Triple chain SXT-HG ac.JPG
Does it persist a Wireless interface reset? or reset to no defaults? Have you tried the current channel version (not RC) to rule out a soft bug?
Wireless reset, full reset, downgrade to 3.34.3, 3 chains, each time again…
So this must be a 3 chains unit. However no documentation stating this…
Will have to wait for Mikrotik staff to speak about the matter…
If I were you I couldn’t resist getting a second one and try a PTP… (or opening it up to see if the antenna itself comes with the three polarizations. 
Ok, there is obviously something wrong here…
I bought 2 exactly the same SXT-HG ac units.
One has 3 chains, the other only 2!
One is Model name “SXT G-5HPacD” (=3 Chain) and is located at site 1
The the other has “SXT G-5HPacD r2” (=2Chain) and is located at site 2
On the top bar both show the same name.
Units are aligned towards each other to make a backhaul link, only 305 meters in between with free line of sight.
According the Mikrotik wireless Link Calculator the signal on both ends should read -33
But signal on site 1 is only -47 where site 2 reads -36
CCQ is also only around 70-90% where according the spectral scan the used frequency of 5700MHz is relatively clean.
Imho this unit at site 1 (with the triple (!) chain) has an issue. Something must be wrong…
Oeps, forgot to add the pictures.
SXT-HGac screendump.JPG
Link Calculation.JPG
All SXT units are dual chain. If RouterOS shows 3 chains on an SXT, it is a calibration issue. The unit should work normally though. If you are having some problems, you can send it to RMA for replacement.
Ok, is this some error made in the production process? Can we correct it ourselves?
We contacted the supplier but it would interesting to know what could cause such “calibration issue”?
Do you agree that the signals for a LOS link of 300 meters the signals indeed should be much better?
Calibration can’t be corrected by distributors or users. Calibration data is loaded into the chip, so device knows allowed power and such things.
Ok, thanks. Definitely RMA…