For those of us with a passion for the boondocks, walkie-talkies are handy little devices. Until you try to get one. I’ve been craving peace of mind for my upcoming hikes in out-of-cellular-service bush walks. But when shopping for a transceiver, I banged my head on an anagram wall of choice.
Family Radio Service (FRS), General Mobile Radio Service (GMRS), and Multi-Use Radio Service (MURS) are the dominant personal radio systems in America. Each has at least one relative advantage over the other, and choice depends on the context of an application, mainly regarding team and terrain.
We will consider each in turn, in their order of appearance on the scene. Knowing the individual characteristics will help us carry out the comparison later.
FRS is a walkie-talkie protocol specified by RadioShack in 1994 and authorized two years later. Based on frequency modulation (FM), it replaced the citizen band (CB – see below) and provided improved sound quality and performance. In the US, FRS utilizes ultra-high frequency (UHF) bands around 462 and 467 MHz.
The radios use narrow-band modulation with a deviation less than 2.5KHZ. Channels spacing intervals are 12.5KHZ. Radiation is limited to 2 Watts. On channels 8-14, 0.5W is the limit. Only permanently attached aerials are permitted. Devices often implement privacy codes for filtering out interference.
- The FCC exempts FRS from the licensing requirement.
- Radios are inexpensive and freely available.
- The devices function as cheap extras.
- They have high adoption rates, meaning that there is a higher likelihood of reaching someone in times of distress.
- Frequency modulation results in clear voice communication with no static when the transceiver is in range.
- They share a frequency range with GMRS, further broadening the at-hand community.
- These devices are available as hand-held radios only.
- The ban on external antennae limits the range.
- Ultra-high frequencies are more susceptible to absorption by dense vegetation than lower frequencies. This makes them less hardy in the bush.
- The high adoption rate means that it is harder to find unused channels in populated contexts (think the trip to Disney).
Like FRS, this is a UHF land-based radio system. It is more extensible than FRS and requires a license in the US. The FCC-issued license is valid for ten years and open to every immediate family member of the nominal license holder.
GPRS operates in channels around the 462 and 467 MHZ points. Unlike FRS, mobile-based-station configurations are allowed. GMRS repeaters are allowed for signal strengthening. These repeaters extend the effective range of the devices and must be decoupled from the public telephone network.
- More powerful transmission is allowed. Radiation of 5 watts is permitted on the FRS channels and up to 50watts on the remaining slots.
- The FRS frequency overlap allows communication with unlicensed users.
- The combination of high radiation and external antennas creates an effective range of five to ten miles, barring intervening barriers (walls, canyons, etc.)
- Repeaters extend the effective range.
- In practice finding an unused channel can be difficult. This is a downside to the FRS overlap.
- As with FRS, dense vegetation creates a problem.
- A $35 license is required. There’s no test (unlike HAM), and it covers the entire immediate family.
- The effective range drops 30% inside a vehicle. Between a hand-held and mobile installation, the drop-off is in the 10-15% range.
MURS is a former business-use radio access service that has been available to the general public since 2000. It operates in the VHF band and places a maximum radiation limit of 2watt on transceivers. MURS base stations must be decoupled from the public telephone system, and they are not allowed to support store and forward operations.
This service is relatively unknown, and it is not clear how the adoption rate will evolve in the near term. MURS operates on five channels staggered around 151MHZ and 154MHZ. All channels work in narrow-band mode. The two 154MHz channels also work on the standard 25KHz band.
- VHF is more resilient to vegetation interference than FRS.
- The low adoption rate means that free channels are easier to find and interference less likely to encounter.
- External antennae are allowed.
- As with FRS, the FM means voice is crisper.
- As with FRS and GMRS, the devices are relatively inexpensive, though some more advanced configurations reach a higher price bracket.
- The low adoption rate makes it harder to be heard on this medium.
- There are only five available channels, portending problems if the adoption rate increases.
- The legacy as a business service means there’s a risk of interference from legacy commercial users.
- MURS is configured to yield to emergency services, but finding one is unlikely as they tend to be on the other services.
