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Wireless Networking Hardware

WiFi Interference Problems in Urban Environments? 51

Posted by Cliff from the handling-clutter-the-airwaves dept.
EagleEyez asks: "We're running a wireless network (802.11g) in our apartment: four computers connecting to a Linksys wireless router. But living in a high-rise building in a major city (NYC) there are at least 3 other wireless networks nearby, plus numerous microwaves and cordless phones in the apartments around us -- all of which make the wireless network less than stable. We've pumped up the signal strength on our router, but we lose the connection from time to time disrupting our internet connection and LAN games. What other options are there to help ensure a consistent and reliable network connection? We've tracked the channels the other networks use and chosen one that doesn't conflict, but there's little we can do to prevent the interference from cordless phones, in other people's apartments. As more and more people go wireless, especially in denser urban areas, there has to be some sort of solution..." If you've run into this problem before, did you find any way to solve (or at least mitigate) the outside interference?
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WiFi Interference Problems in Urban Environments? More

WiFi Interference Problems in Urban Environments?

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  • Use 802.11a (Score:5, Informative)

    by Elik ( 12920 ) on Tuesday February 10, 2004 @10:56PM (#8244772)
    I use 802.11a for my wireless network and never had any problems with it since it don't get interface from other wireless or raditiation crap like telephone, microwaves and such.
    • except from my new 5.8ghz phone... you're just delaying the inevitable and paying a premium for it.

      • Re:Use 802.11a (Score:1, Informative)

        by Anonymous Coward
        802.11a uses 5 GHz... your new 5.8ghz phone shouldn't interfere unless you've got some weird harmonics...

  • Shielding (Score:2, Interesting)

    by k4_pacific ( 736911 )
    Consider lining the walls of your apartment with aluminum foil or aluminum window screen (don't use the fiberglass stuff). Be sure to ground it well and install it in accordance with all FCC regulations and local building codes.

    Hope this works for you!

  • Easy answer (Score:5, Insightful)

    by BeatdownGeek ( 687929 ) on Tuesday February 10, 2004 @11:01PM (#8244827) Homepage
    What other options are there to help ensure a consistent and reliable network connection?
    Cat5 works great.

    • don't mod down! (Score:4, Insightful)

      by TheSHAD0W ( 258774 ) on Tuesday February 10, 2004 @11:05PM (#8244871) Homepage
      This "troll" makes an excellent point. Wireless has its benefits and drawbacks, and especially in an urban environment the drawbacks are enormous. Something as stupid as a neighbor's leaky microwave oven can drive one to tears. A wired ethernet connection is faster, more reliable and more secure.
    • Unfortunately, the configuration of our apartment makes cabling easier said than done; it's one of the reasons we went the WiFi route...

      • Re:Easy answer (Score:2, Insightful)

        by BeatdownGeek ( 687929 )
        Yeah, I knew that was kinda a jerky answer. But since the question didn't specify why exactly it needed to be wireless, my mind jumped to the simplest conclusion. Which sometimes turns out to be the best anyways- but maybe not this time.
      • Bah, what's a few holes in the walls?
        • You left out the last bit: "Bah, what's a few holes in the walls between friends?"
        • Reminds me of my last place...

          We were in an apartment, and the computers were in two rooms side by side. The router was in my roomate's room, next to a phone jack.

          We both had cellular phones, so we just opened up the wall jack and fed a cable through.

          No, we didn't always have the best eye for aesthetics...

      • Re:Easy answer (Score:2, Informative)

        by notsoclever ( 748131 )
        There's no such thing as an impossible cabling situation. You don't have to punch holes in the walls or have them visible or be tripped on easily. For example, you can run it under the carpet, or along the baseboards, or even along the ceiling (using staples every foot or so to tuck the cable nicely in the corner, or strategically run them behind the curtains or whatever.
        • While it's true there is ALWAYS a way to get cabling around, it's not always easyh. No carpets in the apartment, and to run the cabling from where the router is to the other key room would require 150' of cabling, at least, if we ran it along the ceiling or the baseboard because of doorframes and tricky corners.

          This then means ensuring no signal loss in the cables, the cost of running it and so forth.

      • Re:Easy answer (Score:4, Funny)

        by ScuzzMonkey ( 208981 ) on Wednesday February 11, 2004 @06:12PM (#8253703) Homepage
        Dude, what are you even worrying about? You've got three other wireless networks that already cover your apartment? I call that free Internet access, with none of the configuration hassles!

