Analysis of the basic scheme of wireless intercom system with mobile phone signal screen
The structure of modern buildings is generally complex, and the wall shields the signal greatly. The walkie-talkie itself cannot meet the call requirements, resulting in a large blind spot. This caused the signal to be unstable during communication. The cell phone signal jammer business has made a good solution for this phenomenon. Let's take a look.
1. The wireless intercom system should be designed according to the specified principles
1. Under the premise of ensuring the quality system, the design scheme should be designed in a low-cost way as much as possible;
2. Reasonably set the position, quantity and output power of the antenna to ensure the use of fewer antennas and lower output power to achieve good coverage;
3. Due to frequent high-level switching and high call drop rate, the design should try to achieve uniform indoor field strength and good signal strength;
4. Establish a more perfect digital wireless coverage network;
5. At the same time, consider the ease of construction and construction power, especially reasonable wiring;
6. The link meets the carrier-to-noise ratio in the coverage area ≤ 15dB.
Second, according to the specified frequency classification
1. 136-174MHz for civil use;
2. 350- 370MHz for public security fire protection;
3. 400-430MHz for civil use;
4. 450-470MHz railway.
Three, six wireless intercom weak signal analysis and processing methods are ready
1. A set of tools for making feeder connectors;
2. A signal field strength tester;
3. Standing wave instrument - Taiwan;
4. One antenna, several devices and feeders.
Analyze the cause of the failure:
1. The equipment is not debugged and the RF switch is not turned on normally;
2. The main hall is not connected, and the branch line is not connected; treatment method: construct according to the required specifications, connect active equipment, connect main phase passive components and antenna feeder system.
3. The feeder head is not made according to the specification or the joint is loose and falling off, and the aluminum core inside the feeder connection is too short; treatment method: construction according to the requirements of the specification, the joint is remade, and the vertical trunk needs to fix the trunk and devices;
4. The device is connected in reverse, the inlet is connected to the outlet, and the outlet is connected to the inlet.
Processing method: Connect passive devices according to the requirements of the specifications, and correctly connect the input and output terminals.
