Application of wireless bridge in long-distance monitoring

Applicable scenarios

• Crossing roads, rivers, factories, etc. Scenarios where it is inconvenient to excavate and wire cabling.
• Scenarios that require rapid deployment or migration such as construction sites and temporary locations.
• Elevator shafts, tower cranes and other locations where wiring cannot be fixed.
• As a backup link for fiber optics.

Note: Wireless bridges are not a one-size-fits-all solution to all long-distance problems. Where conditions permit, optical fiber is still the best choice.

Frequency band selection

Visual (LOS) and Fresnel zone

The wireless bridge requires visibility from both ends. But it’s not enough to just “see it with the naked eye”, you also need to ensure There is no obstruction in the Fresnel zone. Experience: In the middle area connecting the two ends, Allow at least 60% of the first Fresnel zone radius of clearance.

Common obstructions: trees (especially after growing during the rainy season), new buildings, billboards, large vehicles. In densely wooded scenes, it is recommended to use other options.

Bandwidth planning

• First calculate the total bit rate: number of channels × single channel bit rate × 1.2 (overhead).
• The nominal rate of the bridge is the physical layer rate, and the actual available throughput is usually only 40% to 60%.
• Allow 30% margin for weather attenuation.
• When multiple cameras are aggregated and returned, the port speed of the aggregation point switch must also be calculated.

Installation and stability

• The antennas at both ends must be accurately aligned and fine-tuned to the best using the signal strength indicator that comes with the device.
• The fixation must be firm. Wind load will cause the antenna to shift. This is often the reason why the signal changes with the seasons.
• Do a good job of lightning protection and grounding. Outdoor network bridges are equipment prone to lightning strikes.
• Priority is given to PoE for power supply. Pay attention to the length and voltage drop of the network cable.
• To avoid co-channel interference from multiple network bridges, plan the channel and polarization direction well.