Would appreciate it is someone will explain which base frequency should I set for 5GHz 80MHz width 42 or 155 channel?
According to what I can understand from here https://en.wikipedia.org/wiki/List_of_WLAN_channels is 5210 & 5775 respectively.
However, both option shows "no supported channels", when selected.

Channel 42 would be from 36 up to 48.

You start with a control channel (20MHz wide) and add 3 x 20MHz extension channels to it.
I.e. Control channel 5180 (channel 36) and extension channels Ceee would be from 5170 to 5250.

You can also select a control channel somewhere in between (can't think of a reason why, caused by limmited knowledge on my site):"
I.e. Control channel 5200 (channel 40) and extension channels eCee would also be from 5170 to 5250.

Channel 155 could be:
5745, Ceee (and would make from 5735 to 5815)

Hopes this makes sense?

Thank you for prompt reply!
I've set 5745 as my frequency. However client (MacBook Pro M1) shows that I'm on 149 channel. Not on 155. Is it ok?

I do not have a deep knowledge of the subject, but what I understand from various articles 42 & 155 are the best channels (each consists of 4 * 20MHz) because they are not "overlapped with the others". Meanwhile I can not setup my hAP ax2 in a way that MacBook show that it is using either of them. Am I understanding / doing something wrong?

Hop this clarifies it a bit more:



So, your channel 42 is exactely in the middle as well as 155.

Anyway it is not clear for me, why for example, 5825 is listed in a list of supported channels, Meanwhile, when I set it in the interface, it shows "no supported channels" (red alert in the bottom)

Have no experience with Wave2 (yet), but I would assume that the combination channelwidth 80MHz and frequency 5825 doesn't make sense.
There doesn't seem to be a filter on the frequency dropdownlist, dependant on the channelwidth selected.

As far as I can see, frequency 5825 is only supported when you use 20MHz channel width.

Wikipedia has a really nice article on WiFi channels ... with shown standard channels according to channel widths.

When trying to implement them, keep in mind that on Mikrotik one always sets center frequency of 20MHz control channel and separately adds Channel layout.

In particular: 5825MHz is center frequency of 20MHz channel #165 ... and can be used as part of 40MHz cgannel #167 in channel layout Ce ... or as part of 80MHz channel #171 in channel layout Ceee.

And gotcha: I've noticed (while using hAP ac lite) that ROS doesn't like to use channels aligned to 5MHz boundary ... I had to revert to 5800/Ce (when 5795/eC or 5815/Ce would be proper config). But OTOH many normal wireless clients don't like when AP uses non-standard channels. So you'll have to experiment, but it might turn out that UNII-3 is not part of band that you can use.

The way we need to configure it on WifiWave2 is confusing.
In my case, I have a recommended freq setup:

/interface wifiwave2 channel
add name=ch-5ghz frequency=5180,5260,5500 width=20/40/80mhz

Mostly selected channel by my devices is named DFS, 100 (5GHz, 80MHz) both on Mac and Windows

Based on Wiki, channel 100 can be 80Mhz and starts at 5500 (center).

It looks like we need to set up the first center frequency of each 80Mhz channel block we want to use.

Anyway it is not clear for me, why for example, 5825 is listed in a list of supported channels,

I have noticed more than once that when checking the available channels, only the combination " Ceee" is used. In this combination, at 80MHz width, the range of frequencies occupied at 5825 will be 5815-5895 and is outside the permitted range for European countries, and even more so for Ukraine.

/interface/wireless/info> country-info ukraine
ranges: 5170-5250/a,an20,an40,ac20,ac40,ac80,ac160,ac80+80(20dBm)/passive,indoor
5250-5330/a,an20,an40,ac20,ac40,ac80,ac160,ac80+80(20dBm)/dfs,passive
5490-5710/a,an20,an40,ac20,ac40,ac80,ac160,ac80+80(20dBm)/dfs,passive
5735-5835/a,an20,an40,ac20,ac40,ac80,ac160,ac80+80(20dBm)/passive,outdoor
5190-5310/a-turbo(20dBm)/dfs
5180-5300/a-turbo(20dBm)/dfs
5520-5680/a-turbo(27dBm)/dfs,passive
5510-5670/a-turbo(27dBm)/dfs,passive
2402-2482/b,g,gn20,gn40(20dBm)
2417-2457/g-turbo(20dBm)
902-927/b,g,g-turbo,gn20,gn40(30dBm)

Set the USA country and the channels will be supported, see the article recommended above.
The output of the command /interface/wifiwave2/radio print detail shows the physical capabilities of the interface, it does not show the country restriction.

