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Technology

Possible Big Boost in WiFi Range 156

goger writes "An article in the New York Times this morning (insert obligatory note about free registration here, and don't forget the yada's) talks about a startup company in CA that says it will announce WiFi antenna technology today that can give a 2000 ft. range indoors (and up to 4 mi. outdoors). This would be awesome if they really deliver, of course (and if it doesn't require me to set up something the size of a rooftop TV antenna next to my laptop in the coffee shop...)."
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Possible Big Boost in WiFi Range

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  • by draziw ( 7737 ) on Monday November 04, 2002 @11:14AM (#4594188) Journal
    There is no magic here. In Amateur radio, and in radio, every now and then someone will announce they have a magic way to get 6db more signal with the same amount of metal, and in the same amount of space... Not gonna happen. It's RF. You can get more distance in exchange for not getting uniform coverage. The more you are willing to bias towards distance, the more of a narrow rf beam you get.
    • by Anonymous Coward on Monday November 04, 2002 @11:32AM (#4594224)
      Having just the article on wired.com about what I assume is the same technology... they're not claiming to squeeze more signal out of the same bit of metal or anything magical like that. They're using a computer to monitor and track the signal direction of clients and beaming the signal directly towards them. By making it more efficient in where the signals are being sent they get more distance.

      I think it's a great idea, but obviously there's quite a bit more complexity involved so the cost is sure to be much higher and might warrant comparisons between installing a single example of this new tech vs 10 of the older wi-fi base stations to get the same result.

      • I saw a company that had a product that did this at CTIA, though I don't remember the company name right off. They had an antenna that looked like an oversized hockeypuck with a cable coming out of it. From what I gathered it is a phase array setup, and they use a processor in the antenna itself to seek out and lock onto the strongest signals. All this processing is done in the antenna itself, so the enduser just sees it as a high gain antenna that points itself. Ingenious if you ask me =)
      • I think it's a great idea, but obviously there's quite a bit more complexity involved so the cost is sure to be much higher and might warrant comparisons between installing a single example of this new tech vs 10 of the older wi-fi base stations to get the same result.

        Depends on your application, too. If you have places to put those 10 older wi-fi base stations, then your comparisons are warranted. But if you want to (or have to) broadcast for four miles from a single point, then any cost difference is pretty much marginalized.

    • by Anonymous Coward on Monday November 04, 2002 @11:49AM (#4594266)
      Your statements are true for a passive antenna design. There's only so much effeciency you can squeeze out of a chunk of metal.

      However, this antena is not a passive antenna. It's a fully active antenna, specifically a phased array antenna. Because it's an active antenna, and it's probably got quite a few DSP's in it to sort out all the antenna signals, I'll bet this antenna is going to cost signifigantly more than a plain access point. I really do think that what they're claiming is possible. It's not like it boosts the S/N ratio in the passive antenna sense. It's able to tease out and build a better signal by watching a great many tiny antennas. It's an awful lot of DSP horsepower to get that done, though.

      I'll venture it'll cost about $800, which includes an integral access point. And they'll say "to get the same coverage, you'd need 8 regular access points, or 8 * $200."
      • I've been invloved in phased array antenna design and military RADAR since the late 80's. The above comment is NOT Score:5 Informative!

        1. "phased array antenna" DOES NOT EQUAL "active antenna". A phased array can receive benefits from active circuitry just the same way a simple single vertically polarized "whip" can.

        2. "Your statements are true for a passive antenna design." This statement... "You can get more distance in exchange for not getting uniform coverage." is true for any particular moment in time, for EVERY antenna design, bar none. And the whole paragraph of draziw's post stands out glaringly to me, that he knows antenna design practicalities.

        Antenna gain depends completely on how well the antenna is tuned for the intended frequency and the radiation/sensitivity pattern it creates.

        If you want signals to travel VERY far for example, you could design an antenna that (in laymens terms) compresses it's transmitted power (as in Effective Radiated Power) to a beam, or from a receiver point of view focuses in one particular direction. What this also does, is effectively quieten/deafen the antenna to areas other than that direction intended to communicate with. Thus, his comment about loss of uniform coverage.

        Now before anyone argues the virtues of active designs, they MUST consider that the circuitry added to "active antennas" (usually wide-band receiver amplification) does NOT constitute and nor should it, an antenna at all! This is merely a traditional antenna, with active radio amplification which serves to feed ANOTHER radio and APPEARS to be a very effective antenna.

