What is the difference between the UHF and VHF bands?
UHF (300 ~ 3000MHz) and VHF (30 ~ 300MHz) amateur frequency wavelengths of 0.7 meters and 2 meters, respectively, are in the category of ultrashort waves. For the radio waves in these two frequency bands, the ionosphere is basically non-reflective, so UHF and VHF radio waves are mainly transmitted by line-of-sight, that is, like light, and will be reflected when encountering obstacles such as buildings or mountains. Therefore, these two bands are often used for short-range walkie-talkie communication.
In terms of frequency usage, the VHF amateur frequency is 144-148 MHz (dedicated), and the UHF amateur is 430-440 MHz (shared). The VHF amateur frequency band is much less than UHF, so the signal in this band is often very crowded. If you are going to climb a mountain, the VHF walkie-talkie is very suitable, because the VHF intercom mechanical wave is diffracted, this time the VHF walkie-talkie can play its great role. Of course, the premise is that you must set your walkie-talkie frequency to a legal frequency. Because there are more people using the UHF handset and the car platform, if the channel is rich enough, the probability of the frequency is also very high according to the hexadecimal frequency set by the walkie-talkie frequency. High. In the same way, everyone is advised to use the walkie-talkie legally.
In the propagation of radio waves, since the propagation loss of high-frequency signals in the air is relatively low, the VHF propagation effect is better than that of UHF in long-distance communication. If in the same position, the same antenna and position, the signal received on the UHF channel is unstable, easy to jam, it is difficult to copy clearly, but on the VHF channel, although the signal is relatively late, but the copy is stable Clear, no stagnation. And, theoretically, using the same UV two-segment antenna, the VHF signal gain is much smaller than the UHF signal gain.