science

Multi-Use Radio Service

Multi-Use Radio Service is a science topic covered in the lgStudy science library. This page brings together a partial reference excerpt, illustrations, worked examples, real-world applications and a short study plan, so you can understand Multi-Use Radio Service rather than just read about it. In short: In the United States, the Multi-Use Radio Service (MURS) is licensed by rule (i.e. under part 95, subpart J, of title 47, Code of Federal Regulations) two-way radio service similar to the Citizens band (CB). Established by the U.S.

Key takeaways

Multi-Use Radio Service belongs to science; place it in that map before memorising details.
Learn the definition first, then one example that makes the definition concrete.
Connect Multi-Use Radio Service to a quantity you can measure, compute or draw — that is where exam questions come from.
Reproduce the core statement of Multi-Use Radio Service from memory before moving on to harder problems.

Reference excerpt

In the United States, the Multi-Use Radio Service (MURS) is licensed by rule (i.e. under part 95, subpart J, of title 47, Code of Federal Regulations) two-way radio service similar to the Citizens band (CB). Established by the U.S. Federal Communications Commission in the fall of 2000, MURS created a radio service allowing for licensed by rule (Part 95) operation in a narrow selection of the VHF band, with a power limit of 2 watts. The FCC formally defines MURS as "a private, two-way, short-distance voice or data communications service for personal or business activities of the general public." MURS stations may not be connected to the public telephone network, may not be used for store and forward operations, and radio repeaters are not permitted. In 2009, Industry Canada (IC) established a five-year transition plan, which would have permitted the use of MURS in Canada starting June 2014. In August 2014 IC announced a deferral of MURS introduction, as "the Department does not feel that the introduction of MURS devices in Canada is warranted at this time, and has decided to defer the introduction of MURS devices in Canada until a clearer indication of actual need is provided by Canadian MURS advocates and/or stakeholders ..."

Eligibility No licenses are required or issued for MURS within the United States.

Any person is authorized to use the MURS frequencies given that it: Is not a foreign government or a representative of a foreign government. Uses the transmitter in accordance with 47 CFR. 95.1309. Operates in accordance with the rules contained in Sections 95.1301-95.1309. Operates only legal, type-accepted MURS equipment.

Frequencies MURS comprises the following five frequencies:

Channels 1–3 must use "narrowband" frequency modulation (2.5 kHz deviation; 11.25 kHz bandwidth). Channels 4 and 5 may use either "wideband" FM (5 kHz deviation; 20 kHz bandwidth) or "narrowband" FM. All five channels may use amplitude modulation with a bandwidth up to 8 kHz. MURS falls under part 95 and was not mandated for narrow-banding, such as those of Part 90 in the public service bands by January 2013. Because previous business band licensees who have maintained their active license remain grandfathered with their existing operating privileges, it is possible to find repeaters or other operations not authorized by Part 95 taking place. These are not necessarily illegal. If legal, such operations may enjoy primary status on their licensed frequency and as such are legally protected from harmful interference by MURS users.

Range MURS range will vary, depending on antenna size and placement. With an external antenna, ranges of 10 miles (16 km) or more can be expected. Since MURS radios use frequencies in the VHF business band, they are subject to obstructions in line of sight, which includes the curvature of the Earth. The higher you can place the antennas on both transmit and receive sides (within legal limits), the further you can transmit and receive. Some antenna manufacturers claim an external antenna can increase the effective radiated power of a transmitter by a factor of 4.

Authorized modes

Permitted areas of operation MURS operation is authorized anywhere a CB radio station is authorized and within or over any area of the world where radio services are regulated by the FCC. Those areas are within the territorial limits of:

The fifty United States The District of Columbia American Samoa (seven islands) Baker Island Caribbean Insular areas Commonwealth of Northern Mariana Islands Commonwealth of Puerto Rico Guam Island Howland Island Jarvis Island Johnston Atoll (Islets East, Johnston, North and Sand) Kingman Reef Midway Atoll (Islets Eastern and Sand) Navassa Island Pacific Insular areas Palmyra Atoll (more than fifty islets) United States Virgin Islands (50 islets and cays) Wake Island Aboard any vessel of the United States, with the permission of the captain, while the vessel is traveling either domestically or in international waters

Restrictions Transmitter power output is limited to 2 watts. The highest point of any MURS antenna must not be more than 18.3 meters (60 feet) above the ground or 6.10 meters (20.0 feet) above the highest point of the structure to which it is mounted, whichever is higher. Transmitting on MURS frequencies is not allowed while aboard aircraft in flight. Devices that use MURS must be specially labeled and certified.