FRS Vs. GRMS
Given the trade-offs listed above, we conclude that FRS beats GRMS when:
- A family solution is being sought, e.g., for holidays involving children.
- Many users are envisaged in a short time with no time to coordinate licensing.
- There are cost constraints on the equipment procured.
GRMS beats FRS when
- There are likely to be more radio users in the area, and whence more pressure on available frequencies.
- Greater range is needed.
- The area has installed repeaters, or the user intends to install some.
FRS Vs. MURS
Similarly, FRS pips MURS where:
- The context is similar to FRS beats GMRS.
- There is a need to find strangers. This is likelier with FRS’s vaster user base.
- There is a need to communicate with emergency services.
MURS is preferred when.
- The terrain is rife with dense vegetation.
- The area of deployment has many other users whom the user does not need to communicate with. In that case, MURS provides extra channels.
- More range is required, or the user has the capacity for base stations and antennae.
GMRS Vs. MURS
This is the more current matchup, and two predictable views prevail. There are those who assume that MURS is better simply because it’s newer. Then there are GMRS loyalists, who won’t stomach an upstart.
The biggest single differentiator is the current installed base. Because this favors GMRS at the moment, it gives that protocol a higher effective range, as the availability of repeaters is likelier.
MURS gives more availability of channels in applications where there is a saturation of radio users. Specific equipment configurations that favor narrow-band may also prefer this protocol. In time, the specific circumstance of an installed MURS repeater base will grow likelier and tilt the balance of relative advantage.
In addition, MURS is license-free.
What Else Is Out There?
The current debate around personal radio services is dominated by FRS, GMRS, and MURS. But other tech exists and merits a mention. CBR will not shift the balance, although it has retro appeal. HAM and LPRS may be what best fits the user, especially as adoption of the latter evolves.
Citizen Band Radio (CBR) is the forerunner of the personal radio services of today. Authorized in 1945, it grew in popularity during the 1970s as truckers and motorists found it a useful tool to respond to oil shortages and speed restrictions.
CB allows two-way bidirectional communication in forty high-frequency channels in the 27MHz band. Callers take turns talking, pressing a “push to talk” button, which alters the direction of communication.
This service has fallen out of favor because of its limited range, poor sound quality (a function of its use of amplitude modulation rather than frequency modulation), and susceptibility to noise.
The Amateur Radio Service was established by the International Telecommunications Union (ITU) in order to create an open-ended regulated spectrum for non-professional radio enthusiasts pursuing not-for-profit objectives.
Licencing is dependent on passing an exam. Applicants need to demonstrate an understanding of technical aspects of electronics, radio equipment, and radio propagation. Clubs with suitably qualified individuals may be licensed.
Band plans and frequency allocation are handled by the ITU in consultation with member states. The medium allows the transmission of a range of media, including voice, text, data, and images.
The so-called “Business Band” provides Low Power Radio Services for institutional entities. Here the institution gets a license that covers radio transmission on its own equipment. The licensed frequencies are available for use in different areas.
On the plus side, the institutional license covers every member. VHF and UHF frequencies are available, allowing choice in different terrain. Again, this is based on frequency modulation, leading to improved voice quality and reduced static.
On the flip side, the licensing very narrowly constrains the deployable equipment, restricting choice and application. The assigned frequencies are not unique, which opens the risk scheduling overhead.
The advantages over MURS and GMRS are not clear.
Radio is subject to US and international regulations. Users should be aware that their choice of equipment has implications for the rules that restrict their use.
For GMRS, a license should be obtained from the FCC. This can be done through an online application.
- Login to the FCC Universal Licensing System.
- Get a (free) FRN number.
- Register with the FRN number provided.
- Under “Select Service,” pick “ZA – General Mobile Radio (GMRS)” in the dropdown.
- Provide your particulars.
- The license is valid for ten years.
- It covers transmission only on the demarcated frequencies.
As mentioned, licensing is not required for FRS and MURS.
Apart from licensing, the FCC places restrictions and conditions on how the equipment is to be configured and used. This is worth paying attention to as it may rule out deployments you have in mind. Personal radio has a long history of legal default due to ignorance or sheer disregard.
