Before I sent my H back for compass errors, I was doing some distance testing. I would loose video and telemetry around 3000 to 3200 feet. At 3500 feet RTH was auto activated. Not bad for stock antennas. My real problem was seeing the H with out the help of my P610 60x zoom lens. If there were some nice white clouds behind it, you could clearly see a black dot. If I was in front of some darker sky forget it. I have RED flytron strobe on the rear of the landing gear that helps some. Trying to remember what tree, phone pole, or other land mark I am above helps, but very easy to totally loose site at those distances. What do you guys do to help locate your H when at extreme distances.