I noticed in one of the alternate versions of the uBITX software the WSPR mode was implemented by sending the frequency shifts to the SI5351 chip registers. Have not looked into if the SI5351 chip, and the related uBITX software, can reliably change the frequency at the rate needed for RTTY, but if so, adding a RTTY mode to the software could shift the frequency digitally using the CW key jack to make the mark/space frequency shifts.?
