RT-AC5300 5GHz channels issue

[BiOs2k]

Hello all, I just bought a used RT-AC5300 to have a dual 5GHz band capability and dedicate 1 band for backhaul my DDWRT as wifi Client.

I flash the RT-5300 with the latest Merlin firmware.

My issue is that when I go into the Wifi config, the 5GHz-1 only give me lower channel (36-40-44-48) and the 5GHz-2 only give me higher channel choice (149-153-157-161-165)
I want to be able to seet higher channel on the 5ghz-1 too..
I've been searching on the internet a solution.. I don't understand why I can't get all channel list on both 5GHz Radio?

I've try many nvram set command but never get a fix to have complete channel list on both radio.
Anyone can help me to understand why and is there a way to get full channel on both 5GHz-1 and 5GHz-2

Thanks.!

 

[Tech9]

This is how "tri-band" routers with 2x 5GHz radios work. You can't have 2x radios tuned on the same channels on single device.

 

[BiOs2k]

Thank You Tech9 for the reply.
Ok I understand why, on 80mhz there is only 1 channel available on the UNI-1 and UNI-3. and I guest I can't get extended channels whitout flashing ddwrt..