raulico
and i would like to know hot to use CA on the lte interface.
When you enable that bands what are in your Tower-s/BTS and your ISP send signal then that Bands can be connected.
You can connect to single bands to discover all bands what work with your sim card.
Usefull is a /interface lte cell-monitor ... feature !.
I see only B3 and B20 (20 and 10 mhz) , but how can i force which one and how many bands to aggregate?
CA is receiving from your Tower, your UE send to BTS what he have enabled bands and what CA he can use and Tower response with CA activation - it's very general answer for complex technology.
check for example list of bands at wiki
https://en.wikipedia.org/wiki/List_of_LTE_networks or use cellmapper and select country&isp to see what Bands he use....
i can select bands on the lte interface 1+3+5+etc etc, but not to specify which and how many.
Every ISP per every country has own policy... CA is receiving from BTS. You can do a selection a primary band by CellLock feature but all other bands are automatical assign and very often dynamic, means when you download stg then then you see that CA active.
Another question is, why i should use a beta os, and i can't reverse to 6.xx?
Because that RB use and work only 7.xx who not have a stable yet. Ask MikroTik directly.