https://mikrotik.com/calculator
Here you can play with diferent antenas
Thank you for right direction. MTU for IPv6 worked.What is you PPPoE interface Actual MTU?
Anyway, take a look on this topic too: viewtopic.php?f=2&t=169757&p=832247#p831447
Leds work on boot. But after router come in working state they switch off.Upgrade from 6.40 last rc to 6.41.3 my 2011UiAS-2HnD all leds on active interfaces are off, Except led on eth10 is on witch is POE Out and is active. Is this normal or something wrong with this.