General Mobile Radio Service
The General Mobile Radio Service (GMRS) is a licensed land-mobile radio service in the United States, regulated by the Federal Communications Commission (FCC), that provides short-distance two-way voice communications and limited data applications, such as text messaging and GPS location sharing, using channels in the ultra-high frequency (UHF) band around 462 MHz and 467 MHz.[1] Primarily intended for personal or family use, GMRS facilitates activities like emergency assistance, traveler aid, and group coordination through portable, mobile, fixed, or repeater stations, with typical ranges of 1 to 25 miles depending on terrain, power output, and equipment.[1] GMRS operates on 30 shared channels, including eight primary 462 MHz channels for transmission (with up to 50 watts of power for mobile, base, or repeater stations) and corresponding 467 MHz receive-only channels, plus seven interstitial channels each in the 462 MHz and 467 MHz bands for lower-power operations (up to 5 watts on transmit interstitials and 0.5 watts on receive interstitials). Established in the mid-20th century as an evolution of earlier citizens radio services, GMRS was formalized under FCC rules to promote reliable personal communications without requiring individual operator exams, distinguishing it from amateur radio services.[1] To use GMRS, individuals aged 18 or older must obtain a 10-year FCC license via a simple application process, which covers immediate family members (including minors) for operation without additional fees or testing; the license fee is $35 and can be renewed indefinitely, though pre-1987 non-individual licenses are grandfathered with restrictions.[1] Key operational rules emphasize etiquette, such as listening before transmitting on shared channels, identifying transmissions with the FCC call sign every 15 minutes or at the end of communications, and prohibiting music, advertisements, coded messages (beyond standard 10-codes), or continuous transmissions longer than 30 seconds without pauses. In 2017, the FCC modernized GMRS by adding interstitial channels, extending license terms from five to ten years, and permitting limited data features to enhance interoperability with Family Radio Service (FRS) devices, while maintaining no interconnection with public telephone networks except for repeater control.[1][2]Overview and Licensing
Definition and Purpose
The General Mobile Radio Service (GMRS) is a licensed land-mobile frequency modulation (FM) ultra-high frequency (UHF) radio service operating in the 462–467 MHz band, intended for short-distance two-way voice communications among users, with allowances for limited data transmissions, such as text messaging and GPS location sharing.[1][3] This service enables reliable, localized connectivity using handheld, mobile, or repeater-equipped radios, distinguishing it as a personal communication tool rather than a broadcast or long-range system.[4] The primary purposes of GMRS include facilitating personal and immediate family communications, such as coordinating off-road recreational activities, supporting family-based business operations, and providing emergency coordination where voice and basic data exchanges can aid in safety and response efforts.[5][1] By design, it promotes accessible short-range interoperability without the technical barriers of more advanced radio services, emphasizing practical use in everyday and situational scenarios.[4] Unlike amateur radio, which requires operators to obtain a license through examinations testing technical knowledge, GMRS demands no such exams or code skills, making it more approachable for non-technical users.[6] It also contrasts with Citizens Band (CB) radio, an unlicensed service operating around 27 MHz with broader but less regulated access, as GMRS employs dedicated UHF channels and enforces licensing to ensure orderly spectrum use.[1] GMRS is regulated under the Federal Communications Commission's Title 47, Code of Federal Regulations, Part 95, Subpart E, which outlines eligibility, operational standards, and compliance obligations.[7] A fundamental rule mandates that each station transmit its FCC-assigned call sign or a three-character alphanumeric unit identifier at the conclusion of transmissions and at intervals of no more than 15 minutes during transmissions lasting more than 15 minutes, ensuring accountability and interference mitigation.[8]Licensing Process and Requirements
