Using DSB modulation to Tx a FT8 signal means that you will end up transmitting a second FT8 signal a few KHz away from your intended one.
From what I understand, this will have legal issues also with FCC, it will not be characterized as a 'spurious' but it will certainly be characterized as a 'Out of Band' (OoB) whereas a different method of what is legal or not applies than in the case of spurious, but will definitively be IMHO falling into the non-legal.
Of course based on IARU's determination of what signals should be used in the digital segments, it is obvious that this is not allowed as all digimodes are mainly narrowband.
73,
Christos SV1EIA
