There are two main formats for two-way radios. They are ultra high frequency (UHF) radio and very high frequency (VHF) radio. No frequency band is inherently better than the other. Each has its advantages and disadvantages. Both formats are effective ways to communicate with another person. But how do you decide which one fits your needs? Let’s go over the key components of both frequencies to help you decide.

Two-way radios communicate with each other by using radio waves. Radio waves have different frequencies, and by tuning a radio receiver to a specific frequency, it can pick up a specific signal.

Radio waves are transmitted as a series of cycles, one after another. You will always see the abbreviation “Hz” used to indicate the frequency of a radio. Hertz is equal to one cycle per second.

Radio waves are measured in kilohertz (kHz), which is equal to 1,000 cycles per second, or megahertz (MHz), which is equal to 1,000,000 cycles per second, or 1,000 kHz. The relationship between these units is as follows: 1,000,000 Hertz = 1000 kilohertz = 1 megahertz.

You may also hear the term “wavelength” when listening over radio waves. This term is from the early days of radio when frequencies were measured in terms of the distance between the peaks of two consecutive cycles of a radio wave rather than the number of cycles per second. Lower frequencies produce a longer wavelength.

While the wavelength measures the distance between the peaks of the cycles, the frequency refers to the time measured between the “crest” and the “trough” of a wave arriving at the source. So frequency measures time rather than distance, but essentially they both say the same thing.

What is important about wavelength for two-way radios is that it affects transmission range under certain conditions. A longer wavelength, as a general rule, allows a radio signal to travel a greater distance.

Lower frequencies or wavelengths have greater penetrating power. That is one of the reasons why they are used to communicate with submarines. VLF radio waves (3-30 kHz) can penetrate seawater to a depth of approximately 20 meters. So a submarine at a shallow depth can use these frequencies.

So from what you’ve read above, you might think that VHF is always the best choice for a two-way radio, no matter where you’re using it. That is not necessarily true. Although VHF has better penetration capabilities, that doesn’t necessarily make it the best option for buildings. Remember the conversation about wavelength earlier? Wavelength has a big impact on transmission.

To explain this, suppose we communicate from one side of a commercial building to the other. Between these two points is a metal wall with a three-foot gate. Metal is an enemy of radio waves, and they usually don’t pass through.

For our example, let’s assume the UHF wavelength the radio uses is about a foot and a half long and a similar VHF radio is about five feet long. These are in the ballpark of their normal wavelengths.

When the UHF transmits its signal, the one and a half foot long wave will go through the gate, since the gate is wider than the wavelength. The VHF signal will be fully reflected as it is wider than the door opening.

Your microwave oven is an example of this. The glass entrance door has a metal mesh with very small holes. Microwaves, which have a very high frequency, have wavelengths only several inches long. The mesh keeps microwaves trapped in the oven but allows you to see inside because light waves have a microscopic wavelength.

Imagine walking through the building carrying a five-foot-wide pole. You will encounter the same challenges that a VHF signal faces. Now imagine walking around the building with a pole that is only a foot and a half wide like a UHF wave. There are far fewer doors you couldn’t get through.

The only difference is that wireless signals will penetrate through drywall, masonry, human bodies, furniture, wall panels, and other solid objects. However, all these objects will reduce the signal strength. The denser the object, the more it reduces the signal. VHF will get through these obstacles better than UHF, but that doesn’t necessarily mean VHF is better for indoor applications, as we’ll see in the UHF section below.

In our example above, we assumed you had a metal wall with an opening. If you reverse this and have a three foot metal object in front of the transmitting radio then VHF would win. Since the object is three feet wide, it will totally block the UHF signal, while the VHF signal will surround it. Lower frequencies, such as VHF, diffract around large smooth obstacles more easily, and also travel more easily through bricks and stones.

For most applications, lower radio frequencies are better for longer range. A television broadcast station illustrates this. A typical VHF station operates at about 100,000 watts and has a coverage radius of about 60 miles. A UHF station with a coverage radius of 60 miles requires transmitting at 3,000,000 watts.

So there is no clear choice as to which is better, VHF or UHF. There is a lot of “black magic” in radio technology, so it’s not always easy to know which one will work best for your application. To help you decide which technology is best for you, more details about each are included below.

