Yesterday during a Ground station 500m range mission, i lost Control Link at arround 490m, so i checked my battery voltage and everything seem ok, then i tryed to see if i could switch to CE mode and screwed the lower screw on the back of the transmitter counter clockwise, turned controller on, 2 beeps again. So i plugged controller into pc and noticed it was still FCC mode even with the screw counter clockwise, switched to CE in software, turned off controller and back on, 1 beep. So i putted the screw in FCC mode with software still in CE, turned the controller, 1 beep with screw fully clockwise in CE mode... Do anyone know what is the real FCC mode and real CE mode, because now im confused, i can get 2 beep with screw in both positions, and 1 beep with screw in both positions, controller came stuck in 2 beep mode with screw fully clockwise and only give me about 490m range. And the screw look like its doing nothing on the beeping. I wish i add something to check rf power of my controller in all those 4 possibilities... Anyone seen this ?