I found most of the delay.
I automatically turn on RXID and TXID in my macros to select the modem protocol.
So fldigi must send the ID at the start of the transmission.
Not sure why it then sends something at the //end// of the transmission, though. Perhaps an essential part of closing the RSID protocol?
BUT...turning off RXID and TXID reduces the time to drop PTT from 5s to 2.2 s, so that is OK. And it means that PTT will always be held on after a transmission, if TXID is ON.
73 Rich NE1EE
The Dusty Key
On the banks of the Piscataqua
Rich NE1EE