The circuit is a simple RF booster, it is powered by a voltage of 5v at the input with a current of at most 2A. The whole secret of the circuit is in the two bipolar BC195 transistors that can operate at high frequencies above 800Mhz. You can also use any other general purpose NPN transistor for mounting but pay attention to the component's datasheet.
I added two coaxial connectors to the circuit so that threaded antennas could be used, but you can also modify and exchange for simple elliptical type antennas.
The two variable capacitors are used to fine tune the frequency, if you do not get a good result in the received signal strength, you can adjust the capacitors CTRIM1 and CTRIM2 that serve as a filter and fine adjustment.
The project was tested on GSM voice networks in the 750Mhz to 950Mhz bands, as it was some time ago that I had built it and I got rid of the model, I can't say at the moment if it can operate in bands above these. But in the described RF bands it has a good response depending on the conditions it can provide an increase of up to 10Db's in the received signal.