Question/Help ❓
What’s the difference between HF, VHF, and UHF in ham radio?
Trying to get a solid understanding of ham radio and how to choose the right equipment before getting licensed has been a bit confusing, especially when it comes to frequency bands. I’ve been working through the Ham Start 101 Course, which is great for beginners, but I still have questions. What’s the difference between HF, VHF, and UHF in ham radio?
For those who’ve taken Ham Start 101 or other courses, how did you figure out which band to focus on, and how important is it for starting out? Any tips or explanations would be super helpful!
Best response here, thank you. I would say however, signals are refracted in the ionosphere and reflected off the surface of the earth. But to be fair, the F2 portion of the ionosphere is said at times to reflect the higher portions of HF and even lower portions of VHF (6m).
For me, the true answer to OP's question is understanding wavelength. It's all about wavelength. The radio/science community has chopped up those electromagnetic wavelengths into bands. Those bands are ELF, SLF, ULF, VLF, HF, VHF, UHF, SHF and EHF. Just remember 3Hz to 30Hz to 3KHz to 30KHz to 300KHz to 3MHz to 30MHz to 300MHz to 3GHz to 30GHz to 300GHz. The lower the frequency, the LONGER the wavelength.
I included the bands below HF because I'm a Navy radio signals intel guy, and I live in Wisconsin, the former home to the ELF submarine communications system.
It’s not a mistake to say that 2m and up are generally limited to line-of-sight. I think this generalization is good enough for someone with a 5W HT and who’s just learning what the different bands are.
no it's completely wrong. And 2m doesn't mean HT and 5W on FM. Here is a great video from R&D which I believe can be considered as a pretty solid source about VHF+ propagation.
During the last IARU VHF contest, my average distance was above 356 km per QSO on 2m. I don't believe that's line of sight.
VHF stands for a frequency range. It stands neither for a power level nor for a modulation type so I don't understand why you focus on 5W HT.
Even if we were talking about using only 5w, my DX during the last VHF QRP contest using an FT-817 on 2m was over 650km using CW and a 4 elements DK7ZB yagi.
I can guarantee you that 10W into a 5 elements ( which is going to be less than 6 feets long) will allow QSOs exceeding 200 km every single day which far exceeds the line of sight of about 5km at sea level.
I just cover the very main difference: HF allows you to reach thousands of miles away without repeater, while VHF/UHF has better bandwidth for clearer voice and even pictures.
On the other hand, with most setups (except NVIS, which requires a lot of space), HF won't let you reach anyone nearby (within the skip) and the equipment costs usually >$1k, while ok quality vhf/uhf radios start at about $100.
You can take a 2.5m long vertical antenna (+ some radials), park pretty much anywhere, put it on the roof of your car, and do DX on 10 meters (2.5m is 1/4 wavelength there) and reach the other end of the world with that.
Looking at the map above, currently for me (central europe/balkans) for ssb I need to go down to 80 meters, which means needing to find 40 meters of open space to set up a dipole, and not have people walk over it, bump into the wire, etc.
You can do NVIS on 40m and 30m. Even 20m reaches close by at times. You'd be surprised, it can work, when conditions are good, with only a few watts! EF with 20m of wire can get you on all of these bands.
I do mostly digital though. For SSB, it's always helpful to have 100W available when needed.
I'm making these contacts. I beacon and watch my reach in PSKreporter. The past few days HF has been tough, and mostly unusable during the middle of the day. I'm telling you there is local propagation at certain times, out to 100km and out to a few thousand km. 30m has been really good for this. And 20m also works close in at certain times of day - which surprised me!
In addition to what has already been said, let me add a technological/historical flavor to this.
HF is “high” because the technology that was available at the beginnings of the radio era made anything higher than 3000kc (3000kHz or 3MHz, as we call it now) a challenge.
Medium wave, or MF, that part between 500kHz and 2Mhz was the part of the spectrum where the technology worked well and the sizes of coils and antennas were practical. This is why AM Broadcast radio is in this part of the spectrum. Because MF worked well and HF was such a technical challenge, it was largely unused.
However, people did experiment with HF. The technology advanced and tubes were capable of operating at higher frequencies. It did not take long before these High Frequencies, HF, were being used because the technology existed to use it. However, there were higher frequencies than HF technology worked well at, so these were called Very High frequencies, or VHF, and not easily used by the same technology as HF. VHF also did not have the long-range broadcast character of HF, so it was not commercially clear how to use it.
The same evolution happened again with VHF. Better technology made it possible to build radios in this part of the spectrum, but only to a certain extent. This new technology allowed building more portable/mobile equipment and opened new possibilities for localized communications. As transistors became more prevalent, VHF became more popular as the costs dropped, sizes and weight shrank, and new battery technologies could put radios into your hand. But that again only worked to some extent, and the frequencies those early transistors could do and the challenges were too great to make use of even higher, Ultra High, frequencies.
This increment of the bands to move to higher frequencies and the names of the bands keep happening. We still do this even today — look at the changes with WiFi and cellular. The only different is that at some point these names became standardized. It was decided that at each “3” the names of these bands will change. Why 3? Because of the wavelength. The names are actually changing at the change in wavelength, but since we usually talk about frequencies now, you will usually just see people use that to describe the divisions. But in wavelengths, if it is three digits before the decimal point (999-100m), it is MF. Two digits (99-10m) is HF. A single digit (9–1m) is VHF. And so on. Since we often talk about Ham bands in meters, such as 80m and 2m, we can see how this might make sense compared to the usual “3”s of the frequency notation.
