I have a question, if I have 2 sets of RBK753 (i.e. 2 units of RBR750 + 4 units of RBS750), I will use my own Ubiquiti router and all Orbi are function as WiFi Mesh APs only. May I know if I can configure one of the RBR750 as satellite of another? so that I can have 6 units of Orbi are running mesh WiFi. Thanks for answering.
No. The 2 rbr's won't integrate together. and you can't make the RBR act as a satellite.
You can set one up separate as its own ap (if its hardwired in) but I'd put it on a different ssid and make sure its on a different channel to prevent interference.
