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Standard User PhilWebspace
(newbie) Sun 26-Feb-12 11:30:05
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Excessive wi-fi interference from neighbours


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Hi everyone,

I've just got myself set up in my new house with Digital Region broadband at ~40Mbps. Great! (For reference, I've tested the speed with a wired connection and get 39.7Mbps.)

However, I'm having quite severe issues with interference from neighbours' routers, which are consistently stronger in signal than mine within my own house. I've used InSSIDer to monitor the channels in use, and the main issue appears to be with a Belkin router which is slap bang in the middle of the available channels and is stronger than mine. It's causing slow speeds and failed connections on a computer one room away from the access point.

I've moved my channel to be as far away as possible from the Belkin, and even bought a new "high gain" wireless dongle for the computer, which got me a connection speed of ~5Mbps over wi-fi yesterday. Quite a significant speed drop from what I'm paying for and getting, I'm sure you'll agree, but at least there was a connection.

This morning, I've tried to connect, and nothing--the computer simply fails to associate with my access point. Firing up InSSIDer reveals that the offending Belkin, or its owner, seems to have increased the transmit power and is now significantly stronger than my own router, meaning I can't connect to my wi-fi unless I'm physically in the same room as it. In every other room, it's swamped by this neighbouring network.

Does anyone have any tips on how to combat this sort of interference? I'm willing to get a new router if anyone can recommend one with a consistently robust signal, as I need the connection for work and I'm currently stuck on a laptop three feet from my access point all day!

I know I could move the router, or move the PC, or use Ethernet, but the house is quite awkwardly laid-out for cabling (old house, lots of twists and turns, and rented so I can't drill the walls!) so either option would require quite lengthy wiring. They're as close together physically as they can be without some significant wiring required. And I've got the PC where I want it, in the home office, I don't want a computer in my front room. Help!

Edited by PhilWebspace (Sun 26-Feb-12 11:39:03)

Standard User mixt
(experienced) Sun 26-Feb-12 11:42:53
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Re: Excessive wi-fi interference from neighbours


[re: PhilWebspace] [link to this post]
 
Possible solutions:

1) Move onto a less congested channel. 13 normally works well (most wireless kit uses channels 1, 6 and 11 by default). 13 still over laps with channel 11, but not as much.

2) Rather than focussing on higher gain antennas, consider a directional antenna which is pointed in the general direction where you mostly use the laptop. You could even try making your own parabolic antenna out of some tin-foil and cardboard just to see if there is any improvement before forking out money on a proper setup. In fact, the DIY approach might just solve your problems anyway!

DIY parabolic antenna details: http://ebanzai.blogspot.com/2006/04/tech-diy-parabol...

Now on <aaisp.net> (21CN+IPv6)
Previous ISPs: Virgin Media (50Mb/Cable), Be* Un Limited, ZeN
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Standard User PhilWebspace
(newbie) Sun 26-Feb-12 12:00:28
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Re: Excessive wi-fi interference from neighbours


[re: mixt] [link to this post]
 
Many thanks for your help.

I'm not too up-to-date with the technical issues surrounding wi-fi channels as I had a perfect connection at my old house and never needed to research it, but my router (and the interfering Belkin) seems to "spread" across several channels - I'm on roughly 2-7 and the interferer is on around 6-11. I can turn mine down, to a narrower bandwidth, by changing a setting marked "20/40MHz" to "20MHz", and then moving to Channel 13 (or Channel 1, which is also relatively clear). But doing this seems to have an effect on the coverage, which then doesn't reach the upstairs rooms at all.

A different antenna looks like it might be a decent solution, although I'd probably just buy one, as I don't really have a great deal more time to throw at this problem with Monday looming and another week of work. I've spent most of this weekend playing with it, and don't fancy the prospect of another weekend of computer fiddling!

I'm actually using 3G mobile broadband upstairs at present, on the work computer, because it's the only way I can get a connection that stays there. But it's obviously not ideal to be paying Three for a 1Mbps connection, when I'm also paying for FTTC at 40Mbps.


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Standard User mixt
(experienced) Sun 26-Feb-12 12:25:18
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Re: Excessive wi-fi interference from neighbours


[re: PhilWebspace] [link to this post]
 
Is the offending router using MIMO by any chance? That uses up 2 channels. I have some Edimax wireless units that can be configured to do this, and I was playing about with that feature for a while until I realised I wasn't gaining much speed increase, and also, when you look at inSSIDer, and see the greediness of MIMO, I then realised just how selfish I was potentially being to others around me in terms of hogging the wireless bandwidth.

So I canned that idea and now just use one channel (20Mhz).

It does sound like your neighbour is being a bit selfish (unfortunately).

What type of walls are you trying to send the wireless signal through? I was going to suggest maybe looking at 5Ghz wireless kit, which is faster, but has less range than 2.4Ghz, so I doubt that will solve your issues. Well it would solve the issue of interfering with your neighbour, but would not travel through walls as well, which is what you need.

Not sure what else to suggest for the moment. The units I have are: http://www.dabs.com/products/edimax-wireless-n--802-...

