Overland Communication Basics: Two-Way Radios
Whether you are on a weekend off-road trip or a months-long overland expedition, being able to communicate from one vehicle to another while on the trail is critical. While mobile phones can be very helpful for communicating when you’re near cell towers, many backcountry areas lack coverage. That’s where two-way radios come in.
In this article, we’ll go over the various radios typically used by overlanders and off-roaders for communications.
The most common use for radios in vehicle-based adventure is communicating among vehicles traveling together in a group. For instance, the lead vehicle on the trail may warn others of an upcoming hazard, tell them what fork in the road to take, or provide beta on the best line through difficult terrain.
Another use for radios is during emergency situations. Two-way radios can help everyone in the vicinity stay in contact and coordinate during a rescue situation. Generally speaking, we recommend GMRS radios as they are relatively inexpensive, easy to use, and can also communicate with FRS radios. If you’re planning to head out with a local off-road or overlanding group, find out what type of radio they use.
Two-way radios shouldn’t be relied on as a way to call for help from distant emergency services, as their range is relatively limited (a ham radio used by an experienced operator being the possible exception).
Consider carrying an additional satellite communication device from companies such as SPOT or inReach for calling search and rescue in an emergency.
How do Two-Way Radios Work
We’ll go through the various flavors of two-way radio technologies below – CB, FRS, GMRS, etc – and explain how they differ. First, though, let’s talk about how they are similar.
Signal Power and Range
At the most basic level, radios communicate by transmitting and receiving electromagnetic waves. The transmitter emits a wave signal which travels outward in all directions for some distance (its range) that depends on the power of the signal (measured in watts). For instance, a 2-watt handheld radio might have a usable range of only 1 mile, while a 50-watt radio might have a range of over 50 miles.
Terrain obstacles such as mountains and buildings can block radio signals, so range may be reduced. Temperature, humidity, and air pressure can also affect radio signal range.
The frequency of the radio signal is measured in hertz and derives from the wavelength of the radio wave. In radio communications, the transmitter and receiver radios must be tuned to the same frequency to send and receive a signal.
The radio waves include frequencies of the electromagnetic spectrum from 30 hertz to 300 gigahertz (GHz). Radios used for backcountry communication fall in the 3-3,000 megahertz (MHz) range, which includes the High Frequency (HF), Very High Frequency (VHF), and Ultra High Frequency (UF) ranges.
Lower frequency radio waves generally travel further. On the flip side, higher frequency waves are better at passing through buildings, trees, and other obstacles.
Citizen band radio (CB), long the goto comms for off-roaders, uses the HF band. In recent years, family radio service (FRS) and general mobile radio service (GMRS) radios, which use the VHF band, have become more popular among overlanders and off-roaders and for other backcountry activities.
It’s important to note that radio technologies and government regulation of the radio spectrum vary by country. The information provided here is applicable in the United States and Canada. If you will be traveling internationally, do some research in advance to determine whether you will be able to use your radios in the countries you will visit. For instance, it is illegal in Europe to operate the FRS radios sold for use in the United States.
Modulation: FM vs AM
Another key factor that differentiates different types of radios is how the signal is modulated to carry information. With frequency modulation (FM) radios, the frequency of the radio wave is altered to carry the information that the receiving radio converts into music or voices.
With amplitude modulation (AM), the amplitude (overall strength) of the wave is altered to carry the information. Generally speaking, FM signals tend to produce a cleaner sound than AM when you are in range of the signal, which makes it easier to understand voices.
Types of Radios
There are many different types of radios, but just a few are commonly used for backcountry recreation, including for off-roading and overlanding.
Handheld walkie-talkies have been used by professional guides and first responders for decades. As technology has improved and prices come down, these have become increasingly popular among outdoors recreation enthusiasts as well.
A major reason for their growing popularity is their compact size, ease of setup and use, affordability, and versatility. You can use them in your vehicles or throw them in backpacks in case you get separated while hiking, skiing, or mountain biking.
Both GMRS and FSR operate on frequencies between 462 and 467 MHz and both types of devices broadcast and receive FM waves. MURS radios operate in the VHF band from 151.820 MHz to 154.600 MHz. Below we’ll go into a bit more about each and the differences between them.
General Mobile Radio Service (GMRS) Radios
General Mobile Radio Service (GMRS) devices operate in the 462 and 467 MHz frequency range. Most GMRS radios use between 1 and 5 watts of power, although they can use up to 50 watts on channels 15-22. They have a better range than FRS radios and CBs (see below), with a typical maximum range between 1 to 2 miles, and some devices with larger antennas broadcasting further. The extra wattage also makes the signal a bit clearer than FRS.
One cool thing about GMRS radios is that their range can be dramatically boosted by a growing network of radio towers. These repeater towers can carry signals from tower to tower, increasing the range of a radio by hundreds of miles. That said, not all areas have towers nearby, so you can’t necessarily count on your signals getting such amplification.
