Dec 222011
 

If you have several close neighbors, the odds are high that they may also have a wireless network – and if the wireless signal from their router is strong enough, it could interfere with yours if it uses the same channel – causing you a poor connection, intermittent slowdowns or dropouts.

The wireless signal range in standard 2.4GHz wireless routers is divided into a number of channels. There are 11 channels (1 to 11) available for wireless signals in the US whereas the UK and most of the world have 13 channels (1 to 13).

Without going into too much techie detail, only 3 of these channels do not overlap or interfere with each other and therefore provide a good strong signal – channels 1, 6 and 11. Most routers are preconfigured ‘out of the box’ to use one of these 3 channels.

However, because there are only three good channels to choose from, there is a high chance that a neighbor’s router may be using the same channel as yours. This could cause interference between both routers – and make your wireless connection slow or unreliable.

To avoid your router ‘clashing’ with others, it is a good idea to scan for nearby wireless networks and see which channel they are using – then change your router to use a different one. E.g. if nearby networks with a strong signal are using channels 6 and 11, then you should choose channel 1 for your own wireless network. It is easy to scan for nearby wireless networks either in Windows or using a free Android app:

Windows – The tiny program WirelessNetView is available from Nirsoft here as a standalone (portable) version – just scroll down the page to ‘download it in a zip file’, unzip the contents and run the WirelessNetView program (NB you must run it on a computer with working wireless capability e.g. a laptop/netbook in order for it to detect wireless networks).

The program detects any wireless networks nearby and shows you the Channel used and the signal strength etc as shown below:

wirelessnetview

Scroll to the right of the program to see the wireless Channel that each network is using – if one of the 1, 6 or 11 channel numbers is free you should use that one for your own wireless network to ensure there is no interference.

Android – The free app WiFi Analyzer available here is a similar program for Android which shows the wireless networks around you, including the Channel (CH) being used and the signal strength (green bar):

analyzer

Again, this helps you find a less crowded (hopefully empty) wireless channel which you can allocate to your wireless router.

What If Nearby Networks Are Using All Three Channels?

You will have to share a channel with at least one of the other networks – but which one? The answer is to share a channel with the network that has the lowest signal strength – the lower the signal strength, the less likely it will cause you interference.

If there are multiple strong signals using all available channels (e.g. in an apartment block) and causing major interference then you have to consider whether you would be better off using a faster and more stable wired network instead – using powerline adapters to cheaply extend internet access around the home is a great solution if you can’t run additional network cables between rooms.

How To Change The Wireless Channel On Your Router

Now you know which is the best channel for your router to use, check if it is already using it. If not, change it – see ‘set up a cable router‘ for an illustrated guide if you have a cable router, especially the ‘Wireless Network’ section in Step 5.

If you have an ADSL router see ‘set up a ADSL router‘, especially the ‘Wireless Network’ section in Step 4.

  9 Responses to “Prevent Interference From Other Wireless Networks”

  1. Thanks for the Android app link – handy to test at my mums house as her wifi is just one of a dozen very close with good signals – walls like paper…

  2. Both Microsoft Smartscreen and AVG Antivirus report problems with wireless netview v1.4 download. Microsoft blocks the download of the exe file and AVG reports trojans in the zip file download.

  3. Recently my connection slowed down massively – I am at times only getting dial-up level speeds 45-120kbps. I don’t have the fastest broadband speed in the world but it should be 10 times that (it does briefly at times speed up to its old speed, but on average only for a minute or two every hour). Spoke to my provider who allege all appears well at their end. I checked a little program called ProcNetMonitor installed which tells me what is connected to the web, which port and how many connections etc, but to be honest I don’t really understand what processes should or shouldn’t be connecting and in any case, the main culprit seems to be Avast (right now Avast has 46, Opera has 23, java has 8, and for some reason System Idle has 31 connections too (how can it be both an idle process and connecting at the same time?) Some processes are not connected but have TCP and UDP counts but I have no idea what this means. Like I say, nothing stands out as being the culprit. Next I unplugged my SMART TV and things did speed up but it was very short lived – since the next time I booted up and I am back to slow speeds. Any advice on the above appreciated but the point of my post is to say that after all that I tried the tip you provide above. No problems on the download and running it but the software cannot even find MY wireless connection never mind my neighbours so I am still trying to find out if this could be the problem. Do you guys no any other tricks for sussing out overlapping connection channels or any idea why my version hasn’t found them? Thanks, Trev.

