So I bought a DJI Phantom 2 Vision+ (V3), second hand for a decent price. Everything works like it should. It takes off. It hovers. It moves up, down, left, right, 360 degrees, whatever I tell it to do it does it... but it wont go past about 650 feet without losing Tx signal. I am using the DJI vision app on a Samsung Galaxy Note 4. The receive and wifi extender have been modified to accept 3 9dbi Omni directional antennas. 1 on the remote. 2 on the wifi extender. I have only had one hiccup on the video feed since I have flown it where it lost feed for a brief moment. But as a novice phantom flyer and being a little nervous I never got real high in the air, altitude wise. But as time has gone on I get braver and depend more on my video feed rather than physically watching where the phantom was flying and obviously with this I got higher... I finally found out that at around 500-550 feet I loose tx signal but I can regain it with flicking the S1 and fly a little higher and then loose it again. Flick the S1 and get the signal back and fly a little higher before I loose it again. So and so forth fighting my way to about 630 feet before it tries to fly home and wont let me take control back until it gets back down to 600 or so but its a never ending battle. But it seems 630 is my cap right now; whether I am flying right on top of myself or 250 feet away. I have tried orientating the antenna different ways. Point the receiver different direction. Nothing changes. I am not sure where to start on this because technically there is not anything wrong besides range of reception. I have tried this on my grandparents farm with clear land and 120 acres, in my rural neighborhood with generally flat ground, as well as open space around a near lake. Same result every time. I have logged into the software and checked the settings. I have reset them to default values and made sure everything was up to date. I set the max altitude and distance at 5000 feet. Set the S1 and S2 switches. Its set in NAZA mode. Everything appears to be calibrated. I am not flying in a no fly zone seeing as my buddy with his Vision 2+ can conquer 1000 feet in the same neighborhood without a modified receiver. I have 3 batteries. I can slap a fully charged battery in it, and directly go straight an altitude test and its the same result with a full battery. This is all pretty new to me so I am not sure where to check or what to start with or even how to trouble shoot it. Any tips, tricks, advice, and help is greatly appreciated.