim to too many technologies that didn't make it. I am cheering for this all the way. Hope it makes it and stays.
  • Comment removed based on user account deletion
    • How can the ISP industry survive when anyone can connect to a WAN over 802.11b? AND FOR FREE?

      Um... the Internet connectivity has to come from somewhere.

      • You are missing the point, the wireless mesh network IS the internet. Of course longhaul links would be a bitch with the need for a repeater every 25-30 miles or so.
        • You are missing the point, the wireless mesh network IS the internet. Of course longhaul links would be a bitch with the need for a repeater every 25-30 miles or so.

          Ugh, I'd hate to see the BGP routing tables on something like that......
    • Who cares?
      The Internet is a bunch of networks hooked together. Whether those networks are chiefly isp's networks, or community networks it doesn't matter.

  • "It's the Jetsons". Not Jetson's.

    C'mon, guys. You're running a major online news service. I'd let this one slide but I see these your/you're its/it's mistakes at least once per day.


  • I saw 'by Timothy' and opened this link to check if it would be another duplicate. I wasn't disappointed.

    Don't worry, Tim. We still love ya :-)

  • what about the not-slow people (Score:5, Funny)

    by hfastedge ( 542013 ) on Monday November 04, 2002 @09:11PM (#4596971) Homepage Journal
    From the wired article:
    "We think it'll work reasonably well at pedestrian speed," said CEO Ken Biba,


    This company will surely fail. Its technology isnt taking into account laptop joggers, laptop motorcyclists, laptop unicyclists. And leisure, urban helicopterists and skydivers...

  • Asymmetry and number of users (Score:5, Interesting)

    by Anonymous Coward on Monday November 04, 2002 @09:13PM (#4596978)
    The use of a phased array antenna for transmission to the client is nice, but I wonder if it requires the client to be modified to run special tracking software that sends back multipath information to the basestation to enable it to tune its beam.

    This makes me think that the data-link would probably end up being asymmetric --- high data rate down to the client but not so good coming back. Not only would the upstream rate be partially consumed by the multipath measurements, but also the single antenna on the client would have a harder time beamforming out to the receiver array.

    The power constraint is probably on the total output from one array and as such, the number of users that any one of them can support is probably fairly limited. This suggests that things can get quite interesting if we put a bunch of these in close quarters. The optimal solution would be for the AP to collaborate and divide up the users among them not by simple distance (voronoi regions) but by effective distance involving the specific multipath environment! Otherwise interference would be a serious problem.

    • but I wonder if it requires the client to be modified to run special tracking software that sends back multipath information to the basestation to enable it to tune its beam.


      It would seem not. In the Wired article, Paul Boutin says he took his own laptop to make sure they weren't doing anything tricky on the client side. He could go everywhere the demonstation engineer went and get good access.

    • The fairly wide spectrum helps a bit with multipath and fading, so it should do ok in that regard.

      Antenna gain works both ways, so bandwidth should be good in both directions. The real fun would be having two of these systems talking to each other.

      When are we going to get true 802.11b mesh?
      --Mike--

  • Why...... (Score:5, Informative)

    by jwilcox154 ( 469038 ) on Monday November 04, 2002 @09:14PM (#4596980) Journal
    use a Phased-Array AP to Boost the 802.11b Range, when you can use a Pringles Can [techtv.com] as the Wi-Fi Antenna to Boost the Range? ;)
    • The pringles can is there, just that it is a virtual one instead of a physcial one. Phased-arrays use a bunch of antennas to simulate a beam-type antenna (pringles can), this site http://home.earthlink.net/~jimlux/radio/antenna/ph ased/phased1.htm was the first one I found with useful information, explains the basics and also has some links to some other sites explaining it.
    • The advantages of a phased array AP are two:

      -Multiple simultaneous beams. The maximum number of possible beams is equal to the number of radiating elements in the array. The Pringles can, of course, has only one main lobe (beam).

      -Near-instantaneous beam switching from one direction to another or, said another way, the ability to track very quickly, since the beamsteering is done electrically, rather than mechanically, as the Pringles can does.

      The big question I've not seen answered is, how do they handle the Wi-Fi beacons? A beacon serves multiple purposes--synchronizing the network nodes and advertising the presence of the network to prospective new network members being two of them. If the beamforming is used to reach long distances, the beam is very narrow; new nodes won't be able to detect the network since it's unlikely they'll be in the beam. Conversely, if a wide beam is used to enable new nodes to join, range to existing LAN members will suffer.

      I wonder if it's significant that, in the Wired article, the tests were performed starting close to the AP, then walking away from it. It would be interesting to try the reverse...

  • Silence nay sayers, slashdot rules thee (Score:1, Insightful)

    by Anonymous Coward
    this isn't a repost, this is an update worthy of a new story, given the few details of the last.

    helluva lot better than CNN or nyt where they'd just revise the story and you'd never know.

