How to connect/bridge two subnets within the same router

[hkblue]

@psherman Thanks a lot!

I just read this link

How to use OpenWrt as a wi-fi repeater using a different SSID

i didnt see @bill888 message til now, but yeah i studied that page and when i just connect to the wifi network it works all right, that was the first thing i tried, i tried setting the country code and leaving it on driver default and none of those options do anything different in any scenario, and i thought limited wifi was just having bg and no n compatibility? but honestly not surprised if it doesnt let me have several APs, i might try to have two acess points at the same time to see what hap…

My router, tp-link archer a7 ac1750, should support this, right?

I tried several times. Sometimes, the 5G radio can see the upstream "hjx8" wifi. But just when I try to connect to it, my router disconnects/restarts.
So, I feel editing the Openwrt network configure file directly to add the 5G radio may solve my problem.

Also, are you sure that use the same radio for up and down will reduce performance?
Could you explain this?