You’ve enabled both chains, on both sides, with two antennas or a dual-polarity antenna (is this what that “duplex” antenna you mentioned is?), and you’re using the extension channel with 20mhz width?
Look at the tx/rx datarates and see if they are at the max. what are you using to speed test with, and do the CPUs hit 100% on either side when you are testing? (built-in bandwidth test with tcp? (in which case it might be a cpu problem) what does it get on udp?)
If you put it in 802.11 mode is your CCQ always 100%/100%?
If its not always 270/300mbit on the wireless link, you could try each chain on separate physical antennas with some space between them.
dude, read from the start. Its in my lab whit an distance of 20m
and its an ordinary wds setup whit wireless N mode and nv2 whit tdma 1ms. dual chain whit above control.
outside the lab we have an ptp link thrue some trees where we use rb711 whit the same config and achieve stable 40mbit duplex upd traffic. this is just because we can just use one chain.
This link only works whit r5.0rc1. when we used 4.11 the signal and the ccq was horrible and not stable. whit r5.0rc1 its stable and havent drops anyting for a week.
the distance is about 500m whit an signal -68 and ccq about 80