Using SunSDR2 DX with the stealth loop from I3VHF.
www.ciromazzoni.com/the-stealth-loop-by-i3vhf
Upgrade the ATU to v4.0.9
Connect null modem cable to the ATU and computer
Configure ATU to use CAT MODE 3
In SunSDR CAT menu enable ECATv1
Now the loop is tuning either by FULL AUTO, SEMI AUTO or DISABLED depending on what you want.
73 de LA3QMA