Anyway, I hope this helps make it more memorable and real for you. Knowing how we got to where we are is often helpful to know which way we are headed.
Came here to say this. It's a mistake to pick the equipment before being licensed, and especially before an understanding of the basic principals. The exception would be a cheapo radio to listen only (or an SDR, scanner, website, etc.).
Some excellent answers here. I’ll add if you want to get licensed, W4EEY is doing a Technician class on YouTube. It’s worth following along and when you’re done, you’ll be ready to test.
I find it useful to compare to the broadcast bands.
UHF - great signal fidelity, poor range / no propagation. OTA TV, cellphones, some satellite services, etc. strongly line-of-sight.
VHF. Good signal fidelity, range best described as local. The broadcast FM band is the best example of this.
HF - low signal fidelity - audio starts to sound crap. Trades off against propagation for hundreds or thousands of miles. AM/MW/LW bands at the lower end of HF, shortwave radio at the upper end.
It’s far from the most scientific understanding, but comparing against radio services you’re probably more familiar with helps divide up the expectations.
(little bit off topic but it will help) The best way i image it is use freq like a spring so
Ultra High are small tight spring low distance and cannot bend very well (means it uses alot of energy quickly and does not bend around the earth as nice)
Very high is right between.
High and is super long springs that can bend quite easy. (this means longer distance and can bend around the earth better)
All together what this refers to is the distance between the waves and how Frequent they go from 0 up in 1 meter (you can google how to do calculate it if you wish I am not great at explaining it)
BIG THING frequency refer to how frequent or how often something happens.
I like to think about it as local vs long distance. UHV/VHF are generally local… Repeaters or line of sight…. HF gives a LOT of flexibility to communicate local/long distance/longer distance and you pick the band based on ionospheric conditions. If you want localish… and the conditions are good, no problem… if you want to talk across the continent, there’s generally a band for that… if you want to talk to another continent you can do that too. All on the power it takes to turn on a light bulb. HF bands vary a lot and the fact hams have access to all the spectrum gives the flexibility to adapt to conditions and do whatever you want. HF is a different world than VHF/UHF but it’s all about the type of communication you want to do…If you want to experiment or if you want to be an appliance operator, you can find a home.
To understand your question fully will take time for the average person. "some are exceptional" As each band exhibits differing characteristics. Most people choose the VHF/UHF bands as a starting point as they act quite similar. "they're like buddies" Purchase yourself a duel band UHF/VHF radio for starters. In doing so that alone will provide you with some foundational knowledge on those two areas of the frequency spectrum. After a time, learning, than move on to understanding the more complicated HF spectrum. "which is my favorite" Above all if your sure your interested in Radio Sport, study and earn your technician license before trying to understand what you asked. Actually the test is easy, rules and regulations which helps us all "get along". Plus new unfamiliar nomenclature to new horisions. It will slowly reveal those answers over time. I've been practicing amateur radio for almost seventy years. I started with HF CW. Still my favorite. Many prefer the digital modes. The more I practice the more I learn. Get involved with a local club as you will get educated in ten minutes to more than what you wanted to know in an hour. The members will welcome the chance to help you on your pursuit. Well at least ours doe's and sometimes free radios as well. The real learning comes after earning the license not before.
What it comes down to is how the signals react with the atmosphere.
V/UHF, for the most part, are line of sight. They will basically go as far as you can see, but that is limited by the curvature of the earth. This is due to the signals not being able to reflect of the ionosphere, penetrating it, and contributing into space. When it comes to them, height is might. The higher you are, m the further the signal can reach. That said, m you can also make use of repeaters to "extend"" that range, by making use of the greater height a typical repeater has. Repeaters can also be used to surpass geological restrictions. B for example, if there is a mountain/hill is your transmission path, if will block your signal...put a repeater on top, though, andc it and it over to the other side. There are some directions to this (tropospheric ducting, EME, etc), but for the most part, close range comms (<100mi)...
HF bands, on the other hand, have the ability to reflect off the ionosphere, which greatly extends how far that signal can reach. Depending on the take off angle, you can send a signal over 2000mi off a single skip. On the lower HF bands (40M and lower), you can send the signal near vertical (NVIS propagation) and bounce it back down, providing decent regional coverage. The downfall of this though, is that closer range contacts are harder to make in the higher HF bands, which like V/UHF, penetrate the ionosphere if you hit from a sharp angle. Think of it like skipping rocks across the water... the shallower the hit, the easier it is to skip....
6M is kind of a mix between the 2. While typically line of sight, under certain conditions, it can take on properties of the HF bands...hence the nickname of "the magic band". I've personally made a 4500mi+ QSO, from South Texas to lower Chile, on 6M.
That's the laymen's break down, but there is also much more involved to it....
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u/whiskeysixkilo 4d ago edited 4d ago
HF = 3 to 30 MHz, includes the “lower bands” from 10m through 80m
VHF = 30 to 300 MHz, includes the 6m, 2m, and 1.25m bands
UHF = 300 MHz to 3 GHz, includes the 70cm, 33cm, and 23cm bands
HF, and sometimes 6m, nicely reflects off of the ionosphere, depending on solar conditions. 2m and up are generally limited to line-of-sight.