Split VFO not holding settings

Lasse Moell

While having split enabled and TX on VFO B, changing band and then returning will have both VFO active but TX is magically moved back to VFO A.  A bit annoying as I have ended up transmitting on wrong frequency.  Not sure if this is a bug or done on purpose...
Running s/w version 1.10.15

Tim - W4TME

On purpose.  Change bands removes the "split" transmitter designation off of B and back to A.  This is the default behavior of PowerSDR too.

Pat N6PAT

I was going to ask the exact same question. It is annoying as I have also found myself transmitting on A when I return to the split band. I've gotten more than a few angry messages from some folks yelling "Up Up!"

My feeling is it should return to the previous state that it was when you return to the split band and B should be set to TX

Pat N6PAT

But why is it done like that? What is the advantage of the system changing the TX split configuration? Doesn't it make more sense to return to the configuration that was in place when you return to the band?  What is the purpose of the change?

Tim - W4TME

It is the slightly lesser than 2 evils situation because it complies with our premise of making transmit function under positive user control after a radio state change.  

For example, you are in split and operating.  Then you change bands and operate someone else in simplex mode (a radio state change).  You may not change bands back to the original band you were working split for a while.  You change back and persistence makes slice B the transmitter.  Since you did not directly control the state of the transmitter, you forget that the transmitter is on a different slice and end up QRMing a different frequency.  

The transmitter is put on the active slice after a band change to prevent the possibility of QRM.  If you want to operate split again, the operator has to make a change to the transmitter state (an example of a positive user control operation).  There is a use case for leaving it in split mode too, but as I noted, this is the slightly lesser than 2 evils compromise.