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
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 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
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
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.