I have one running as an access point, the other 2 running in bridge mode. All running at only 10% power (I have a small flat with thin walls). You could try getting one and see what the range is like on 100% power - it may just be enough to out shine your neighbour. smile

Now on <aaisp.net> (21CN+IPv6)
Previous ISPs: Virgin Media (50Mb/Cable), Be* Un Limited, ZeN
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Standard User micksharpe
(eat-sleep-adslguide) Sun 26-Feb-12 12:39:34
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Re: Excessive wi-fi interference from neighbours


[re: PhilWebspace] [link to this post]
 
It sounds like you need to talk to your neighbour and agree on which channels to use. If he's uncooperative, try talking to other neighbours. They may have similar problems.

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Standard User prlzx
(committed) Sun 26-Feb-12 13:24:59
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Re: Excessive wi-fi interference from neighbours


[re: PhilWebspace] [link to this post]
 
While the offending neighbour's router is being selfish, it should not normally prevent you connecting at all, rather that you will be sharing the medium. If the neighbour happens to be streaming / downloading none stop then it will certainly slow things down.

But you should still be able to at least connect even if your routers were on the same channel, as long as you are using different SSIDs.

If routers that come supplied with channel width defaulting to 40MHz in the 2.4GHz band I consider that to be completely unsuitable in most situations, unless you happen to be physically well away from any neighbouring networks. In routers this default may be shown as channel width: 20/40 (Auto).

In channels 1-13 there is just about room for only 2 sets of 40MHz, and only if centred on specific channels, and not if there is already other stuff using 1,6,11
http://en.wikipedia.org/wiki/List_of_WLAN_channels

You can still coexist with your neighbour if you can have a chat with them. The settings you will need are likely to be 1 (+5) on one router and 13 (+9) on the other.
But there are any other networks around you both need to be on 20MHz leaving spaces for channel 6 (or 5,9).

In very congested urban settings 1,5,9,13 packs the most networks into the band but it is almost impossible to get everyone onto this plan when US-based kit defaults to 1,6,11



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Edited by prlzx (Sun 26-Feb-12 13:45:29)

Standard User hoopla
(member) Sun 26-Feb-12 13:34:53
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Re: Excessive wi-fi interference from neighbours


[re: PhilWebspace] [link to this post]
 
There is a lot of overlap across channels, as you will have discovered.

My advice is this: switch to using the standard bandwidth, and only use the same channel as your neighbour or one that he is not using at all. If you are on the SAME channel, the units will be able to wait for a gap, but if you are on a NEAR channel, it is just shouting over the noise.

I would switch to 20MHz and choose channel 1 or channel 11. To get coverage upstairs, forget messing with high-gain antennas. Buy another Access Point for upstairs coverage and use the same SSID and security, but the other channel (11 or 1).

Remember, though that nothing beats a bit of wire for reliability, speed and security. You can get flat cat6 network cable for running under carpets if necessary.

If a cable is out of the question (sometimes is) use homeplug. It's amazingly good.
Standard User prlzx
(committed) Sun 26-Feb-12 14:04:06
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Re: Excessive wi-fi interference from neighbours


[re: hoopla] [link to this post]
 
In reply to a post by hoopla:
... only use the same channel as your neighbour or one that he is not using at all. If you are on the SAME channel, the units will be able to wait for a gap, but if you are on a NEAR channel, it is just shouting over the noise.

Indeed, as this is sometimes a cause of confusion if all the usual 1,6,11 (or less often 1,5,9,13) "slots" are taken.
The intuitive thing might be to pick an in-between channel but as per above, being on the same channels allows radios to hear the other stations and APs (including the beacons) to know when the next transmit opportunity is likely.

In that case my hunch is it's better to choose the channel with the least number of APs showing (even if it is one very strong one) than lots of weak APs (where there will be more collisions and maybe hidden nodes). Free tools like InSSIDer, Wifi Analyzer and similar can help find "least occupied" channels.



prompt $P - Invalid drive specification - Abort, Retry, Fail? $G
prlzx on n e w n e t: ADSL2+ / 21CN at 2.5Mbps / 800k

Edited by prlzx (Sun 26-Feb-12 14:05:00)

Standard User PhilWebspace
(newbie) Sun 04-Mar-12 13:57:45
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Re: Excessive wi-fi interference from neighbours


[re: hoopla] [link to this post]
 
Thanks for your help, everyone. I spent a few evenings trying everyone's suggestions, but only managed to get a middling speed increase (up to 8Mbps), and the stability was pretty poor on wireless, no matter what I tried. It seemed to be the case that just after 9pm every night, when the chip shop next door closed (and they presumably went on the internet), mine would just stop working and cut off.

I am now the proud owner of a 30m length of cat-5 cable, which runs a tortuous route behind furniture, under the fridge, up the bannister, under the carpet, you name it--but provides my full ~40Mbps connection speed, low latency, 100% stability and no interference. I've kept my wi-fi running for use on my phone, but frankly, I get a better 3G signal than wi-fi, so I may as well just turn it off completely!

Many thanks for all your assistance, guys smile
Standard User Moradin
(member) Sun 25-Mar-12 13:13:09
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Re: Excessive wi-fi interference from neighbours


[re: PhilWebspace] [link to this post]
 
I would have just used homeplugs.....

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