General Mobile Radio Service

General Mobile Radio Service

The General Mobile Radio Service (GMRS) is a licensed land-mobile FM UHF radio service in the United States available for short-distance two-way communication. It is intended for use by an adult individual who possesses a valid GMRS license, as well as his or her immediate family members. [ The FCC definition of immediate family includes a spouse, children, parents, grandparents, aunts, uncles, nephews, nieces, and in-laws , see 47 CFR 95.179 ] Immediate relatives of the GMRS system licensee are entitled to communicate among themselves for personal or business purposes, but employees of the licensee, who are not family members, may not use this service.

GMRS radios are typically handheld portable devices much like Family Radio Service (FRS) radios, and share some frequencies with FRS. Mobile and base station-style radios are available as well, but these are normally commercial UHF radios as often used in the public service and commercial land mobile bands. These are legal for use in this service as long as they are GMRS type-approved. They are more expensive than the walkie talkies typically found in discount electronics stores, but are higher quality.

Licensing

Any individual in the United States who is at least 18 years of age and not a representative of a foreign government may apply for a GMRS license by completing the application form (either on paper or through the FCC's Universal Licensing System) and paying the license fee (currently $85.00). No exam is required. Prior to July 31, 1987, the FCC issued GMRS licenses to non-individuals (corporations, partnerships, government entities, etc). These licensees are grandfathered and may renew their existing licenses. No new GMRS licenses are being issued to non-individuals, nor may existing non-individual licensees make major modifications to their licenses. [ [http://wireless.fcc.gov/services/index.htm?job=licensing_1&id=general_mobile FCC: Wireless Services: General Mobile Radio Service: Licensing: Eligibility] ]

The license extends privileges of the primary licensee to include communications with the licensee's immediate family members, and authorizes immediate family members to use the licensee's station(s) to conduct the activities of the licensee. Additionally, the FCC rules allow GMRS licensees to communicate with other GMRS licensees. GMRS licensees are allowed to communicate with FRS users on those frequencies that are shared between the two services. The rules require each GMRS user family to have a license, rather than (as in the case of commercial and public safety land mobile license) authorizing a licensee's employees to use the same license.

Frequency assignments and FRS

The GMRS-only channels are defined in pairs, with one frequency in the 462 MHz range for simplex and repeater outputs, and another frequency 5 MHz higher for repeater inputs. There are eight channels exclusively for GMRS and seven "interstitial" channels shared with Family Radio Service. GMRS use requires an FCC license, and licensees are permitted to transmit at up to 50 watts on GMRS frequencies (although 1 to 5 watts is more common), as well as have detachable or external antennas.

GMRS licensees are also able to use the first 7 FRS frequencies (the "interstitial" GMRS frequencies), but at the lower 5 watt maximum power output, for a total of 15 channels. FRS channels 8 through 14 are not available for GMRS use; use of these frequencies requires an FRS transceiver. [ [http://www.provide.net/~prsg/part95ae.htm GMRS Rules] ]

Recently, hybrid FRS/GMRS consumer radios have been introduced with 22 channels, instead of the 14 channels associated with FRS. On this type of radio, channels 8-14 are strictly license-free FRS channels. Transmitting on all channels above channel 14 requires a license. Transmitting on the shared FRS/GMRS channels 1-7 requires a license, if using more than 1/2 watt. It is the responsibility of the radio user to read and understand all applicable rules and regulations regarding GMRS.

The FCC rules for use of hybrid radios on channels 1-7 require licensing only when operating under the rules that apply to the GMRS. Many hybrid radios have an ERP that is lower than 1/2 watt on channels 1-7, or can be set by the user to operate at low power on these channels. This allows hybrid radios to be used under the license free FRS rules if the ERP is less than 1/2 watt and the unit is certified for FRS operation. Only one maker of hybrid FRS/GMRS radios (Garmin) presently sells radios that will operate on the GMRS repeater channels; the common "22 channel" radios cannot be used with GMRS repeaters.

