June 02, 2018

You may be wondering what the difference is between UHF and VHF. Is one better than the other?


Let's start by defining UHF and VHF. There are a total of twelve frequency bands named by the International Telecommunications Union (ITU). VHF and UHF make up two of these. UHF stands for Ultra High Frequency and VHF stands for Very High Frequency. Each of these refer to specific frequency bands.


The VHF band consists of frequencies from 30 MHz to 300 MHz and just above that is the UHF band from 300 MHz to 1 GHz. Within each of these are smaller frequency bands designated for specific use by regulating agencies depending on the country.


Common uses of UHF include TV broadcasting, WiFi, GPS communication, and personal radio services. In the USA, 450-470 MHz in the UHF range is designated for General Mobile Radio Service (GMRS) and Family Radio Service (FRS). We’ll cover these specifically in our next posts.


Common uses of the VHF band includes FM broadcasting, TV broadcasting, long range data communications, and air traffic control communications. Specifically designated bands within VHF in the USA include amateur radio bands, Multi-Use Radio Service (MURS), and VHF Marine Radio.


VHF is mainly line-of-sight (LOS). This means that radio waves travel in a direct path from the source to receiver. VHF waves can not penetrate hills and mountains. They do not follow the contour of the earth but can refract slightly against the atmosphere and propagate slightly beyond the horizon.


UHF is almost entirely line-of-sight and propagates along the ground. Similar to VHF, it is blocked by hills and mountains. It is limited to about 30-40 miles by the visual horizon. However, local terrain will further limit this distance. UHF is more susceptible to degradation from moisture in the air because of it’s higher frequency. Because of the line of sight limitations on UHF, it allows frequency reuse in neighboring geographic areas.


VHF and UHF both have their advantages but neither is inherently better than the other. VHF will be slightly better for transmitting longer distances and penetrating obstacles. For short range UHF may be a better option. Also consider which channels you can legally transmit on. No matter what your needs are, Rally Radios has you covered with several radio options that support both UHF and VHF frequencies.