Radio jammer. Encyclopedia of radio electronics and electrical engineering
Encyclopedia of radio electronics and electrical engineering / Security devices and object signaling
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The jammer is designed to work in an active information protection system. The radio jammer in the on state creates electromagnetic interference on the air with an intensity sufficient to mask informative radiation from office equipment used, including electronic computers, and also provides effective suppression of radiation from low-power transmitters in the range of 30 MHz - 1000 MHz. This modification of the device, in addition, can be used to prevent the activation of radio microphones with remote control by influencing the input circuits of the remote control receiver.
Main Specifications
1. The level of the interference signal at the output connectors in the frequency subbands
10 kHz-100 kHz (H=200 Hz) not less than 65 dB
150 kHz-30 MHz (H=9 kHz) not less than 65 dB
30 MHz-1 GHz (H=12 0 kHz) not less than 45 dB
2. Normalized spectral density of interference generated by npn (measured at a distance of 2m from the antenna system, made in the form of a frame of wire 2xXNUMX m in size)
10 kHz-30 MHz not less than 95-103 dB
Z0 MHz-300 MHz not less than 103-118 dB
30MHz-0GHz not less than 1-100dB
3. Entropy coefficient of interference quality not less than 0.8
4. Supply voltage 220 V 50 Hz
Schematic diagram of the device
(click to enlarge)
The device is built according to the classical scheme of the noise generator of the radio frequency range. Comments, as they say, are unnecessary. However, it should be noted that the thermal regime of the circuit is very difficult. For transistors VT1-VT4, radiators of at least 100 square meters are required. see each, subject to good internal ventilation of the case. It is better to replace resistors R1 and R2 with one 4,7 Ohm with a power of 10 watts.
Recommendations for room equipment
1. Mounting of antenna systems is carried out by attaching to the wall with plastic mounting brackets.
2. For masking the frequency range above 1 MHz, the X4 / X3 output is used. Antennas are mounted in 3 mutually perpendicular planes in the form of 2 short-circuited loops of a single-core wire of the MGSHV type, laid along the perimeter of the room. Solder and connect all three loops according to Figure XNUMX.
Ris.2
The optimal dimensions of the frames are (1.5-3) mx (2-5) m, provided that the distance from the corner of the room is no more than 1 m.
Z. If it is necessary to mask the frequency range below 1 MHz with noise, connect two three-turn loop antennas to the X1 / X2 input. Connect the beginnings and ends of both frames, respectively, and connect according to Fig. 3.
Ris.3
The frames are located in two mutually perpendicular planes on the walls of the room together with HF antennas. The dimensions of the frames according to claim 2. The wire connected to X2 must be grounded (in the most extreme case, connect to the "0" power outlet, a slightly better option is a heating battery, but the neighbors will not be grateful to you).
Publication: cxem.net
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