I have updated my description about the MHL21336 amplifier at www.dd1us.de
Hi Matthias DD1US .
I made this amplifier using your schematic. I bought the module in september 2019 (Ebay) but i assembly this week. My module isnt counterfait. I supply with 28v in both pins and i have approximately 2 until 3 watts ( sorry, but i dont have how calibrate measurement equipment ).