Are you looking for a way to increase the power output of your GMRS radio in order to get more range? Aside from using repeaters, there are several ways to increase GMRS radio range – some of them legal, some not. First, let’s take a look at using a linear amplifier for GMRS radio, and see if that’s a good idea or not.
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GMRS Radio Linear Amplifiers
GMRS radio is quickly replacing CB in the off-road and overland community. Because of the rapid adoption of these useful radios, along with the availability of cheap imported gear – much of which isn’t FCC approved – there seems to be some confusion about what’s legal on GMRS – such as linear power amplifiers. If the legal output for GMRS is 50 watts, couldn’t you just get a 50 watt linear amplifier for your 15 watt Midland Micromobile, and make it transmit farther?
Linear amplifiers, which increase RF power with very little distortion, have been popular with CB users for years, despite the fact they’re illegal. Ham radio operators may legally use linear amplifiers – up to 1,500 watts on some bands – however GMRS users aren’t allowed the same privileges.
Can You Use A Linear Amplifier For GMRS Radio?
The answer unfortunately, is no, you can’t use a linear amplifier on any GMRS radio. That’s because all equipment used on GMRS channels must be FCC part 95 type accepted. There’s no legal, part 95 accepted linear amplifier for GMRS on the market.
While these devices may be “part 90 accepted” they’re not “part 95 accepted” and that falls short in the eyes of the FCC. Amplifiers like the BTech models sold online also don’t contain any kind of circuitry which would limit power on channels 1-7 (where only 5 watts is allowed), so there’s that problem.
Simply because equipment is available for sale online, and it operates on GMRS channels, such as the Baofeng UV-5R handheld units, they’re still not legal to use on GMRS. Although enforcement of the law is rare, the FCC has levied fines of more than $10,000 for the use of linear amplifiers.
How To Legally Boost GMRS Radio Power
Fortunately there are a few legal ways to boost GMRS radio output which won’t get you an expensive fine from the FCC.
Setting GMRS Radio SWR
In a previous post, How to Easily Tune your GMRS Radio Antenna for Low SWR we took a look at how to match your radio to your antenna, a crucial step in your GMRS mobile installation. Power that’s being reflected back into your radio because of a mismatched antenna is that much less that could be radiated in the direction you want it to go. For example, at 50 watts of output, a high SWR of 2.0:1 would result in approximately 5.5 watts of power loss, and worse, could cause damage to your radio.
Power Isn’t Everything
It’s important to note that when it comes to GMRS radios, having “line of sight” between you and another radio is more important than increasing power. You won’t notice much improvement from increasing power when there are obstacles in the way, or if the other radio is below the “radio horizon” which is just slightly longer than actual line of sight.
Proper Antenna Placement For GMRS Radio Antennas
The very best place to mount a GMRS radio antenna is the center of your vehicle’s roof. That’s because the “ground plane” formed by your vehicle’s metal roof creates the most unilateral distribution of radiated power, and because the higher you place your antenna, the better it will work. This may not always be the most practical for off-road use, especially if there are overhanging limbs.
Australian overlanders typically place their HF outback radio antennas up front, on their large grill guards, which also make a nice ground plane. For our overland setup, we first tried mounting ours on the side of our truck’s bed rack, which proved less than ideal. We later installed a NMO mount in the center of our truck’s cab, which works much better for our 5/8 wave GMRS antenna.
Below is an illustration showing how power is radiated from different antenna placements on a vehicle.
Replacing Your Stock Mobile or Handheld GMRS Antenna With a High Gain Model
One of the most effective, legal ways to boost GMRS radio power output is to increase the ERP or effective radiated power, by upgrading to a high-gain GMRS antenna. For our mobile setup, our own antenna of choice is the Tram Browning BR-180-B, which is actually a dual band antenna designed for VHF and UHF ham radio frequencies. Since GMRS falls within the UHF range, it fits the bill perfectly and offers 5.5 dB gain on GMRS channels. With an NMO mount, we can easily unscrew it and replace it with a Midland ghost antenna when traveling along trails that have lots of overhanging branches.
Another excellent choice for off-road vehicles is the Midland MXTA-26, (also a NMO mount) which we use on our old Jeep. It’s a single band GMRS antenna, with a cleaner look, minus the second loading coil of the ANLI WH-713, and it offers an impressive 6 dB of gain.
The MXTA-26 has a strong spring base to protect it if you brush an overhead limb or two. It’s compatible with Midland magnetic and L-bracket mounts, or if you prefer a cleaner install and are ready to commit, you can drill a hole in the roof of your cab and do a flush mount.
Boosting GMRS Handheld Range
The single best way to boost your GMRS handheld radio’s range is to change out the stock antenna for a higher-gain model. For radios such as the Baofeng/BTECH models which accept a SMA female connection, a Nagoya NA-771G 15″ (longest range) or NA-701G 5.5″ whip (better for pocket carry) is perfectly tuned for GMRS channels and can really boost output and receive capabilities. (Ones without the “G” are for ham use, not tuned for GMRS.)
The Nagoya antennas are durable and flexible, but the 15″ whips are not well suited for carrying a radio in your pocket as is the shorter, 5.5″ NA-701G whip.
Why Replace Your GMRS Handheld’s Stock Antenna?
Because many handhelds are just versions of that brand’s amateur radios, models of Baofeng/BTECH radios, Wouxun, Radioddity, etc., are often sold with generic UHF/VHF whips that work better on ham bands than they do on GMRS. For best range we strongly suggest replacing your stock antenna with something like the Nagoya “G” series that’s more resonant.
