Following a suggestion in another post to carry out a transmitter calibration using these instructions http://wiki.dji.com/en/index.php/Phantom-Transmitter_Calibration ie not via the RC Assistant I followed the reasonably clear instructions and managed to enter the calibration mode however this was as far as I got. This was the procedure as I interpreted it: (1) Set S1 and S2 to the UP positions. (2) Turn on transmitter while holding the throttle and Pitch controls in the UP position and get a "DI - DI DI - DI -DI DI" tone. (3) Continue holding the throttle and pitch controls in the UP position and move S2 to the CL position. A "DI" tone indicates calibration mode has started. (4) Release the pitch control and pull the throttle control to the central position (ie release both controls) and you should hear a "DI" tone. this is where it went wrong for me, I didn't get a "DI" tone at this point so couldn't continue. Have I interpreted the instructions correctly (presumably not), where have I gone wrong?