        In short, technically, there is no such thing as an "active antenna".

        I've been designing my own WiFi massive phased array, a-la flat jet fighter RADAR arrays. I'm currently trying to figure out whether just building a good parabolic design would be easier as the many highly tuned and quite small dipoles would be hard to tune and assemble in phase well enough.

        I'll venture it'll cost about $800

        I'll venture you don't fully know, that which you speak. I am really starting to hate /. Someone posts a comment here that is absolute textbook and then some dick comes along and pisses on his parade with a completely incorrect rebuttal, which in turn gets Score:5 Informative.

        • BTW, something I really hate about /., is that when I see stuff like this, I feel very compelled to post, rather than moderate (even if I did have moderator points right now).

          I imagine this is a feeling most others share, which leads me to the logical and very sad conclusion, moderators are usually ignorant about what they moderate, plain and simple.

          Which is why complete crap often gets moderated up and PhD's often get moderated down.

    • by Anonymous Coward
      You can bias towards distance and not narrow the beam width. Think of how FM broadcasters get increased erp and still have a circular coverage area. They design the antenna to move the rf from the non-useful areas and add it to the useful areas. Think of compressing a sphere into a donut.

      By creative use of phasing and stacking of elements you can achieve almost any pattern you desire.
      • Think of how FM broadcasters get increased erp and still have a circular coverage area.

        This is absolutely correct, but does not argue in any way the comment that this reduces the uniform coverage.

        You can bias towards distance and not narrow the beam width.

        If you compare the two designs you are referring to, but only look at vertical pattern at any one particular horizontal angle, you will actually find, that the virtual "beam" IS in fact narrowed vertically and thus the gain is made possible. Just because it is narrowed toward human population does not make his comments about loss of uniform coverage less true.

        We should not delve too far into practicalities and at the same time move away from the technicalities, because we gain the practicalities from the technicalities.

    • Yes and no .... if me assume that current wifi antennas represent the most efficient onmidirectornal antenna design available then yes I will agree with your point.

      But given that most of these antennas are made for cheapness / compact size I have no doubt that more efficient ones are possible.
    • Increasing wi-fi range of this magnitude changes everything. It now makes wi-fi directly competitive with existing "auctioned" spectrum, and enables the creatipm of a bottom-up, P2P, ad-hoc wirless mesh-network that requires no centralized server, provider or carrier. The combination of long-range wi-fi and mesh-network software is totally disruptive to the entire communications economy. I personally see this as a very good thing, as it means that promise of the "internet" of decentralized and anonymous communications is finally dawning.

      Planet P Weblog [planetp.cc]

      http://planetp.cc/ [planetp.cc]
      • Indeed it changes everything, but not for the better. In some urban areas WiFi is already close to unusable due to the number of participants, or at least the effective bandwidth per participant slows down to a crawl.
        If there is an easy and cheap way to boost the range by that magnitude, this will only speed up the process, since everyone will now not only pollute the airspace of their direct neighbors but also 5 blocks away (their target are business customers offices).
        It will be completely disruptive indeed, but of WiFi communications. Imagine 50+ hosts on a single coax ethernet cable trying to get medium access with CSMA/CD. It just won't work anymore.

        Out on the countryside it's another issue and I agree with you that in some cases this hopefully will help break up telecomm monopolies.
        But I fear the first effects we'll see is Starbucks and McDo fight for the airspace on the neighboring parking lot/plaza.

  • by Anonymous Coward on Monday November 04, 2002 @11:18AM (#4594198)
    Pringles will now be selling just the cans - no chips to dispose of first.
  • In 2 years we could all be War-Couch-Surfing....

