Hi Gary. I'm already in conversation with the developer Simon. I'm also trying to help him out by trying to understand what the exact CAT commands issued by VarAC are for these two different operations in VarAC but if nobody has the information then no problem. I will try and deduce it from monitoring sent CAT commands across the COM port.

Hi Gary. What I am seeing is that if I "sniff" the cursor on the display of SDRC moves to the sniff frequency, but from listening to it it's very clear that the receiver is not actually changing frequency, unlike the full slider frequency change, where the actually frequency of the receiver does change and can clearly be heard changing. What CAT definition are you using in VarAC to drive SDRC, or are you using OmniRig? I am using CAT with the Kenwood Generic definition. For SDRC it should be TS2000, but that is not available in the VarAC CAT files, although I don't actually think this is the issue? I'd like to know the actual exact CAT commands sent for each operation because for me there is definitely a difference between the two commands, even though looking at the sent CAT commands in the SDRC CAT Monitor tool, the two commands look exactly the same. But the result (for me) is clearly different for some reason. That's why I'd like to be able to see the raw CAT data on the Com port. Operationally it's no big deal but I'm interested to know the root of this behaviour.