Ir Eliza Sukiman MM MA
YB 0 BAJ Indonesian Amateur Radio Station
This is my base station of MosFet Rf Amplifier. The MosFets are APT5020BN ,I have used them in my base station and they produce a good 600w from 36V on 160 and 80,and 400w on 7 Mhz. , I've had 600w out of four at 36V on 160 with a one turn primary / four secondary on the output transformer. (Tubing Transformer).
The circuit is basically the same but this is two devices with combiner on each side of the push-pull. The golden rule is to use a fet capable of withstanding three times your maximum supply voltage.
lets see . . . Schematic.
See Youtube 300w ... Click Here
See Youtube 600w ... Click Here
See Youtube 800w ... Click Here
New power-MosFets coming out every week or so, look for ones with a low Rds-on and high power dissipation. The main drawback is the high gate capacitance, several thousand pF, which makes them hard to drive above 7MHz. Check out IRF , IXYS and APT ( FET manufacturers)