Different channel on 2.4GHz causes poor performance

So I have a GL iNet AR300M16 running 22.03 snapshot (No ext antennas) and I'm using a wifi adapter with an antenna

It's a TL-WN722N V1 ( AR9271 ) and I'm using it to connect to my main wifi network (((because it has an external antenna and I'm extending it with a usb extender for range and no the cable doesn't seem to have an effect because it isn't that long))) and have the iNet broadcast its own wifi net on another channel for interference reasons

Ethernet runs extremely well when not using WiFi but when starting to use WiFi everything gets slow
I thought why not change the iNet's channel to the same one as my main WiFi network

I did and the performance increased by 10x on WiFi, I'll probably keep it this way but I just want to know why having my iNet on a different channel slows it down

Thanks in advance!

There may be interference from a neighbour's router on the 2.4Ghz channel you originally chose for the iNet. You might also have chosen a channel that due to the channel width you selected, overlapped the frequency range of the wifi adapter.

You can use an android app such as Wifi Analyzer to view all the routers / channels in the surrounding area along with the width of each channel.

I checked but there are pretty much no close routers on the channel that I chose, only ones that are very very low signal

As for the channel width it's 40 mhz on main router and it's on channel 6 does it interfere with channel 1 on second router? I think it's far enough no?

It is a weird problem because there is more routers on the main router's channel than on channel 1 so you would think channel 6 would be slower haha

Thank you

If you make the channel width 40Mhz, then yes, 1 and 6 will overlap. Make them 20Mhz


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Ooh okay but I still don't understand why channel 1 would be slower than channel 6

Like wouldn't being on same channel interfere more than being on a farther away channel?

Like on channel 1 I get 3mbps and on channel 6 I get 20mbps shouldn't it be the reverse?

Thank you

Setting 2.4Ghz channels to 40Mhz in width is a bad idea in principle. You're not going to get much better performance and you're going to have interference issues.

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Being on the same channel would very likely interfere less.

With adjacent channel interference, portions of the wave-front from each of the radios cancels each other out and results in noise and destructive interference.

With co-channel interference, it's more like congestion that occurs rather than destructive interference.


Hi, thank you so much for explaining it

I tried your advice and set main router (tp-link) to 20mhz, problem is that every software I use still reports it at 40mhz but my second openwrt running router still runs at 20mhz which is good I guess

It does not want to budge, it does not use openwrt because it is not supported so I guess this is not the place for help

I will get new better router in future and make it 20mhz

Thank you!

I checked but there are pretty much no close routers on the channel that I chose, only ones that are very very low signal

Theoretically, using 40 MHz can be ok, if dbm of these neighbouring networks is roughly < - 85 something. It also depends on the Singal / Noise Ratio (NSR). Of course, if you get better results with 20 MHz, then by no means, use 20 MHz. I would say, choose the channel that gives you the best results.

wifi 5 and both wifi 6 achieve highest throughput on the 5 GHz band (although range might be slightly lower), so when you buy a new router, check if it is 802.11ac (wifi 5) or maybe even preferably 802.11ax (wifi 6) capable. The device you have is super old and slow, as it is a 802.11b device, so overall poor performance is to be expected, but I have to say, what you experience with switching channels is quite extreme :smiley:

Edit: and btw. wifi 5 and wifi 6 both operate with 20, 40, 80 and 160 MHz, so it mostly depends on, if the channels are contested... There is no specific requirement to use 20 MHz. I would only use 20 MHz or switch a channel, if neighbours operate on the same channel.


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Yeah I will probably buy 5GHz because I don't have a single device that supports WiFi 6 in the house :sweat_smile:

Thank you for the resources!

If you can't alter the 40Mhz width, then set the first 2.4Ghz channel to 3 and the second channel to 11.

That way, you won't get adjacent channel interference between the two devices (although you may still get it from other nearby routers).

Also here's a small update

While waiting for a new router I decided to test another USB adapter

I tried a ralink rt3070 USB adapter and WOW it improved WiFi performance by 200% (~7mbps on the tl-wn722n vs ~20mbps now) my ISP's speed is 30mbps so this is really good

I guess it interferes less with the iNet router even though it uses 1000mw?

But using ethernet (~25 before vs ~29after ) gets slightly slower speeds but it's still excellent

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