Hello, we have the new cortex with the new controller and are using the wifi usb plugs for the wireless. If we go about 20 feet away it looses range and we have to resync the controller to the cortex. On the controller it does a sequence on red lights until we sync it.

Two suggestions:
- you could hook up the 9V backup battery to the Cortex, if you haven't already
- you can use USB extension cables to raise the USB VEXnet key higher on your robot