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MCS and chains

Posted: Wed May 09, 2018 12:21 am
by lcpwc
Hello,
most Mikrotik devices have 2 "antennas" (chains).
Based on 802.11n, only MCS from 0 to 15 should be configured as "HT supported MCS" when using 2 spatial streams
I noticed that Winbox allows to select any MCS without considering the number of "chains". However, in the forum I found that the board doesn't care MCS-16 to 23 if it has only 2 antennas.

Does this mean that even if I configure up to MCS-23, RouterBoard announces only up to MCS-15 when using 2 antennas OR up to MCS-7 when using a single chain?
In other words, is there a performance benefit in configuring proper MCS values based on the number of spatial stream (max MCS-15 for two chains) or the board automagically announces proper MCS values without looking at the configured values?
Thanks

Re: MCS and chains

Posted: Wed May 09, 2018 5:06 pm
by Aufan388
You are correct.

MCS-16-23 are for a third chain. Just because they are there doesn't mean they are usable. The options are just baked into the RouterOS and no "per device".
Each chain (antenna) has 8 MCS options, so 0-15.