BTW I can't understand the use if FT4 in satellite even in HF.... I always thought that FTx modes where developed for extremely bad propagation >conditions or for those who have a very poor setup to help them enjoying ham radio.
Ham radio is a wonderful thing in that we can enjoy various technologies developed over the years ... we can continue to use just about any modulation scheme we have traditionally used except that from a spark gap transmitter. We can also experiment with new techniques to trade antenna/transmitter/battery size for modulation complexity. This wonderful article from James Miller shows the promise of good digital codes:
The article is 30 years old now, I am surprised we still use so much SSB/FM/SSTV!
de KM1P Joe