What is GMRS? Why do those four letters keep popping up in campfire conversations when discussing off-road communication? What do those four letters mean? Why should you care? To answer those questions, let’s explore the basics of GMRS.
What This Story Isn’t About
This story is about GMRS (General Mobile Radio Service) and how it can benefit off-roaders. There are several other types of radio services available in the U.S., and all are regulated by the FCC (Federal Communications Commission), including some you’ve undoubtedly heard of and may have used on the trail, such as CB (Citizen’s Band Radio Service), FRS (Family Radio Service), MURS (Multi-Use Radio Service), and Amateur Radio Service (aka ham radio). Each is unique and worthy of study, but GMRS is the topic of the day. Oh, and it’s important to note that this story is reflective of the U.S. market.
GMRS Simply Defined
As noted on fcc.gov, GMRS has 30 total channels. Channels 1-7 are limited to a maximum effective radiated power (ERP) of 5 watts, channels 8-14 are limited to a maximum of ½-watt ERP (the FCC only allows handheld radios to transmit on these channels), channels 15-22 (and the eight repeater channels—more on those later) can have a maximum ERP of 50 watts. GMRS allows analog FM voice operation in the UHF (ultra high frequency) band, around 462 MHz and 467 MHz. Note: FCC rules allow GMRS radios to transmit digital data (“a brief text message,” per the FCC’s description) and share GPS location information from handheld portable radios, but the pool of radios capable of this are small at this time.
Notice we’re using the term “channels” and not “frequencies.” Of course, GMRS radios transmit and receive on specific frequencies, but GMRS radios are “channelized.” This means that most GMRS radios display channel numbers by default, and not frequencies. The benefit to this is ease of use. You can simply say “let’s use channel 16,” for example, and anyone on an FCC-approved GMRS radio should be able to talk to you. This is by design, and is easier than saying “go to 462.575 megahertz,” which is the frequency for GMRS channel 16.
It’s important to note that GMRS requires an FCC license to transmit, but one is easy and inexpensive to acquire. You may apply for a GMRS license if you are “18 years or older and not a representative of a foreign government.” A GMRS license requires no test, it’s only $35, it’s good for 10 years, and according to the FCC, “If you receive a license, any family member, regardless of age, can operate GMRS stations and units within the licensed system.” A license can be obtained by going to the FCC Universal Licensing System (ULS) website to complete the application and pay the fee. Once approved, you’ll be issued a call sign consisting of four letters and three digits. GMRS rules require that you ID using your callsign “following a single transmission or a series of transmissions and after 15 minutes and at least every 15 minutes thereafter during a series of transmissions lasting longer than 15 minutes.”
The preceding is a portion of the FCC’s GMRS requirements. A more detailed overview of GMRS rules and requirements can be found in the GMRS section of the National Archives and Records Administration website.
How GMRS Can Benefit Off-Roaders
You know how important it is to have reliable communication when you’re off-roading. Cell phones typically aren’t an option for always-on communication between vehicles, even if there is cell service where you’re ‘wheeling. Two-way radios have been used for decades in the off-road community, with CB being the dominant choice, but GMRS is quickly becoming prevalent. This is partly due to a massive number of GMRS radio choices for a wide range of budgets. Also a biggie: GMRS’s ability to access repeaters to vastly increase communication range and potentially give you the ability to summon help in an emergency when cell phone service is unavailable.
GMRS Radio Choices
Selecting a GMRS radio is similar to selecting the right locking differential for your 4×4. Just as there’s a slew of lockers on the market, there’s a slew of GMRS radios, and like lockers, GMRS radios vary in features and cost. You need to determine how you plan to use the radio and how many dollars you wish to spend.
The vast majority of GMRS radios on the market are “handy-talkies” (commonly known in the radio world as “HTs”). These are probably not like the walkie-talkies you played with as a kid. These have much higher transmit power (like 2-5 watts) and more features. GMRS HTs range from inexpensive and basic to what is often referred to as “prosumer,” with all the bells and whistles … and a higher price tag. Some GMRS HTs offer a removable antenna, so you can add a stubby antenna for use in tight quarters or an upgraded antenna to maximize transmit and receive range. Most radios with removable antennas also allow you to connect to an external antenna to increase range (for example, a magnet-mount antenna on the roof of your 4×4). Some HTs require a dock to charge, while others have a charge port that makes charging on the go easier. Some have repeater capability that can vastly increase communication range. Some HTs can be customized via software and/or the front panel. Also, some radios are IP rated to ensure they will work in dirty and/or wet conditions, such as those found when off-roading.
