What is General Mobile Radio Service (GMRS)?
Just what is GMRS? The FCC says the General Mobile Radio Service (GMRS) is a licensed radio service that uses channels around 462 MHz and 467 MHz. The most common use of GMRS channels is for short-distance, two-way voice communications using hand-held radios, mobile radios and repeater systems. In 2017, the FCC expanded GMRS to also allow short data messaging applications including text messaging and GPS location information.
Services that provide functionality similar to GMRS include the Citizens Band Radio Service (CBRS), the Family Radio Service (FRS) and the Multi-Use Radio Service (MURS).
The GMRS is available to an individual (one man or one woman) for short-distance two-way communications to facilitate the activities of licensees and their immediate family members. Each licensee manages a system consisting of one or more transmitting units (stations.) The rules for GMRS limit eligibility for new GMRS system licenses to individuals in order to make the service available to personal users. (Some previously licensed non-individual systems are allowed to continue using GMRS.)
In 2017, the FCC updated the GMRS by allotting additional interstitial (lower power, between existing) channels in the 467 MHz band, increased the license term from 5 to 10 years, allowed transmission of limited data applications such as text messaging and GPS location information and made other updates to the GMRS rules to reflect modern application of the service.
Channel
A common frequency standardized either within a radio service or within a manufacturer of radios. The GMRS has 22 channels defined by the FCC, and an additional 8 channels to be used as repeater input frequency (for a total of 30)
CTCSS
Continuous Tone Coded Squelch System, also marketed as Private Line (PL), Privacy Code or Sub-Channels, this is a constant tone which the radio sends out when transmitting, that is usually outside of the audible portion of a radio’s receiver and thus not apparent to the user. The tone is used to control the squelch on the receiving end, and lets radios and repeaters better handle channel interference, either from other stations on the same frequency, or other sources. Almost all repeaters require the use of a CTCSS tone, although they can use an open squelch for operation. Commonly called input and/or output ‘tone’.
DCS
Digital Coded Squelch; a digital variant of the CTCSS tone. The radio sends out a continuous data pulse that represents a squelch code, again, typically outside of the audible portion of a radio’s receiver. DCS is less common on repeaters, but still commonly used. It is more resilient to interference than CTCSS, but also more sensitive to weak-signal problems.
Duplex
A method of radio operation where users transmit on one frequency/channel, and receive on another. This method of operation is used for operations with repeater stations.
FCC
Federal Communication Commission; the branch of government that administers and regulates communication services, including wireless radio.
Frequency
The rate at which something oscillates, usually measured in terms of oscillations per second. Megahertz is a unit of measurement for frequency, meaning millions of oscillations, or cycles, per second.
GMRS
General Mobile Radio Service; the name of the radio service created by the FCC located around 462Mhz and 467Mhz that is available for licensed use, and what we’re all about!
Repeater
A remote radio station that receives and rebroadcasts signals in real time. They are typically located at advantageous sites in terms of height above average terrain, including mountain and hilltops, on top of tall buildings or radio towers, or both! Repeaters can greatly boost the coverage range for radio communication devices, such as walkie talkies, vehicle mounted (mobile) stations, and fixed (base) stations.
Simplex
A method of radio operation where users transmit and receive on the same frequency/channel. This is most common for consumer-type handheld and mobile radios, and common in direct radio-to-radio communications. Simplex operation generally works well over shorter distances, or when communicating using a base, mobile or handheld station that’s in a high location. It is most easily deployed in the field among groups of people.
UHF
Ultra High Frequency; the name for the broad band in which the GMRS and many other radio services are located.
There are 30 GMRS channels allocated by the FCC with a bandwidth of 25 kHz (20 KHz authorized bandwidth) or 12.5 kHz as outlined below:
| Channel | Authorized Bandwidth |
|---|---|
| 462.5500 | 20 kHz |
| 462.5625 | 20 kHz |
| 462.5750 | 20 kHz |
| 462.5875 | 20 kHz |
| 462.6000 | 20 kHz |
| 462.6125 | 20 kHz |
| 462.6250 | 20 kHz |
| 462.6375 | 20 kHz |
| 462.6500 | 20 kHz |
| 462.6625 | 20 kHz |
| 462.6750 | 20 kHz |
| 462.6875 | 20 kHz |
| 462.7000 | 20 kHz |
| 462.7125 | 20 kHz |
| 462.7250 | 20 kHz |
| 467.5500 | 20 kHz |
| 467.5625 | 12.5 kHz |
| 467.5750 | 20 kHz |
| 467.6125 | 12.5 kHz |
| 467.6000 | 20 kHz |
| 467.6625 | 12.5 kHz |
| 467.6250 | 20 kHz |
| 467.7125 | 12.5 kHz |
| 467.6500 | 20 kHz |
| 467.5875 | 12.5 kHz |
| 467.6750 | 20 kHz |
| 467.6375 | 12.5 kHz |
| 467.7000 | 20 kHz |
| 467.6875 | 12.5 kHz |
| 467.7250 | 20 kHz |
Q: Do I need a license to use a GMRS Radio?