Tactical Antennas For GMRS Handhelds
Folding, military style “tactical” antennas are a great idea in concept, but have not been without problems when used on GMRS channels. High SWR is the number one reason these high-gain antennas don’t typically perform that well on General Mobile Radio Service handhelds. For us, the exception to that has been the Abbree AR-152 fold-over tactical GMRS antenna, which performed very well in our tests with low SWR and greatly increased range vs. the stock handheld antenna. While this antenna offers good performance, it’s not really practical for day to day handheld use. See our comparison of it to the Nagoya 771G for more info.
Using a Tiger Tail or Counterpoise on Your HT
Many ham radio operators swear by using a device called a “tiger tail” or counterpoise on their handheld transceivers. These typically consist of a length of wire that’s cut to match the antenna’s wavelength, attached by a terminal lug connector to the base of the rubber-duck antenna. These can help performance by providing more of a proper ground plane than what the small amount of metal inside your radio offers. We’ve found that these do provide a small amount of power boost to GMRS radios like our Baofeng UV-9G. For more on these you can see our article Using a Tiger Tail to Increase GMRS Handheld Performance.
How Much More Power Can You Get From a High Gain GMRS Antenna?
Assuming your radio’s output power was 50 watts, if you were to replace its short, stock antenna with one having a gain of 6 dB – compared to a hypothetical 0 dB gain of the stock antenna – you’d increase the ERP (Effective Radiated Power) to 121 watts, well more than doubling the effective power output of your GMRS radio, legally. In addition, you’d be getting more signal into your radio’s receiver, thereby receiving distant stations better, which is something a linear amplifier can’t do. Changing out your antenna is perhaps the best thing you can do to boost GMRS radio range.
What About GMRS Ghost Antennas?
Stealth or ghost GMRS antennas are gaining popularity. The Midland MXTA25 offers 3db of gain and we sometimes use it in place of our 37″ whip when we don’t need maximum range. We did a test of the Midland GMRS ghost antenna, and it performed quite well. The key to getting good performance out of a stealth or ghost antenna is placing them as high as possible, on the center of the cab if feasible for an effective ground plane.
High Gain Directional Yagi Antennas For GMRS
Besides a linear amplifier, another way to boost GMRS radio range is to use a directional GMRS antenna. These antennas can theoretically boost a 50 watt radio’s ERP to an impressive 242 watts ERP, as well as to help greatly on the receiving end. These small directional antennas are compact enough to take along and set up at base camp, and can allow you to connect to repeaters and mobiles to up to 60 miles or more, if you’re camped at a high elevation.
(We met some campers who’d set up a GMRS yagi antenna on a long painters pole off the side of their RV, so as to be able to keep in touch with their kids, who were riding ATV’s in Coral Pink Sand Dunes State Park in Utah.)
Are Directional Antennas Legal On GMRS?
According to the FCC:
“462 MHz interstitial channels: The effective radiated power (ERP) of mobile, hand-held portable and base stations transmitting on the 462 MHz interstitial channels must not exceed 5 Watts.” So, would my mobile’s 5.5 dB gain antenna – which causes it to transmit with an ERP of over 10 watts on channels 1-7 – then make my overland radio setup illegal? I do think that I probably think too much.
Note: There’s no ERP limit mentioned in Part 95, Subpart E for the main GMRS channels, 15-22 – so using a 9 dB yagi on those channels “should be” as legal there as any other kind of antenna.
Don’t take our word on this and see the FCC’s rules in the link below – and then draw your own conclusions before using a directional antenna with GMRS – and if you do – you probably shouldn’t use one on channels 1-7.
Reference: FCC Part 95 Subpart E
Below: A 11 dB Gain GMRS Antenna Set Up at Camp
Other Ways To Increase GMRS Radio Range
For longer range, use the high power GMRS channels, 15-22, where 50 watts of power is allowed, if you have a full power mobile. Your set should have a high/low power mode, and you can switch this to high for more power output. For day to day use, try to use as low of a power setting as you can get by with, and consider using one of the 5 watt channels, 1-7 when possible, to prevent congestion of heavily used channels 15-22.
When making a call from your handheld or mobile, try to wait until you’re away from nearby obstacles and are out in the open, preferably up on some elevated ground. This will prevent the RF from your radio by being absorbed by nearby objects.
GMRS Repeaters
If you own a repeater-capable GMRS radio you can take advantage of repeater stations across the US. These act as a kind of relay station, to re-broadcast your signal over a much wider area, even up to nationwide in some cases, when these are linked through the internet. While some of these are private and not open to use by the public, many others are available for the general public to respectfully use. For more info you can see our article How to Use GMRS Repeaters For Longer Range.
Two Examples of GMRS Radio Range
Below is an illustration of real-world GMRS radio range – base to mobile, mobile to mobile and mobile to handheld. Range varies greatly and your results may be very different from this example.
The second illustration (below) was created using an online radio range calculator called Radio Mobile, developed for amateur radio operators. It shows the theoretical range one should be able to achieve from atop Pikes Peak (elevation 14,115″) using GMRS radio. We added this just to show that range is a very subjective thing that’s dependent largely on your antenna elevation, followed by output power and the height of the receiving antenna. In some places a full power GMRS radio might give you a mile, in others, half of the state of Colorado!
