RE: hitec receiver not compatible with 9C?
The original poster thought that changing the Rx's Frequency crystal can change the modulation shift and the point is changing a freq. crystal will not and cannot change the Rx's modulation shift. What you are referring to is an internal changeover and not within pratical application of the ordinary user.
Your statement will cause no end of consfusion to that user. Changing a RX crystal Will not alter a Rx's modulation shift.
John