thanks, Waydownsouth, for that info! I admit I didn't know that the modulation system was also changing. Fortunately, from what you say, it's not to a QAM system - which would decrease SNR and give some problems - but I'd have thought that increasing phase resolution would demand much higher demod standards inside the new receivers, not least much better clocking, etc.
Yes, I can see that "heirarchical mode" would be possible, and both combined on 1 transponder seems a good idea, must look up the details (when I've time ....).
(added) oops I'm wrong again (!), having just looked at some info on the new DVB-S2 standard at:
www.tandbergtv.com/pdfs/dvbinfo.pdf .
Is seems there's a large variety of different new modulation options - including QAM ones - but combined with newer fec error codings, to keep system SNR ("link margin") roughly the same!
(Simply going to QAM - with no other change - would of course lower the link margin, and 8psk will require better demod resolution inside the receiver!).
(Sorry, poor terminology, I should say "APSK", for combined phase/amplitude modulation, "QAM" is stricly the version used in DVB-T, for "Freeview" etc.).