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Standard User oldskool
(member) Tue 13-Nov-12 11:38:14
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Which Wifi Channel


[link to this post]
 
I recently moved house and now seem to pick up silly amounts of wifi traffic. To top it off i have neighbors with wifi channels like 2+6 and 7+11.

I've been through a few different channels trying to get an uninterrupted connection. By that i mean on some channels loading web pages very slow, i assume from all the interference. I can't stream airplay music from itunes on channel 1 without drop outs for example but yet it appears to be the lowest powered channel on the following graph. It's just about 10 different AP's use channel 1.

I've been using channel 7 for days perfectly and yesterday it started exhibiting the same slow behavior.

[IMG]http://farm9.staticflickr.com/8065/8181820254_fd9035...[/IMG]
Administrator MrSaffron
(staff) Tue 13-Nov-12 11:47:12
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Re: Which Wifi Channel


[re: oldskool] [link to this post]
 
Switch to 5GHz?

Andrew Ferguson, andrew@thinkbroadband.com
www.thinkbroadband.com - formerly known as ADSLguide.org.uk
The author of the above post is a thinkbroadband staff member. It may not constitute an official statement on behalf of thinkbroadband.
Standard User oldskool
(member) Tue 13-Nov-12 12:31:35
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Re: Which Wifi Channel


[re: MrSaffron] [link to this post]
 
My billion 7700n only operates on 2.4ghz frown

I have a 3 storey house and i need it to reach the top floor too.

thanks


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Standard User Jimneybob
(newbie) Tue 13-Nov-12 12:47:42
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Re: Which Wifi Channel


[re: oldskool] [link to this post]
 
Don't know if you get on with your new neighbours yet, but may I suggest you have a get together and discuss the wi-fi channels situation. They will be getting same interference/poor performance problems too. Its in everyones best interest to stick to channels 1,6 or 11 so as to reduce interference. I suspect like the majority of folks your neighbours may not be techies and don't understand the implications of the channels they have their routers set too. Worth a try.
Standard User MHC
(sensei) Tue 13-Nov-12 12:54:25
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Re: Which Wifi Channel


[re: oldskool] [link to this post]
 
Work out a scheme with the neighbours - I would guess that they have 2 WAPs each and similar problems in reaching the whole house.

From experience, it is possible to use 1, 5, 9 & 13 without any interference issue.

Put a scheme to your immediate neighbours that you will use Ch1 on the ground floor and Ch9 on the top floor. A neighbour on one side will use Ch5 on the ground and Ch13 on the top and the other neighbour Ch13 on the ground and Ch5 on top. They then agree with their neighbours to use Ch9 and Ch1 ...


~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~

M H C


taurus excreta cerebrum vincit
Standard User ggremlin
(committed) Tue 13-Nov-12 12:55:30
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Re: Which Wifi Channel


[re: oldskool] [link to this post]
 
I have a 3 storey house and i need it to reach the top floor too.

try laying the aerials on the router flat, so at least some of the signal goes between floors.

they /do not/ radiate in the direction they point
Standard User MHC
(sensei) Tue 13-Nov-12 12:56:27
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Re: Which Wifi Channel


[re: Jimneybob] [link to this post]
 
Why like so many others do you perpetuate the 1, 6, 11 settings? It is quite feasible to use 1, 5, 9, 13 without problems.


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M H C


taurus excreta cerebrum vincit
Administrator MrSaffron
(staff) Tue 13-Nov-12 13:39:22
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Re: Which Wifi Channel


[re: ggremlin] [link to this post]
 
Take a peek at our router reviews.

I leave antenna in the config manufacturer shows and get decent up/down results. Wooden floors mind you, if concrete then problems are to be expected

Andrew Ferguson, andrew@thinkbroadband.com
www.thinkbroadband.com - formerly known as ADSLguide.org.uk
The author of the above post is a thinkbroadband staff member. It may not constitute an official statement on behalf of thinkbroadband.
Standard User Jimneybob
(newbie) Tue 13-Nov-12 13:41:01
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Re: Which Wifi Channel


[re: MHC] [link to this post]
 
I'm not a great expert on this topic but I had similar problems with neighbour wifi interference. I Googled and came up with some free sofware called inSSIDer from a company called Metageek. (see www.metageek.net)

I read some of their tutorials and using the inSSIDer software it shows you graphically what is happening with the surrounding wifi networks to you.

