I understand why most people dont use FGCom. There are some drawbacks or bugs.
1) If i set the frequency to ATIS and hit 'space', FGCom says "[SPEAK] unmute mic, mute speaker", but i hear the ATIS.
I think FGCom and FG itself work not fully together.
2) I cant change the radio with 'shift-space' in FG 2017.3.1. FGCom works only on Com1.
3) 'shift-space' works correctly in FG 2016.4, but set allways the property 'ptt' under 'com[0]' (never under 'com[1]' if it set too)
4) If you set your comms to different frequencies and there are other pilots or ATCs talking on both frequencies, you hear only one call. FGCom can only work with one stream.
I cant fix this problems, sorry. I only know C but not C++. This code is too different.
Jomo also stated that many pilots forget to say his/her callsign and he can see on Mumble who is talking.
Originaly this is a problem of the pilots. But FGCom can also send the aircraft who is talking to OpenRadar, so that on the radar screen a trasmit sign will be shown beside the aircraft. I think this will be a great help for ATCs.