Marc has figured out what was causing his Mini Tricopter to fall out of the sky. Fortunately FrSky have a solution with a firmware update. They have a good reputation for listening to their customers. Well done I say. I am no expert on this subject but the oscilloscope is from www.bitscope.com and it seems to work well for me. I chose it because the software was cross platform.
The rest is here:
RCHacker #23 – FrSky D4R-II PPM Problems. Investigation and Solution with a KK2 and Bitscope.