    Is it just me, or is /. HELLA slow today?
  • Too slow (Score:3, Funny)

    by friendofafriend ( 602350 ) on Monday November 04, 2002 @11:19AM (#4594202)
    The 20 microsecond delay would ruin on-line gaming. Wake me when they use faster than light protocols.
    • by Anonymous Coward
      Who moderated this clearly joking comment as insightful? Did somebody actually believe this guy was being serious? 20 microseconds is so short that if there's a 20 microsecond gap in something you're listening to your ear can't detect it! This post is a joke. A funny one, even.
  • by Zech Harvey ( 604609 ) on Monday November 04, 2002 @11:21AM (#4594205)

    For people sharing their connection in an area? I mean, I think it's a good thing, but with ISPs coming down on open access points, I can see them trying to limit the area in which your WiFi connection is broadcast. Are they able to do that? IANABroadcaster, but will this come under the same restrictions possibly as HAM operators or other radio broadcasters?
  • by arc.light ( 125142 ) <dbcurry@@@hotmail...com> on Monday November 04, 2002 @11:22AM (#4594206)
  • The Obvious way (Score:1, Interesting)

    by Anonymous Coward
    of doing this is to make cards with a higher transmit power - the highest power that I've seen on the market in the usa is 200mw (100mw is the limit in the eu). I think the fcc will allow cards upto a watt (1000mw) maybe more.

    No I didn't read the article. There is no way I'm going to register.
    • Re:The Obvious way (Score:3, Interesting)

      by Helter ( 593482 )
      Yeah, but where is that 1 watt of power going to come from? That would be a great idea if it wouldn't kill your laptops battery in a half hour (random guess).
    • The Obvious way of doing this is to make cards with a higher transmit power

      While that will get you more range, I believe in this case it's better to stay with the lower output. Higher power transmitters will just cause more inteference to everyone.

      At 30mw, you can get good coverage of a small office or home. And if you need more range, that same 30mw can get you a few miles with the proper antennas.

      I have a 100mw Linksys AP, and a 30mw Orinoco card in the laptop - I can get a signal 5 houses away. Normal users don't even need that range!
  • FCC (Score:1, Interesting)

    by Anonymous Coward
    What do they think? These things have to accept all interference, and make none themselves. Will this 'new' product do that?
  • At how many concurrent users, how much total bandwidth ? If those numbers remain the same
    for 100m circle and 2 mile circle, then I'd give
    it a thumbs down.
    If this is about sending a narrow RF beam to some
    point 2 miles away, then that's point to point,
    good stuff but no breaktbrough to get excited about !

  • by Tetravus ( 79831 ) on Monday November 04, 2002 @11:33AM (#4594227) Homepage
    They have indeed decided to forfeit width of coverage for distance, by using a self adjusting array of antennas.

    http://www.wired.com/news/wireless/0,1382,56166, 00 .html
  • and if it doesn't require me to set up something the size of a rooftop TV antenna next to my laptop in the coffee shop...

    Rest assured ti won't be the case. They're working with the company who recently made the "handshaking as a Palm communication device" and will use your whole body as an antenna.
    The only little remaining problem is that you still have to plug the cord from the pcmcia card right into your ... err .. in your body, that is. Ahem.

  • Phased Array Antenna (Score:5, Informative)

    by grayrest ( 468197 ) on Monday November 04, 2002 @11:37AM (#4594237) Homepage
    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...
    • 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.

      This is not a description of a "phased array" antenna design, this is a description of an application of a particular phased array design.

      Not all phased array designs allow simple pattern changes based on phase manipulation.

      Some can have none, requiring physical antenna pointing, some have simple switched 90 degree changes (forward+back/left+right vertical designs) and then others can be super advanced and highly variable of the likes of military designs with all sorts in between.

  • Here's the answer for the rev. A PowerBooks. Not only would be able to share your internet connection with the whole neigborhood, but you'll also be able to get reception on your PowerBook in at least (maybe at most) the next room over!
  • by cyberbrian ( 15778 ) on Monday November 04, 2002 @11:39AM (#4594244) Homepage
    Vivato's new ad campaign:

    Can you ping me now? Good.

    B.

  • by yack0 ( 2832 ) <keimel@g[ ]l.com ['mai' in gap]> on Monday November 04, 2002 @11:40AM (#4594246) Homepage
    Midcoast Internet in Maine has an active 9 mile link. It uses 802.11 (FHSS) technology, so how is all this new? They've even tested 18 and 32 miles links. link here [midcoast.net]

    Saying that this is all nifty keen and something new is a bit of a fib, as I'm sure there's plenty of other providers doing this as well. Heck, even Robert X. Cringeley has some long link (or had one) through to someone elses house.

