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Three factors affecting the distance of the walkie-talkie
[ Pacific Security Network News ]
In the process of contacting many walkie-talkie consumers, it is found that the talk distance of the walkie-talkie is a problem that customers often consult. The distance of the walkie-talkie directly affects the customer's use. Today, we will discuss the related issues of the walk-through distance of the walkie-talkie.
In the wireless communication profession, the concept of "distance" is generally not mentioned, because ultrashort wave communication is line-of-sight communication, and signals are blocked and interfered by buildings, hills, trees, electromagnetic fields, etc., affecting the actual call distance and quality, so ultrashort waves are considered. The quality of the call.
Under ideal conditions (without any blocking and interference), the distance of the professional walkie-talkie will be very long, and the actual talk distance can only be between 0 and 10 kilometers. In the case of tall buildings or mountains blocking, the call distance is still It will be relatively short. When there is a system base station (relay) support, the talk distance of the walkie-talkie can reach more than ten kilometers or even tens of kilometers.
The 4W/5W walkie-talkie sold on the market, the maximum talk distance of the manufacturer's nominal walkie-talkie is 10 kilometers. In fact, this maximum talk distance is only a theoretical calculation data, that is, the walkie-talkie without any obstacles and without any electromagnetic interference. Maximum call distance. In actual use, because the environment in which the user is located is different, the background noise is large or small, the electromagnetic interference is strong and weak, and the actual walkie-talkie talk distance is generally between 0 and 10 km, because no manufacturer It is possible to predict the user's usage environment, and of course it is impossible to give the actual talk distance of the walkie-talkie.
Note: In theory, the transmission power of the walkie-talkie is increased by 4 times, and the transmission distance will be doubled under the same environment. Therefore, the "power theory" is unscientific.
Factors limiting the distance of the intercom
1. Interphone output power and receiver sensitivity The greater the output power, the larger the signal coverage. The higher the sensitivity, the farther the talker distance is.
2. 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.
3. The stronger the output power of the transmitter, 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 conversation effect of others, and also causing radiation pollution. Radio management agencies in various countries have clearly defined the transmission power of communication equipment.
Walkie-talkie distance environmental factors
1. There are no obstacles: As mentioned above, the 5W walkie-talkie can easily reach about 2.5 kilometers in the open area, and about 1 km in the middle of the city. If the walkie-talkie climbs to a high place, it is relatively visible to the receiving side, which is equivalent to increasing the line-of-sight distance. At this time, the communication distance of the open area can be referred to.
2. Electromagnetic environment: The electromagnetic environment refers to “all electromagnetic phenomena and sums existing in a given placeâ€. With the development of science and technology, the quality of human life is increasing. Informatization, automation and rapid entry into the ordinary households, households use more and more electronic and electrical equipment, resulting in an increasingly deteriorating electromagnetic environment.
Affect the interferential distance of other interfering 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 does not match, which will seriously affect the talk distance of the walkie-talkie. For the user, pay attention to tightening the antenna when switching to the antenna of the walkie-talkie. 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.