This rf amplifier ensure the power you need to boost a small transmitter.
Depending of input rf power, power supply and transistor, this amplifier can boost from 15W up to 30W.
The most important components : 7805, 1N4001 diodes mounted in series, 120 ohm / 2W resistor and 1N4145 diodes.
The setup : trim P (220 ohm ) untill you obtain 50mA thru T1 and 100mA thru T2. Without any input signal you must measure 1.5V like in the schematic, if the voltage is higher the 2 transistors can burn.
At 12V and 0.1W input rf power the output is 6W and with 0.5W the output is 15W.
At 24V and 0.1W input power the output is 10W and with 0.5W the output is 25W.
RF power amplifier circuit diagram
* T1 = KT920A, KT920b, KT920B, KT925A, KT925b ( in 12V )
* T1 = KT922A, KT934A, KT934b ( in 18V – 24V )
* T2 = KT925B, KT934B ( in 12V )
* T2 = KT922b, KT922B, KT930 ( in 24V )
* L1 = 3turns/1mm/6mm
* L2 = 5turns/1mm/6mm
* L3 = L4 =5turns/1mm/6mm
* L5 = 4turns/1mm/7mm
* F1 = F2 = 18turns/0.5mm/2.5mm/ferite
* S1 = S2 = 20turns/0.3mm/ferite