The requirement for GMRS licensing is ignored by the vast majority of users of these frequencies. Estimates of the number of hybrid FRS/GMRS radios sold to date range from 20 to 50 million units or more. This is compared with approximately 80,000 active GMRS licensees (per the FCC database). Enforcement against individuals is rarely, if ever, attempted. This has led to a lot of consternation among the "non-blister-pack" segment of the GMRS user population, who have significantly more expensive equipment, and have paid $85 for a license. (GMRS and FRS/GMRS radios are often sold in "blister packs" at electronic stores with the required application form for a license included among the warranty cards and safety notices.) Online communities such as [http://www.gmrs.net.tc GMRS Radio Information and Forums] and [http://www.popularwireless.com/ Popular Wireless Magazines] are encouraging GMRS enforcement.

Frequency chart

The "Friendly Name" of a frequency is the portion of the frequency to the right of the decimal.

This first set of frequencies shows the split frequency pairs used in duplex operational mode, often used with repeaters. Simplex (same frequency for receiving and transmitting) mode only utilizes the lower set of frequencies.

All channels are used with narrow-band frequency modulation.

This second set of frequencies shows the interstitial ranges shared with the Family Radio Service services. These frequencies can only be used for simplex operations.

Note 1: [http://www.provide.net/~prsg/home.htm The Personal Radio Steering Group (PRSG)] and [http://www.gmrsweb.com/gmrs.html Popular Wireless Magazines] adopted CTCSS 141.3 Hz as the national travel tone for use on all GMRS channels. It is not known how many GMRS licensees have adopted the standard. You can make the travel tone system work by setting one or more of your base-station frequencies to the 141.3 Hz tone.

Note 2: Some groups have recommended FRS Channel 1 as a national emergency/calling channel, such as [http://www.reactintl.org REACT] (Radio Emergency Associated Communications Teams) and the [http://www.nationalsos.com National SOS Radio Network] .

History

GMRS, General Mobile Radio Service, was originally named Class A Citizens Radio Service when it was rolled out in the 1960s. Tube type transceivers were used and output power was limited to 60 watts plate input power to the final amplifier tube. The original service ran wideband FM with ±15 kHz transmitter deviation and 50 kHz channel spacing. At the time, this was the norm for all U.S. land mobile services. There was also a Class B Citizens Radio Service which used a different set of 461 MHz channels and was limited to 5 watts output. Business users were permitted to license in this radio service. Radios were built by consumer electronics firms and commercial two-way radio vendors.

In the 1960s, the UHF 450-470 MHz band was re-allocated to 25 kHz channels. This meant transmitter deviation was reduced to ±5 kHz. This doubled the number of channels available across the entire 450-470 MHz band. Class B Citizens Radio Service channels were re-allocated to other radio services.

In the 1970s, allowed power was again changed to 50 watts across the output terminals of the transmitter. In the 1980s, licensing of business users was discontinued and businesses were allowed to continue operating until their licenses expired. There was congestion on all channels in larger metropolitan statistical areas and moving businesses to Business Radio Service channels would provide some relief. The radio service was changed to its present name.

Use of GMRS equipment in other countries

The use of radio transmitters is regulated by national laws and international agreements. Often radio equipment accepted for use in one part of the world may not be operated in other parts due to conflicts with frequency assignments and technical standards. Some of the roles that the licensed GMRS service fills in the United States are, in other countries, filled by unlicensed or class-licensed services. Generally these services have strict technical standards for equipment to prevent interference with licensed transmitters and systems.

In Canada, hand-held GMRS radios up to 2 watts have been approved for use without a license since September 2004. [ See Industry Canada RSS 210 "Low-Power Licence Exempt Radiocommunications Devices ] Typically these are dual FRS and GMRS units, with fixed antennas, and operating at 2 watts on some GMRS channels and 0.5 watts on the FRS-only channels. Mobile units (permanently mounted in vehicles), base stations and repeaters are not currently permitted on the GMRS channels in Canada.

Other countries have licensed and unlicensed personal radio services with somewhat similar characteristics, but technical details and operating conditions vary according to national rules. Many European countries use a similar 8 channel system near 446MHz known as PMR446.