    4 miles is hardly a huge jump, even legally done by FCC guidelines (thus the 'you can have more power on point to point links' rules of the FCC)

    It's all in the antennae, that's right, but been there, done that.
    • ok, so the inside stuff (2000 foot range) is new, but the long hop stuff is already running elsewhere.

      remember, replying to your own posts is rude. ;)

      j
    • by Helter ( 593482 ) on Monday November 04, 2002 @12:59PM (#4594464)
      Yeah, but those are point to point links right? Aeronet wireless bridges claim out of the box point to point bridging in excess of 25 miles. No big deal.
      This is different though, this is more like a roaming point to point connection. It monitors all of the users within the area, then establishes and monitors multiple point to point connections using a phased array antennae.

      Basically they get both an omnidirectional AND directional signal (not really, but that's the effect).
    • It's not about distance: it's about coverage. If you run point to point over a short distance, the signal becomes highly focused. These guys are not talking about boosting distances, but rather about increasing coverage without increasing ERP inside buildings, as one example.

      If you had a 10,000 square foot facility and could put several access points (let's say 3 to 6) in a single server room with one of these antennas, you'd save a small fortune over, say, 20 to 30 access points all distributed across the actual area.

      We'll see how it pans out.
    • Beyond a few hundred feet wifi requires line of sight because it is low power and the high frequencies do not penetrate solid objects easily.
      The Maine setup you linked to requires line of sight between the two points. The antenna arrays described in the article do not, or at least are able to counteract not having it to a significant extent.

      Getting line of sight is a large barrier to using wifi to provide broadband service in cities, so yes this is a big deal.
  • Apostrophe's (Score:1, Offtopic)

    by matt-fu ( 96262 )
    don't forget the yada's

    Please see Bob's Guide to the Apostrophe [angryflower.com].
  • From the article ...The announcement on Monday, instead, will be devoted to discussing the technology, which employs an antenna shaped like a large picture frame, about three feet by four feet and about three inches thick.

    I don't think most of us will be mounting a solid metal plate to our walls. Of course there is always a few extreemists. And if the price is low it may decrease the cost to enter the market as an internet provider. If that is true then I would love to see the increse in competition. If you listen carefully when it is released you just might hear your monthly internet price drop.
  • Google Link [nytimes.com]
  • I assume this would create an enormous EMF in the vicinity so that I would get an even bigger headache at work. How would this affect pacemakers, crt montiors, security cameras, magnetic doors, et. al? Don't point that death ray at me!
    • The FCC specified maximum power of any ISM band emission is lower than that which you might find from a cheap microwave oven.

      HTH

      j

      (and yeah, slashdot is wicked slow today)
  • by carlmenezes ( 204187 ) on Monday November 04, 2002 @11:49AM (#4594265) Homepage
    The article mentions phased array antennas. You can do some really wonderful things with phased arrays, so I don't doubt their claim. The problem is that they are usually quite expensive, take up a lot of space, AND usually require considerable processing (note that they do mention the antenna must be placed in "the corner of a large office"). It remains to be seen how these guys plan to work around those obstacles.
    Another thing ofcourse is the question as to whether the range on the antennas is programmable. It's quite natural for a business organization not to want someone a few blocks away to be able to take a crack at network security
    • The problem is that they are usually quite expensive, take up a lot of space, AND usually require considerable processing

      Phased array antenna's don't require any processing at all.

      The application of automatic manipulation of the individual phases (in particular designs that allow it), to give dynamic patterns that change with detected requirements, is something that requires considerable processing power.

  • Doubt (Score:4, Interesting)

    by Cheese Cracker ( 615402 ) on Monday November 04, 2002 @11:49AM (#4594267)
    WiFi antenna technology today that can give a 2000 ft. range indoors...

    I doubt this applies to a building filled with electric interference, like a telco switch centre
    or a large server centre. When I was working for Nortel Networks, we had problems
    using wireless scanners inside the labs. The only solution was to put up more antennas.
  • www.fractenna.com

    Has anyone tested these yet? Lets see some numbers.
  • Oh, so now wardrivers can be 2-3 streets away to hack into the network instead of right next to the house? Wonderful.

    What about something better than WEP for encryption? Hmm?
    • Oh, so now wardrivers can be 2-3 streets away to hack into the network instead of right next to the house? Wonderful.

