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What are the losses of wireless bridges in wireless transmission?
Note that the friends who look at the parameters of the wireless bridge will see that each parameter has two indexes, the transmit power and the equipment frequency. In the wireless bridge video transmission system, the transmission distance of the wireless bridge has a great relationship with the transmission power and frequency of the wireless bridge and the antenna gain.
In the actual transmission process, wireless bridges transmit in the air in the form of microwaves, which are lossy in the transmission process. The following formula illustrates the loss of microwave transmission in free space:
Los = 32.44 + 20lg d(Km) + 20lg f(MHz). Los is the propagation loss in dB; d is the distance in Km; f is the operating frequency in MHz.
The following example illustrates the propagation distance of a system in free space with a working frequency of 433.92 MHz, a transmission power of +10 dBm (10 mW) and a receiving sensitivity of -105 dBm:
1, transmit power +10dBm, receive sensitivity -105dBm, Los = 115dB.
2, calculated by Los, f d = 30 km.
This is the ideal transmission distance. The actual application will be lower than this value. This is because the wireless communication is affected by various external factors, such as the loss caused by atmosphere, obstacles, multipath, etc. The reference value is included in the above equation, and the approximate communication distance can be calculated.
Assuming that the loss caused by the atmosphere, shielding, etc. is 25 dB, the communication distance can be calculated as: d = 1.7 km.
Conclusion: For every 6 dB increase in wireless transmission loss, the transmission distance is reduced by a factor of two.
It can be seen that some of the most important factors affecting the transmission distance of a wireless bridge are: transmission power, antenna gain, operating frequency, and whether the site environment is blocked or not. Therefore, we must clearly understand the situation on the site before the plan is determined. Otherwise, the solution may be very different.
In the use of the wireless bridge should try to avoid blocking, blocking should be regarded as the biggest obstacle, if there is only a few trees Lean's wireless bridge blocked, the problem is not large, if it is jungle, house, hillside block , it is necessary to consider through the relay to avoid, or elevated.