UHF radio frequency

UHF equipment operates between the frequencies of 300 MHz and 3000 MHz. Until recently, it was not widely used. Now, the UHF radio frequency is used for GPS, Bluetooth, cordless phones, and WiFi.

There are more channels available with UHF, so in more populated areas UHF is less likely to have interference from other systems. If you are in an area where the population is sparse, VHF should work fine for you. Not too long ago, the FCC also opened up a new VHF frequency called MURS which is not widely used in most areas so far. There is more on WALLS below in the VHF section. If you are in an area where interference from other radios can be a problem, UHF transmitters and receivers might be your best option unless you use a MURS VHF radio. UHF is best for passing through physical barriers like walls, buildings, and rugged landscapes. Anything that obstructs a radio wave will weaken the radio signal. UHF lessens that effect. Although it may not travel as far, UHF radio waves will pass through obstacles better than VHF.

To highlight the differences in range indoors, below is an excerpt from a brochure from a leading manufacturer of two-way radios on the expected range of one of their lines of portable VHF and UHF two-way radios:

“Coverage Estimates: At full power, line of sight, unobstructed, range is approximately 4 miles or more. Indoor coverage on VHF is approximately 270,000 square feet and 300,000 square feet on UHF. Expect a Vertical coverage from approximately 20 stories on VHF and up to 30 stories on UHF Note: Range and coverage are estimates and not guaranteed.”

VHF waves are not very good at finding their way around walls, buildings, and rugged landscapes. Therefore, the range will be significantly reduced for VHF radios in these environments. That may not necessarily be a problem if the range needed is only a few hundred feet. You can also add an external antenna to an indoor VHF base station which will reduce or eliminate this problem.

One of the disadvantages of UHF is that the FCC requires you to obtain a license to operate on these frequencies. Although many frequencies in the commercial VHF band also require a license. If you choose a radio on the VHF MURS frequencies, you can operate it without a license. UHF equipment is usually more expensive. Components must be precisely fitted and are more expensive to build. This doesn’t mean it’s necessarily better, just more expensive.

One advantage of UHF transmission is the physically short wave that the high frequency produces. That means the radio’s antenna may be shorter than an equivalent VHF radio.

VHF station

VHF equipment operates between the frequencies of 30 MHz and 300 MHz. FM radio, two-way radios, and television broadcasts operate in this range.

Both UHF and VHF radios are prone to line-of-sight factors, but VHF a bit more. The waves pass through trees and rugged landscapes, but not as well as UHF frequencies. However, if a VHF wave and a UHF wave were transmitted over an area without barriers, the VHF wave would travel almost twice as far. This makes VHF easier to transmit over a long range. If you work primarily outdoors, a VHF radio is probably the best option, especially if you’re using a base station radio indoors and add the external antenna.

Since VHF has been around longer and is not as complicated to manufacture, the equipment is often cheaper compared to similar UHF equipment. A disadvantage of this equipment can be its size. Since the frequency waves are larger, an antenna must be larger.

VHF radios also have fewer frequencies available. Interference with other radios is more likely to be a problem. However, the FCC recently made this less of an issue when they opened up the MURS frequencies. The 150 MHz frequency is a Citizens Band radio spectrum called MURS service. MURS stands for Multi-Use Radio Service. This service is for use in the United States and Canada. It is a low power and short range service in the VHF 150 MHz Citizen Band radio spectrum. There are 5 channels on the MURS frequencies with 38 privacy codes under each that allow you to pick up conversations with just your code. The FCC does not require that users of MURS products be licensed.

With MURS you can add a larger or external antenna to improve range. If you want to put an antenna on top of your house or business, you can do it with MURS. Some antenna manufacturers claim that an external antenna can increase the effective radiated power of a transmitter by a factor of 4. These MURS intercoms can transmit up to four miles, and perhaps more with an external antenna depending on the terrain.

One advantage of VHF wireless radios is that battery life is almost always better than similar UHF units. For handheld radios this is an advantage.

VHF equipment is usually lower cost for those on a limited budget. The equipment may be cheaper than similar UHF products.

In short, if you plan to use your two-way radios primarily inside buildings, then UHF is likely the best solution for you. If you’re primarily using your two-way radios to communicate with the outside world, VHF would be a good choice. Any of the radio technologies may work for you if you don’t really have a long range to cover. In that case, you may want to choose VHF for its lower cost.