I'm new to OpenWRT, having previously relied on more basic consumer-level network solutions. I've got both my 2.4ghz and 5ghz radios set to low power and 20mhz, and am satisfied with the coverage and WiFi speeds we're getting throughout the house (5 stories of two-foot thick stone - thank you GliNet!).
My question is, assuming that the Flint 2 correctly reverts to 20mhz when it detects interference, if there's really any downside to letting the router autoselect between 20 and 40mhz? If not, would it not be beneficial for the router to also be able to auto select between 20, 40, and 80mhz on the 5ghz radio?
I apologise if this is a very stupid question. Thank you for indulging me.
General best practice is to not use 20/40 mode. If you are in an urban environment you will almost always be on 20Mhz anyway so you are a better neighbour to not advertise that you are trying to use 40MHz in the first place. Often this will result in a better experience for you and your neighbours for various reasons.
In addition try not to let the router pick an auto channel that is not 1,6 or 11 as this will cause adjacent channel interference which is really bad for performance and worse than a direct overlap on the same channel on 1,6 or 11. If you can use a 3rd party tool to scan what others are using and use the one with the lowest signal level from any of the neighbouring APs/routers
Set the bandwidth to the max for the 2.4 and 5GHz, Then do a speed test make a note of the results.
If you are testing the 2.4 set it to 40 at first and then do a test with 20. If there is not much difference in the speed test leave it at 20. If the the results for the 40 are a lot more use that.
Do the same for 5ghz
Just for example if you do a speed test and get 100MB download on the first test and on the second test at a lower bandwidth you get 95MB or close to it just leave it at the lower setting.
One thing you should know the lower the bandwidth you use your signal will carry further, Switching from 40mhz to 20mhz will not double your distance but it will be a noticeable improvement on distant clients.
Don’t worry about your neighbors, If you want to be nice don’t reduce your download speed just reduce the power output for example right now my power is set to 10 while the max is 23
##My example for speed test results were using imaginary numbers and only used to make a point
Speed isn’t just about download rates though, latency is important and congestion the 2.4GHz band unessasarily seems pretty selfish. High throughput clients shouldn’t be using 2.4GHz this is what 5/6GHz is for with proper AP density. If you have a client utilising 40MHz on 2.4 you are doing something wrong.
Don’t worry about your neighbors, If you want to be nice don’t reduce your download speed just reduce the power output for example right now my power is set to 10 while the max is 23
100% reduce the Tx power anyway, but sticking on 40MHz will cause unessasary speed issues at times where the other channels are in use, so as above, anyone that cares about throughput shouldn’t be using 2.4GHz in the first place.
In addition this 40MHz advice totally ignores co-exitence with things like Zigbee that a 40MHz channel may be stomping all over.