What I learned if I can explain myself clearly is that each wifi channel uses I believe a 20Mhz spread of frequency. When you look at this shown on the inSSIDer software if a wifi network is using channel 1 for example it is using 10Mhz of frequency to the left of channel 1 down the frequency scale and 10Mhz to the right of channel 1 up the frequency scale which in the 2.4Ghz band takes you to the channel 3 frequency.

Which ever channel you pick to use for your network you use frequency spread of two channels to the left and two channels to the right

so channel 1 uses left of 1 and up to 3
2 overlaps 1 and up to 4
3 covers 1 to 5
4 covers 2 to 6 and so on up channel 11 covers 9 to 13

When you are in a congested area there are only the 3 channels of 1, 6 and 11 that dont overlap and therefore can not cause any interference.

What you said is correct you can use any channel you like when you have no neighbouring networks, if you want to use channel 7 thats fine and it will use frequencies from channel 5 to 9, but you neighbours must not be using any channels at either end to overlap with these or you might get interference.

Hope that explains not too technically what I learn't recently. I regularly use inSSIDer on laptop and Android app to see what is going on in the wifi world around me.

The other influencing factor is how physically close the neighbouring routers are to each other. If you live in suberbia in detached houses you will get less chance of interference because there will be weaker signals than if you live in a block of flats where neighbouring routers might only be a few feet apart the other side of the wall to your neighbours flat.

Edited by Jimneybob (Tue 13-Nov-12 13:45:52)

Standard User oldskool
(member) Tue 13-Nov-12 14:45:16
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Re: Which Wifi Channel


[re: Jimneybob] [link to this post]
 
Thanks

The image i posted was from inssider app

No matter which way i cut it, i seem to get strong signals from other AP's.

I can't believe it really, it's a 5 bed 3 storey detached house. I have neighbours left and right but nothing behind and in front they are across the road.

Our rooms are divided by thermalite block too and the router is in the hall which being a 3 storey has an open stairwell which i assume helps the signal travel up but the interference and wifi congested despite being detached is something i've never experienced outside of big cities.

I'm still trying to find a decent channel but it seems some AP's around me have dynamic channel allocation and these are the ones that spread over 40mhz. I've noticed them changing channel.
Standard User greenglide
(committed) Tue 13-Nov-12 15:50:18
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Re: Which Wifi Channel


[re: oldskool] [link to this post]
 
I really think you need a 5GHz router - even if it is installed on the first floor and run off the present router via wired (preferably) or wireless bridge if the new AP supports true dual band?

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Standard User eckiedoo
(regular) Tue 13-Nov-12 16:05:42
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Re: Which Wifi Channel


[re: oldskool] [link to this post]
 
Afternoon oldskool

Re the location of your router, if it is on the ground floor, have you tried moving it to the middle floor, ie central within your house dimensions?

where-abouts did you use the inSSiIDer device, immediately adjacent to your WAP; or at some distance from it?

I suggest that generally, the situation is going to get worse, as more and more devices take advantage of WiFi, as a "convenient" means of communicating.

With the quantity of WiFi circuits around you, and discounting the various "free" ones, it looks as though you would have great difficulty organising co-operative allocation with several neighbours, so I suggest that the solution has to be found directly in your own domain, apart from whether your neighbours having the knowledge to actually access their devices.

The devices you have noted changing channels are probably doing this automatically, to reduce/avoid the contention you are observing.

It may be that you have to improve on any screening achieved with your outer walls etc, may have to be supplemented by painting them with a suitable screening paint.

If as you state, the internal walls are thermalite, I suspect that you may have to have separate WAPs on each floor.

Then it may be that you have to replace your router with a more up-to-date one, to get similar automatic switching facilities.

I have noted with my recently supplied Bright Box, that it switches from the double-channel mode to a single channel, simultaneously changing from 300 MHz to 54 MHz; and also moving to a distinctly different channel.

