im using this wireless setting but my station cant get more than 10 mbps with -55/-49 signal strenght, 54/54 ccq and %55 signal to noise can anyone tell me what am i doing wrong?
Quite probably the channel your AP decided to use is used by another AP nearby. Which creates lots of noise. Hence low ccq (ideally it should be close to 100 while channel is active) as well as low SINR.
The problem when using nv2 is that "normal" 802.11 APs and stations might not detect your AP and consider channel as not used. Which will cause mutual interference.
thanks, I chose the one with the least usage using the frequency scanner, but the result was the same, or even worse. Do I need to find the best frequency by trying?
To me, this frequency seems pretty bad ... so yes, try to find another one.
Tied to what I already wrote about nv2 being possibly "invisible" to other APs: many (if not most) APs are configured to occasionally reselect frequency to find a less congested one ... which means that conditions around you can change. And your AP being "invisible" makes possibility of another AP select same frequency as your AP is using quite a bit higher.
U-NNI 3 (and 4) bands are not widely supported ... so it might be better if you choose to use one of those high frequencies (around 5750MHz).
When setting fixed frequency and superchannel: beware of DFS frequencies and possible interferences. You really don't want to get a visit from your local RF agency (or even military) because your gear might be jamming some important radar.