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Ultra high frequency
The Differences Between UHF And VHF Radio Frequencies
When operating a radio in the field, getting the best out of your equipment relies on understanding what is the best communications device to use in a given situation. HF frequencies in the MHz band are propagated by transmission from a radio transceiver, where it is reflected by the ionosphere back to Earth for reception by another radio set. This communications medium is perfect for long-range communications, and is widely used in tactical operations as a method of conversing between remote field operators and a central base. These transmissions, due to their higher frequency, penetrate through the Ionosphere, with little or no refraction. Terrestrial transmissions make VHF the perfect medium for communications between field operators and other ground squads.
VHF or UHF Two Way Radio?
Lower frequency signals fall into the VHF very high frequency or lower bands. UHF radio waves propagate mainly by line of sight ; they are blocked by hills and large buildings although the transmission through building walls is strong enough for indoor reception. They are used for television broadcasting , cell phones , satellite communication including GPS , personal radio services including Wi-Fi and Bluetooth , walkie-talkies , cordless phones , and numerous other applications. Radio waves in the UHF band travel almost entirely by line-of-sight propagation LOS and ground reflection; unlike in the HF band there is little to no reflection from the ionosphere skywave propagation , or ground wave.
Until recently, it wasn't widely used. There are more available channels with UHF so in more populated areas UHF may be less likely to have interference from other systems. If you are in an area where population is thin, VHF should work fine for you. UHF is better at penetrating physical barriers like walls, buildings, and rugged landscape. Anything that obstructs a radio wave, will weaken a radio signal.