The use of GMSR handheld radios is a common method of wireless communication by the Taliban and Al Qaeda in Afganistan. Most notably, the iCom handheld radio, which has recently been adopted by both the Taliban and the US Military for use in squad-level tactical communications. [cite journal|url=http://www.afji.com/2006/02/1404902/
accessdate=2008-09-11
title=The waiting game
journal=ARMED FORCES JOURNAL
month=February
year=2006
first=Sean D
last=Naylor
quote=The Taliban forces have demonstrated a better ability to ... using hand-held ICOM radios to command and control formations of more than 100 fighters.
]

ee also

*Multi-Use Radio Service

References

External links

* [http://www.geocities.com/gmrspage/ GMRS Consumer Information] Very detailed.
* [http://strategis.ic.gc.ca/epic/internet/insmt-gst.nsf/en/sf08478e.html#annex6 Industry Canada: FRS & GMRS specifications in Canada]
* [http://wireless.fcc.gov/services/personal/generalmobile/ FCC: GMRS Specifications and U.S. Licensing Info]
* [http://wireless.fcc.gov/services/index.htm?job=service_bandplan&id=family FRS Band Plan]
* [http://www.provide.net/~prsg/wi-gmrs.htm The Personal Radio Steering Group]
* [http://www.f-r-s.org/ F-R-S Communications Center]
* [http://www.mygmrs.com/ myGMRS.com -- User-Submitted GMRS Repeater Directory]
* [http://www.g-m-r-s.org/ G-M-R-S.org ... an On-Line GMRS Repeater Directory]
* [http://www.trisquare.us TriSquare eXRS web site]
* [http://wadsworthsales.com/gmrs.aspx MURS AND GMRS INFORMATION]


Wikimedia Foundation. 2010.

Игры ⚽ Поможем написать реферат

Look at other dictionaries:

  • General Mobile Radio Service — (GMRS) ist eine Funkanwendung, die besonders in den USA und Südamerika gebräuchlich ist. Jeder, der über eine GMRS Funklizenz verfügt, darf GMRS Geräte sogar an Verwandte, Lebenspartner und Mitglieder der unmittelbaren Familie übergeben, auch… …   Deutsch Wikipedia

  • General Packet Radio Service — (GPRS) is a packet oriented mobile data service on the 2G and 3G cellular communication system s global system for mobile communications (GSM). GPRS was originally standardized by European Telecommunications Standards Institute (ETSI) in response …   Wikipedia

  • General Packet Radio Service — (GPRS) (deutsch: „Allgemeiner paketorientierter Funkdienst“) ist die Bezeichnung für den paketorientierten Dienst zur Datenübertragung in GSM und UMTS Netzen[1][2]. Inhaltsverzeichnis 1 Datenübertragung 1.1 Kanalbündelung …   Deutsch Wikipedia

  • General Packet Radio Service — Le General Packet Radio Service ou GPRS est une norme pour la téléphonie mobile dérivée du GSM permettant un débit de données plus élevé. On le qualifie souvent de 2,5G. Le G est l abréviation de génération et le 2,5 indique que c est une… …   Wikipédia en Français

  • General Packet Radio Service — noun a packet oriented Mobile Data Service available to users of Global System for Mobile Communications (GSM) and IS 136 mobile phones. It provides data rates from 56 up to 114 kbit/s …   Wiktionary

  • Mobile radio — This article is about professional equipment. For mobile radios used in amateur radio, see amateur radio mobile operation. Mobile radio or mobiles refer to wireless communications systems and devices which are based on radio frequencies, and… …   Wikipedia

  • Multi-Use Radio Service — In the United States, the Multi Use Radio Service (MURS) is an unlicensed 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… …   Wikipedia

  • Family Radio Service — The Family Radio Service (FRS) is an improved walkie talkie radio system authorized in the United States since 1996. This personal radio service uses channelized frequencies in the ultra high frequency (UHF) band. It does not suffer the… …   Wikipedia

  • Family Radio Service — Der Family Radio Service (FRS) ist eine seit 1996 in den USA (wegen der Beliebtheit später auch in Kanada und Mexiko) freigegebene Jedermannfunkanwendung. In Europa grundsätzlich vergleichbar mit dem Freenet, PMR Funk (PMR446) oder dem SRD Funk… …   Deutsch Wikipedia

  • Mobile Telephone Service — The Mobile Telephone Service (MTS) is a pre cellular VHF radio system that links to the Public Switched Telephone Network (PSTN). MTS was the radiotelephone equivalent of land dial phone service. As of 2005[update], only rural and wilderness… …   Wikipedia

Share the article and excerpts

Direct link
Do a right-click on the link above
and select “Copy Link”