My Phanom 3 SE lost signal around 150 m. I tested it in open areas free of interferences. I just tried to go as high as possible right above me (earlier it was 500 m).
What could be the problem and what can i do to fix this.

Are you sure you're aiming correctly?

you must check in your city where is big 5 ghz antennas my 3 se fly in Poland ue 489 m but in my city where is internet provider on 5 ghz phantom 3 se fly only 340 meters  

Straight above you is where the signal is weakest.

your FW ...u APK Version? just update the latest ?

I have exactly the same limitations. In Germany (CE region), wide open country side, no visible obstructions/possible interference.
Strange enough others in CE get much better results, even without antenna mods. (I'm on the original antenna)
I gave up on the P3S.
Anyone wants it?

[Edit: I bought it in L.A. and flew it in Maui. I never met the limitations there that I have in Germany. I know - US is FCC...]

Just testing the last version 3.1.34 FCC Mod . it is better than earlier versions

People are suffering using CE mode ..  just try FCC  and feel the difference

Thanks to Bro Siam

Here in Portugal the same Bad Bussines Pantom 3 SE

It is not recommended to fly above the head directly as the signal might be obstructed.

I will make up the third person to point out that directly overhead is the worst position to fly, the antennas in the aircraft are in their worst position.

Thank you all. So it can be because of the cell towers and local regulations? (Im running the latest App and the drones firmware is updated.)

I have same issue for phantom 3 Standard, but at 30 - 40m higher I have losing signal and 30- 40m distance I am losing signal :-(