Antenna is a metal device for transmitting and receiving radio waves. No matter what type of Signal Jammer equipment, it will be equipped with antenna to interfere with the signal of the base station. The antennas installed in common low-power signal jammers are generally built-in omnidirectional antennas with soft edges, and only a few are built-in directional antennas.

 Directional antenna is defined as radiation in a certain angle range in the horizontal direction, which is often said to be directional. They also transmit wireless interference signals. The smaller the lobe width is, the greater the gain is. The advantage of directional antenna is that the shielded signal is used in the environment with long communication distance, small coverage, high target density and high frequency utilization.

 Omnidirectional antenna is defined as 360 ° uniform radiation and no directivity in the horizontal pattern. Omnidirectional antenna has the advantages of short application distance, large coverage and relatively cheap price.

 Since the directional antenna is oriented at an angle when in use, it can directly point to its direction like a satellite, so as to prevent signal diffusion and effectively face the specified signal source, so the application distance is relatively long; The omnidirectional antenna signal is easy to diffuse and not easy to concentrate, resulting in short application distance.

Relationship between omnidirectional antenna and directional antenna: omnidirectional antenna is interference signal in all directions, which can be interfered in front, back, left and right. Directional antenna is like covering a reflecting surface behind the antenna, and the signal can only be transmitted to the front. The signal reflecting surface shooting at the back blocks and reflects to the front, which strengthens the signal strength in front.