FRS is licensed by rule, which means that the user is not required to obtain a license, provided that she complies with the rules as set out in FCC Title 47 Part 85 Subpart B. Restrictions include the types of transmissible digital data (images are excluded), one-way data, and limits on frequency carrier accuracy.
The sale or resale of FRS combination radios is prohibited.
In addition to the licensing described above, GMRS users are required to comply with the rules as set out in FCC Title 47 Part 85 Subpart E. This schedule sets out eligibility and responsibilities for licensees and limitations on grandfathered licenses.
Limits are placed on permissible uses and provide a protocol for inspection of GMRS stations. Prohibited (like whistling) uses are comprehensively listed.
MURS is licensed by rule, which means that the user is not required to obtain a license, provided that she complies with the rules as set out in FCC Title 47 Part 85 Subpart J. This covers grandfathering, forbids the airborne use of MURS, and such issues as antenna height limits, continuous carry store, and forward.
There are no age restrictions on the use of MURS.
Within each category, different OEMs offer different models, individuated by ruggedness, compactness, and design. These factors should be taken into account when picking a solution as they often have practical effects. Technical specifications can be viewed online.
Navigating the options requires some technical understanding. Without delving too deeply, we consider some basic concepts that recur.
Wattage measures the power at which the transceiver emits its signal. Higher wattage allows stronger signals that can be propagated further. The FCC regulates upper limits on signal strength for different categories of radio services.
Note that radios are often marketed on the basis of “peak wattage,” which is an indication of their best wattage and generally differs from their average output. Be sure to find an indication of the consistent power output of a device you intend to buy.
AM Vs. FM?
In radio applications, users who share a physical space want to preserve the integrity of their communications by tunneling their messages through private pathways. Amplitude Modulation (AM) and Frequency Modulation (FM) are two different ways of carving up the spectrum for different users.
In AM, the available spectrum is divided into amplitude (“loudness”) segments. Different users then communicate at different levels of loudness. FM is a similar idea, with frequency replacing amplitude. Frequency division is more robust over distance and less susceptible to static and interference.
What’s The FCC Got To Do With It?
The United States Federal Communications Commission is a government agency that regulates (inter alia) radio communications. It seeks to provide optimal use of the available airwaves and to stimulate competition in the communications sector.
The FCC is responsible for the regulation and enforcement of US law on communications and interacts with the ITU and other international communications authorities in order to harmonize standards and foster cooperation.
Radios for business use are programmed to oscillate at frequencies that correspond with their license. FRS and GMRS radios are programmed to exactly the frequencies allotted to those services.
Apart from the GMRS frequencies, there are standard frequencies that can be put to general use. These are referred to as dot/star frequencies.
And Business Band?
This is the frequency pool which the FCC has demarcated for industrial/business use in Subpart C of Part 90 in the CFR Title 47.
Institutional activities (churches, hospitals, commercial operations, and the like) are given VHF and UHF frequencies spread over non-contiguous bands. They are limited to 2Watt transmission. In some areas, forestry operations have sole access to specified frequencies.
What Are Hybrids?
These are radios that support more than one protocol. Currently, that would be FRS/GMRS, as MURS does not feature as an option in any hybrid devices. Having a hybrid allows the user to switch between protocols, thereby accessing both networks at a time.
Hybrids requiring over 2 watts of radiation or on GMRS repeater input channels will require full GMRS licensing.
What’s A Channel?
A channel represents a frequency range around a reference frequency. Communications in the channel target the reference frequency and may vary within a prescribed tolerance.
There’s speculation that the coming years will see a relaxation of GMRS regulation. The hunch is that there will be a 2watt limit on all frequency bands, rendering GMRS an extension of FRS (FRS with repeaters). The licensing requirements will then be dropped.
As a nervous loner, my preference is for a GMRS/FRS hybrid. I have no specific coordination requirements with other people, and the combination puts me in touch with the largest possible number of Samaritans at any one time. The license requirements are far from onerous.
How you choose in general is a matter of application. FRS’s days are numbered, and unless you have a large team to coordinate quickly over safe terrain, it’s a decreasingly likely choice. Over time MURS’s prohibitive adoption rate will be less of a barrier.