While many frequency bands define the broad spectrum of radio waves, from VLF to LF and EHF, the three most common bands you will encounter are HF, VHF, and UHF. Each of these frequency bands has a different range of wavelength, which means the radio waves behave in different ways.
Understanding how HF differs from VHF, and how they both differ from UHF is vital if you want to use field radio and two-way radio technology properly.
It isn't simple, but once you get the hang of all the terminology, it's a piece of cake. Keep reading to learn more.
What Does HF, VHF & UHF Mean?
HF, VHF, and UHF stand for High Frequency, Very High Frequency, and Ultra High Frequency, respectively.
But before you understand what that means and how they all differ, it's important to know more about the system that organises all these terms.
The Radio Spectrum
The International Telecommunications Union, or ITU, is the international organization that regulates personal and commercial use of the radio spectrum. Because the radio spectrum ranges from as low as .003MHz to as high as 300,000 MHz, it was decided that the radio spectrum would be segmented into frequency ranges that share certain properties.
Right in the middle of the spectrum are high frequency (3 - 30 MHz), very high frequency (30 - 300 MHz), and ultra-high frequency (300 - 3,000 MHz).
The radio spectrum could easily have been organised by wavelength or the difference between identical peaks in radio waves. For instance, extremely low-frequency waves have the same frequency (or number of waves generated per second) as high-frequency waves (3 - 30MHz). They differ greatly in the fact that the wavelength of HF waves is 1000 times shorter than that of ELF waves.
HF, VHF, & UHF: Defined
High, very high, and ultra-high frequency spectrum bands represent radio waves that have both median frequency and median wavelength. But the way they travel, how far they travel, and what kind of communication they're best suited for could not be more different.
High-frequency radio waves are good for one set of communication needs, whereas VHF and UHF radio waves would be completely insufficient, and vice versa.
Who Uses HF, UHF and VHF?
High-frequency radio waves travel from the base unit or handheld transceiver, where they are transmitted into the sky. They penetrate Earth's atmosphere, ricochet off the ionosphere, which is the electrically charged (ionised) layer of the thermosphere, and fall back to earth.
It's because of the longer wavelength (10-100m) of high-frequency radio waves that they travel higher and further than very high and ultra-high frequency radio waves. Due to their great journey in relaying communications from one user to another, they're better suited to long-distance communication in the hundreds to 1000s of kilometres. High-frequency signals have often been used in warfare, military training, oceanographic exploration, and other activities involving vast distances.
Very high and ultra-high frequency signals can be grouped together because, while there is a difference in wavelength and frequency between the two, they're both used for short-distance communications. VHF operates between 30 - 300 MHz, and UHF goes between 300 MHz and 3 GHz. Rather than rocketing into the ionosphere and back, they travel invisibly over land. That's what makes these signals ideal for short-distance land communications and even indoor applications. Keep it to a 1-kilometre radius.
Which Is Better, HF, VHF, or UHF?
Whether HF, VHF, or UHF bands are better is like determining whether ice cream, sushi, or pizza is the best. They're incomparably different, and thus each has its vital purpose.
Even if you’re just a casual radio telecommunications enthusiast, it's not like you should research the different frequency bands to decide which is the “best” and then only use that going forward.
You may use VHF for some communications and HF for others, at different times as your needs shift. It's situational, meaning HF, VHF, and UHF are each best at something that the others aren't.
What Is the Difference Between HF, UHF, and VHF?
To determine which frequency band is the ideal match for your needs, you have to dive into the differences.
The most salient difference between these three is range. UHF waves are smaller than VHF waves, which are smaller than HF waves. Remember that frequency and wavelength have an inverse relationship, meaning if you double one, you halve the other.
UHF frequencies produce the widest reception because they have the smallest waves. Conversely, HF frequencies produce the most narrow reception because they produce the biggest waves.
This difference is pretty straightforward. The higher frequency of the radio waves you will be communicating on means the more intense the energy use. Constantly using UHF will wear your radio equipment out. But with HF, you'll get a bit more juice.
How the Radio Waves Travel
Where HF waves travel into the atmosphere and ping back down to your intended destination, VHF and UHF travel across the surface of the Earth. This is what determines what distance you can communicate with on each.
Compatibility with Existing Systems
The rule of thumb is to match your radio to existing radio systems. If you're using very high frequency radio, you must ensure your new radio has a VHF operating mode. Otherwise, communication will be impossible.
Got Questions? Contact Moonraker Today!
Radio technology can get quite confusing. If you ever have questions, don't hesitate to contact us here at Moonraker. Our broad and diverse product range is matched by the professional expertise of our staff. If we can't answer your radio question, no one can.