        Trust me, they wouldn't be broadcasting into your apartment if they didn't want you to take advantage of it. ;)

  • Faraday cage (Score:4, Funny)

    by LastToKnow ( 449735 ) on Tuesday February 10, 2004 @11:05PM (#8244862) Homepage
    Aluminum foil wallpaper! Stylish and functional.

  • The only thing that worked for me (Score:3, Interesting)

    by Hardwyred ( 71704 ) on Tuesday February 10, 2004 @11:07PM (#8244906) Homepage
    I have a similar problem, but due to SBC giving out free wireless hardware to people that don't need it. The only success I had was when I decided I would just out power everyone else. I picked up a pair of 7db gain antennas, smacked one on my AP and the other on my laptop. I then switched to channel 9, nothing seemed to be using that channel. While it's not the most friendly, It works. Unfortunatly, the next step involves an op-amp and figuring out a way to insulate my toaster.

  • Channel 11 (Score:4, Informative)

    by Rheingold ( 2741 ) <wcooley@@@nakedape...cc> on Tuesday February 10, 2004 @11:09PM (#8244927) Homepage

    This might be relevant only for b, but using channel 11 will considerably reduce interference from cordless phones. I'm assuming it applies to g also.

  • Obvious... (Score:4, Funny)

    by phraktyl ( 92649 ) * <wyattNO@SPAMdraggoo.com> on Tuesday February 10, 2004 @11:14PM (#8244980) Homepage Journal
    The answer, of course, is to sell your wireleess router on eBay, and start sucking bandwidth off of your neighbor's connection. The more people who do this in the building, up to a point, the less interferance you will have.

    Problem solved!

  • Walk around the apartment with your router (Score:5, Informative)

    by ChaseTec ( 447725 ) <chase@osdev.org> on Tuesday February 10, 2004 @11:16PM (#8245001) Homepage
    I have an apartment in Houston and I pick up at least two other wireless networks. I'm using 802.11b and what helped me was plugging my wap (linksys wap11) into a long cat5 cable and an extension cord. It turns out that I get better coverage with my wap off to one side of the apartment then in the middle. The signals bounce thru walls in ways you don't always forsee. Don't forget to try out each location with your microwave and cordless phones in use. I see a much more noticable difference with placement then I do with channel changing or even hacking the signal stregth.

  • directional (Score:2, Informative)

    by Cyberop5 ( 520141 ) *
    Try using directional antennas on your AP. I don't know how your appartment is oriented, but you could try putting it into a corner and using something like a parabolic or yagi antenna directing it into the rest of the appartment.

    If interference is still a problem, try a 802.11a AP. It opperates on the 5.8ghz spectrume and is less likely to have consumer products interefere. The downside to 802.11a is that you will lose distance; so hope your walls are like paper or buy a repeater for each room.

    I don'

  • Don't amp the signal (Score:5, Insightful)

    by Fallon ( 33975 ) <[moc.liamG] [ta] [leoN.niveD]> on Tuesday February 10, 2004 @11:51PM (#8245280) Homepage Journal
    "We've pumped up the signal strength on our router, but we lose the connection from time to time"

    Quite probably other people are doing the same. All of a sudden the spectrum becomes unusable because a couple people decide to blast the hell out of it with excessive power. It's quite easy to pack in a good number of WiFi devices if you follow proper WiFi etiquette

    The best course of action is to only use the least amount of signal necessary to get a stable connection & use directional antennas. Directional antennas cause less RF pollution and interference with the rest of the spectrum and when properly aligned give you much better signal to noise ratios. Errant signals from sources not in line with the antennas are rejected much better and your signal should have much less interference.

    Using amplifiers isn't the way to a better WiFi world.
    • As you note, the wireless spectrum is a shared resource, one that it's *very* difficult to eliminate abuse of.

      The problem is, the wireless spectrum falls prey to the public good problem. It's in everyone's benefit to try to outpower the others, and as a result, nobody can get through.

      Wireless devices simply profliferate. There are few areas that are going from wireless to wired, and more and more people are picking up wireless devices.

