it's XBee-Pro 900 RF?
workink power (50mW?)
the data transfer rate is almost constant before you lost the signal? If no, can you create a test? (distance vs power maybe...)
It's power from the main power? not drain…"
OFF
I only ask. why "everybody" using GoPro? No better, or another solution? (what do you think about FlyCamOne?) I not have experience, but in the near future I want to create my own drone :)