At present, the intercom communication equipments on the market are mainly classified into three types: hand-held walkie-talkies, car walkie-talkies, and repeaters. Among them, the hand-held walkie-talkie is the most widely used and has the largest number of users.
(1) Frequency range: The frequency range of general professional walkie-talkie VHF: 136-174MHz UHF: 400-470MHz. Because of the high density of buildings in the city, it needs strong penetration of electric waves, so it should be suitable for U segment (400-470MHZ). The use of long-distance walkie-talkies in such open areas as the wilderness or the sea requires radio waves with strong diffraction power, so it is appropriate to use the V-segment (136-174MHZ);
(2) Transmit power: The maximum transmit power of the handheld walkie-talkie is generally less than 5W, of which V segment is 5W maximum and U segment is 4W maximum. For the nominal 10W on Taobao, 15W is generally the virtual target power, too large transmit power. Not only is it harmful to health, but also the battery life of the walkie-talkie will be shorter;
(3) The distance of the intercom: 1-3 km in the urban area and 3-5 km in the suburbs;
(4) Number of channels: The average walkie-talkie is at least 16 channels, and the number of channels is up to 1024, but generally 16 are basically enough;
(5) Battery working time: generally according to 5-5-90 working cycle (5 minutes launch, 5 minutes reception, 90 minutes standby), high power transmission to calculate the general analog walkie-talkie 7-10 hours, digital walkie-talkie up to 16-20 hours;
(6) Environmental indicators: For ultra-long-distance walkie-talkies that are often used outdoors, it is necessary to consider the dustproof and waterproof performance of the walkie-talkie. Ordinary rain IP54-55 can be used. For high-performance waterproof walkie-talkies that require IP67 or higher on the surface of the water ( Soak for half an hour under 1 meter deep);
(7) Analog walkie-talkie and digital walkie-talkie: With the development of digital walkie-talkies, there are more and more digital walkie-talkies on the market. The general digital walkie-talkies support digital-analog dual-use. The digital walkie-talkie has the advantages of saving frequency resources and good call performance. Many advantages, such as power saving, are the future development trend... And the digital walkie-talkie is divided into DMR digital walkie-talkie and DPMR digital walkie-talkie.
About domestically produced machines and imported machines: Although the prices of domestically produced machines and imported machines vary greatly, machines of the same power are indistinguishable in terms of communication distance. The gap between domestically produced machines and imported machines is mainly in terms of sound quality, workmanship, and stability. If used every day: 80% of the machines will have various failures in one year, and 80% of the machines will still be used normally after 10 years of import. If it is only used once or twice, it is recommended to buy a domestic machine. After all, the price is very cheap, and the communication distance is similar to that of the imported machine. If you want to use it every day, and the environment is very bad, you must buy an imported machine. The imported machine has good workmanship, loud sound and good stability. More common imported brand walkie-talkies such as: Motorola walkie-talkie, Kenwood walkie-talkie, Weitex walkie-talkie, Ai Kemu walkie-talkie and so on.
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