It may be worth turning IOC on. It's a handy tool to have, especially if you get disoriented on which way your phantom is facing. I'm really not sure why it's defaulted off on the FC40. You do this in the naza assistant on your PC. You can look over YouTube and see all about IOC. YouTube can also help you link the phantom to your PC.
You can also check your firmware in the naza assistant. Another thing that some new users will do is set limits on how far it can go away from the home point, as well as his high it can go. If you're really new this makes it stop moving away at a certain point. There are pros and cons to it, but it's something to think about. You can always raise the limits down the line.
One last thing, if you're in the US, is to change your controller from CE to FCC mode. This basically boosts your controllers transmit. It's done by adjusting a screw on the back of the controller. Once again YouTube can prob help you with that. This is legal to do in the US, and probably some other countries, but I don't know specifics.
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