I thought with omniRig the ft874 it works.
Doesn't and can't: omniRig 2.1 makes only endless error messages. Earlier omniRig don't PTT with RTS in varac. FT847 needs RTS PTT on HF-data-in, when not PTT on HF-data-in it will not modulate from HF-data-in. So varac CAT file might do it but doesn' find ft847. OmniRig "works" but does PTT with CAT commands (no modulation) and omniRig can't switch RTS (would modulate) with varac.
So it only can "send" without modulation.
The "best" but also crazy was that varac with omniRig and ft847 switches PTT permanently on after it received CQ (??? funy ?). Fortunately PTT without modulation makes no significant SSB power.
So pleace, if CAT ft847 could be solved (and found in menu), my old ft847 could also participate.