I also have the D72 and D74. Full duplex in the context of these radios means while PTT is enabled and you are speaking into the mic, receive on the second band is also enabled and ideally you can also hear yourself on the downlink simultaneously. D74 does not have this.

Regards Dwayne NA6US

I have logged well over a 2000 satellite QSOs all full duplex using a TH-D74a on RX, both FM and SSB satellites.

So what is your question?