A simple design of a signal booster that can be used to extend the GSM frequency.

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This is a simple design of a signal booster that can be used to extend the GSM frequency range.
If you live in a large urban center you may never have heard of such a device, but it is still widely used in isolated or more remote locations in cities, this type of project has applications in several small villages around the world.
You may want to set up such a project to carry with you on your trips to distant locations or even for fun. As this is a very simple project, I will not pay attention to explaining technical details, but if you want to know more, you can feel free to ask. I will also be making all files available for download.

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.


KiCad arquives and outrs.

RAR Archive - 604.56 kB - 08/05/2020 at 23:09



Soldering mask

Adobe Portable Document Format - 111.01 kB - 08/05/2020 at 23:09



Face 1

Adobe Portable Document Format - 108.90 kB - 08/05/2020 at 23:09



Face 2

Adobe Portable Document Format - 141.52 kB - 08/05/2020 at 23:08



Components face

Adobe Portable Document Format - 120.32 kB - 08/05/2020 at 23:07


  • 2 × BF195 Discrete Semiconductors / Transistors, MOSFETs, FETs, IGBTs
  • 1 × 220k Resistor RESISTOR
  • 1 × DC JACK

View all 14 components

  • 1
    PCB manufacturing

    If it is possible to build the PCB with a fibar board, avoid common phenolite boards, as well as being less resistant, fiberglass has a better capacity when dealing with radio frequency interference.

  • 2

    You can use a 24AWG wire to build the antennas, you can make two antennas with an average of 20 to 30 windings that will also work.

  • 3
    Inductor coils

    The two inductor coils can be built by you using a 24AWG copper wire. Just calculate the number of windings.

View all 4 instructions

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drcyberg wrote 08/11/2020 at 07:55 point


The Project is good, but the DIP Switch is too little for the power through (max: 12V 50mA). Change SLIDE Switch, because support more Ampere.

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Tiago wrote 08/11/2020 at 13:25 point

Hello thanks for the information, and sorry for the error, in fact the circuit must be powered with + 5V. I hadn't made that observation.

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Ken Yap wrote 08/05/2020 at 23:04 point

Can something similar be done for UMTS and LTE?

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Tiago wrote 08/05/2020 at 23:20 point

Hello friend I am working on some projects aimed at LTE, I tested this project on older GSM networks, in the voice frequency it is great, but I cannot say if it has the same performance in LTE and UMTS bands.

  Are you sure? yes | no

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