Hello everyone,
I have problem after change some options in wireless card. Change is maked in section Channel Width (from 20/40/80MHz eeeC to 20/40MHz eC), Frequency (from 5825 to 5680), Country (from no_country_set to Serbia).
Problem what I see is:
Configure on AP & Virtual AP & Station:
AP (just bridge becouse we have virtual ap)
Virtual AP
Station
Does someone have solutions to this problem?
On DFS Channels you have to deal with this
You choose a frequency and when the AP detect radar on this one, the AP select new channel
Solution is simple: switch off all radars (air control, military and weather ones) around your AP (radius of 100km would probably be enough) …
Or a more complex solution: change to a channel with no radar interference. Oh, wait, your RB did it already.
I change Frequency on station to auto and after re registration on AP, status Channel is changed to 5280.
So, that will resolve my problem? (This problem is show once per day, I need to wait to be sure)
My problem is not resolved 
It is not a problem, it is unexpected behaviour (for you). Switching channels is de Dynamic part in DFS. The Wiki: https://en.wikipedia.org/wiki/List_of_WLAN_channels gives you an overview on all allowed channels you can select. Perhaps you can do a WiFi scan with a client to find out the best channel?
There are only four 5GHz channels without enforced DFS by most regulatories:
36 (5180MHz)
40 (5200MHz)
44 (5220MHz)
48 (5240MHz)
Usually those channels are only allowed for indoor use and/or with lower power (100mW instead of 1W).
After disable WPS Mode in wireless card, problem didn’t manifest (for now, 23h+)
I hope this problem will not be repeated.
Thanks to everyone!
WPS is totally unrelated to this issue (DFS).
Radar problems can sometimes be temporary due to tropospheric propagation conditions (inversion layer).
So it can be coincidence that you were affected for some time and later it disappeared.
E.g. over western Europe (France/Belgium/Netherlands/UK) there has been good tropospheric propagation the last two days,
but now that is back to normal. Don’t know about Serbia.
This is matifest after upgrade for 6.43.7 to 6.43.8 and change Frequency mode, country and installation..
My problem is not resolved.
Can I disable radar detection?
It is a legal requirement to use radar detection when you want to use certain channels on 5 GHz.
This is because the “primary user” of this band is RADAR and you are only allowed to use those channels where RADAR is not present.
When you run a WiFi link on a RADAR frequency you disturb their operation. E.g. on a weather rain map you will see streaks of
fake rain areas in the direction from the RADAR site to your link site.
When weather institutes become sufficiently fed up with this, they will send out the telecom authority to locate the offenders
and isssue them a ticket.
So you should not operate your links/access points on frequencies where there is RADAR, and the DFS is taking care of that.
It only becomes a problem when the DFS software makes false decisions, but we have not seen proof of that in your case.
As an ex MNO radio engineer and current weather service employee I’d …
[joke-mode=yes]… find rogue wireless operators and execute them on the spot.[joke-mode=no]
Seriously: I can’t understand certain wireless operators complaining about recent restrictions regarding use of free radio spectrum. I’d understand if somebody was complaining about new restrictions when using paid spectrum chunk which originally came with less restrictions.
I can remember outrage among weather radar crowd when 5GHz spectrum first got allowed for unlicensed use some 20 years ago. First problems soon started to show so current “witch hunt” is only (one of) climax(es) of the whole story.
@pe1chl Ok, let’s say you are right. What now I can to do to resolve this? My AP is set auto freq, my stations is set auto freq. So, what to do in practice to resolve this?
Use a 5Ghz channel that is not in use in your area, one not under DFS restriction.
Make a channel list and put those channels in that are not affected by radar.
This requires some manual work, the channel list editor in RouterOS is not very user-friendly, but when you have done it once you
can copy it to other access points via the commandline.
So, I need to set no_country_set and put frequency like 5825..
Stupid rule, stupid law, stupid country..
Ty @pe1chl and @pcunite.
Would it not made more sense that the log would indicate the Radar Identity rather than just “Radar Detected” so that we can trace if we have
(1) Actual Radar present
(2) Co-location interference
(3) Nearby operator on same frequency
As a WISP I would question the wisdom of allowing dual usage of frequencies that both Radar and wireless operators use? It would be best to remove these frequencies from the unlicensed band.
Main issue with radar detection is the unreliability. If it only detected WX radars and nothing else, it would be fine. But for that, radars would have to transmit some digitally signed beacon that could be verified to be 100% reliable and avoid the spoofing. Currently entire detection algorithm relies on detecting series of pulses, it’s too easy for it to be triggered by noise, non-WIFI signals and non-WX radar devices.
In the end it’s a government mandated backdoor that will turn off your WIFI and all you need to trigger it is $2 radar module from China. The idea of protection for WX radars is good, but actual implementation is more than dubious. Getting a lot of radar detection errors on your channels? Maybe your competitor put this small radar module somewhere near your AP and is just having a good laugh…