handmade-jammer-circuit

Recently internet started to pay more and more attention to cell phone jammers, particularly to how you can create one by yourself. Jammer Store Inc. and our manufacturing specialists could not stand apart so they decided to make their own guide for you. It is necessary to remember that making such complex device is quite hard and it will need some electronic skills and knowledge.

Going 3-Way

At first you should know that there are three ways of jamming mobile phone signals:

no-signal

  • Spoofing (a fake signal is send to the device and the device turns itself off or gets another malfunction)
  • DoS (denial of service, when signal band gets filled with radio junk which takes place of normal signal and don’t let it in or out)
  • TEMPEST (EMF) shielding (covers an object with bubble shielding all incoming and outgoing signals)

Our specialists are using the second one and that is why: spoofing is a nice method but it requires precise adjustment and control, though it may be quite hard to operate for untrained user. The EMF shielding is cool in general but it is bound to one location, so you can forget about any kind of portability.

Thus DoS remains the best choice due to the ability to jam all mobile devices of selected frequencies in a specified area covered by jammer.

electronic-partsGathering Parts

To make a nice operating cell phone jammer you will need some details to combine. Among them are:

  • Voltage Controlled Oscillator (VCO)
  • Tuning Circuit (to select desirable frequency to be jammed)
  • Noise Source (commonly built-in in Tuning Circuit)
  • RF Amplification Unit (so-called “gain stage”)
  • Transmitting Antenna

VCO is the most important among other parts. It is like a heart of your jammer. VCO produces RF signal which will interact with the blocked device. Firstly you must select frequencies which will be used in your signal blocking device. Here is the list of standards:

  • voltage-controlled-oscillatorAMPS (800MHz)
  • PCS (800MHz, 1800MHz and 1900MHz)
  • GSM (850MHz and 1900MHz in America, 900MHz and 1800MHz in Europe)
  • GPS (1227MHz military and 1575MHz civil)
  • Wi-Fi/Bluetooth (2400MHz – 2500MHz)
  • RFID (also known as UHF/VHF, 14MHz – 400MHz, 800MHz and 2450MHz)

It is also important to think about its size because you might wish to create a desktop mobile phone jammer or a portable handheld jamming device.

jammer-tunung-circuitTuning Circuit can be of two types: open-loop and feedback. Open-loop is quite simple and requires just a few op-amps with additional passive components. It is a sawtooth-wave generator which makes VCO to go from lowest to highest frequency. The feedback is using PLL to adjust the VCO’s frequency constantly. For this purpose you need to use microcontroller. It is programmed once and then connected to the VCO, thus it is not adjustable.

gain-stageRF Amplification Unit is what you need when you wish to increase the area covered by your jammer along with its signal blocking power. The more power has your signal blocker, the bigger radius it jams. The cost is, as you may guess, battery working time. More power equals less time for battery to live.

There is a huge selection of gain stage units on the electronics market (7dbm, 17dbm, even 20+dbm). But consider that more powerful amps are bigger and need better power supply.

sma-antennaTransmitting Antenna is a tool which transmits signals produced by your jammer. The main characteristic of antenna is VSWR (Voltage Standing Wave Ratio). If your antenna has VSWR of 3 or lower, then this is what you need, because the return loss of this antenna is minimal.

Jammer Store specialists use SMA antennas due to their ability of being removed or replaced easily. It is worth to mention that omnidirectional antennas are preferable, unless you like to use your cell phone jammer in a TV remote style.

Power Source makes your creation to become alive. Generally mobile phone jammers use 5VDC to operate. Thus you may use Lithium-ion battery to supply your creation. In the case of using common power source you will need power adapter. The power adapter may be of one of two types: switched-capacitor voltage doubler or inductor-based boost regulator.

lithium-ion-batteryThe first one is simple and efficient yet not regulated solution, so you will need LDO regulator to fix the voltage. The second one is regulated but it has bigger cost, more complex and requires precise specification of all components to work properly.

Our manufacturing guys use boost regulators for their creations. It takes more time and work but gives better result. AC-DC and DC-DC adapters are made for almost all types of mobile signal jammers.

Additional Notes

  • Older generations of mobile devices are easier to jam because of lower working power. Respectively they would be jammed at the bigger distance than modern cell phones.
  • More powerful jamming devices might be in need of cooling system to prevent malfunctions.
  • If you have enough skills, training and experience (along with specific equipment), you can use programmable PLL with microcontroller to make your cell signal jammer adjustable.

In The End

So how do you like it? Now you can imagine what work is done by our respected research and manufacturing specialists to invent, design, create and produce all those cool and reliable cell phone jammers for you to enjoy.

The world of electronic gadgets is so big and interesting place! It has a lot to demonstrate and to surprise with. It can help us to enjoy modern, useful and simply cool things.

And you are welcome to become a part of it.

Schematics

First part

Second part

Third part

Fourth part

Fifth part

Sixth part

Seventh part

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