Hello.
I am using CAPSMAN with 3 CAP AP XL antennas and I have fixed a channel on 2.4 Ghz frequency on each of the antennas. I am using RouterOS 7.6.
Even when I am forcing the channels on each antenna as well as the 20 Mhz frequency, but neither the frequency nor the channel width is correct on when I scan the wifi frequencies.
Here are my settings.
Here are the scanning results.
Any suggestions of what I am doing wrong or why the antennas do not use the configured channels.
Regards..
eC vs Ce. That changes the center point.
Please share config in textual form. From screen shots it’s impossible to see everything.
However, it does seem that you did not successfully configure use of 20MHz channels, all APs use 20+20. And using channels wider than 20MHz in 2.4GHz band is really not a good thing.
Looks like when you configure “2ghz-b,g and n”, the antennas select automatically the 40Mhz frequencies and ignores all other settings.
If I configure “2ghz- b and g” , the antennas use 20 Mhz and the channels that I configured are used..
so I found the problem after experimenting a lot.
If you can avoid the others, drop b and g, only use n.
Unless you really have to support 802.11b, you usually want to get rid of it. Use g/n or n-only mode.
Regarding your frequency question: As already mentioned you probably fcked up the extension channel config.
In capsman channel width is controlled with channel property extension-channel. If it’s set to disabled, then radio will be provisioned to 20MHz only channel, even if band is N or AC. If that’s set to anything else, then channel width will be appropriately wide. E.g. if setting is extension-channel=XX, then radio will be provisioned for 40MHz channel width (20+20). Likewise if extension-channel=XXXX, radio will be provisioned to 80MHz channel width (4*20MHz).
Basically channel is constructed of one Control channel and zero, one or more Extension channels. Pre-N devices support only 20MHz channels and will only see/use Control channel. If you limit AP to only older standard, then it’ll only emit Control channel obviously. It’s benefitial to use N standard on 20MHz-only channels due to support for MIMO (multi-chain) which improves throughput without using wider frequency channels.
If you want to control extension channels kayout, configure it explicitly - e.g. instead of configuring it to XXXX, use eCee.
In mikrotik world, when you set frequency, this means Control channel centre frequency. Depending on channel layout wider channels will be centered at lower or higher frequency (never centered because wide channels never use odd number of 20MHz channels).
This is an interesting explanation about the extention-channel, I haven’t configured anything about extention-channel yet.
funny there is nothing in the documentation at Mikrotik concerning these settings and which setting corresponds to what.
As I am talking about the 2.4 Ghz wifi settings, so the standard will be 20 Mhz , and you can set 5, 10, 20 and 40 Mhz on that frequency band.
No documentation ?
https://help.mikrotik.com/docs/display/ROS/Wireless+Interface
channel-width (20/40/80/160mhz-Ceeeeeee | 20/40/80/160mhz-XXXXXXXX | 20/40/80/160mhz-eCeeeeee | 20/40/80/160mhz-eeCeeeee | 20/40/80/160mhz-eeeCeeee | 20/40/80/160mhz-eeeeCeee | 20/40/80/160mhz-eeeeeCee | 20/40/80/160mhz-eeeeeeCe | 20/40/80/160mhz-eeeeeeeC | 20/40/80mhz-Ceee | 20/40/80mhz-eCee | 20/40/80mhz-eeCe | 20/40/80mhz-eeeC | 20/40/80mhz-XXXX | 20/40mhz-Ce | 20/40mhz-eC | 20/40mhz-XX | 40mhz-turbo | 20mhz | 10mhz | 5mhz; Default: 20mhz)
Use of extension channels (e.g. Ce, eC etc) allows additional 20MHz extension channels and if it should be located below or above the control (main) channel. Extension channel allows 802.11n devices to use up to 40MHz (802.11ac up to 160MHz) of spectrum in total thus increasing max throughput. Channel widths with XX and XXXX extensions automatically scan for a less crowded control channel frequency based on the number of concurrent devices running in every frequency and chooses the “C” - Control channel frequency automatically.
https://help.mikrotik.com/docs/display/ROS/CAPsMAN
extension-channel (Ce | Ceee | eC | eCee | eeCe | eeeC | disabled; Default: )
Extension channel configuration. (E.g. Ce = extension channel is above Control channel, eC = extension channel is below Control channel)
The 802.11 standard channel width is 20MHz, on all frequency bands. Period. Some devices support (vendor-specific) channel widths (e.g. 5,10 or 40MHz), but not many stations will support it. So unless you’re working with equipment that explicitly supports non-standard channel widths in a pretty quiet environment, don’t do it (using non-standard channel widths will likely degrade performance of standard-compliant equipment … just like using nstreme messes 802.11 clients as they can only sense interference but are unable to avoid it because they don’t recognize it).