I started measuring the gain of the amplifier at different frequencies
Using a signal generator at 10 milliWatt I measured output at different
output power (mWatt)
I decided to try and see if I could optimise the amplifier
After adding two tuning capacitors at the input I increased gain from 11,7
dB to 18,9 dB so quite a lot difference
Power output increased to 200 Watt max.
I tried adding a tuning capacitor on the output and power output
increased to 250 Watt with 17 ampere total current, I replaced this with two
small SMD capacitors of 5,6 pF on each output of the BLF861A so 4 in total
With 5 watt power drive the output power was 250 Watt a gain of 17 dB
I got some questions to further explain what I did so here is a bit more
I added on the input of each transistor a trimmer see the picture
The maximum capacitance of the trimmer is 45 pF
I added on the output of each transistor two SMD capacitors, nothing
special, of 5,6 pF
On the picture below is visible were I did put these,
the capacitor on the right is mounted on top of the capacitor which is
already on the circuit.
The way I mounted the coax cable:
total amplifier ready for use,
the output dummy is mounted on a small alu block to level of the connecting
strip to the circuit board.