There is also a variety of 12-volt-powered “mobile” GMRS radios for use in vehicles or as a base station. Mobile radios typically offer much higher ERP than a HT (up to the GMRS 50-watt max limit). This can translate to more communication range. There are many mobile radios on the market today, and like HTs, they range from basic to prosumer. One important thing to keep in mind is that a higher-wattage GMRS radio, like a 50-watt radio, will generally give you better range than a lower-wattage radio, but it will need to be wired directly to your 4×4’s battery due to the high amp-draw. However, some of the lower power GMRS mobile radios can be powered by your vehicle’s 12-volt power point due to their lower amp draw, and most of those come with a power plug installed on the wiring.
Antenna Is Important
Choosing a GMRS radio is only part of the equation to achieving solid off-road communication. The other half is choosing a quality antenna and mounting it correctly to maximize radio performance. For example, a high-output GMRS radio connected to a subpar or improperly mounted antenna is like stuffing a potent big-block engine in your 4×4 and then connecting it to an undersized, poorly routed exhaust system. Just as your 4×4’s engine performance would be negatively affected, your radio won’t be operating at peak performance.
There are several high dB gain GMRS-tuned antennas with quality coaxial cable available. Some require a ground plane (like the metal roof of your 4×4), and others don’t. Additionally, there are various mounting methods for antennas, and your method will be dependent on the type of 4×4 you have and the surface (metal, aluminum, or fiberglass) where you wish to mount the antenna. If you wish to maximize your radios range, it’s important to get the antenna as high on your vehicle as possible. Height is might in the antenna world. The feasibility of a high-mount antenna will vary depending on how and where you ‘wheel.
Repeaters and GMRS
A very cool feature of many GMRS radios is a capability to utilize repeaters to vastly increase communication range. Quite simply, most GMRS repeater systems typically receive a radio transmission on one frequency, amplify it, and then transmit it on a different frequency. Most repeater antennas are located on a building, tower, hill, or mountaintop to increase receive and transmit range (again, height is might in the antenna world). Since GMRS is a line-of-sight communication medium, range is often limited by obstructions, but as noted, a repeater system can offer a vastly increased communication range.
For an example of how a repeater can help you communicate while off-roading, imagine that you can’t access cell service, but you need to talk with a fellow ‘wheeler who is 5 miles distant, and there’s a mountain between you. Your GMRS radio signal cannot penetrate the mountain, so communication isn’t happening. However, if there’s a repeater on top of that mountain, it can receive your radio signal, amplify it, and retransmit it, vastly increasing your range. How far you will be able to communicate using a repeater will depend on several factors including your altitude, obstructions between you and the repeater, the altitude of the repeater’s antenna, the output power of your radio, the output power of the repeater, and atmospheric conditions. Optimum example: If a repeater has a range of 30 miles in a circular radius and your radio can access the repeater at its 30-mile southern end, the repeater makes it possible for you to talk to another GMRS radio that is 30 miles north of the repeater. That 60-mile overall range is notable for sure.
As noted earlier, many GMRS radios are repeater-capable, but not all, so if you desire to utilize repeaters, you’ll need to ensure the GMRS radio you’re purchasing is capable of repeater use. Repeater-capable GMRS radios will generally be noted as such by the manufacturer and have channel settings that transmit on the input frequency of the repeater and receive on the output frequency of the repeater. Repeater capable GMRS radios will also offer the capability to select and transmit the repeater’s “PL tone,” which allows access to the repeater. The PL tone is a subaudible tone that opens the input side of the repeater to accept your radio transmission. If this PL tone is not received, the repeater will not allow your radio communication to be accepted by the repeater.
To find if there’s a repeater near you or your favorite ‘wheeling spot, go to mygmrs.com. This website is a great source of GMRS repeater information. We often visit the site prior to going on off-road forays to gather repeater information so we can get permissions if necessary and program the required PL tones into our GMRS radios.
The U.S. has many GMRS repeaters, and most are free to use by licensed GMRS users. Repeaters are expensive to purchase, install, and maintain, and often the owners absorb these substantial costs. However, some repeaters and/or repeater networks require payment, and some require permission from the repeater owner to use.
And on the subject of repeater networks, it’s worth noting that some GMRS repeaters are linked (usually via the Internet), meaning you can transmit to a linked repeater and your voice will be sent to all the repeaters on that linked network. In some cases, these linked networks can cover several states, allowing you to talk to other GMRS users hundreds or even thousands of miles from your location. Some of these networks are free to use, but others require payment.
What About Range?
The transmit range of GMRS radios is a question that comes up often, and the answer depends on several factors. Using radio-to-radio (non-repeater) as a first example, the range of communication will depend on the output power of the radios, the altitude at which each radio is being used, obstructions between the radios (trees, buildings, and such), the antenna each radio is using, and other factors. We’ve used 5-watt HTs that could only communicate around ½-mile in the city but could transmit over 7 miles in rolling farmland with each radio on high ground relative to the surrounding terrain.
