On May 23, 2002, the Federal Communication Commission (FCC) in the United States updated their rules regarding five Industrial/Business Pool VHF frequencies known as the VHF color dot frequencies. These frequencies were moved from Part 90 to Part 95 and became a new Citizens Band Radio Service (CB) named the Multi-Use Radio Service (MURS).
The Commission defines MURS as a private, two-way, short-distance voice or data communications service for personal or business activities of the general public. The FCC defines short distance this way: "The usual range of communications between MURS devices is less than a few miles; connecting the unit to an external antenna can extend the range to ten miles or more." The range you actually achieve could be far less depending on your surroundings and height of receiving and transmitting antennas.
The most common use of MURS spectrum is for two-way communications using small, portable hand-held devices that function similar to walkie-talkies. See the section titled MURS Products for a description of available devices.
No License Required
The Multi-Use Radio Service (MURS) is "licensed by rule". This means an individual license is not required to operate a MURS device. You can operate a MURS device regardless of your age and for personal or business use so long as you are not a foreign government, representative of a foreign government, and you operate it according to the rules.
The channels authorized to MURS systems are available on a shared basis only and will not be assigned for the exclusive use of any entity. Those using MURS transmitters must cooperate in the selection and use of channels in order to reduce interference and make the most effective use of authorized facilities. Channels must be selected in an effort to avoid interference to other MURS transmissions. All communications on MURS must yield to any emergency communication on the same channel.
The frequencies available in the Multi-Use Radio Service are shown in the table.
MURS operation is authorized:
- 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
Caribbean Insular areas:
- Commonwealth of Puerto Rico (see rules below if near the Arecibo Observatory)
- Navassa Island
- United States Virgin Islands (50 islets and cays)
Pacific Insular areas:
- American Samoa (seven islands)
- Baker Island
- Commonwealth of Northern Mariana Islands
- Guam Island
- Howland Island
- Jarvis Island
- Johnston Island (Islets East, Johnston, North and Sand)
- Kingman Reef
- Midway Island (Islets Eastern and Sand)
- Palmyra Island (more than 50 islets)
- Wake Island
- Any other area of the world, except within the territorial limits of areas where radio services are regulated by:
- An agency of the United States other than the FCC (You are subject to its rules.)
- Any foreign government (You are subject to its rules.)
- Aboard any vessel of the United States, with the permission of the captain, while the vessel is traveling either domestically or in international waters.
- MURS operation is NOT authorized aboard aircraft in flight.
Operating MURS Near Arecibo Observatory in Puerto Rico
Anyone intending to operate a MURS unit on the islands of Puerto Rico, Desecheo, Mona, Vieques, and Culebra in a manner that could pose an interference threat to the Arecibo Observatory shall notify the Interference Office, Arecibo Observatory, HC3 Box 53995, Arecibo, Puerto Rico 00612, in writing or electronically, of the location of the unit. Operators may wish to consult interference guidelines, which will be provided by Cornell University. Operators who choose to transmit information electronically should e-mail to: [email protected]
The notification to the Interference Office, Arecibo Observatory shall be made 45 days prior to commencing operation of the unit. The notification shall state the geographical coordinates of the unit.
After receipt of such notifications, the Commission will allow the Arecibo Observatory a period of 20 days for comments or objections. The operator will be required to make reasonable efforts in order to resolve or mitigate any potential interference problem with the Arecibo Observatory. If the Commission determines that an operator has satisfied its responsibility to make reasonable efforts to protect the Observatory from interference, the unit may be allowed to operate.
MURS in Canada
In Canada, many commercial/industrial mobile and public safety licensees are authorized on the five MURS frequencies. A large number of these frequencies are licensed on a private/commercial basis. The remaining users are made up of government (i.e. municipal, provincial or federal government) and public safety (i.e. police, fire and ambulance). It is expected that the operation of MURS devices will cause, in certain situations, harmful interference to land mobile use. Also, operation of MURS devices could, in certain situations cause interference to users on adjacent land mobile frequencies, as set out in the suballocation channelling plan in Standard Radio System Plan 500, Technical Requirements for Land Mobile and Fixed Radio Services Operating in the Bands 138144 MHz and 148174 MHz (SRSP-500).
Industry Canada (IC) established a long transition period for licensed incumbents before permitting the sale and distribution of MURS devices for consumers. In accordance with Spectrum Utilization Policy Gen, General Information Related to Spectrum Utilization and Radio Systems Policies (SP-Gen), a five-year transition period from the issuance of the spectrum policy was proposed. Notification has been provided to licensed incumbents at the start of the transition period (Year 0) and will again two years before the end of the transition period (starting at Year 4).
This plan will permit the use of MURS in Canada starting June 2014. IC has not yet published rules for MURS, other than frequency limits.
- You can operate a MURS device in any place where the FCC regulates radio communications.
- FCC Rules require that you transmit on a MURS frequency only with a radio model certificated for MURS.
- You do not need to identify your MURS station by any particular callsign or other designation.
- A MURS device must be certified by the FCC. A certified MURS device has an identifying label placed on it by the manufacturer.
