Ran my P4 tonight with copper windsurfers, lost full connection @ 11,850 Ft.
Used to run my p3p, with same windsurfers to about 13,000ft with almost full singal. Only reason I would return was battery.
Both flights were on the same path, with a clear line of sight.
P3P returned at 23% battery
P4 returned with 55% battery (flew 25% in sport mode, rest in gps)
A bit disappointed. The 10 flights I had with the p4 I lost signal during low flight. In closer ranges, I have the fly the p4 100 ft higher to maintain the same signal as the p3p.