[Webinar] Learn how to a build a cloud-first strategyRegister Now

x
  • Status: Solved
  • Priority: Medium
  • Security: Public
  • Views: 1699
  • Last Modified:

Choosing Optimal Wifi Channels - 25 Other routers in range on various channels

A couple of months ago I started having problems with my WIFI network. Connections dropped regularly for no reason. As it turned out two of my neighbours had just bought themselves a Sky broadband modem and my own router interferred with theirs. I therfore switched from channel 11 to channel 1.
Now I am having similar problems.
I checked all wifi  networks in our range using Network Stumbler and it turns out that there are more than 30 different SSIDs in reach.
I also spoke to the SONOS support (a wireless audio streamer system) who checked my Sonos logfiles and observed a very high level of frequencey interference.

Channel  Networks
1              10
2               1
6                6
9               4
11             19
13             2

I heard that I should only choose 1,6, or 11 because of overlaps.
Now, above are the numbers of all the networks in range.

which channel should I choose?

Is it better to choose something like "4" because no one else is using it? Or will I then get all interference from the channel 1 and channel 6 users?
Same for channel 7, 10 or 12?

Is it better to be on your "own" channel or do I need to stick to the channel 1,6,11 rule?
0
tomanizer
Asked:
tomanizer
  • 9
  • 7
  • 3
  • +3
3 Solutions
 
calltmsCommented:
I think 2, 3, 4 would all be feasible, as well as any other number not being used. While not "recommended", they are completely usable. Also, you could consider switching to 802.11A which would operate on a different band altogether.

OR

Look into a router with Network Robustness - it works better when there are a lot of other signals around that can mess with it (Apple Airport is an example of a router with this feature)
0
 
Darr247Commented:
It's unfortunate (for those in your area that would like to use 2.4GHz) that some uninformed people have strayed from sticking to 1, 6 and 11.
The channel 2 network will interfere heavily with nearby networks using channel 1; only slightly with channel 6. Likewise (or vice-versa), the channel 1 networks will interfere heavily with the one network using channel 2.

The worse cases are in the upper ranges... channel 9 will interere fairly heavy with channel 6 and slightly more-so with channel 11, which is also getting hammered by channel 13 networks.

Save the data in netstumbler for quite a while and then compare the signal:noise graphs it generates. If your card doesn't report noise figures, the graphs won't do much for you. Noise is purple and signal is green in the graphs, if I recall correctly. It can detect lots of APs that you could never get a reliable connection to (and your own AP could step all over that signal locally).

For a clearer picture of just how much the channels overlap in the 2.4GHz ISM band, see http://www.moonblinkwifi.com/2point4freq.cfm, though the the charts on this Cisco page - http://www.cisco.com/en/US/docs/wireless/technology/channel/deployment/guide/Channel.html - are more technically correct, since they illustrate how the dBi rolloff occurs as you move further away from the center frequency of the channel.

I really wish the IEEE would specifiy that 11b/11g WiFi devices make only channels 1, 6 and 11 available (and 14 in Japan, since it just barely overlaps 11 thanks to a larger offset than any other channel has in the 2.4GHz ISM band)... manufacturers will never do it on their own for fear of other brands using the subterfuge that their routers were ''better'' because they featured 13 channels instead of that other brand's mere 3 channels.

The best solution may be switching to 11a, and dual-band 11n after that spec is finalized late next year (crossing fingers hoping it's not delayed further).
0
 
H_HarryCommented:
Someone trying to hack your WLAN will also cause your connection to drop. Does it happen to all clients to just a single one?
It is possible (and easy) to send de-authentication packets to all clients connected to the WLAN and force them to re-associate - regardless of if encryption is in use, and is usually the first sign that someone is trying to get on to your WLAN.
0
NFR key for Veeam Agent for Linux

Veeam is happy to provide a free NFR license for one year.  It allows for the non‑production use and valid for five workstations and two servers. Veeam Agent for Linux is a simple backup tool for your Linux installations, both on‑premises and in the public cloud.

 
akahanCommented:
If you have to choose from those channels (that is, Wireless G), you should give some weight to not just the NUMBER of other users on a particular channel, but their signal strength.  You want, to the extent possible, to avoid channels where there is STRONG interference; that's more significant than the NUMBER of others who are using the channel.   Are you using a utility that measures the relative strength of the other transmitters in your area?
0
 
Darr247Commented:
> Are you using a utility that measures the relative strength of the other transmitters in your area?

Apparently you're not familiar with NetStumbler.  :-)
0
 
akahanCommented:
I am familiar with netstumbler; but wasn't sure if the original poster is.
0
 
Darr247Commented:
I see... well, from this thread's original message:

''I checked all wifi  networks in our range using Network Stumbler and it turns out that there are more than 30 different SSIDs in reach.''
0
 
akahanCommented:
Ah, I didn't NOTICE that!

