if you want to buy one 900 mhz jammer

Because the directional antenna covers the main lobe, side lobe and back lobe. The main lobe coverage angle is defined as the mobile phone signal shielding coverage angle when the external power of the main lobe drops by 3dB. This means that the radiation intensity on the side and back of the directional antenna is only much lower than the main lobe. Therefore, if the space close to the antenna is still relatively shielded, and the reflection of the shielded building will still cause external disturbance. In addition, if it is not used properly, it will also cause disturbance to the upstream, which will increase the scale of disturbance.

Everyone thinks that the cell phone jammer is a hard indicator. In fact, the interval is not an absolute value. It is related to the strength and quality of the space signal. In other words, the interval does not have any meaning. For the same shielding power, if the interval is between 100 meters and 70 decibels at the weaker level, then only 12.5 meters at the strong level is -52 decibels. The 900 Mhz Jammer is related to the antenna gain. And the same power shielding host uses different gain antennas, and its interval will be very different.

Nowadays, all kinds of jammers are common in the market, and everyone's understanding of jammers is uneven. It can be seen from this that when selecting a mobile phone signal jammer, the actual situation of the on-site environment must be integrated, not hearsay, but personal testing. For example, an antenna with a gain of 16 db has an interval of 100 meters, and an antenna with a gain of 4 db has an interval of only 25 meters.Therefore, whether the equipment skills can satisfy the conditions, the use of antennas and the debugging of the system are far more meaningful than whether to use directional antennas.