Last year I have build 3 QRP-LAB U3S multimode beacon transmitters. The goal was 5W on all HF and 6m to be used as WSPR beacon on a remote location in PY This goal was never reached. the QRP-LABS 5W PA could only make 1W at 50MHz 3W at 28MHz it delivers 5W at the low bands only. The QRP LAB "5W PA" uses the IRF510 or RD15HVF1 with 9:1 wide band transformer out As simple as can be. The RD15HVF1 is a VHF 10W FET it should easy deliver 5W at all bands up to 144MHz f.i. the excellent 144MHz XVTR (@ transverter-store) uses the RD15HVF Its output is over 10W But whatever i tried with the QRPLAB 5W PA at 12V 3W at 50MHz was the max I need a conservative reliable 5W that can run 24*7 I gave up the time consuming experiments had to accept the 3W at 28 MHz 12V Recent found some eBay RF amplifiers that looked promising. The 2W 1-930MHz f.i. 2 of them could make 4W? But 0.5W maximum carrier at 5V...
Ham radio in JO33hg31 53.15N 6.35E