SXT Lite5 problem.
During the below zero temperatures the device is not connected to the station under N 20/40 Mhz in the log there is no information about the attempt of connection to.
The unit has new 6.7 software and bios 3.10.
This failure occurs only on SXT devices Lite5. During the last frost killed more than 20 pieces of equipment.
Translated from Polish to English google translator 
Is there on the sxt snow or ice
If so wipe this off and see if they connect with each other
Maby ice in the sxt device
- Does this happen with regular 802.11 or with Nv2?
- What kind of AP do you have?
- Does reboot help?
- Does the “scan” show the AP or any other AP devices?
1 ) Currently , the units operate only in NV2 , the problem with the device appears like a boomerang when the outside temperature drops below zero .
2 ) My AP operating in 40 MHz mode N and N MIMO 40 MHz is:
40 devices OmniTik U- 5HnD
20 SXT devices SAr2
15 pcs 711A - 5Hn - MMCX
other devices work only in a 20 MHz
3) If the device is mounted on the outside and the temperature is negative reboot the device does not help just does not connect and that’s it.
4) When you scan Lite 5 SXT device at the beginning there is a pair of devices while scanning stops for about 3 seconds and then appear again next device stops after some time appear next AP and that to which it should connect to the device but does not connect the .
Devices removed and examined at room temperature work ok .
The problem occurs only on the SXT Lite 5
Part of the set of devices only damaged N 20/40 Mhz while scanning AP does not see in the range of 5320 to 5680 .
Try use the sxt’s on 20 MHz bandwidth this is more stabiler than 40 MHz
We have possibly found an issue that could be causing this. We will provide a test-version hopefully tomorrow.
Ja zrozumiałem 
No ciekawe co wymyślą : )
Any news about that I have this problem now temperature drop below -10 - no snow yet and this only happen on SXT Lite 5
When set to 20Mhz seem fine until I use 20/40 Below/Above is there fix?
This problem is fixed in newer RouterOS releases. Please upgrade to the latest RouterOS and the issue should be gone.
On a SXT Lite5 I have the same problem as Lakis, I was running on 6.22 with 40Mhz width.
Upgraded to 6.23 and did a reset-configuration… still the same.
With 20 Mhz everything ok.
please contact support@mikrotik.com about the issue with 20/40mhz width.
Outside -10 SXT 5nD r2 (lite5) failed to connect using channel width 20/40MHz OS ver 6.9
at 20Mhz channel width no problem at all, unit connects in a second
I m using protocol nv2 signal -54/-56, OmniTik as AP
After upgrade to 6.24 unit need 47min to establish connection with AP
this is print screen from unit log
Problem is not entirely solved