Data analysis on the communication distance of walkie-talkies

In the professional of wireless communication, there is no technical parameter of "distance". Because radio transmits signals by electromagnetic waves, there are many factors that can affect the long-distance transmission of wireless signals. The internal influencing factors include the transmitting power, receiving sensitivity and antenna of the equipment. Gain and height, external influence factors include the use environment, air interference waves, and so on. Although the communication distance of the walkie-talkie is hard to say clearly, everyone is still very concerned about this issue.

1, handheld walkie-talkie

7 watts of transmitting power: 2-4 km in urban areas and 4-7 km in open space;

5 watts / 4 watts of transmitting power: 1-3 kilometers in urban areas, 3-5 kilometers in open space;

3 watts / 2 watts of transmitting power: 500 meters to 2 kilometers in the urban area, 1-3 kilometers in open space;

1 watt / 0.5 watt transmission power: urban area 200 meters - 800 meters / open space 500 meters - 1.5 kilometers.

2, car radio

50 watts / 40 watts of transmitting power: 5-15 km in urban areas and 10-25 km in open space;

25 watts / 20 watts of launch power: 3-10 km in the urban area and 5-15 km in open space;

10 watts/5 watts of launch power: 1-5 km in urban areas and 3-8 km in open space;

3. Short-wave intercom: It is very far away. Under the circumstances of external environmental influence factors, it can cross-province or even cross-border communication. However, short-wave intercom needs B-level amateur radio operation certificate, otherwise it is considered illegal operation.

4, cluster walkie-talkie: the distance is very far, basically can communicate throughout the city, generally used in public security networks, the need for high cluster networking costs.

5. Installation of relay station: The cost of the relay station is relatively high, but the handheld walkie-talkie and the car radio can increase the effective communication distance by the upper relay.

Interphone operation notes:

1. When the walkie-talkie is launching, keep the walkie-talkie in a vertical position and keep the distance between the microphone and the mouth 2.5-5 cm. When launching, the intercom is at least 2.5 cm from the head or body.

2. Do not perform multiple power-on and power-off actions during use, and adjust the volume to a volume suitable for your hearing.

Walkie-talkie safety precautions:

1. In a car with an airbag, do not place the walkie-talkie in the range that may be involved when the airbag is deployed. If the walkie-talkie is in the range of areas that may be involved in the deployment of the airbag, once the airbag is deployed quickly, the walkie-talkie may injure the person inside the vehicle with great impact.

2. In a potentially explosive atmosphere or occasion, the walkie-talkie must be turned off unless the walkie-talkie is a specially certified explosion-proof walkie-talkie. In potentially explosive atmospheres, electric sparks can cause an explosion or fire.

3. Do not replace or charge the battery in a potentially explosive atmosphere. Installation and removal of the battery may cause contact sparks and cause an explosion.

4. Before the blasting area and the area where the detonator is located, the intercom must be turned off to avoid possible explosion.

Walkie-talkie routine maintenance:

1. After long-term use of the walkie-talkie, press the control button and the casing is easy to get dirty. Please remove the control knob from the walkie-talkie and clean the case with a neutral detergent (do not use strong corrosive chemicals) and a damp cloth. The use of chemicals such as decontaminants, alcohol, sprays or petroleum preparations can cause damage to the surface and casing of the radio.

2, gently take the walkie-talkie, do not carry the antenna to move the walkie-talkie.

3. When not using accessories such as headphones, please cover the dust cover (if equipped).

Factors affecting the distance and effect of the intercom

1, system parameters:

1) The stronger the transmitter output power, the larger the coverage of the transmitted signal and the farther the communication distance. However, the transmission power should not be too large, and the transmission power is too large, which not only consumes electricity, but also affects the life of the power amplifier components, and is highly interfering, affecting the call effect of others, and also causing radiation pollution. Radio management agencies in various countries have clearly defined the transmission power of communication equipment.

2) The higher the receiving sensitivity of the communication machine, the farther the communication distance is.

3) The gain of the antenna. When the antenna is matched with the machine, the antenna height is generally increased, and the receiving or transmitting capability is enhanced. The antenna used for the walkie-talkie is generally a helical antenna, and its bandwidth and gain are smaller than other types of antennas, and are more susceptible to human influence.

2. Environmental factors:

Environmental factors mainly include paths, tree density, environmental electromagnetic interference, buildings, weather conditions, and terrain differences. These and other parameters directly affect the field strength and coverage of the signal.

3. Other influencing factors:

1) The battery is low. When the battery is low, the call quality will deteriorate. In severe cases, there will be noise, affecting normal calls.

2) Antenna matching, the frequency band of the antenna is inconsistent with the machine frequency band, and the antenna impedance is not matched, which will seriously affect the call distance. For the user, when switching the antenna, pay attention to tightening the antenna. In addition, you should not use the antenna provided by the manufacturer, or use the antenna that does not meet the frequency of the machine.

3) The quality of the sound depends mainly on the pre-emphasis and de-emphasis circuits. At present, there are more advanced speech processing circuits "applications of speech companding circuits and low-level expansion circuits", which have a good effect on fidelity speech. 4) Factors affecting the distance and effect of the intercom are also related to the season, and summer is better than winter.