Multi-Use Radio Service

In the United States, the Multi-Use Radio Service (MURS) is a licensed by rule two-way radio service similar to 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.

For the American rapper Murs, sometimes stylized as MURS, see Murs (rapper).

In 2009 Industry Canada (IC) established a five-year transition plan, which would have permitted the use of MURS in Canada starting June 2014.[1] 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 ..."[2]

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:[3]
  • 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:

Channel Frequency Maximum
authorized bandwidth		 Channel name
1 151.82 MHz 11.25 kHz MURS 1
2 151.88 MHz 11.25 kHz MURS 2
3 151.94 MHz 11.25 kHz MURS 3
4 154.57 MHz 20.00 kHz Blue Dot
5 154.60 MHz 20.00 kHz Green Dot

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.[4] All five channels may use amplitude modulation with a bandwidth up to 8 kHz.[5] 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.[6]

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.[7]

Authorized modes
DesignatorCommon name
A1D Amplitude modulation; on off keyed or quantized; no modulation; Data, telemetry, telecommand
A2B Amplitude modulation; Digital, with modulation; Telegraphy for machine copy (RTTY, fast Morse)
A2D Amplitude modulation; Digital, with modulation; Data, telemetry, telecommand
A3E Amplitude modulation; Single analog channel; Telephony, voice, sound broadcasting
F2B Angle modulation, straight FM; Digital, with modulation; Telegraphy for machine copy (RTTY, fast Morse)
F1D Angle modulation, straight FM; on off keyed or quantized; Data, telemetry, telecommand
F2D Angle modulation, straight FM; Digital, with modulation; Data, telemetry, telecommand
F3E Angle modulation, straight FM; Single analog channel; Telephony, voice, sound broadcasting
G3E Angle modulation, phase modulation; Single analog channel; Telephony, voice, sound broadcasting

Permitted areas of operation

MURS operation is authorized anywhere a CB 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:

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.[8]
  • Transmitting on MURS frequencies is not allowed while aboard aircraft in flight.[8]
  • When transmitting in Puerto Rico, Desecheo, Mona, Vieques, and Culebra, care must be taken to not interfere with the Arecibo Observatory.
  • Devices that use MURS must be specially labeled and certified.[7]

Products

There are a wide variety of radio products that use MURS frequencies. MURS devices consist of 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 version1 (non-mesh) 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.[9][10][11]

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[12]. Blue-dot is now frequency number 4 in the MURS frequency specification table.

Walmart and Sam's Club use a two way radio, made by 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[13].

See also

References
  1. "Spectrum Allocation and Utilization Policy Regarding the Use of Certain Frequency Bands Below 1.7 GHz for a Range of Radio Applications" (PDF). Industry Canada. June 2009. Retrieved September 2, 2011. A five-year transition period is established from the publication date of this spectrum policy, after which the distribution and sale of MURS devices will be permitted.
  2. http://www.ic.gc.ca/eic/site/smt-gst.nsf/eng/sf10822.html
  3. http://wireless.fcc.gov/services/index.htm?job=service_home&id=multi_use
  4. 47 C.F.R. 95.2773
  5. 47 C.F.R. 95.2773c
  6. 47 C.F.R. 95.1317
  7. http://www.fcc.gov/encyclopedia/multi-use-radio-service-murs-0
  8. http://www.gpo.gov/fdsys/pkg/CFR-2009-title47-vol5/pdf/CFR-2009-title47-vol5-part95.pdf
  9. "Hacker News — goTenna". news.ycombinator.com. Retrieved 3 November 2015.
  10. Statt, Nick. "GoTenna creates a cell network out of thin air anywhere on Earth". CNET. CBS Interactive. Retrieved 3 November 2015.
  11. Nelson, Patrick. "Device lets smartphones communicate during network outage". Network World. Network World. Retrieved 3 November 2015.
  12. Everything You Always Wanted to Know About Blue Dot Radios... But Were Afraid to Ask
  13. Multi-Use Radio Service (RadioReference)
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