LMRS
Land Mobile Radio Service (LMRS) also known is Land Mobile Radio (LMR) - FCC Title 47 Part 90; Private land mobile radio systems are used by companies, local governments, and other organizations for communication. Many businesses and industries throughout the world use it as their primary means of communication, especially from a fixed location to mobile units. These licensed systems often share frequencies with other private users in the United States.
Private Land Mobile Radio Service licensees in the 150-174 MHz and 421-512 MHz bands have been mandated by the FCC to move to narrowband only use before January 1, 2013. The narrow band requirement is at 12.5 kHz maximum.
LMRS can be described as the following two components:
- The Land mobile radio system
- The Land mobile service
LMRS is often referred to as the "business band." It was established in 1927 to permit commercial and public safety uses of two-way radio by commercial entities and non-Federal government agencies. The available frequencies in the US have traditionally been separated into two pools. One is for industrial and business users which we call LMRS, including some special categories such as petroleum, manufacturing and forestry and the other is for public safety including medical, police, fire and others.
Also referred short as simply LMR, it is denoted as professional mobile radio in North America and private mobile radio In UK. Land mobile radio system is widely utilized for emergency first responder. It can be used in commercial, military, transportation and construction.
Contents
Equipment
Any radio equipment used on LMRS frequencies must be FCC Part 90 certified. There's plenty of ham radio equipment that is capable of operation on LMRS frequencies, at wide and narrow band. Previously ham equipment had to be specially modified to operate out of ham radio bands on frequencies such as LMRS. With the introduction of new, low cost, non-FCC compliant Chinese ham gear there are a number of radios that can operate on LMRS and public safety frequencies without modification. It is not legal to use these radios on LMRS frequencies.
Volunteer firefighters that also hold a ham radio license often mistakenly program their mobile ham radios to operate on emergency responder frequencies that they, as an individual are authorized to use. However, even though the individual is authorized, the use of a non-FCC Part 90 certified radio is not lawful for radio transmission. These public safety officials using non-certified radios instead of their assigned Part 90 radios are subject to fines and penalties from the FCC. There is only one exception to the rule with very narrow and specific requirements that does not apply to normal use and in the event that there is absolutely no other means of communication available and as only a last resort, which applies to any operator.
In short, it is legal to listen with the ham radio that is not Part 90 certified, however, it is not legal to transmit out of ham radio band even if you are a public safety official, including firefighters and police.
Frequency charts
A quick overview of this fragmented spectrum shows LMRS in relation to some of the ham radio bands. LMRS bands are in blue and the frequency range displayed above is LMRS only. The green shows ham radio in relation to position. This is not to scale.
LMRS use has far more allocation of the spectrum than does ham radio.
Although the term "business band" refers to several discrete frequencies that are not grouped into a single band, examples of some of the frequencies are grouped by band and listed below. These charts also list other frequencies not specifically part of the "business band" but commonly used by businesses. An individual license is still required under GMRS rules. A few manufacturers added these DOT frequencies to Business radios in the 1990s to have more "channels" and aid in selling radios.
Low-band frequencies
| Name | Frequency | Notes |
|---|---|---|
| 27.490 MHz | Low power, itinerant | |
| 27.510 MHz | Low power | |
| 27.555 MHz | Low power | |
| 30.840 MHz | Low power | |
| 33.120 MHz | Low power | |
| 33.140 MHz | Low power | |
| 33.400 MHz | Low power | |
| 35.020 MHz | Low power | |
| 35.040 MHz | Low power, itinerant | |
| 42.980 MHz | Low power | |
| 43.040 MHz | Low power |
VHF frequencies
| Name | Frequency | Notes |
|---|---|---|
| 151.505 MHz | Itinerant | |
| 151.5125 MHz | Itinerant (narrow band) | |
| Red Dot | 151.625 MHz | Itinerant |
| 151.700 MHz | Itinerant | |
| 151.760 MHz | Itinerant | |
| 151.820 MHz | Multi-Use Radio Service (MURS); 2 watts, 11.25 kHz bandwidth | |
| 151.880 MHz | Multi-Use Radio Service (MURS); 2 watts, 11.25 kHz bandwidth | |
| 151.940 MHz | Multi-Use Radio Service (MURS); 2 watts, 11.25 kHz bandwidth | |
| Purple Dot | 151.955 MHz | |
| 154.515 MHz | ||
| 154.540 MHz | ||
| Blue Dot | 154.570 MHz | Multi-Use Radio Service (MURS); 2 watts, 20 kHz bandwidth |
| Green Dot | 154.600 MHz | Multi-Use Radio Service (MURS); 2 watts, 20 kHz bandwidth |
| 158.400 MHz | Itinerant | |
| 158.4075 MHz | Itinerant (narrow band) |
UHF and GMRS frequencies
| Name | Frequency | Notes |
|---|---|---|
| White Dot | 462.575 MHz | GMRS |
| Black Dot | 462.625 MHz | GMRS |
| Orange Dot | 462.675 MHz | GMRS |
| Brown Dot | 464.500 MHz | Itinerant |
| Yellow Dot | 464.550 MHz | Itinerant |
| Silver Star | 467.850 MHz | |
| Gold Star | 467.875 MHz | |
| Red Star | 467.900 MHz | |
| Blue Star | 467.925 MHz | |
| (Brown dpx) | 469.500 MHz | Itinerant |
| (Yellow dpx) | 469.550 MHz | Itinerant |
An itinerant frequency is normally used for mobile commercial activity, such as construction work or event planning. This comes in contrast to a license issued for a fixed location.
PMR
In the United Kingdom they have PMR / Private Mobile Radio or Professional Mobile Radio which is similar to LMRS in the United States. Like LMRS these are field radio communications systems which use portable, mobile, base station, and dispatch console radios.
In general narrow band frequency modulation is the chosen form of modulation, although airport services use amplitude modulation. Typically a deviation of 2.5 kHz is used for FM and this enables a channel spacing of 12.5 kHz to be implemented. As the demands for PMR are high, it is necessary to make effective use of the channels available. This is achieved by re-using the frequencies in different areas. Base stations must be located sufficiently far apart so that interference is not experienced, and also selective calling techniques such as CTCSS and DTMF are used to ensure that as many mobiles as possible can use a given channel.
- TETRA is a modern standard for digital private mobile radio (PMR) and public access mobile radio (PAMR).
- MPT1327 is a popular PMR trunking system