  • War Driving .... (Score:3, Funny)

    by bizitch ( 546406 ) on Monday November 04, 2002 @09:15PM (#4596986) Homepage
    Fuck war driving - try war standing around and hopping on to x number of nets!
    • that was not a funny post !

      with a 18 db antenna on the roof of a building there're something like 50 APs available. And wlan equipment is more expensive on this side of the atlantic.

  • In other news (Score:4, Funny)

    by yorgasor ( 109984 ) <(ten.shcetirt) (ta) (nor)> on Monday November 04, 2002 @09:16PM (#4596990) Homepage
    Slashdot was able to boost its reach of certain articles by a factor of 2. Says slashdot editor, Timothy, "The results are very impressive and the technique was surprisingly simple. All we had to do to double the readership for a particular article was to post it once in the morning, and again at night. If our /. readers are anything like the editors, most of them are too lazy to read more than the top couple of articles. If they happened to miss the morning edition of /. we can rebroadcast a "best of /." again in the evening so our lazy readers don't miss out and all the action here."
  • C&P the highly modded posts from the first post of this article. Its still there on the front page, just scroll down.
  • ok, i just needed to say this: think of what this can do for Voice over IP!
  • it's odd that nytimes says the main proposed use is in the corporate world, while wired mentions dorms. audience demographics?
  • A new repost record, I do believe...
  • it's the Jetson's, folks!
    Until I get my flying car and robot maid it not going to be the Jetsons. Somehow AIBO on a skateboard just doesn't cut it for me.

  • We're Proud to Present... (Score:3, Funny)

    by Twintop ( 579924 ) <david@twintop-tahoe.com> on Monday November 04, 2002 @09:32PM (#4597069) Homepage Journal
    Don't have time to sit on a computer in a dark room? Get Pr0n on the Go! Download from the park, from your porch, or even in the car!

  • Duplicate (Score:1, Redundant)

    by alanjstr ( 131045 )
    Already on Slashdot [slashdot.org]

  • Question.... (Score:5, Insightful)

    by hawkbug ( 94280 ) <psx.fimble@com> on Monday November 04, 2002 @09:38PM (#4597092) Homepage
    Maybe somebody can answer this for me, but I see a major problem with current wireless technology. I currently have an 802.11b access point in my home. I love it, and it gets great range - in fact, so great it goes clear over onto my neighbors property. I had my laptop outside (probably looked like a dork walking around running a constant ping on my thinkpad), and I was able to walk clear onto their property and get a great signal. At first I was impressed... then I started to think about my neighbor. Wouldn't this be a problem for them if they wanted their *own* access point for their network?? I would think that my access point also interferes with 2.4ghz phones in the area. As an example, I had to sell mine because they quit working the second I got this thing. So, if you could expand the range of 802.11b to *miles* - isn't that really going to screw over Joe Blow who wants his own wireless network that just happens to be within range of a provider mentioned in the story???

    • Re:Question.... (Score:5, Funny)

      by ealar dlanvuli ( 523604 ) <froggie6@mchsi.com> on Monday November 04, 2002 @10:15PM (#4597208) Homepage
      (probably looked like a dork walking around running a constant ping on my thinkpad)

      My neighbor got worried enough to poke their heads out and ask me what I was doing when I mapped my network range :0

      It was... fun... explaining I was accessing the internet.

    • Re:Question.... (Score:2, Informative)

      by mindstrm ( 20013 )
      No, it's all about power.

      Yes, there can be interference.. but it's also about power. As long as one signal is significantly stronger than another, it should prevail...
      This is also why there are multiple channels... so you can try to avoid overlap.

      You can't extend the range of 802.11b to miles.... not omnidirectional anyway... you can in a certain direction, yes.... but the higher the gain, the narrower the 'beam'.

      In the case of your neighbor, chances are his AP will be what his cards will see, and yours is what your cards will see, because the signal of the local ap will be significantly stronger.

    • Comment removed based on user account deletion
    • I don't know what kind of access point you have, but mine has eleven different channels you can choose from. And even if they do overlap on the same channel, your total bandwidth would probably be limited to 11Mbps between the two of you, but otherwise there shouldn't be any ill effects.
    • You can just set yourself to use a different channel than the access point in question. Voila, no interference. Besides, as mentioned in the article, the reason it's as powerful as it is is because it's directional - it beams the signal to you, not to everywhere, so you could be sitting beside it, but if you're not between it and a client, you probably won't pick anything up.

      --Dan

  • Not a duplicate... (Score:3, Insightful)

    by Penguinoflight ( 517245 ) on Monday November 04, 2002 @09:47PM (#4597125) Journal
    This must not be a duplicate from all the people getting modded down... not only are the 4,5, and 6th posters getting redundant, the first guy got a troll mod. Is this really not another story, and are the editors really awake?

