First steps to re-design PA

As you may have read below, my QRP PA failed. Actually it failed twice and cost me money since I just replaced the amplifier module with another one, which then again failed - no idea why!

So I have decided to build my own amplifier. Here's me breadboarding the first stage



I decided to use the common RD16HHF1 transistor, I discovered that it has a grounded tab, connected to the Source of the MOSFET. Good. An amp stage using this will give about +20dB gan. So for an output of +40dBm 10W 22V, I will need an input drive of 2.2V. I will need a preamp to get up to this level from my VFO 0dBm output. I chose to try a very simple circuit. This preamp seems to work well and is giving me the drive I wanr for the output stage. Here's the planned circuit



Moe news later when I have built the complete PA. Should get up to 10W output...