The RF amplifier is designed based on the M/A-Com LF2810A MOSFET. The transistor is basically a 10 watt, 28 volt part, but supplies sufficient gain for this application at 12 VDC. The amplifier delivers higher than 40% of efficiency in the desired output capability. Trimmer capacitors are applied for input and output matching. Output power is altered by a trimmer potensiometer (trimpot) which sets the gate bias voltage.
RF Amplifier circuit source: http://www.ham-radio.com/wb6zsu/components/exciter/exciter_mods.html
This is a demonstration about 01A RF Amplifier which is build used old tube component to amplify the signal.
Watch the video: