How to jam your neighbor's Wi-Fi legally

How to jam your neighbor's Wi-Fi legally

Summary: While Airgo's third generation product achieves record breaking throughput, it annihilates any legacy 802.11 b/g product in the vicinity and effectively shuts them down. The other products from Broadcom and Marvel weren't quite as devastating to the neighbors, but the damage is still severe. What's crazy is that these products are FCC legal and are being sold on store shelves today.

TOPICS: Government US

Do you ever get frustrated with your neighbor hogging all the Internet bandwidth on the block?  Tired of your neighbor using his Wi-Fi gear on channel 1, 6, or 11 (that's all the possible choices) on the 2.4 GHz spectrum?  Well now's your chance to get even!  Introducing Draft N and Pre-N Wi-Fi!  They might not interoperate at high speeds with each other but they're FCC legal and they're guaranteed to shut your neighbor down or your money back!

While Airgo's third generation product achieves record breaking throughput, it annihilates any legacy 802.11 b/g product in the vicinity and effectively shuts them down. Ok that's not an actual advertisement, but it might as well be one.  Our friend Tim Higgins has been at it again testing so called "Draft N" and "Pre N" Wi-Fi gear (implied compatibility with 802.11n) and he has some very interesting results about the interoperability and interference characteristics of these products.  Earlier this month, Tim ran a battery of tests on these wannabe 802.11n Wi-Fi products to see if they lived up to the kind of throughput and range being promised by the Wi-Fi vendors. 

What the first set of tests reveals is that Airgo's product still beats the "Draft N" competition from Broadcom and Marvell hands down with their third generation MIMO product in range and throughput.  Note: The results showing the Cisco business-grade 802.11g gear performing so well on range may not be a good test of chipset efficiency since it can use 100 mW of transmit power which may be higher than the consumer gear tested.  One could also easily quadruple the range on a Cisco Access Point with the right kind of high-powered antenna but that wouldn't be a fair measurement on how good the radio and chipset design is.

In the second set of tests examining interoperability and interference characteristics on neighboring 802.11g Access Points, the results are alarming.  While the Draft N and Pre N products technically work with each other, it would seem that most of them don't interoperate at the higher speeds.  Broadcom announced that their Draft N products will interoperate at high speeds with Atheros Draft N products, but the Atheros based products weren't available for testing yet at the time of the review.  Broadcom and Atheros feeling the heat from relative newcomer Airgo have put their fiercely competitive past behind them though I'm not sure if this will help if they can't post good throughput versus range numbers against Airgo.  When I asked Broadcom's representative if they were guaranteeing future compatibility with 802.11n in writing, I couldn't really get a straight answer and was told that their Draft G product was eventually compatible with 802.11g and that they are using a flexible design that can change if the 802.11n draft standard changes.  I finally got them to admit that there are no such guarantees for actual 802.11n compatibility.

Airgo is a very interesting story by itself.  I've praised them in the past for having the cleanest design in terms of staying in a single 20 MHz channel while retaining the speed crown.  Airgo's competitors eventually pushed past the performance of Airgo's first and second generation products by hogging two radio channels and Airgo quickly answered with their third generation product that also used a 40 MHz wide signal and regained a massive lead in throughput which holds today.  The problem is that Airgo when from being the nicest single-channel neighbor in town to being the absolute worst Wi-Fi neighbor in town.

While Airgo's third generation product achieves record breaking throughput, it annihilates any legacy 802.11 b/g product in the vicinity and effectively shuts them down.  The other products from Broadcom and Marvel weren't quite as devastating to the neighbors, but the damage is still severe.  What's crazy is that these products are FCC legal and are being sold on store shelves today.  This is a serious problem in the city where town homes and condominiums are right next to each other and it's even a problem for businesses which primarily uses 802.11 b/g.  While these products are aimed at the home market, they're also sometimes used in a small office environment and these radio jamming characteristics are intermittent (when data is being sent) and difficult to track down.

So who is to blame for all of this?  Airgo to its credit pushed for spectrum efficiency among the 802.11n standards body as long as it could and tried to lead by example while everyone else was spectrum hogging.  Once it was clear that the 802.11n draft standard wasn't going to be swayed on spectrum efficiency, Airgo turned to the dark side and became the biggest spectrum hog of all.  The industry was moving the right direction with dual band 2.4/5 GHz products which mitigate interference issues until the arrival of the 802.11n MIMO type products because customers are easily seduced by higher speeds when what's really needed is less interference and better range.

The range issues could have been easily solved with higher gain antennas which ironically are frowned upon by the FCC but don't do nearly as much damage to the neighbors.  Since larger antennas are optional, people won't resort to them unless they really needed the longer range in which case no one's nearby to begin with.  With these N based products, they come off the factory floor ready to jam everything within its operating radius and this seems to be what the 802.11n standards body is encouraging with its decision to allow for wider channels.  The fact that almost none of these new "N" products interoperate with each other and none of them guarantee future compatibility with 802.11n is sad.  The best solution for anyone wishing to avoid the radio jam is to move to 802.11a and the 5 GHz band as soon as possible.