With GMRS radios, you can also install an external antenna on your vehicle to boost the signal. In unobstructed terrain, this can give you 5 to 10 miles of range.
GMRS radios have started to replace CB radios as the go-to communications devices for some off-roading and overlanding clubs, as they are relatively inexpensive, easy to set up and use, and have a longer range and more clarity than CBs. GMRS radios require purchasing a license from the FCC (though no test is required), which costs $70 and is good for 10 years. Check out our guide to handheld GMRS radios for recommendations on models that are good for off-roading and overlanding.
Family Service Radio (FSR)
Family Service Radio (FSR) devices, also referred to as HT (hand-talkie) devices, are personalized radios that use 22 channels in the 462 and 467 MHz frequency range, which are shared by GMRS devices. FSR radios are limited to a maximum power of 2 watts, which limits their upper range of FSR devices to about a mile, depending on the terrain and what channel you use.
These are the most popular hand-held radios among outdoors enthusiasts and are great starter radios for off-roading and overlanding. They are relatively inexpensive, easy to use and may be all you ever need. That said, the GMRS radios provide more range, which can come in handy for vehicle-based exploration, where it’s relatively easy for vehicles to quickly become separated by a greater distance than hiking or other human-powered activities.
Many radios on the market now are marketed as FRS and GMRS compatible. One thing to keep in mind is that you can use the FRS channels without a license, but if you want to use the higher power GMRS channels, you’ll need to pay for the FCC license.
Multi-Use Radio Service (MURS) radios are similar to FRS radios but operate on 5 channels in the VHF band from 151.820 MHz to 154.600 MHz. MURS radios have a maximum power of 2 watts and, similar to FRS, can’t use repeater towers. Unlike FRS radios, you can use a larger external antenna to boost the unit signal, which can add quite a bit of range.
MURS radios stack up well against FRS radios overall. However, the deal-breaker for us is that they operate outside of the range of the more common FRS and GMRS radios, so you won’t be able to communicate with other vehicles using those technologies.
Citizen’s band (CB) radios have long been the standard communications technology for off-road enthusiasts. They are relatively affordable, easy to install, have a good range for short-distance comms, and for a long time were the only game in town.
In the United States, the power of CB radios is limited to 4 watts, and they have a range of around 3 to 20 miles, depending on the terrain. CB radio operations in the High Frequency (HF) band on 40 channels with frequencies ranging from 26.965 to 27.405 MHz. In many countries, including the United States, CB doesn’t require a license.
The lower frequency range of CBs gives them more theoretical range than GMRS and FRS radios, but the signal can struggle to travel through terrain that’s obstructed by buildings or forests. Also, the limitations on their wattage limit their signal power, particularly compared to ham radios which can also use lower frequency bands (see below). CBs don’t use repeater towers, and so can’t use that strategy to boost their signal.
Another downside of CB radios is that, due to operating in a different radio band, they can’t communicate with the other hand-held radios that are becoming more popular (FRS, GMRS, MURS, and ham). The others can communicate with one another, which is one reason they are becoming more popular, as people with different types of radios can communicate with one another.
With prices of GMRS and FRS devices dropping significantly over the past couple of decades and their tech improving, they are rapidly replacing CBs for backcountry pursuits. For serious radio enthusiasts, mobile ham radios are becoming more popular.
Long a desk-bound hobby of hard-core enthusiasts, Amature Radio, also known as ham radio, has entered the off-road adventure fray only in recent time with the advent of hand-held ham devices.
The major benefit of ham radios is their output strength and low cost. Most handheld ham radios operate at around 4-5 watts, but hard-wired mobile ham radios may operate in the 50-watt range. A mobile ham radio operating at 50 watts could reliably transmit a signal in the 50-mile range and possibly quite a bit further in optimal conditions. Ham radios can also use repeaters, which can expand their signal range into hundreds of miles.
Ham radios use FM signals and operate at a wide range of frequencies in the VHF and UHF bands, so their clarity is typically better than CBs.
Because of their long-distance capabilities, ham radios are the only two-way radios that might be considered a go-to for calling in emergency responders in a crisis. Another advantage is that ham licenses and devices are generally accepted across international borders, which allows you to use the same devices even if you’re traveling internationally.
The major downside of ham radios is that you have to be a licensed ham operator to transmit signals. This raises the bar for entry and will limit your ability to communicate with other vehicles when you are traveling in groups where not everyone has a ham license and radio.
If you are willing to go down the rabbit hole and learn quite a bit about radio technology, newer programmable radios made by companies such as Rugged Radios and Baofeng can let you receive and transmit signals on many of the frequencies mentioned above (CB, FRS, GMRS, HAM).
The catch is that these radios can be complicated to use and that you must have appropriate licensing to use HAM and GMRS-only frequencies. Remember, that while you can listen in on HAM and GMRS frequencies, it’s illegal to transmit on them unless you are licensed.
Programmable radios are the most versatile option for two-way radio communications. If you are willing to spend the time and money they can be a great choice. The main downside is their complexity.