Based on Wiki, channel 100 can be 80Mhz and starts at 5500 (center).

No, based on Wiki, channel 100 is 20MHz wide and spans 5490-5510 MHz (with 5500MHz center frequency).

Then there's a 40MHz wide channel 102 which happens to overlap 20MHz channels 100 and 104. Nominally channel 102 has center frequency of 5510MHz, in Mikrotik world it's configured as 20+20 channel with certain channel layout (either Ce or eC) and matching center frequency of control channel. According to standard layout (which is shown in wikipedia article) combination of channel layout Ce and control channel center frequency of 5520 (channel 104) is invalid because there's no 40 MHz channel spanning range between 5510 and 5550 MHz.

The 80MHz channel, which includes channel 100, is nominally channel 106 with center frequency 5530. If one sticks to (seemingly best supported in ROS) channel layout of Ceee, this means setting center frequency 5500 ... but that still doesn't make channel 100 to be 80MHz wide.
Dependin on client cpaability, one client might use 20MHz channel 100, another client might use 40MHz channel 102 and yet another client might use 80MHz channel 106. All at the same time (well, time divided multiple access which is supported by all wifi generations).

Going off of old wifi configs, 5825 is "too high" on Mikrotik devices for 80mhz band.

If using this channel without setting center channel to a lower frequency, 5795 for example, the router assumes that the selected channel is the base frequency and goes up from there (Ceee in legacy driver)
For channel 5825 to work, you'd need to set the center frequency to that. In some countries we support above 5845, but Mikrotik does not allow those channels at this time.

For example of frequency selection, 5805 could have 5775 (eeeC) or 5795 (eeCe) as centre (C in both cases being 5805) frequency, and 5775 could have 5745, 5755, 5775 5795 or 5805 as centre

Apologies if the "Ceee" representations are incorrect, is very late and I'm searching up another issue. The point is the default is channel, then extensions (Ceee), and if you want the "primary" frequency anywhere else in the chain you need to tell it with the center frequency.

Hope this helps, If not please correct me.

The 80MHz channel, which includes channel 100, is nominally channel 106 with center frequency 5530. If one sticks to (seemingly best supported in ROS) channel layout of Ceee, this means setting center frequency 5500 ... but that still doesn't make channel 100 to be 80MHz wide.
Dependin on client cpaability, one client might use 20MHz channel 100, another client might use 40MHz channel 102 and yet another client might use 80MHz channel 106. All at the same time (well, time divided multiple access which is supported by all wifi generations).

Well, in reality, user's devices show channel 100 as 80Mhz, both MacOS and Windows. I think there is a similar logic in the WifiWave2 frequency setting. You need to set the first block of range, not a middle one. I understand your description above. The frequency setting here is not perfectly described.

My setup (hAP ax3) is: frequency=5180,5260,5500 width=20/40/80mhz

Radio status:
State running
Channel 5500/ax/Ceee

Client reports:

PHY Mode: 802.11ac
Channel: DFS, 100 (5GHz, 80Mhz)
Country Code: DE
Network Type: Infrastructure
Security: WPA2/WPA3 Personal
Signal / Noise: -52 dBm / -89 dBm
Transmit Rate: 527
MCS Index: 6

Oh, and as for the channel numbers (36, 100, 102, 155, etc) they are somewhat meaningless.

Generally the 40 and 80 mhz channe numbers are not "read" bu devices. Most devices I have come across read the 20 mhz channels and give you a representation from there.
An example would be channel 155, generally being read/displayed as 149/80 or 149+153+157+161.
This is all down to devices though, I generally read frequency and go from there.

