As a salesperson of walkie-talkies, there are often people who ask you the communication distance of walkie-talkies. It is estimated that you cannot communicate with customers when encountering such problems. In fact, in the field of professional wireless communication, there is no "distance" technical parameter, because the radio Electromagnetic waves propagate signals, and there are many factors that can affect the distance that wireless signals can propagate. Among them, internal factors include the device's transmit power, receiving sensitivity, antenna gain, and height. External factors include the use environment, air interference radio waves, and so on. Today, the editor will talk to you about the calculation method of the intercom's communication distance: Calculation method of intercom communication distance The communication distance of the two-way radio depends on the antenna gain, height, transmitter output power, receiver sensitivity, electromagnetic environment, and obstacle-free objects. Here we take Kelixun DP405 handheld radio as an example to describe the calculation method of the communication distance of the radio. We took two Kelixun DP405 handheld walkie-talkies, which work in the 400MHz ~ 470MHz band, the center frequency is 435MHz; the length of the antenna is about 20cm, the effective height of the antenna is 1.5m; the antenna gain is about 0dBi (-2.15dBd) About; the transmission power is 4W; the receiving sensitivity is about 0.35 uV. The test environment is suburban. Here we are based on Okumura's propagation prediction model, and the calculation process is as follows: 1. Minimum receiving field strength 12Db SINAD (dbuV / m) = 105 + receiver sensitivity (dBW) + 20logf (MHz) = 105 + 10log (V * V / R) + 20log460 = 105 + 10log (0.35 uV * 0.35 uV / 50) + 53.255 = 105 + (-146) + 53.255 = 12.255 (dBW) 2. System gain Transmitting antenna gain (dBd) -2.15 Environmental correction factor: urban to suburban 11.00 Total system gain (dB) 8.85 3. System loss RF power correction 1000W to 4W 24.00 Human body influence loss (handheld machine is parallel to mouth) 1.60 Other losses (dB) 10.00 (estimated) System reliability correction 50% to 90% 12.00 4. Total system loss 47.60 Actual minimum receiving field strength (dbuV / m) (System loss + minimum receiving field strength-system gain) 51.005 The communication distance of the handheld radio is about 6 kilometers. If a walkie-talkie is used in a building, assuming that the loss of the building is 6dB, the communication distance becomes 4 kilometers. Note: Other losses include antenna standing wave ratio loss, connector loss, etc. The above calculation is that the communication distance of the general communication environment (no interference, no large obstacles) and the actual environment communication distance will have some errors. The above is the calculation method of the communication distance of the interphone. After reading the text, do you have a deeper understanding of the calculation method of the communication distance of the interphone?
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