RE: Interchangable frequency crystals
I flew an XPD-8 with a "park flyer" single conversion receiver with an 800' range...
BIG MISTAKE.
The little jet was very fast and quickly hit that limit which was really closer to 600', then tumbled out of the sky....
( Yes I could see it, no I could not tell which way it was oriented though... as I sometimes fly via response to inputs... ).