Topic: Government US

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  • Cook and Jam at the same time

    Warming up leftovers or a cup o' jo in my non-UL-compliant RF-nuclear-emitting microwave oven jams channel 11 quite well!

    But, thank you for the how-to! ;)
    D T Schmitz
    • Time for Metal Shop

      A good ole Arc Welder seems to do the trick of knocking out about every frequency there is to have. 802.11A,B, whatever else is out there....

      I was more interested in taking back the bandwidth of my neighbors. I pay good money for that 3 MB pipe to newsgroups, and damnit, I plan to use it... for the month.

      Never fails though, I set up an AP and they take up the same three channels, leaving me out of luck. What is really sad is that I was there first. Bumns...!!!
      • MAC Addresses

        Have you ever thought of restricting the MAC addresses that the router gives IP addresses to?
        • I use that now....

          but what does that have to do with anything I posted. Interference is interference. If you spill a tonne of garbage into the radio spectrum, no one will be able to see anything they actually want.

          Think of it like this... You want to go star gazing, but you want to do it from the street of a busy city. Due to the massive amounts of lumens put out by street lamps, you can't see but only the brightest stars in the sky because the others are simply not powerful enough to show up through the soup of light that is your neighborhood's streets.

          An Arc Welder is much like setting a strobe light in front of your telescope while you are trying to see the little dipper. Filter all you want, you still won't be able to see a thing

          RIP Sk0t. :~(
          • Oh man (LoL)

            nucrash: "Filter all you want, you still won't be able to see a thing"

            . . . Ever again, I would suspect! : )
  • Please can you give me an example of a high gain antenna?

    I have not been able to find any for sale in the UK.
    • Antennas

      If you search for "2.4GHZ antenna" or look at some of the "Wardriving" websites you should find more than enough links to information on antennas and companies selling professional antennas. Almost any of these should improve your system.
    • High gain antenna

      You can likely find antennae that work from ham sources, or make your own. High gain types are parabolic dishes or Yagi types. The Yagi style are linear units with additional elements that act as reflectors and re-radiators. An example of the design is a TV antenna. The "high gain" antennas are directional in nature - concentrating the transmnitted energy in a single direction. They do not output any more power overall

      I would suggest looking at the hajm literature - such as the AARL antenna manual.
    • High Gain Antenna

      If you want to go a few miles - make sure you can attach external antenna such as a Proxim card.

      Have to be B/G can't attach external to A legally(at least in USA)
      john public
      • Says who on 802.11a?

        Cisco and all the other enterprise vendors offer Access Points with N type connectors for 802.11a and they sell large 9 dBi antennas in north america.
    • Not legal in UK

      • Weird

        OK well thanks anyway guys.
    • D-Link DWL-M60AT

      This little indoor directional antenna saved my network connection. My antenna was shielded by the computer it was mounted to. The antenna I bought is rated for a 6dB gain, but putting it up on the windowsill, aimed at my router, boosted my S/N ratio by 40+ dB, a factor of 10,000 or better!
  • Spectrum

    Yeah, so 2.4-2.5 GHz is getting frickin crowded. I've been getting around this problem by containing my high frequency data streams in an elongated, tubular RF proof ecnlosure. I even go so far as to provide a separate PVC coated waveguide for send an recieve. It's even flexible so I can route it around furniture or under rugs. It can even be directed to run inside the walls. It's totally secure. Unless someone can beat the firewall and get in through the wired side, they'll never see my network traffic on any RF scanners.
    • You should try for a patent!

      Sounds like a great invention you have there! Submit that description to the Patent Office.

      Given the current behavior of the US PTO regarding high-tech, seems like you'd have a 50-50 chance. Then you could sue for a royalty on every foot of CAT-5/6 cable produced!
      B. Short
    • okay.... i have to run and show this to everyone now...

      yeah..... i'll have to recount this comment after i start breathing again.

      Best comment ever.

      Valis Keogh
      Valis Enterprises
      Valis Keogh
    • I like your thinking but....

      The problem with your PVC Wave guides is that they don't really go the distance. My guess is that yours are made of copper. I decided to increase the distance of mine here at work by making them out of glass. That seems to work quite well. Your wave guides have problem with magnetic interference and you really shouldn't run them near electrical wiring or anything of that nature. My glass wave guides appear to be much more resistant to this sort of interference. Infact, other than cost, I haven't found a single downside to my glass wave guides.
      • no subject title..well except for this


        you are a total geek!

        keep up the experimenting man!
      • What ARE You Talking About?

        Do you have any idea what the skin depth is like on 2.4 GHz? It really doesn't matter whether the wave guide is made of copper or not, since he already coated it with his conductor of choice.

        And where do you get the idea that it has problem with "magnetic interference"? That is almost as far out there as your glass wave guides. Glass isn't a conductor! What you have is not a waveguide, but just a reflecting canyon.
    • Waveguide, hmm.

      I suspect you're a CAT person.