During the 2021 Four Wheeler Overland Adventure in Utah, we were able to clearly communicate over 20 miles (as the crow flies, per our onX map) using a pair of 50-watt mobile radios. Both radios were in vehicles that were located on high ground in mountainous terrain. When in winding canyons, the distance we could communicate decreased substantially, as expected.
As noted previously, when using repeaters, range can increase exponentially. For example, on one occasion this author has used a 50-watt radio mated to a flagpole-mounted GMRS-specific antenna to access a repeater in Wisconsin that was 60 miles distant from his location in northern Illinois. In Tennessee, he used a 5-watt HT to access a repeater 12 miles distant. Both repeaters were on high ground.
The aforementioned are random examples only, gathered from our experience, and the range of your radios will vary.
We’ve used a variety of radio services and transceivers over the years while off-roading, and each has pros and cons. We’ve been using GMRS often in our recent on- and off-road travels and have been impressed at the clarity and range. We’re also impressed at the vast number of GMRS radios available. We also like that the license is easy and inexpensive to obtain and can be shared with family. The ability to access repeaters to increase range is the icing on the cake.
4 GMRS Radio Questions for Midland Radio
Midland Radio is a longtime radio manufacturer with a storied history. Among other things, the company is known as the first CB radio manufacturer in the U.S., and it has been involved in GMRS radios since the late 1990s. Midland knows radios, and the company was the Official Communication Product of the 2021 and 2022 Four Wheeler Overland Adventure Presented by Jeep, which ensured that all of the participants could reliably communicate.
One of the cool things about the company’s GMRS product line is that it offers a variety of HTs and several mobile radios. Midland’s mobile radio lineup is one of the largest on the market, with 5-, 10-, 15-, 40-, and 50-watt GMRS radios available. This makes Midland appealing to 4×4 owners looking to add or upgrade a GMRS radio in their rig no matter how much power they want.
Midland is an expert in the field of GMRS, so we shot the company a few questions to get its take on GMRS.
Why do you think GMRS has become so popular?
Answer: GMRS has become popular because of its range, voice clarity, and ease of use when comparing it to CB, which most people make the switch from. GMRS allows up to 50 watts of power on channels 15-22, compared to only 4 watts of power for CB. Midland GMRS radios come plug-and-play out of the box. There is no programming of the radio or tuning of the antenna required. The radios come with preprogrammed channels, ready for you to start communicating immediately.
What is Midland’s product philosophy for GMRS radios?
Answer: Our philosophy is to make high-quality radios for the general user. Our interfaces are as simple as can be. However, if you want to nerd out, our higher-end radios will allow for that too.
Can Midland offer information to help folks get their GMRS license?
What is the best purchasing advice you can give to someone looking to acquire a GMRS radio?
Answer: Instead of asking what is the maximum range of the radio, ask yourself how much range do I really need? The majority of users will be perfectly fine with a 15-watt radio, however there are those “power-pushers” out there, and for those people Midland offers two 50-watt radios.
Mobile GMRS Radio Gear We’re Using
Which mobile GMRS radio gear are we using? Well, this author has several Midland-based radio setups. When in the office, there’s a MXT500 50-watt radio scanning the local repeaters and other GMRS traffic. Among other components, it uses a portable, high-mount, GMRS-specific antenna.
In the 4×4, we have an MXT575 50-watt radio paired with Midland’s exceptional NMO-mount MXTA26 6 dB gain whip antenna on Midland’s MXTA12 magnetic antenna mount. We have the antenna on the roof, but move it to our pickup’s bedrail when ‘wheeling on trails where there are low-hanging tree limbs.
When we need to utilize air-travel to get somewhere, or when we’re shuffling from vehicle to vehicle, the MXT115 15-watt radio or the MXT275 15-watt radio get the nod. The beauty of these radios is that they’re small and lightweight, perfect for tossing in a checked or carry-on bag. And because of their low amp-draw, these radios can simply be powered from a 4×4’s 12-volt power port. Each radio is paired with Midland’s MXTA51 2.1 dB gain NMO antenna kit that is also small and easy to pack.
Watch! Jeep vs. Jeep Off-Road Races!
Dirt Every Day hosts Fred Williams and Dave Chappelle have raced everywhere. They’ve done long desert races, off-road treks in old trucks, and old-fashioned mud races with Jeeps. Check out this compilation of their best races, then sign up for a free trial to MotorTrend+ and start watching every episode of Dirt Every Day! Video created by Little Dot Studios.