Gentleman.. the Amsat Organisation is clear.. they Will Not allow Any FM in qo100
NB USB is currently the only Working solution and the rest is not practical...
Totally agree with you.
Someone has to work real ATV and DATV to know what talkback channel is and how to use it.
Simply said, grab a mic and talk instantly, without complex equipment, tuning, and voice delay.
If these conditions are not met, there is little point of talkback channel.
I know that Amsat won't allow NBFM, but the reasons given here are not convincing.
NBFM still occupies less bandwidth than any RBDATV, and it doesn't need to be S9 R5 to be used.
Moreover we saw abuse on all modes and bands, so this has nothing with normal ham operators.