The Detrum DT9 Transmitter and SR86AG GPS receiver used in this video were provided by http://bitgohobby.com

Bitgohobby sent me answers to a couple of frequently asked questions they receive on the SR86A/G:

Return Home: There is currently no programming option to change the circle diameter or altitude.

Circle Diameter: 100m (I believe that to be accurate based on the flight test).

Altitude:
If altitude is below 60 m when RTH is triggered, aircraft will climb to 60 m.
If altitude is above 120m, when RTH is triggered, aircraft will descend to 120 m.


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This is a video demonstration of a radio controlled airplane using the Detrum SR86AG GPS Flight Controller focusing specifically on the Return to Home capabilities.

One point I didn't really make in the video: This entire flight controller system is configurable directly from the radio. No scripts, no wires, no drivers: Just turn the radio equipment on and make the necessary adjustments.