- None of the MURS channels are assigned for the exclusive use of any system. You must cooperate in the selection and use of the channels in order to make the most effective use of them and to reduce the possibility of interference.
- No MURS unit, under any condition of modulation, shall exceed 2 Watts transmitter power output. No power boosters are allowed, but there is no limit on antenna gain.
- A MURS station is not required to transmit a station identification announcement.
- MURS stations may transmit voice or data signals as follows: A MURS transmitter must transmit only emission types A1D, A2B, A2D, A3E, F2B, F1D, F2D, F3E, G3E. Emission types A3E, F3E and G3E include selective calling or tone-operated squelch tones to establish or continue voice communications. (Info on emission types: https://en.wikipedia.org/wiki/Types_of_radio_emissions )
- ALL A3E emissions are limited to 8 kHz.
- Bandwidth transmissions of a maximum of 11.25 KHz per channel bandwidth, with +/- 2.5 KHz deviation are permissible on all five MURS channels. The older +/- 5 KHz deviation signals (with a maximum 20 KHz channel bandwidth) are also permitted (but not required) on the two upper channels (in the 154 MHz band).
- Emissions other than A3E on frequencies 151.820 MHz, 151.880 MHz, and 151.940 MHz are limited to 11.25 kHz.
- Emissions other than A3E on frequencies 154.570 and 154.600 MHz are limited to 20.0 kHz.
- Data communications in MURS can only occur on radios certificated for data communications, or of those transmissions otherwise comply with the rules and those transmissions can be imposed on a conventional voice emission. You may not make any internal modifications or additions to a MURS radio to transmit data communications.
- MURS frequencies may be used for remote control and telemetering functions.
- The FCC prohibits image, video, and radio-facsimile transmissions on MURS.
- The FCC rules do not address transmission of music over MURS.
- MURS transmitters may not be operated in the continuous carrier transmit mode. (The FCC has not yet defined what "continuous" means or yet set specific transmitter time limits)
- MURS users shall take reasonable precautions to avoid causing harmful interference. This includes monitoring the transmitting frequency for communications in progress and such other measures as may be necessary to minimize the potential for causing interference.
- Antenna height is limited to 20 feet above a structure or 60 feet above ground, whichever is the greater.
- MURS stations are prohibited from operating as a repeater station or as a signal booster. This prohibition includes store-and-forward packet operation.
- MURS stations are prohibited from interconnection with the public switched network. Interconnection Defined: Connection through automatic or manual means of MURS stations with the facilities of the public switched telephone network to permit the transmission of messages or signals between points in the wireline or radio network of a public telephone company and persons served by MURS stations. Not considered to be interconnection: Wireline or radio circuits or links furnished by common carriers, which are used by licensees or other authorized persons for transmitter control (including dial-up transmitter control circuits) or as an integral part of an authorized, private, internal system of communication or as an integral part of dispatch point circuits in a MURS station.
Military use of MURS Radios
In some military applications, two-way radios normally require a frequency clearance via a DD 1494, APPLICATION FOR EQUIPMENT FREQUENCY ALLOCATION before they can be used. However, if a DD 1494 is submitted using radios on MURS frequencies, the it will be rejected because the MURS frequencies are not allocated for federal usage.
Even though the MURS frequencies are not allocated for federal usage, regardless they can be and are still used by government and military agencies.
The five MURS frequencies are licensed-by-rule, which means they do not require the user to obtain a license. Therefore even government agencies do not need a frequency clearance for MURS devices.
For military applications, there may still be a need to evaluate MURS radios for Hazards of Electromagnetic Radiation to Ordnance (HERO) Impacts for each facility due to the types of ordinances stored there.
MURS devices are not limited to just handheld two-way radios. There are a variety of devices available as detailed below:
Handheld Radios: There are a few handheld two-way radios that have MURS capability. These operate like any two-way radio, but specifically use the MURS frequencies.
Base Station Intercoms: a base station intercom is essentially a handheld two way radio in a desktop form. Instead of holding it in your hand it sits on a horizontal surface, or in some cases it can be wall-mounted.
Wireless Call Boxes: A wireless call box uses two-way radio technology in a water resistant housing that can be used outdoors. Vandal proof versions are available as well.
Wireless Public Address: A wireless public address system uses receive only two-way radio technology. You can use a base station intercom or two-way radio to make announcements from long distances.
Wireless Switch Control: A wireless switch control device is used for any ideal for any application where a contact closure is needed to remotely control a light, turn on/off a pump, activate a siren, or other application.
Voice Notification Wireless Monitor: A voice notification wireless monitor is a wireless radio transmitter that reports changes in the status of switches by transmitting user-recorded voice messages to handheld two-way radios or base station intercoms. It transmits a recorded voice message when the switch change occurs, and at intervals you select.
Wireless Customer Service Intercoms: A customer service intercom provides a fast, and easy wireless method for customers to summon a sales associate to a specific department or store location. When a customer presses the button on the intercom, it transmits user-recordable voice messages to two-way radios, wireless intercoms, or a wireless PA system.
Motion Sensor Devices: A motion sensor device can detect people, vehicles, or large animals, and then send an alert message to the MURS base station or handheld.