来源：http://www.zzzhongtebao.com/ 点击次数： 发布时间：2018-08-27
How far is the interphone spacing? Hand-held intercom in no relay cooperative operation, according to the intercom transmission power point of view, the normal useful communication interval between 1-6 kilometers, different transmission power, different communication environment has a greater impact on the intercom communication interval. Our article first describes the useful communication intervals of interphones in different environments.
In the past sale process, the user's most concerned problem is the intercom call interval, often to the seller throw a series of questions about the communication interval. How far can a walkie call the farthest? Why are there some local calls to the same walkie talkie far away? Is there a walkie talkie that can call 10 kilometers?
In fact, the regular and planned manufacturers of walkie-talkies, whether their product promotion color pages, product brochures, or the official brand website will not indicate the type of walkie-talkies communication interval. If the intercom interval is marked out, it is more conducive to the sale of the product, but responsible companies will not do so, because no company can predict the user's use of the environment, to know that the communication environment plays a decisive role in the intercom communication interval, so it is impossible to distinguish the use of intercom interval.
In addition to the external factors of the operating environment, the technical specifications of the interphone itself are also very important. For example, the transmitting power of the interphone, the reception sensitivity, whether the antenna is original, whether the antenna is damaged or not, all of these will have a certain impact on the communication interval. Of course, the user's correct use can also affect the maximum communication interval of the interphone to a certain extent.
If you're buying a walkie-talkie and you ask the salesman about the communication interval, if he answers you that his walkie-talkie has at least 5 kilometers of traffic, and may even reach 8-10 kilometers. Trust me, it's irresponsible to conclude that no matter how much experience he's had, without actually testing it on the user's site.
Commonly used wireless walkie-talkies generally use 130-170MHz; 403-470MHz two bands, these two bands are also the national law allows individuals or units to use the band size. Generally speaking, both frequencies are transmitted in a straight line. Maritime communication is an ambitious communication environment for radio intercom on the earth. Generally, there are no obstacles and little disturbance. But in practice, handheld intercom on the sea can only communicate about 10-20 nautical miles, because the earth is round and far away from the center. Blocked by seawater (so the antenna is higher and the distance between calls will be farther away).
When used in cities, obstacles are the most important factors affecting signal transmission intervals. Professional walkie-talkies with a power of up to 5 watts usually have a practical call interval of only 2 to 5 kilometers in the city. In rooms with Highlands, more buildings or relatively sealed rooms, the interval between calls will be shorter. But when there is a system base station to support, the scale of intercom calls can reach more than ten kilometers or even dozens of kilometers, (if both intercom are high, also can reach more than ten kilometers).
The 0.5W intercom sold on the market, some manufacturers nominal intercom is the farthest call interval is 3 km, in practice this call interval is only a theoretical calculation data, it is based on the transmission power, that is, 0.5W intercom in the absence of obstacles, no electromagnetic disturbance, the maximum call interval. In practice, because the user's environment is different, the background noise is big or small, the electromagnetic disturbance is strong or weak, so the practical call interval is generally less than 3 km. Many users in the purchase of walkie-talkies are often mistaken for use in the city, the call interval can reach 3 km, this is unlikely! It is impossible for any manufacturer to predict the user's operating environment, and of course, it is impossible to give practical call intervals.
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