So yes, obviously he's able to determine the relative strength of the other transmitters.
0
 
Darr247Commented:
That's why I said (in message 22969170),

Save the data in netstumbler for quite a while and then compare the signal:noise graphs it generates. If your card doesn't report noise figures, the graphs won't do much for you. Noise is purple and signal is green in the graphs, if I recall correctly. It can detect lots of APs that you could never get a reliable connection to (and your own AP could step all over that signal locally).

0
 
kyleb84Commented:
If its really that important to you to have a good connection I'd seriously consider getting a quality 5.8GHz AP - and a good WNIC that supports an external antenna.

If your just going to be surfing the net, the previous suggestions will give you an answer.
0
 
tomanizerAuthor Commented:
Hi Kyleb84,
What is an 5.8GHz  HO?
I am using a Belkin G Mimo Router. Is that the same thing?

I am wondering if my router is broken because it continually drops the connections and if tis really the large number of networks.

It connects stating "excellent signal" and very good connection and 5 minutes later disconnects and reconnects with "weak signal" "poor connection" and 5 minutes later connects again with excellent connection with the laptop staying in the same place, very close to the router.
0
 
Darr247Commented:
802.11b and 802.11g use the 2.4GHz ISM band;
802.11a use the 5GHz UNII band (actually from 5.1GHz to just barely into 5.8GHz), which is what I suggested as a possible solution at the end of message http:#22969170.

The 802.11n allows use of either/both of those bands, but the overcrowding in the 2.4GHz band is not going to go away any time soon.
0
 
tomanizerAuthor Commented:
I found this
http://www.wisegeek.com/what-are-mimo-routers.htm

which seems to suggest that my MIMO router is a 802.11n  router.
So I understand that you would expect it to be more stable.

Could it be broken?
Do I need a special card in my Laptop as well in order to connect to 802.11n.
I assume it is just connceting using 802.11g .
0
 
Darr247Commented:
Belkin does not currently make a draft-n labeled as ''MIMO''... they're all 11b/11g (2.4GHz) devices.
0
 
tomanizerAuthor Commented:
0
 
Darr247Commented:
I see... but that's the amazon store's hype. See http://www.belkin.com/uk/support/product/?lid=enu&pid=F5D8630uk4A
Doesn't say MIMO anywhere in the title, quick start guide, or anywhere that I could find on Belkin's web sites. That's what I meant by Belkin didn't make one labeled MIMO... I guess that doesn't mean others can't call them MIMO.

Your router is 2.4GHz-only, so you won't be able to get away from the overcrowding on the b/g band using that equipment, even if you bought a different adapter for your computer.
0
 
tomanizerAuthor Commented:
It says "TRUE MIMO" on the router itself :-)
0
 
tomanizerAuthor Commented:
Alright. I guess I need to buy a new router. I will let you know how it goes.

But what happens when all others upgrade too?
Are we going to have some kind of escalating upgrade war between neighbours to distort each others wifi networks?
0
 
Darr247Commented:
> It says "TRUE MIMO" on the router itself :-)

I didn't notice that.  I just looked on belkin's sites (belkin.com and belkin.co.uk) and all the units with MIMO in their titles were G-only.


> But what happens when all others upgrade too?

If you get a dual-band, you shouldn't need to worry about running out of space for a while using 5GHz 11a (or 5GHz 11n when it's finalized).  The channels used for WiFi don't overlap in that band. See the attached... in Europe/UK the 20MHz-wide WiFi channels available in the 5GHz U-NII band are the 19 shown in the ETSI column. The bottom 3 or 4 have a much-shorter range because they have a lower power limit, but that also means there will be less interference from competing units (using those channels) in high-density areas; The power limits for the 3 non-overlapping channels are the same acrosss the 2.4GHz ISM band, though they may vary by enforcement zone.

WiMAX and LTE may well relieve some of the overcrowding on WiFi as well, but those are still at least a year away from widespread rollout/adoption. Chipsets with WiMAX and WiFi integrated are due out soon, with WiMAX/WiFi/GPS
5GHz-Frequency-map.jpg
0
 
Darr247Commented:
Hmmm...  part got chopped off:

with WiMAX/WiFi/GPS/et al combo chips due in 2010.
0
 
tomanizerAuthor Commented:
hm. a new N-router and still the same problem.
Connection is excellent for an hour or two and then suddenly the connection drops and the network disappears for a while (up to 10 15 minutes). then it comes on again with "excellent connection".
Meanwhile the laptop has not moved a bit. no settings were changed.
0
 
tomanizerAuthor Commented:
problem has not been solved but I guess there is no solution.
0

Featured Post

Free Tool: IP Lookup

Get more info about an IP address or domain name, such as organization, abuse contacts and geolocation.

One of a set of tools we are providing to everyone as a way of saying thank you for being a part of the community.

  • 9
  • 7
  • 3
  • +3
Tackle projects and never again get stuck behind a technical roadblock.
Join Now