Omnidirectional antenna:
Omnidirectional antenna, which figure in the horizontal direction are uniformly showed 360 ° radiation, which is usually referred to non-directional. Under normal circumstances the smaller beam width, the greater the gain. Omnidirectional antenna communication system in general application from the past, large coverage and cheaper prices. 9dB gain is generally less. The following figure shows the signal omnidirectional antenna radiation pattern.
Omnidirectional antenna range more like an apple
Directional Antenna:
Directional antenna in the horizontal direction in FIG showed a range of angles of radiation, which is usually referred to directional. Omnidirectional antenna with the same beam width is smaller, the greater the gain. Directional antennas generally used in a communication system the communication distance, small-coverage, high target density, high frequency utilization efficiency environment.In this way we can also come to think about the whole relationship between the antenna and the directional antenna: All will transmit signals in all directions to the antenna can receive signals all around, directional antenna like a bowl after a strong antenna mask reflective surface, signal is transmitted to only the front toward the back of the signal is blocked by the reflecting surface and is reflected to the front, in front of the enhanced signal strength. Below is a directional antenna radiation pattern signal.
The main scope of radiation directional antenna like a less complete inverted cone
Through the image above we can understand what is omni-directional antenna, what is a directional antenna, so in practice what to pay attention to it?
Optional antenna If you need to meet multiple sites, and these sites are located in different directions when the AP, the need to use an omnidirectional antenna; if in one direction, recommend the use of directional antennas; Also consider whether the joint form AP antenna matching antenna gain size meets your needs;
Mounted antenna For an outdoor antenna, the need to increase between the antenna and the wireless AP mine equipment; directional antenna to pay attention to the front of the antenna in the direction toward the distal site; antenna should be mounted as high as possible in the position between the antenna and the site as much as possible to meet the horizon (visible in the middle to avoid obstacles).