      Hackers have been hacking from streets away long before this came out. Good old high gain antenna designs would allow this with searching done with antenna direction changes as opposed to antenna location changes that driving around facilitates. This new product might just make it quicker and easier to find victim networks. :)

  • What about security/encryption? I wouldn't get too excited everytime a company comes out with some wireless gadget without documented proof that they actualy made it secure for the user to use.
    And not just give him/her the illusion that they are wireless,"free". The true freedom is given to the hackers/crackers to access their data.
    • I wouldn't get too excited everytime a company comes out with some wireless gadget without documented proof that they actualy made it secure for the user to use.

      If you need your wireless network security to be provided by the antenna, you have very serious security problems.

  • This, if it's for real, will make mesh topologies a real threat to the existing landline-based ISPs. Effective inter-node range has always been the biggest barrier to the potential acceptance of mesh systems. With this kind of range, only a few people in a community would need to run mesh routers in order to provide access to the whole community.
  • I am suprised that Pringles hasn't picked upon the free publicity like Jolt did...

    ttyl
    Farrell
  • phased array (Score:5, Informative)

    by zejackal ( 186296 ) on Monday November 04, 2002 @12:08PM (#4594314)
    Nothing new here. All it is is a phased array. By definition a phased array is directive, meaning it only covers a portion of the spherical space around the antenna. The reason this is good, is because directivity means gain. So yes, this new antenna will increase range, but only in a given direction. There are antenna schemes for 802.11b that get 10's of miles in range by using very directive antennas. There have been some articles on slashdot about this. The only interesting thing here is that the directivity is achieved by a phased array so it should be stearable. They may scan the 3 dimensional space (but this will cut availabitlity and thus bandwidth at any point). Or they may be able to stear multiple beams to point at areas with a concentration of devices. They may even be able to do it on the fly as demand changes, but there is no big breakthrough here. This technology is older than I am and probably older than most of you too.
    • I suspect it's smarter than that .... I bet the access point spends time figuring out where each client is in the 3-space and tracks it - then directs the antenna at it when transmitting or receiving .... they probably use the idle times lookming for new clients
    • This technology is older than I am and probably older than most of you too. : )

      I have an old FORTRAN text book that has a programming case study about FORTRAN code running on old VAXen being used in RADAR and communications surveillance for the USAF.

      The picture in the case study depicts (what is obvious to me as an ex RADAR tech), a few groups of typical RADAR frequency phased arrays.

      Back then (late 80's) the technologies I witnessed were amazing, and I have a little chuckle when I see whittled down versions of these various technologies in domestic equipment 20 years later. ; )

  • Company Site (Score:2, Informative)

    by BShive ( 573771 )
    I'm suprised the posting didn't link to the company website [vivato.net]. The tech info [vivato.net] doesn't really offer a whole lot in the way of useful information though. Anyone know a place with better details? (/. seems slow for me this morning too)
  • I'm curious if the power boost needed to accomplish this task must sure boost the amout of Rad's your body is injesting by being around such equipment. That can't be good. I don't particularly want to die that way. Can anyone say MICROWAVE? I knew you could.
    • There seems to be a common belief that folks become ill from radiated electrical power. However, I've never seen any published studies that show this. I seem to recall one study that showed a slight increase in childhood leukemia in folks that live under powerlines, but that this was later disproven in a larger study.

      I'm sure that there's a problem if you pump in enough energy to heat tissue, but short of that, is there any evidence at all that electromagnetic fields impact health? Or is this an unproven or disproven hypothesis?
      • I've never seen any published studies that show this.

        Agreed wholeheartedly occamboy. There have been absolutely tons of studies showing overwhelming evidence that ionizing radiation causes cancers and yet tons of studies that failed to show any evidence that non-ionizing radiation (microwaves, mobile phones, WiFi, etc) even slightly highten cancer incidents.

        I take that as pretty overwhelming evidence that there is little to no risk with these devices.

        Besides that, more effective use of effective radiated power can only serve to reduce overall radiated power.

  • This this is going to have to be hooked up to some serious hardware if it will connect 3.14159*(4miles)^2 worth of users.

    This could be great for college campuses, assuming the price is right.
  • by crush ( 19364 ) on Monday November 04, 2002 @12:27PM (#4594370)
    I'm not sure whether or not increased WiFi ranges are a good thing. This could mean that companies (who are what's being targetted according to the article) will be able to compete for bandwidth over a greater range than ordinary individuals.

