What is land mobile radio (LMR)?

What is land mobile radio (LMR)?

LMR stands for land mobile radio. FCC rules define the land mobile radio service as a mobile service between base stations and land mobile stations, or between land mobile stations. The ITU Radio Regulations, No. 1.26, use the same words for the land mobile service.12

In practice, "LMR" names the whole family of professional two-way radio: handhelds, vehicle radios, base stations and repeaters, on networks that the user or a service provider operates. The FCC rule that governs it in the US is titled Private Land Mobile Radio Services.3 The term covers every kind of two-way radio that talks over its own radio channels rather than a mobile phone network.

CISA, the US cybersecurity agency, says radio has been the main way public safety staff reach dispatchers and each other for almost a century. Today's LMR gives group and individual voice, end-to-end encryption and low-speed data such as location.4

What are the parts of a land mobile radio system?

The FCC defines a land mobile radio system as a regularly interacting group of base, mobile, control and fixed relay stations serving one area. In practice that means handheld and vehicle radios, base stations, repeaters and dispatch consoles, which larger networks link over IP.116

A repeater on a tower or hilltop is why a handheld reaches much farther through a system than radio to radio. The range calculator shows how antenna height changes that distance, and radio over IP covers how sites and consoles connect.

What is the difference between conventional and trunked LMR?

A conventional system assigns channels to base and mobile stations without pooling them: users pick a channel and talk, directly or through a repeater. A trunked system searches two or more paths and automatically assigns an open one when someone presses the button. Both definitions come from the FCC's Part 90.1

ETSI describes TETRA trunking the same way, as channels handed out on demand.5 Systems are often mixed. P25 radios usually include analog operation, and interoperability gateways and consoles patch conventional analog channels into P25 trunking.6

Which technologies count as LMR?

Analog FM, DMR, P25, TETRA, NXDN and dPMR are all LMR. They differ in who standardized them, how they split a channel and where they are strong. Analog FM is the baseline that most of them can still fall back on, and the only mode allowed on US public safety calling channels.68

DHS notes that there is generally no direct digital interoperability between P25 and DMR, NXDN, dPMR or TETRA except through gateways and maker-specific solutions.8 A radio that supports both standards, or an analog fallback, closes part of that gap. The digital radio compatibility tool shows what two radios can do together, for example DMR and P25 Phase 1.

Who uses land mobile radio?

Public safety is the biggest user, and the rest is utilities, transport, industry and government. The P25 trade group lists law enforcement, fire, EMS, federal, state, local and tribal agencies, military, utilities, transit and business users. DHS says DMR, NXDN and dPMR came to the US mainly for business, industrial and transportation systems.68

Two US examples show the spread. Fairfax County, Virginia, ran a dual 800 MHz system: analog for schools, transit and special-needs buses, and digital P25 for police, fire and EMS. The Metropolitan Transportation Authority's five-channel 700 MHz system in the New York area serves commuter and metropolitan railroad lines through 65 radio sites.4

Emergency services in Europe mostly use TETRA and TETRAPOL, covered on public safety radio and what is TETRA. That page also covers land mobile radio for public safety on commercial LTE networks.

What frequency bands does land mobile radio use?

In the US, land mobile radio uses low-band VHF (25–50 MHz), high-band VHF (150–174 MHz), 220 MHz, UHF (450–512 MHz) and the 700, 800 and 900 MHz bands. The FCC splits Part 90 channels into a Public Safety Pool and an Industrial/Business Pool, each with its own frequency table.1011

The 421–430 MHz band is also open to land mobile use in the Detroit, Cleveland and Buffalo areas.1011 Outside the US, regulators use other bands: Europe's TETRA bands are in what is TETRA, and the frequency charts list license-free bands by country.

Part 90 also sets channel widths. Equipment designed for 25 kHz channels is authorized 20 kHz of bandwidth, 12.5 kHz equipment 11.25 kHz, and 6.25 kHz equipment 6 kHz. Since January 1, 2013, stations in 150–174 MHz and 406–512 MHz must use channels of 12.5 kHz or less unless they meet the FCC's efficiency standard: the US narrowbanding rule.12

Do you need a license to use land mobile radio?

Yes, for most LMR. In the US a Part 90 license covers a station or system, most new frequencies need frequency coordination first, and the FCC fee for a new site-based application is $105, for a term of up to 10 years. In Britain, Ofcom issues Business Radio licenses.313171819

In the US, a coordinator's recommendation does not guarantee a license, so buy equipment after authorization.13 Transmitters used under Part 90 must be of a type certified for that part, and public safety voice radios in 150–174 and 450–470 MHz must be able to work in analog FM on the nationwide public safety interoperability channels.14 Eligibility for the Industrial/Business Pool covers commercial activities, educational, philanthropic and ecclesiastical institutions, clergy, and hospitals and clinics.11

Consumer services such as FRS in the US and PMR446 in Europe sit outside these licenses. For an overview by country see the license checker.

How is LMR different from LTE and PoC?

LMR gives one-to-many voice on its own channels, at higher power than a phone, and radios keep talking to each other if the infrastructure fails. LTE gives fast data and wide coverage but depends on cell towers and capacity. CISA expects LTE not to displace LMR in the foreseeable future.4

In one Texas hospital district, LMR carried 95 percent of voice use and LTE the other 5 percent, mostly in ambulances out of LMR coverage or underground.4 For the full comparison with a direct radio network see PoC vs DMR.

How this relates to PoC radio

A PoC radio does the job of an LMR handheld, group talk at the press of a button, but carries voice over 4G/LTE data instead of a licensed radio channel. It reaches wherever the mobile network does and needs no radio license; LMR keeps working where there is no network.

The two are growing together more than they compete. CISA describes gateways and software that already join LMR and LTE: Michigan lets mutual-aid partners join the LMR network from a smartphone app instead of handing out caches of radios, and Fairfax County moved non-public-safety users from analog LMR to LTE push-to-talk at lower recurring cost.4

At the standards level, 3GPP defined interworking functions in Release 15 that link mission-critical push-to-talk to LMR systems such as TETRA and P25, mainly for voice, messaging and location.15 More on that is in MCPTT and What is P25 radio?. For a worker who needs national reach and no license, see 4G LTE walkie-talkies and what is PoC radio.

How an LMR system stacks up against push-to-talk over cellular on coverage, outages, delay and cost: LMR vs PoC.

Questions

Sources

1. 47 CFR 90.7: Definitions · Cornell LII, electronic Code of Federal Regulations
2. Radio Regulations, Article 1 (No. 1.26), in Tractatenblad 2022, 52 · ITU, published by the Dutch government
3. 47 CFR Part 90: Private Land Mobile Radio Services · Cornell LII, electronic Code of Federal Regulations
4. Land Mobile Radio/Long Term Evolution (LMR/LTE) integration: best practices · CISA, SAFECOM
5. Terrestrial Trunked Radio and Critical Communications Evolution (TCCE) · ETSI
6. P25 frequently asked questions, version 1.9 (2025) · P25 Technology Interest Group
7. ETSI TS 102 361-1 V2.7.1 (2026-05): Digital Mobile Radio (DMR), Air Interface protocol · ETSI
8. Public safety interoperability implications of non-P25 radio technologies (July 2016) · DHS Office of Emergency Communications
9. ETSI and TCCA statement on TETRA security algorithms research findings, 24 July 2023 · ETSI
10. 47 CFR 90.20: Public Safety Pool · Cornell LII, electronic Code of Federal Regulations