    • I should say I have contacted NirSoft but while waiting for their reply I figured it could do no harm to get the TechLogon take on the issue.

      • @Trev – the device you are using the Nirsoft prog on DOES have wireless?? If so, not sure why it doesn’t work. Don’t worry about connections – troubleshoot internet speed in logical steps:

        1. check if your wifi router is secure with WPA2 password (as if others are using it then speed will be slow)
        2. disable wireless then plug your laptop straight into router via a ethernet cable.
        3. disconnect all other internet devices/phones etc.
        4. boot into ‘Safe Mode with Networking’ and browse to speedtest.net – if speed is still poor (at different times of day) then you know problem is not wifi or Avast or other non-Windows progs etc (as they don’t run in safe mode), it’s your router/line in or ISP
        5. if speed is good, try the test again in normal windows – if good, would seem likely to be a wifi issue then, if bad, you need to look into which prog is using the connection up…

  4. @Roy, thanks for the advice here. Having followed it I have determined that the problem is definitely my side of the router as I consistently achieved acceptable LAN speeds (both in Safe and Normal modes, but less so in Normal I think.) With ref my issue with WNV from Nirsoft, yes my system is deffo wireless – I use a Wifi card in my desktop instead of a cable to communicate with my router.

    I am still waiting for Nirsoft to respond but I suspect in any case I have something running on my PC which is eating my resources.

    I saw your review of System Explorer which I have installed. Do you know of any similar software that exists that can provide a blow by blow account of what processes/programs are currently communicating with the web and how much bandwidth they are using? I can’t find any. It must be out there – years ago I had something that seemingly did just that but it referenced ports and ip addresses and registry codes instead of friendly front end user phrases (alliteration!) so i had absolutely no clue what it all meant. Proves it can be done, but where and what is it?

    Any ideas as ever gratefully received and acted upon.

    • If speed is much better via LAN then surely processes/progs is a red herring? Either the router wifi is faulty or the wifi card (more likely) or the signal is poor or there is interference. Update the wifi drivers if available then:

      1. do you get 4/5 ‘bars’ wifi signal strength? If not, move closer to router if poss or try a new wireless N USB adapter you can stick on a usb extension lead to lift it above the tower (PCI cards are horrible as so much signal is blocked by the case itself)
      2. test changing the wifi channel between 1, 6 and 11 to eliminate nearby interference
      3. can you test with a laptop in the same position as pc? If still lousy then you know it’s not your wifi card to blame
      4. if there are just too many walls/distance between the router and pc and you can’t run cable between them, consider Powerline instead http://techlogon.com/2011/04/12/using-powerline-adapters-to-extend-internet-around-the-house/

      • Roy. Thanks for your help on this. I recognise you must be very busy and reckon you have given me all the ideas and direction I need for this now. I will post here as an update but more for the sake of completion rather than expecting more of your help and time.

        I haven’t had time to look into this much more as yet but what I can say is that it’s certainly not the location of the puter/wireless card. The puter was upstairs until fairly recently. It worked fine for ages. It started running slowly so I brought it down and the the back of the tower is now 12 inches from the router.

        The card by the way has an aerial on it that I can swivel about and point more directly at the router. Signal strength is excellent – max bars. So I am looking for other reasons but not ruling the hardware out categorically although atm am jobless and uber skint so wont be making any upgrades :( in the near future even if hardware turns out to be the issue. Luckily I already have an old USB G dongle that i can try if all else fails. Incidentally, I think that because I had to go online to find a driver for the WiFi card is the reason that the WirelessNetView isn’t working. Their FAQ pages say that Windows drivers are required for the software. Still waiting to hear from them.

        For now I have changed the channel to 3 (it was on Auto) and will see how that pans out. If after trying all channels I still have a prob, will try the USB dongle. After that will look at processes again. After that will blame my ISP and ring up to shout at them :D

        So once again thanks for your help on this and I am sure I will get to the bottom of it eventually. It’s educational too.