    Look what happened with Starbucks infringing on a WiFi co-op [geek.com] in Portland. Other companies that wan't to share their signal over a large building and don't particularly care about interfering with the signal outside of that building are sure to implement this technology.

  • I'm posting this on a 30+ mile wireless link. 802.11 has more range than many people think, given line of sight and good antennas.

  • by RealBeanDip ( 26604 ) on Monday November 04, 2002 @01:10PM (#4594499)
    This quote from the article;

    "We will change the way people think about the physics of Wi-Fi,"

    Is bull.

    The laws of physics as it applies to RF will not change, nor will this new "magic" antenna change the way people think about the Physics of Wi-Fi.

    This is a directional antenna, the meaning of that has been explained in detail in many comments above this. Also, in the 2Ghz frequency range you won't be punching through mountains and other obstacles (like building walls) any better with this antenna than with already available designs. In other words, you won't be punching through them at all.

    This is pure marketting, there are plently of directional antennas available for the 2Ghz range. Those other antennas don't change the way people think and they don't change anything we already know about RF physics. This antenna won't either. Hats off to 'em for getting all the free publicity, but there is nothing here that isn't available already.
    • Please do tell me where I can buy a dynamically steerable multi-beam phased array antenna for my wireless network. There's a huge difference between a directional antenna, and one that tracks multiple wireless cards as they move with directional beams.
  • by stinkydog ( 191778 ) <sd AT strangedog DOT net> on Monday November 04, 2002 @01:17PM (#4594520) Homepage
    Imagine finding a root hole in these after they install a couple hundred in your area. Using a computer-controlled antenna array you aim 40 or 50 of them at your coffee cup, warm brew all day.

    The key element is the antenna -- more specifically, an electronically steered, planar-phased array of hundreds of antennas connected to a high-speed processor running Linux.

    Forget DOS attacks. Elite hackers will now microwave their enemies. All you need to do is sneak a wireless card into a pen or something and turn it on in 'very' promicious mode and poof.

    Merry Christmas

    SD
  • Nothing new (Score:1, Informative)

    by Anonymous Coward
    This is nothing new - there is a lot of antennas which extend the coverage already on the market. A friend of friend of mine got 27km link with parabolic ones.
    Also there is a lot of omnidirectional antennas avalaible. But as always:

    a) longer range is alwyas at the expense of angular
    coverage (unless there is an amplifier) - it is
    a law of physics - conservation of energy

    b) stronger antennas may violate FCC regulations

    Kubus
  • Here's a better link from Wired [wired.com], it has more technical meat and explains better why this technology is newsworthy.
  • ... a startup company in CA that says it will announce WiFi antenna technology today...

    Announcing the announcment! It's gotta be impressive!
  • Seeing the blurb about "wireless communications" and all the posts about being microwaved by antennae, I thought they were talking about "Gaiacomm" [gaiacomm.org].

    Remember the recent "Saddam Hussein's Email" stories? Remember the "unnamed" company who allegedly had sent him email and claimed to have a 'weapon of mass destruction' based on wireless technology? Found 'em... [pressbox.co.uk]

    Between the wild claims and the flash-based, content free splash page with what I assume are supposed to be whale noises, I'm pretty sure they're nuts .

    The article, on the other hand, seems to be talking about a "real" company...how dull. :-)

  • Now the neighborhood WiFi clueless fools can be unsecure over a wider area!
  • I'll be able to wardrive without leaving my own home! :)
  • Attach this sticker to the back of your wifi unit, and instantly, you can as much as double your reception? Yeah, yeah -- they tried to sell me that for my cellphone too. Doesn't work. :)
    • Yeah, yeah -- they tried to sell me that for my cellphone too. Doesn't work. :)

      This is not some silly snake-oil sticker. This is the commercial application of an old technology that has been waiting for one side of it's technology to catch up (although military, etc have used it for many years).

      Computing power meets manipulated phased arrays!

      PS, they do work, extremely well. So well in fact, that some people will see their claims as snake-oil!

      Look into the REAL technology before passing it by.