Again, good luck and let everyone know if I dun goofed

So, I finally saw the news, UNII-4 support has just come to 7.8beta2, so 5850-5895 is available soon for hAP AX devices, if you wanna go beta (or wait for release I guess). This means you could go 5825 channel without selecting a centre channel. Yay - I guess (about bloody time IMO)

So, I finally saw the news, UNII-4 support has just come to 7.8beta2, so 5850-5895 is available soon for hAP AX devices, if you wanna go beta (or wait for release I guess). This means you could go 5825 channel without selecting a centre channel. Yay - I guess (about bloody time IMO)

on 5825 it gets only 40Mhz (Ce) and poor performance. Yes, there is no one around looking at the scan results.

So far, 5500 and 5660 at 80Mhz work best, still, the range is not nice

I would like to know if the Mikrotik has any country that uses only the UNII-1 (36, 40, 44 and 48) and UNII-3 (149, 153, 157 and 161) channels in the 5GHz frequency?

Just set "skip-dfs-channels=all" for most countries, and you will only get UNII-1 (36, 40, 44 and 48) and UNII-3 (149, 153, 157 and 161)

I would like to know if the Mikrotik has any country that uses only the UNII-1 (36, 40, 44 and 48) and UNII-3 (149, 153, 157 and 161) channels in the 5GHz frequency?

Why? You want to live there?

Ceee, this means setting center frequency 5500 ... but that still doesn't make channel 100 to be 80MHz wide.

Yes it is 80 MHz wide. That is the way Mikrotik does it. It's a matter of notation, MT is NOT using center freq notation for 40MHz or 80 MHz channels, but the center freq of the (C) control channel. At least that's what they do for the classic (WLAN) driver.
See dynamic bandwidth in : https://www.oreilly.com/library/view/80 ... /ch03.html

The 20/40/80MHz notation in Mikrotik, suggests the use of "dynamic bandwidth" only, for wider channels. There is no 40MHz or 80 MHz in the dropdown list for channel width to select in WLAN wireless.(well there is 40MHz-turbo) . Mikrotik wiki calls the e channels "extension channels"

Dynamic channel bandwidth, leading to channel selection, as described in: https://www.oreilly.com/library/view/80 ... /ch05.html ?
Figure 5-4. Channel addition algorithm for 802.11ac

wifiwave2 is totally different. The documentation/help files point to the 40-80 and 160 MHz mid frequencies, at least for " the secondary frequencies : Only official 80MHz channels (5210, 5290, 5530, 5610, 5690, 5775) are supported."

Ceee, this means setting center frequency 5500 ... but that still doesn't make channel 100 to be 80MHz wide.

Yes it is 80 MHz wide. That is the way Mikrotik does it. It's a matter of notation

Not entirely. Either that contigous 80MHz channel is 100+104+108+112 (combination of 4 adjacent 20MHz channels) or it's 106 (a truly 80MHz wide channel). Yes, all APs I've seen so far use the 4x20MHz approach (which allows for compatibility with devices which only support narrower channels, e.g. 2x20MHz or 20MHz only). Which probably makes people believe that "80MHz wide channel 100" is a thing.
Precise wording does matter, channel 100 can be part of 4 combinations of 4x20MHz channels and (as observed by multiple users) some client devices don't like 4x20Mhz channels which don't cover the same frequency range as some 80MHz channel. And with channel 100 this means that only combination that will work with all devices supporting this part of spectrum is 100+104+108+112 because it covers the same ferquency range as 80MHz channel 106.

I would like to know if the Mikrotik has any country that uses only the UNII-1 (36, 40, 44 and 48) and UNII-3 (149, 153, 157 and 161) channels in the 5GHz frequency?

Why? You want to live there?

Yes I will.

Just set "skip-dfs-channels=all" for most countries, and you will only get UNII-1 (36, 40, 44 and 48) and UNII-3 (149, 153, 157 and 161)

Thank you, it helped a lot.