Is possible send DATV to QO-100 with Adalm-Pluto and the SG Labs 20 watts power amplifier? What is the recomended hadware for it?
No,
the SG Labs 20 Watt pa is not a DATV pa!
The operating point of the quiescent current must be increased for DATV for linearity. The power at DATV is then a maximum of 5 watts, you need a very large dish, 1.8m or larger to be able to transmit with small SR at all.