  • by Chicane-UK ( 455253 ) <chicane-uk AT ntlworld DOT com> on Monday November 04, 2002 @02:26PM (#4594863) Homepage
    I dunno... sounds cool, but I can't help but think of the 'F-Ray' bit on a Futurama episode :

    Fry: Ow, my sperm!
    Bender: Wow, neat. Mind if I try that again?
    [he does so]
    Fry: Huh! Didn't hurt that time.
  • Part 15 FCC Rules (Score:2, Informative)

    by kc0dby ( 522118 )
    The problem here, is that the FCC intentionally limits the usefulness of Part 15 devices. Sure, you can build yourself a gigantic super-duper gain antenna and a kW amplifier for your signal, but it won't be legal. Did you ever wonder why you don't see access points or PCMCIA cards with convenient BNC or N-type connectors on them? That's because they can't get type approval to sell them if they are 'easily modifyable' by the consumer.

    The FCC limits not only power output, but also the gain of the antennas matched with the power output. (ERP) If you have a 1W transmitter and a 12dB antenna attatched to it, your effective radiated power would be 16W, which would not fly under part 15. (I believe the maximum ERP for a part 15 device is something like 1W, and the maximum power output at the device is 100mW) That's not saying a manufacturer couldn't make a superb antenna that was fixed to a tremendous coax run, so that the coax loss was recovered by the antenna.

    Basically, the point is, Uncle Sam isn't going to let anything too amazing happen with the tech until he gets some auctioned spectrum money from us. The only thing we can do is work on better reception (pre-amps / low loss coax / DSP) methods, or get a license to operate under a different part.
  • Not WiFi but... (Score:2, Informative)

    by focuss ( 512981 )
    Navini [navini.com] makes a phased-array wireless solution that is supposedly being tested by NTelos [ntelos.net], a regional ISP here in Charlottesville VA. I saw some preliminary documents for the trial: one that showed the coverage area, a roughly circular area with two "pie" slices taken out of it -- essentially shadows cast by mountains near the antenna location. The other document was a map giving signal strength throughought the coverage area produced by a program called "antenna explorer" or something like that. The coverage area was still considerably larger than the DSL coverage area from the same provider. I have not met anyone who is actially on the service. The trial documents indicated that they would add more coverage areas if the trial went well.
  • Keep this in mind: (Score:3, Interesting)

    by mindstrm ( 20013 ) on Monday November 04, 2002 @05:54PM (#4595875)
    To stay within FCC regulations, there are rules about the effective radiated power from an antenna on this stuff. IT's not safe to say that you can just throw any antenna you like on it, and it's okay; if you exceed certain gain levels, you are outside the rules. This differs from country to country of course; I know that you can get more effective power at distance out of 2.4Ghz ISM in the US than you can in canada, for instance.

  • by TechyImmigrant ( 175943 ) on Monday November 04, 2002 @06:37PM (#4596232) Homepage Journal
    802.11 Unicast transmissions could be beam steered to improve range.

    802.11 AP and IBSS Broadcast transmissions need to be heared by everyone. Thus they can't be beam steered.

    So you might be able to communicate via an AP from further away, but you'll never get past the beacon scanning, probe, probe response stuff to get authenticated and associated in the first place.

    • If I had mod points, I'd mod this up. But since I don't, I'll just post.

      I think you're exactly right. How does a user connect to the AP if the AP can't see the user until it points the antenna in the right direction?

      How does the AP know that a client is about to send a packet so that it can point the antenna in the right direction to receive it? Clients can send packets at any time. How do you point the antenna in the right direction first?

      What happens to the collision rate on the network? Normally the clients and the AP use RTS and CTS packets to reserve airtime for large packets. But unless every client receives the CTS packet, that algorithm doesn't work. The end result could be dramatic increases in the collision rate.

      I think this would be great tech if you could put it in the client, so that as you wondered around the client would maintain a directional link back to the AP. That, I think, could work quite well. Clients only talk to a single access point at a time, after all. But I don't think it's realistic to expect this to work worth a damn on the AP side. An access point really does need to be able to send packets to all clients at once. And it really does need to be able to receive from all clients at once. Unfortunatly, laptop makers might balk at the eight square feet required by the current design.
    • That's the first thing that came to mind when I read this.

      The best thing I can come up with is that the client has to be very close when first authenticating, and as you move futher away the directional antenneas 'follow' you up to 4 miles.

      Of course, this doesn't really make for a good solution. Is everyone going to have to walk into the server room with the antennea every morning to authenticate and make sure the laptop stays on all day (oh, you rebooted. You better drive back to the central antenna).

      I'd be curious as to how they propose to handle this.

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