The General Mobile Radio Service (GMRS) requires individuals to obtain a license from the Federal Communications Commission (FCC) to ensure regulated access to designated frequencies for personal communications.[1] Eligibility for a GMRS license is limited to individuals who are at least 18 years old and not representatives of a foreign government; the license extends to the licensee's immediate family members, including spouse, children, stepchildren, parents, stepparents, grandparents, grandchildren, siblings, aunts, uncles, nephews, nieces, and in-laws, regardless of their age.[9] Minors under 18 may operate under the license but are not personally eligible to hold one.[10] The application process begins with obtaining an FCC Registration Number (FRN) through the Commission Registration System (CORES) at no cost, which requires providing personal information such as name, address, and contact details.[11] Once the FRN is obtained, applicants log in to the FCC's Universal Licensing System (ULS) using the FRN and a password, select "General Mobile Radio Service (GMRS)" as the radio service, and complete FCC Form 605 online, providing details like eligibility confirmation and contact information; no examination is required.[11] Applications are typically processed within 1 to 7 business days, after which the license and call sign are issued electronically if approved.[11] The fee for a new or renewal GMRS license is $35, covering a 10-year term from the date of grant.[12] Payment is made online during the ULS application submission.[11] Licensees bear full responsibility for the proper operation of all GMRS stations under their license, including those used by immediate family members, ensuring compliance with FCC rules such as transmitting the assigned call sign at the end of communications and prohibiting use for business or commercial purposes beyond personal or family activities.[13] The licensee is solely liable for any violations by family members, particularly minors.[10] Renewals can be submitted up to 90 days before expiration through the same ULS process using FCC Form 605, with the same $35 fee and 10-year term upon approval; there is no grace period, so applications must be filed before the current license expires to avoid interruption.[9] The FCC provides automatic email reminders to registered applicants prior to expiration.[1]Technical Characteristics
Frequency Assignments
The General Mobile Radio Service (GMRS) is allocated 30 channels in the UHF band, consisting of 16 main channels and 14 interstitial channels, as defined by the Federal Communications Commission (FCC).[14] The main channels support higher-power operations and include both simplex communications and repeater configurations, while the interstitial channels are narrower and primarily intended for lower-power, short-range use. These frequencies are centered around 462 MHz for transmissions and 467 MHz for receptions in repeater setups, enabling personal and family communications within the service's licensed framework.[14] The 16 main channels comprise eight 462 MHz frequencies for primary transmissions (used in simplex mode or as repeater outputs) paired with eight corresponding 467 MHz frequencies (used as repeater inputs). These pairs facilitate extended range through repeaters, with the 462 MHz channels serving as the output and the 467 MHz as the input. The 14 interstitial channels are divided into seven at 462 MHz and seven at 467 MHz, offering additional options for direct simplex communications, though the 467 MHz interstitials are restricted to low-power handheld devices. GMRS shares several of these channels with the Family Radio Service (FRS), particularly the interstitial ones, allowing interoperability under specific power limits.[14][14] Channel numbering in GMRS follows a standardized convention across radios and equipment, numbering from 1 to 30, where channels 1–7 are the 462 MHz interstitial frequencies (shared with FRS), channels 15–22 are the 462 MHz main channels (simplex or repeater output), channels 8–14 are the 467 MHz low-power interstitials (handheld only, shared with FRS), and channels 23–30 are the 467 MHz main repeater input frequencies. This numbering aids in consistent programming and operation. The exact center frequencies for all channels are specified in FCC regulations to ensure non-interfering use.[14][1]| Channel | Frequency (MHz) | Type/Usage |
|---|---|---|
| 1 | 462.5625 | Interstitial (simplex, shared with FRS) |
| 2 | 462.5875 | Interstitial (simplex, shared with FRS) |
| 3 | 462.6125 | Interstitial (simplex, shared with FRS) |
