Hi 

I set up 3 deco hubs from my super hub 3 VM. 
My original set up was super hub in front lounge with Ethernet cable running to net gear nighthawk in back lounge. Back and front lounge very good speeds (c250mbps WiFi) Upstairs was very poor signal. 
I put super hub into modem mode, followed instructions and got node 1 up and running. Next I plugged in the Ethernet cable in the back lounge (other end still in super hub) and connected that. Finally plugged in third M9 upstairs. 
Results very poor. Very weak signal in all areas apart from front lounge (master) with download speeds all over the place (2mbps up to 100mbps).

Anything obvious I'm doing wrong?

thanks