Products There are a wide variety of radio products that use MURS frequencies. MURS devices include wireless base station intercoms, handheld two-way radios, wireless dog training collars, wireless public address units, customer service callboxes, wireless remote switches, and wireless callboxes with or without gate opening ability. Since MURS uses standard frequencies, most devices that use MURS are compatible with each other. Most analog two-way radios utilize a technology called CTCSS or DCS that helps block out unwanted transmissions. To make MURS two-way radios work together, they must have matching CTCSS or DCS tones. This can usually be done via basic programming which almost all MURS two-way radios support. The goTenna, a digital radio product, operates on the MURS band and pairs with smartphones to enable users to send texts and share locations on a peer-to-peer basis. goTenna is not interoperable with other MURS devices, even though they operate on the same spectrum, employing "listen-before-talk" to reduce interference in the band's five channels.

Notable users According to Bill Fawcett's Spaniel Journal, Spaniel pro-handler Dan Langhans was given a set of VHF business-band radios on the frequency of 154.57 MHz which became known by the trade as "blue dot" radios. Costco Wholesale use Motorola DTR600, DLR1020, and Motorola Curve on Frequency 1 for general use among employees and Frequency 2 for communication with major sales departments. Walmart and Sam's Club use a Motorola Solutions model Motorola RDM2070D, which is exclusive to Walmart and Sam's Club. The Motorola RDM2070D is preprogrammed on MURS frequencies with most channels using CTCSS tone 21/4Z/136.5Hz.

See also Business band Family Radio Service General Mobile Radio Service Public Radio Service Unlicensed Personal Communications Services

References

External links FCC Wireless Services: MURS Home

Worked examples

Example 1 — a first encounter with Multi-Use Radio Service

Start with the simplest possible case. Write down what Multi-Use Radio Service claims or describes in one sentence, then invent the smallest concrete situation in which that sentence is true. In science, the smallest case is usually a single object, a single equation or a single measurement. Check that every symbol or term in your sentence has a meaning in that case.

Example 2 — changing one variable

Take the situation from Example 1 and change exactly one quantity: double it, halve it, or set it to zero. Predict what should happen to Multi-Use Radio Service before you calculate. Comparing your prediction with the result is the fastest way to find out whether you understand the idea or only the words.

Example 3 — an exam-style question

Typical questions about Multi-Use Radio Service ask you to (a) state it precisely, (b) apply it to given data, and (c) explain a limitation. Practise writing all three answers in under five minutes; the third part is what separates a full-mark answer from an average one.

Applications of Multi-Use Radio Service

In research: Multi-Use Radio Service appears in science research whenever the underlying quantities have to be modelled precisely. Papers usually cite it as a starting assumption and then explore where it breaks down.
In technology and industry: Engineering practice reuses Multi-Use Radio Service in design rules, simulations and safety margins. Knowing the idea lets you read a specification sheet and understand why the numbers look the way they do.
In the classroom: Multi-Use Radio Service is common in secondary-school and first-year university syllabi. It links to neighbouring topics Bandplans, Radio communications, Radio regulations, so understanding it makes those chapters shorter.
In everyday life: Look for Multi-Use Radio Service outside the textbook — in sport, cooking, traffic, electronics or the sky above you. An example you found yourself is remembered far longer than one you were given.

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How to study Multi-Use Radio Service in 20 minutes

Read the reference excerpt below once, without taking notes.
Close the page and write down what Multi-Use Radio Service means in your own words.
Compare your version with the excerpt and mark what you missed.
Work through the three examples above with pen and paper.
Explain Multi-Use Radio Service out loud to somebody else — or to Teacher Smith in the lgStudy chat.

Frequently asked questions

What is Multi-Use Radio Service in simple terms?

Why does Multi-Use Radio Service matter?

Because it connects several science ideas at once: it gives you a definition you can apply, a quantity you can calculate, and a way to check whether a result is plausible.

How should I study Multi-Use Radio Service?

Read the excerpt, restate it from memory, then work through the examples and applications listed on this page. The five-step study plan above takes about twenty minutes.

What does this page cover?

It gives you a compact reference excerpt plus original lgStudy explanations, examples, applications and study material on Multi-Use Radio Service.