| 4 | 462.6375 | Interstitial (simplex, shared with FRS) |
| 5 | 462.6625 | Interstitial (simplex, shared with FRS) |
| 6 | 462.6875 | Interstitial (simplex, shared with FRS) |
| 7 | 462.7125 | Interstitial (simplex, shared with FRS) |
| 8 | 467.5625 | Interstitial (low-power handheld only, shared with FRS) |
| 9 | 467.5875 | Interstitial (low-power handheld only, shared with FRS) |
| 10 | 467.6125 | Interstitial (low-power handheld only, shared with FRS) |
| 11 | 467.6375 | Interstitial (low-power handheld only, shared with FRS) |
| 12 | 467.6625 | Interstitial (low-power handheld only, shared with FRS) |
| 13 | 467.6875 | Interstitial (low-power handheld only, shared with FRS) |
| 14 | 467.7125 | Interstitial (low-power handheld only, shared with FRS) |
| 15 | 462.5500 | Main (simplex or repeater output) |
| 16 | 462.5750 | Main (simplex or repeater output) |
| 17 | 462.6000 | Main (simplex or repeater output) |
| 18 | 462.6250 | Main (simplex or repeater output) |
| 19 | 462.6500 | Main (simplex or repeater output) |
| 20 | 462.6750 | Main (simplex or repeater output) |
| 21 | 462.7000 | Main (simplex or repeater output) |
| 22 | 462.7250 | Main (simplex or repeater output) |
| 23 | 467.5500 | Main (repeater input for channel 15) |
| 24 | 467.5750 | Main (repeater input for channel 16) |
| 25 | 467.6000 | Main (repeater input for channel 17) |
| 26 | 467.6250 | Main (repeater input for channel 18) |
| 27 | 467.6500 | Main (repeater input for channel 19) |
| 28 | 467.6750 | Main (repeater input for channel 20) |
| 29 | 467.7000 | Main (repeater input for channel 21) |
| 30 | 467.7250 | Main (repeater input for channel 22) |
Power Limits, Bandwidth, and Channel Spacing
The General Mobile Radio Service (GMRS) imposes specific power limits to ensure efficient spectrum use and minimize interference, varying by station type and frequency band rather than strictly by channel type. For all GMRS channels, mobile stations, base stations, fixed stations, and repeater stations are limited to a maximum transmitter power output (TPO) of 50 watts. Hand-held portable units are limited to 5 watts effective radiated power (ERP) when transmitting on any 462 MHz channel (1-7 and 15-22) and 0.5 watts ERP on any 467 MHz channel (8-14 and 23-30). On the 467 MHz interstitial channels (8-14), only hand-held portable units are permitted to transmit; base stations, fixed stations, and mobile stations (except for remote control of repeaters) are prohibited. These limits apply across main and interstitial channels where applicable, following the 2017 FCC rule changes that permitted higher power on 462 MHz interstitial channels for non-handheld stations.[15] Emission bandwidth in GMRS is regulated to align with channel allocations and prevent overlap. The authorized bandwidth is 20 kHz for transmissions on all 462 MHz channels (1-7 interstitial and 15-22 main) and all 467 MHz main channels (23-30 repeater inputs), supporting narrowband frequency modulation (FM) for voice communications. The 467 MHz interstitial channels (8-14) are limited to 12.5 kHz bandwidth. Digital data transmissions, when permitted, are confined to the 462 MHz main and interstitial channels as well as the 467 MHz bands, with emission types such as F3E for analog FM voice and limited digital modes (e.g., F2D, G2D) authorized, subject to unwanted emissions constraints to protect adjacent channels.[16] Channel spacing in GMRS follows the center frequencies defined for each band to enable orderly allocation. The main channels are spaced at 25 kHz intervals, with frequencies ranging from 462.5500 MHz to 462.7250 MHz for the 462 MHz main channels (15-22) and 467.5500 MHz to 467.7250 MHz for the 467 MHz main channels (23-30). Interstitial channels employ 12.5 kHz spacing, positioned between main channels at frequencies such as 462.5625 MHz to 462.7125 MHz (channels 1-7) and 467.5625 MHz to 467.7125 MHz (channels 8-14), allowing denser packing for lower-power uses while maintaining compatibility with the 20 kHz or 12.5 kHz bandwidth limits.[14]| Channel Type | Channels | Power Limit | Bandwidth | Spacing |
|---|---|---|---|---|
| 462 MHz (Interstitial and Main) | 1–7, 15–22 | 50 W TPO (mobile/base/fixed/repeater); 5 W ERP (handheld) | 20 kHz | 12.5 kHz (1-7); 25 kHz (15-22) |
| 467 MHz Main (Repeater Inputs) | 23–30 | 50 W TPO (mobile/base/fixed/repeater); 0.5 W ERP (handheld) | 20 kHz | 25 kHz |
| 467 MHz Interstitial (Handheld Only) | 8–14 | 0.5 W ERP (handheld only; no base/fixed/mobile except repeater control) | 12.5 kHz | 12.5 kHz |