      Spread spectrum devices have been getting more popular for some appl

      • Power Control (Score:3, Insightful)

        by Detritus ( 11846 )
        One solution might be to build power control into these devices. My CDMA cell phone constantly adjusts its transmit power level to the minimum needed to maintain the RF link at an acceptable BER (bit error rate). Besides prolonging battery life, it allows more cell phones to operate in a given area.
      • http://www.hineslab.com/CordlessLightMouse.html

        there you go. God how ugly is that thing.
    • We increased the signal only slightly, using the firmware -- didn't want to overpower the others, per se, but to ensure that within our apartment the router would have the strongest signal.

      I'm fairly certain that a lot of the interference is coming from people's phones and microwaves, moreso than the other networks, and thus a small boost seemed reasonable.

      • Re:Don't amp the signal (Score:2, Insightful)

        by Fallon ( 33975 )
        If your talking about one of the semi-common Linksys hacks, it's a big problem. When those devices are hacked for more signal output they also get very slopy. They pound out all sorts of interference to other WiFi channels (and non-WiFi as well). I don't recall the links off hand, but some people have done some before/after spectrum analysis of the Linksys WAP's when applying that hack, and after the hack isn't pretty.

        Bumping up the power on the WAP is only half the problem. You need a 2 way connection. Pu
  • Lots and lots of tinfoil... around the walls of the apartment of course, not your head.

    --

    This sig is spel cheked

  • interference (Score:2, Interesting)

    by poindextrose ( 640377 )
    given the option, I'd borrow a spectrum analyzer, and have a look see at what else is going on. turn off your router and let the spectrum analyzer sit on peak hold. often you'll find that the channel(s) you were trying to use were either

    a) in use, or
    b) taking a lot of interference from external factors (like microwaves)

    if you can't find a free channel, first step is to stop it at the windows. try and position your router without a view to the outside -- pagers are notorious for sideband splash on their 10
  • Lining the walls with lead...
  • Is it feasible to just run wires? I know wireless is "cool" and the "next big thing", but it may not be the best option if you've got a lot of interference to deal with. I don't know if wireless is the only way to go for you or not, but using wires is worth considering.

    Wireless may be cleaner and less involved when it comes to physical setup, but wires "just work" after you've strung them (unless you've miscrimped them, you poor soul :-). There's no messing with channels, positioning antennae, or worrying

  • Why? (Score:1, Funny)

    by sheapshearer ( 746106 )
    You live in a NYC apt and a 3ft ethernet cord doesn't cover your entire apartment? wow...

  • Hearing aids get interferences too... (Score:5, Informative)

    by antdude ( 79039 ) on Wednesday February 11, 2004 @03:04AM (#8246535) Homepage Journal
    This might be off-topic. I can hear my Linksys WAP11 (802.11b) during heavy file transfers with my bone conduction hearing aid when I am in close range. It is the same type of interferences that I get if I am near radio stations or cellular phones. I believe this situation is going to get worse. I love wireless, but there are conflicts.

  • Work with your neighbors! (Score:3, Insightful)

    by bluGill ( 862 ) on Wednesday February 11, 2004 @10:46AM (#8248537)

    work with your neighbors. Find out who has these devices, have everyone lower their power, and configure the same security. Then use roaming (ipv6 does roaming better than ipv4) for your needs, no matter where you are.

    And get everyone to drop their power, so long as every part of the apartment is covered what do you care which network you reach.

    As for the phones: unless you can knock them off there isn't much to do. Suggest to everyone who has on that a cell phone is easier to use, and perhaps you can solve the problem the easy way.

  • Some cards simply aren't going to work well in your environment with your router. Try using a few different cards, and if that doesn't help, change the router/ap. Use an AP and a regular cat5 router instead of a combo (consumer wireless routers are the cheapest of the bunch).

    Also try using a B router/AP with G cards. You'll find that the G cards connect to a B router better than they connect to a G router and better than B cards connect to a B router.

    Lastly, pay attention to the antennas. Place th
  • Poweline.. it's what I did for home and work..

    at work we have about 40 microwaves.. at home my shed was just too damn far from the house..

    look for a siemens powerline to wifi adapter. excellent... put an AP anywhere.


    14mbs, and consistently too..

  • Hmm, I've been having irregular problems with my 802.11b dropping out. I live in a neighbourhood with houses on each side; guess what I am seeing is the interference described by numerous others here... someone microwaving, phoning or whatever. Most times it happens the system doesn't recover unless you power-cycle the WAP. This had led to me suspect the power supply to the unit, but maybe it just can't handle interference that wipes it out and a cold-restart is the only cure. FYI, I am running with SSID br

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