I made 20W amplifiers in enclosures from WiFi amplifiers.
PTT is controlled by means of a 50R cable which as it transmits attaches the stabilizer to the BIAS transistor.
Power input max: 0,9W,
BIAS BLP9G0722-20G: 460mA for 28V.
Supply voltage - power out:
28V - 20W
24V - 16W
20V - 11W
13.8V - 5W
PCB: FR-4 (no: PCB ROGERS), thick: 0.5mm.