How to troubleshoot WiFi channel overlap issues?

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Apologies for the length.

I changed router recently and have been having issues with the speed dropping randomly. This is all way above my knowledge level but, best I can tell, is when it happens a neighbor and my router are somehow using the same channels and they look like they mimic each other.

I recall a long time ago when setting up the previous router having the same issue. I used an old inSSIDer version 2 and it showed that the neighbor was on both channel 1+6. I moved mine to channel 11 and never had any more issues. Set up the new one the same way I thought but each time I check it the neighbor is using the same channel I am. No matter what channel I set. It is instant. I change and look and theirs is on the same one. I also set mine to a single channel but then that old inSSIDer version 2 shows mine is using two channels like 1+6 or 11+7 etc.

So far I have tried leaving the router to set channel automatically and have set the channel manually to just 1, 6 or 11. Each method has worked until it didn’t seemingly random and when I checked the channel again mine would show the same as theirs and it would show it was using two channels rather than just the one I set it to.

Also, I did see a mention when trying to research this about 20 versus 40 Mhz channel setting. The default is 40 Mhz so I left it on that since I didn’t understand it.

Can anyone recommend a wifi channel scanner to use to troubleshoot, if that old inSIDDer V2 isn’t showing me what I need, and any tips on what I can try to set the router settings so it works without having to keep playing with it?

Thanks.

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What router are using?

Some of comcast routers use a guest network. This cause that both your wifi and the guest wifi on your router have the same channel.

Some Cicso routers have auto channel changing that are <span style=”color: #ff0000;”>very very bad</span> at this. You have channel 1 and other person has channel 1. Both you have Cicso routers so both change it to 6. Again, it change again since conflict again to channel 11. It does not fix the issue.

Some options might be to power off your router for about 30-60 min. Use scanner to see what channel are active. After that, turn on your router and set an far away channel. For example, everyone is on channel 1. You select channel 11. Everyone is on channel 11. You select channel 1. Everyone is on channel 6. It might have to be a guess to go with either 1 or 11.

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This web page should get you up to speed on everything you need to know

https://routersecurity.org/extending.wifi.range.php

In brief, your router is making a BIG mistake. On the 2.4ghz band, all channels should be 20 wide. Yours is 40, change it. Once changed, you will never be using two channels.

FYI: It is normal for the main SSID and the Guest SSID to be on the same channels. That said, Comcast has a Comcast-user-only SSID – so that when you are traveling in a Comcast area, you can use someone else’s network rather than 4G/5G. I would turn that option off if you can. Not sure what channels that uses.

Also, if you can, don’t let the router pick the channel.

Taking a step back, having multiple networks on the same channel is not life and death. Wi-Fi was designed to share channels. In fact, it is better for 3 networks to all be on channel 1 rather than them using channels 1, 2 and 3.

What matters is not the number of networks on the same channel but the amount of data being transmitted on the channel. Very few programs/apps report this. I believe inSSIDer is one of the few.

 

Get up to speed on router security at RouterSecurity.org and Defensive Computing at DefensiveComputingChecklist.com

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Thank you both for the help.

I think that 20/40 Mhz setting might have resolved it.  I don’t understand it but before the signal from mine and my neighbors would eventually somehow become in sync with each other on that inSSIDer graph.  It would start off on different channels but eventually they would use the same channel and then all of a sudden that graph showed them locked in a dance together completely in sync.  That corresponded to when the speed would drop.

It is odd to me because the channel of the neighbor changes pretty constantly.  Sometimes 1, then 6 or 11 and back and forth.  Sometimes it shows they are using 20 Mhz and other times 40 Mhz straddling two channels.  But it hasn’t happened again since I selected one channel that appears the least congested with the weakest signals and using 20 instead of 40.

That ancient inSSIDer version helped by showing the graph and I could see the signals stick to each other and it listed them using two channels.  I didn’t noticed them using two channels on the wifiinfoview program as it just listed the one.

And thank you also Michael as your site was actually the one I stumbled researching how to set up a new router.  I used that and knew to turn off some of the default settings and WPS, UPnP etc.  Missed the 20 versus 40 setting though.

 

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It is odd to me because the channel of the neighbor changes pretty constantly. Sometimes 1, then 6 or 11 and back and forth. Sometimes it shows they are using 20 Mhz and other times 40 Mhz straddling two channels.

That’s strange. I would confirm it with another Wifi scanning app.

That ancient inSSIDer version helped by showing the graph and I could see the signals stick to each other and it listed them using two channels. I didn’t noticed them using two channels on the wifiinfoview program as it just listed the one.

In Wifi InvoView look for the Channels Range column and the Channel Width column. That said, I’m not sure it would pick up a change in channel, so maybe X out of it and restart it every now and then. Or, what the heck, everything is working fine 🙂

 

Get up to speed on router security at RouterSecurity.org and Defensive Computing at DefensiveComputingChecklist.com

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another app beside nirsoft’s WiFiInfoView & inSSIDer is Vistumbler

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👍 Vistumbler 👍

Back before I retired, that’s what I always used to ensure the new WiFi equipment I installed for various businesses was working properly.

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