Recommended Setup
The recommended doppler control solution is to use the in-built rigctld server and Gpredict. If you are using windows there is also a SatPC32 virtual CAT implementation if you prefer however the lightweight Gpredict integration where you save the radio memory settings and then load before engaging doppler control is better in my opinion. The memory functionality within Pycom radio controller includes storing operating modes, filters, RIT offset and tones.
Example Operation
Full duplex doppler control for RS-44 linear satellite via Gpredict and Pycom. The first couple of minutes is waiting for the satellite to come up and then tuning in using RIT via the RC-28 integration; once you can hear yourself on the down link, no further RIT is required and you can use the Gpredict tuning to move up and down the satellite bandwidth looking for a contact. Once you have them tuned in, you can simply transmit and then log and upload to your log server all from within the app.