A: Yes, GMRS needs a license, In the US, the FCC regulates the frequencies used by devices such as two-way radios. The FCC requires that anyone operating equipment on the General Mobile Radio Service (GMRS) must obtain a license.
Q: How do I apply for a GMRS license?
A: The GMRS license requires you to complete FCC Forms 159 and 605, which can be found on the FCC Forms page. You can also apply for a GMRS license online at the FCC Universal License System (ULS) website.
Currently, the GMRS license costs $35 for 10 years, and as long as one person applies, the whole family can use it.
Q: Who can use a GMRS license?
A: If you have the GMRS license, all your immediate family members can use it.
The GMRS is available to an individual (one man or one woman) for short-distance two-way communications to facilitate the activities of licensees and their immediate family members.
Q: Can I use frequencies other than GMRS on GMRS radios?
A: The transmitting frequency must be the specified, allocated frequency of GMRS. However, the receiving frequencies can be in a wide range.
Q: What are the rules for GMRS radio?
You may apply for a GMRS license if you are 18 years or older and not a representative of a foreign government.
The official FCC service rules for the GMRS are located in 47 C.F.R. Part 95 Subpart E.
Q: Can I transmit on GMRS without a license?
A: The FCC requires a GMRS license as a way to regulate frequencies that are used by two-way radio devices.
FRS radios CAN use GMRS simplex channels, on a shared basis, with a max power of 2 watts without a GMRS license. (No repeaters or high power.)
Q: Can GMRS talk to CB or Ham?
A: No, CBs operate at 27 megahertz AM, ham (Amatuer Radio) has specific assigned frequency ranges and transmission modes (CW, SSB, FM, Data, etc..) and GMRS operates at 462/467 megahertz FM. They are completely entirely different services.
Q: What does a GMRS repeater do?
A: GMRS repeater radio system is used to extend the GMRS handheld and mobile talking range. It is an automatically controlled transmitter and receiver that simply transmits what the receiver hears. By placing repeaters at sites with high elevation and antennas atop large towers, usable radio coverage is greatly increased.
Q: How far will an 5 watt GMRS handheld radio transmit?
A: Depends on the usage environment, in an ordinary city, about 3 or 4 miles, if the environment is open or there is a repeater set up, the distance will be further..
Q: How far will a 50 watt GMRS mobile radio transmit?
A: Depending on the user’s environment, antenna gain, feeder attenuation, and other factors, the general distance is 6-10 miles. If the environment is open or there is a repeater set up, the distance will be further..
Licensing Information
An FCC license is required to operate GMRS radio system. Licenses are issued for a ten-year term and can be renewed between 90 days prior to the expiration date and up to the actual expiration date of the license. After a license expires, an individual must request a new GMRS license.
A GMRS system licensed to a non-individual prior to July 31, 1987 is also eligible for renewal, but the licensee may not make any major modification to the system.
You may apply for a GMRS license if you are 18 years or older and not a representative of a foreign government. If you receive a license, any family member, regardless of age, can operate GMRS stations and units within the licensed system.
The FCC service rules for the GMRS are located in 47 C.F.R. Part 95 Subpart E. You can find information about GMRS licensing in the rules.
The FCC license fee is currently $35.00 and is subject to change.
How to Use GMRS
The FCC suggests that a GMRS licensee may use a combination of portable, mobile, fixed and repeater stations consistent with the operational and technical rules in Subpart E of Part 95. The use of some channels is restricted to certain types of stations and certain channels are reserved for voice-only operations, while other channels allow voice and data operations.
None of the GMRS channels are assigned for the exclusive use of any system. You must cooperate in the selection and use of the channels in order to make the most effective use of them and to reduce the possibility of interference.
You can expect a communications range of one to twenty-five miles depending on station class, terrain and repeater use. You cannot directly interconnect a GMRS station with the telephone network or any other network for the purpose of carrying GMRS communications, but these networks can be used for remote control of repeater stations.
Normally, you and your family members would communicate between yourselves directly or through a repeater station. The stations must be within the territorial limits of the fifty United States, the District of Columbia, and the Caribbean and Pacific Insular areas.
In transient (portable or mobile) use, a mobile station from one GMRS system may communicate through a mobile relay station (repeater) in another GMRS system with the permission of its licensee. The communications may also be with mobile stations from other GMRS systems also with permission from the licensee to communicate through the mobile relay station.
Common Operating Practices
- It’s important not to take certain formalities too seriously; one should focus on using the radio in a matter that works well for them. With that said; there are a few general rules to keep in mind for starters:
- GMRS users must identify their transmissions with their FCC issued call-sign every 15 minutes, or at the end of a series of transmissions.
- Foul language is not allowed by the FCC
- Keep a brief pause between transmissions so other stations can have a chance to break in if they need to.
- When using a repeater, wait until after the courtesy tone to transmit – this is a brief beep or tone you may hear shortly after someone keys up the system. The intent is to give a pause for other stations to break in. Some repeaters will time-out after a few minutes if this is not followed and cease to transmit for a brief duration. Not all repeaters will have this.
Listen First, Then Talk.