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20MJ20 - Microphones Jammer

The 20 MJ-20 is a highly effective ultrasonic jammer. It is designed to protect confidential information during meetings and conversations. It generates a unique ultrasound signal that blocks the microphones within the range of the device without interfering in the conversation. When turned on, the jammer virtually blocks the operation of any device with microphone and which are designed to record or transmit an audio signal. Such devices are: Mobile phones, dictaphones, audio recorders, wired and radio microphones used for eavesdropping, video and audio conferencing systems, GSM microphones, etc.
In order to improve the efficiency of the device, there are several unique solutions:
1. Generating a special signal covering a wide frequency range and affecting different types of microphones.
2. Operation on two different frequencies in order to increase the distance of impact and overcome possible measures to counteract the jammer.
3. Ability to operate several devices in a room without going into antiphase, which would lead to periods of reduction or cessation of the jammer’s effectiveness.
4. Control of up to 4 devices with one remote. The Ultrasound jammer is a set of two separate jammers that could work individually (separately) or synchronously. One of the jammers works at 25 KHz and the other at 33 KHz. Several jammers operating at 25 KHz only (respectively at 33 KHz) can be used simultaneously.
Spectrogram of the two transmitters working simultaneously.
In purple is the level of the jammer compared to the standard noise in the room, depicted in white.
Each of the transmitters has a power supply, built-in batteries, built-in control buttons and remote control.
The jamming range depends on the type of the microphone and its design. The optimal microphone jamming is from 0.5 to 2 meters. Highly sensitive microphones can be blocked at 12 meters distance or more. These are the microphones of the top models of mobile phones from various brands. The transmitters can work separately as a stand- alone jammers. The best effect however is when they work together. Based on our experience however we would recommend using two sets- one set on the table, the second one under the table.
- Directional diagram- 60 degree angle in front of the emitters
- Manual control- buttons and light indicators for switching on/off, noise and battery level
- Remote control- switching on/off, range ~40 meters
- Wireless remote control- 433.92 MHz frequency in the ISM (Industrial Scientific and Medical) band
- Power supply- 220 V AC and 12V DC built-in accumulator batteries.
- Working time with battery- up to 7 h.
- Weight of one ultrasonic device with batteries – 0,9 kg.
- Size of one device- 203x158x65 mm
The set includes:
- Ultrasonic Jamming device- 2 pcs.
- Power supply 5V- 2 pcs.
- Remote control- 2 pcs. The remote control can be programmed to work with up to 4 devices.
- Warranty- 12 months.
Technical Specifications
Operating frequency 25Khz, 33Khz
Directional diagram 60o horizontal and vertical
Wireless remote control 433.92 MHz frequency in the ISM band
Power supply 220 V AC and 12V DC built-in accumulator batteries
Operation time with battery up to 7 h
Weight of one ultrasonic device with batteries 0,9 kg
Size of one device 203x158x65 mm

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