to switch the single antenna I use an external changeover relay driven from the Tx pin on the U3 Tx, via a driver transistor.
I then set the U3 Rx sequence to follow whatever WSPR Rx slots I want. Say for example 160m, then 80m, then 60m.
Then follows a CAL period. I set the length to suit what I am doing with the U3 TX. Explain later.
Now I set the U3 TX sequence to ‘RX’ mode slots to cover the time i am receiving above, slots 0,1,2. = RX mode any freq, does not matter.
Then for slots 3,4,5 etc, I set the U3 TX to my WSPR bands, say for example 160m, 80m, 60m, setting freq and LPF settings if multiband operation.
Then follows a CAL period for this Tx, set as long as the U3 Rx slots last.
So for both Tx and Rx U3s, we have a total of 2+2+2+CAL for the FRAME time.
I set CAL on both for 10 240 (4 minutes) and FRAME to 2+2+2+4=10. (10 00).
To start both off, manually set the TIME on both and start them at the same time (right button press).
This works well for me in a Tx and Rx WSPR bandhopping sequence. If you are doing it on one band only just repeat put more ‘RX’ slots into your Tx to pad it out.
Hope this is what you want.
73 Ken G4APB