I have missed point. What does it mean that RB has wireless with two chains? Thanks.

802.11n allows the use of multiple "chains" (antennas) for some of it's advanced features. It is the core behind MIMO setups.

If you want to know more, read up on 802.11n. Rick Frey did a great presentation at MUM US10
Video: http://www.tiktube.com/index.php?video= ... wplooJFKD=
Slides: http://mum.mikrotik.com/presentations/US10/RickFrey.pdf

Thanks. I will examine it more closely.

MIMO means multiple input, multiple output. Basically you can use Dual polarized antennas (one polarization for each connector) and have increased speed. Dual chain is also often referred to as 2x2 MIMO

Very late to this thread, but is tiktube still available?