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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
|
Channel |
Frequency |
Bandwidth |
|
1 |
151.820 MHz |
11.25 KHz |
|
2 |
151.880 MHz |
11.25 KHz |
|
3 |
151.940 MHz |
11.25 KHz |
|
4 |
154.570 MHz |
20.00 KHz |
|
5 |
154.600 MHz |
20.00 KHz |
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.
Authorized Locations
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: prcz@naic.edu.
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 138–144 MHz and 148–174 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.
MURS Rules
- 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:
http://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 Products
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.
Author: David Onslow
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