Then back again.

And that is with only one or two relatively weak WiFi signals observed using inSSIDer.
Standard User micksharpe
(eat-sleep-adslguide) Tue 13-Nov-12 16:24:57
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Re: Which Wifi Channel


[re: oldskool] [link to this post]
 
You could install access points on each floor and/or use homeplugs. Whichever way you go with 2.4GHz, you're still going to have channel contention with nearby dual-channel high-speed routers. If I was living in a busy neighbourhood, I'd move to 5GHz like Andrew said and enjoy some peace and quiet (for a while).

Edit: I've just looked at your inSSIDer output. Move to 5GHz (or wired).

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Edited by micksharpe (Tue 13-Nov-12 16:42:17)

Standard User MHC
(sensei) Tue 13-Nov-12 17:28:35
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Re: Which Wifi Channel


[re: Jimneybob] [link to this post]
 
Almost but not quite ...

The channels are 5MHz apart and 20MHz wide, although on 802.11b they were 22MHz

Take Ch1 centred on 2412 MHz it will spread from 2402 to 2422 and Ch5 is centred on 2432MHz which will spread from 2422 up to 2442 There is NO overlap with that pair - similarly 5 & 9 and 9 &13

The use of 1, 6 & 11 originates in the US where 12 and 13 are not permitted.


I do have quite a few years experience in communications and have a fairly good understanding. Having undertaken some major testing with a manufacturer of networking and wireless equipment and one of my customers in a specific controlled environment we were able to demonstrate full throughput using 1, 5, 9 & 13 and almost near full throughput using 1, 4, 7, 10 &13 and it was only when almost co-located did we see problems.

Get inSSIDer running and look at the channels and notice the lack of overlap.


~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~

M H C


taurus excreta cerebrum vincit
Standard User prlzx
(experienced) Tue 13-Nov-12 21:51:52
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Re: Which Wifi Channel


[re: MHC] [link to this post]
 
Just to endorse MHC and add that if the neighbours insist on leaving their wi-fi in 40MHz mode (sometimes shown as 40/20 auto)
(that's what scans like 2+6 mean), to emphasise this also points towards 1,5,9,13.

The 40MHz-ers may need to choose 1 or 13 (to be certain their router should combine that with 5 or 9 respectively).
If a router auto scans and chooses 40MHz on any other combinations that is not very helpful.

Routers with country settings need to be on UK (or at least Europe) rather than USA (on older laptops Wi-Fi drivers sometimes default to USA incorrectly also).

It is almost always better to be on the same channel as someone than +/- 1,2,3 away (as devices on the same channel can listen for when the next "gap" is due, to retry, whereas adjoining channels just represent interference (and raises the noise floor).

Finally (and that on most routers especially is never done) if someone only needs their router to cover one room, turn down the power if possible (lowers the noise floor nearby).



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Standard User oldskool
(member) Fri 16-Nov-12 16:35:50
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Re: Which Wifi Channel


[re: prlzx] [link to this post]
 
Just wanted to update this thread after all this great advice.

I've tested quite a bit, everything from signal strength to throughput speed.

One poster here mentioned that it is better to be on the same channel than 1 that overlaps. This translates perfectly in my situation.

Channel 1 initially looks quite decent because the signal strength is quite weak in most cases, however it is also peppered with people using 40mhz cross channel configurations.

6 was equally attractive because it was the least used channel, i tried 5 and 7 too and both suffered from poor throughput and stability because of people spanning several channels in 40mhz mode.

Overall, i've settled on channel 13. It has given by far the best signal strength, with both antennas pointing up i get an excellent signal on the top floor, near full throughput speed and none of the stability issues i had with the other channels.

I can't say it's 100% perfect, i am still sharing with 1 or 2 other users but there is no or a lot less cross over.

On the other channels on my iphone it would take forever to load web pages, i assume to due congestion. 3G was much faster, now on channel 13 they load almost instantly, rarely with hiccups now.


When i upgrade my router i will definitely look at getting a couple of 5ghz models and some home plugs. I only just bought my billion router so i will keep this for a while

thanks all
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