  • Actually... (Score:4, Insightful)

    by Bruce Perens ( 3872 ) <bruce@perens.com> on Monday November 04, 2002 @09:50PM (#4597129) Homepage Journal
    I think that 802.11b has a legal limitation on the antenna gain to 6 dB. This is so that devices would not interfere with other, distant networks.

    Bruce

    • Re:Actually... (Score:3, Informative)

      by div_2n ( 525075 )
      The FCC limitations for the 2.4 band is 1 watt (30dBm) for Point-to-Multipoint. For point to point you can get away with a lot more.

      None of that matters though because obtaining true line of sight past 20 miles without more than a 20 percent impedence on the Fresnal Zone is a battle I don't want to fight.

  • Karma Whoring 101 (Score:1, Funny)

    by Anonymous Coward
    A repeat, for the newbies:

    Whenever /. posts a repeat story, one quick way of getting extra karma is to go through the original story, and repost the highest scoring posts.

    This usually gets by the editors too, as we all know that they never read other /. stories.

  • Maybe Tim doesn't reload Slashdot from the server all the time, and is reading older, outdated articles, which leads to him posting duplicates?

    I've seen /. getting a lot of abuse about duplicate posts, but two on the one page?! Oh well, I guess theres nothing better to read online :(
  • With this kind of coverage we can scan networks from the comforts of our own homes.. :)
  • Attention /. editors. I want Timothy's fucking job. I have at least one sure qualification he doesn't: I read Slashdot.

    Duplicate posts, misleading (or just plain "made up") headlines... ARGH!

    See:
    http://apple.slashdot.org/comments.pl?sid= 44091&ci d=4592724

    (I'm gonna post one of these every time and keep adding links to previous posts)

  • I don't know whats funnier... (Score:3, Interesting)

    by tgd ( 2822 ) on Monday November 04, 2002 @11:22PM (#4597441)
    The fact that clearly no one who works at slashdot reads their site, or the fact that 2/3 of the people reading this article don't either.

    FWIW, people, the replies on the story from this morning are better than these. ;-)

  • And now.... (Score:2, Funny)

    by Thai-Pan ( 414112 )
    ... war driving from the comfort of your living room.

  • /. Effect (Score:5, Funny)

    by batboy78 ( 255178 ) on Tuesday November 05, 2002 @12:04AM (#4597538) Homepage
    Apparently they didn't get slashdotted this morning, time for round two. Ding Ding Ding.

  • Uhh, when it (wireless technologies) reaches a few 100Mbit and is used by the masses, then maybe :)

  • This is an active phased array... (Score:5, Informative)

    by Newer Guy ( 520108 ) on Tuesday November 05, 2002 @01:33AM (#4597741)
    It works much like the active radar antennas that do not move. Here in Santa Monica we have a large phased array of hundreds of fixed antennas aimed at the horizon that are sequentially pulsed on and off to get the familiar 'rotating' pattern of a single rotating radar dish. This design is much more robust then a rotating array as there are no mechanical rotating parts at all...everything is switched by PIN diodes. Military jets also use a variation of this for secure communications. In the jets' wings are switched inductor antennas that are used in a fast frequency hopping scheme over a 50 mhz range. The transmissions can be anywhere within a 50 mhz frequency segment at any given fraction of a second. If the frequency synthesizer at all locations are moving to the same frequency at exactly the same time, the transmisison will sound completely continuous.
    They use PIN diodes to change the taps on an inductor to resonate the antenna over the (wide) frequency range. This way, they can use smaller, lighter, narrower bandwith antennas and rapidly tune them to the exact frequency in use at any given moment.

    All in all, a very slick technology and another example of a civilian use of military technology.
  • I was pointed to a an interesting site [hdcom.com] that sells (possibly illegal in your area) boosters, bridges, antennae and other miscellanea for 802.11B.

    This isn't an endorsement - I have no need in my small place, and haven't tried any of this myself, but it sure would be fun playing around with some of this stuff.

  • Crap! (Score:3, Funny)

    by sigwinch ( 115375 ) on Tuesday November 05, 2002 @05:32AM (#4598159) Homepage
    Now I have to upgrade to phased-array chalk for my warchalking efforts!

  • cost (Score:2)

    by rot26 ( 240034 )
    And how much is this puppy? I didn't see price mentioned anywhere.
  • Is this product the higher-tech equivalent of a bunch of WAPs with high-gain antennas pointed in different directions hooked into an Ethernet switch?

    You could use five biquad-bowtie [flakey.info] sector antennas pointed in different directions, since each has a beamwidth of about 70 degrees for the equivalent of an omnidirectional access point, but with 12dB gain. Of course, you'd need five access points and an Ethernet switch, plus short-range interference could be a problem.
  • Couldn't this technology be combined with mesh network technology? Instant cellular replacement, just add handsets.

Slashdot Top Deals

If you think nobody cares if you're alive, try missing a couple of car payments. -- Earl Wilson

Close