Hi all,
I would need to set channel 11 on my hAP ac3 as someone has set an overlapping wifi on channel 3.
I understand that channel 11 has a centre frequency of 2462 which is not in the drop-down list of my router. I can manually select it and it works but if I check after a few days the router is back to “auto” and it selects channel 6 I think.
Can someone please help me? I am on RouterOS 7.6
Thanks
Tony
Can you please share:
/interface/wireless/ export hide-sensitive
of course, thank you! (I’ve masked some data with xxx)
interesting, I see 2462 as 2Ghz interface frequency but the GUI reports “auto”. 5Ghz is intentionally on a separate SSID and hidden.
# dec/21/2022 09:37:17 by RouterOS 7.6
# software id = FB1B-LQD8
#
# model = RBD53iG-5HacD2HnD
# serial number = xxxxxxxxxxxxxxxxx
/interface wireless security-profiles
set [ find default=yes ] supplicant-identity=MikroTik
add authentication-types=wpa2-psk mode=dynamic-keys name=xxxxxxxxxx\
supplicant-identity=""
/interface wireless
set [ find default-name=wlan1 ] band=2ghz-b/g/n channel-width=20/40mhz-XX \
country="united kingdom" disabled=no distance=indoors frequency=2462 mode=\
ap-bridge name=wlan1-2Ghz security-profile=xxxxxxxxxxxxx ssid=xxxxxxxxx \
wireless-protocol=802.11
set [ find default-name=wlan2 ] band=5ghz-a/n/ac channel-width=\
20/40/80mhz-XXXX country="united kingdom" disabled=no distance=indoors \
frequency=auto hide-ssid=yes mode=ap-bridge name=wlan2-5Ghz \
security-profile=xxxxxxxxxx ssid=xxxxxxxxxx wireless-protocol=802.11
UInless you live in a place where there are no nearby Wifi networks, you could better not set a 40MHz bandwidth on the 2.4GHz radio. Instead, turn extension channel off.
Besides (though no problem related), configure extension channels manually (i.e. Ceee), otherwise there is no predictable outcome which control channel is used.
And at last…hidden is like…not hidden. It is just not shown by default in wireless clients.
Thank you.
I’m a bit confused as I previously diagnosed a slow wifi and I was told to leave factory defaults here:
http://forum.mikrotik.com/t/slow-wifi-on-hap-ac3/162621/10
Where can I find the extension channel option?
So by setting 20Mhz on the channel I tell the router NOT to extend the wifi over adjacent channels? I learnt that for best wifi we should use channels 1, 6 and 11 - wouldn’t that give 40Mhz of bandwidth to those channels? With 40Mhz I would overlap from channels 9 to 13. I am not questioning your advice, just trying to understand myself.
As long as the 5Ghz is not shown on Windows and Mac I’m ok - we know it’s there and available, I just don’t want computers to automatically show it. I need the long reach of 2Ghz, not the high speed of 5Ghz.
Thank you so far.
Factory defaults work…well, optimization should be done afterwards.
Every channel (1, 2, 3…11) in 2.4GHz is 5MHz wide. By choosing channel 1,6 or 11, you choose 20MHz it total (hence the adjacent channels). If you select to use extension channel (channel width) instead of using 20MHz you use 40MHz. Which is terrible, unless… Choose 20MHz Channel Width on the 2.4GHz radio and check if that solves the problem. You will do yourself and you neighboors a favor 
[Update]The link describes optimization on the 5GHz radio. There is more bandwidth and it can be usefull to use extnsion channels to get better performance. Still it could cause additional interference.
One image should tell more than quite a few words:
Taken from wikipedia article on WiFi channels (it’s well worth reading, either this or one of other similar ones).
Note that picture above doesn’t apply in Northern America where channels 12 and 13 are off limits for use with anything newer than 802.11b. There the slimmed version applies:
The channel number shown on (lone) 40 MHz channel is not correct, it’s actually channel 1+5 (same as on top picture).
I understand, thanks for explaining that in details.
I agree that in a crowded environment, 20Mhz at 2.4Ghz is definitely recommended. I did not realise I was flooding the frequency spectrum! 
So to switch to 20Mhz width I just select “20Mhz” under “Channel width” and then select channel 11 (2462), is that correct? Any other tweaks you’d recommend? Looking at your previous post, do I “turn extension channel off” when I tell the AP to use 20Mhz width?
Cheers!
Yes, that’s just fine.
My recommendations
Thank you, I appreciate your advice.
Can I check what you mean with “optimise RX power” please? I cannot find an option for that in Advanced mode and google does not help either.
Thanks!
I think it was a typo Tx power.
https://wiki.mikrotik.com/wiki/Manual:Wireless_FAQ
Thanks @own3r1138, I indeed made a tpo.
Can you let us know how things go after making the adjustments, @Tony359?
Thank you both! is 17dBm the maximum? I assume this way we prevent the AP from changing things around.
I shall do of course but I would like to change those options when I am on site - so it’ll take a few weeks.
But thanks for your help so far
I’m back on site and changed the channel width, thanks!
I was reviewing the thread and I would like to double check the “optimise TX power” subject. I see Mikrotik does NOT recommend to set “all rates fixed” but the above screenshot is set that way.
Can I please check with you what is the best setting for a reliable signal?
Thanks so far!
the above screenshot is set that way.
For the screenshot, I put it to all rates fixed so it could enable the value.
Thanks. I understand that you need to enable “all rates fixed” to enable the value field but I am referring to this:
It looks like Mikrotik is explicitly not recommending that setting. What is your thought on that?
Thank you!
Well, I don’t have enough knowledge to comment on this.
When you want to set “all rates fixed” you should set a lower Tx power than the maximum.
Look what powers it sets when you use “default” (automatic power selection depending on country, antenna, and rate) and set a Tx power lower or equal than the lowest power you find there (in the first column).
E.g. when the max power is 17dBm that would be 14dBm or lower.
Thanks, I appreciate your help anyways.
I guess my question is for @erlinden then. Can I know more about “optimising TX power”?
Well, under hypothetical ideal circumstances, e.g. when you are living out in the desert in a building with 10 access points, it could be that you can optimize the installation by not running everything on full power. Each AP only needs to cover an area, and the Tx power can be set to cover only that area, and not the whole building.
Then you can reduce the noise from the other APs when you re-use the channel at another place.
Of course in the real world you have to deal with APs outside of your control, which the owner has set to max legal power and beyond.
It is kind of an arms race. Reducing your own power will not improve things for you, but only for your neighbor. And it can be difficult to convince them to do the same and make it better for both of you.