General Mobile Radio Service

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The General Mobile Radio Service (GMRS) is a land-mobile FM UHF radio service designed for short-distance two-way communication. It requires a license in United States but some GMRS compatible equipment can be used license-free in Canada. The United States permits use by an adult individual who possesses a valid GMRS license, as well as his or her immediate family members. 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, are not covered by the same license.

GMRS radios are typically handheld portable devices much like Family Radio Service (FRS) radios, and share the FRS frequency band near 462 and 467 MHz. 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.

Video General Mobile Radio Service

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 online through the FCC's Universal Licensing System. No exam is required. A GMRS license is issued for a 10-year term. The fee is $70 for most applicants.

A GMRS individual license extends to immediate family members and authorizes them to use the licensed system. GMRS license holders are allowed to communicate with FRS users on those frequencies that are shared between the two services. GMRS individual licenses do not extend to employees.

New GMRS licenses are only being issued to individuals. 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 but not make major modifications to their existing licenses.

In any case, each GMRS station must be identified by transmission of its FCC-assigned call sign at the end of a transmission or a series of transmissions, and at least once every 15 minutes for a series lasting more than 15 minutes. The call sign may be spoken or sent with audible tones using Morse code. A repeater station handling properly identified transmissions of others is not required to send its own station identification. 47 CFR §95.1751.

Maps General Mobile Radio Service

Range

As with other UHF radio services, reliable range is considered to be line-of-sight and the distance to the radio horizon can be estimated based on antenna height. Theoretically, the range between two hand-held units would be about one or two miles (about 1.5-3 km); mobile units have higher antennas and a range of around 5 miles (8 km). A GMRS repeater with an antenna that is high above the surrounding terrain can extend the usable range over a wide area - for example, up to a 20-mile (32.2 km) radius around the repeater station. Obstructions such as hills and buildings can reduce range. Higher power does not necessarily give a proportional increase in range, although it may improve the reliability of communication at the limits of line-of-sight distance.

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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 in the 467 MHz frequency range 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, depending on the type of station, but 1 to 5 watts is more common. Units are allowed to have detachable or external antennas.

GMRS licensees are also able to use the first 7 FRS frequencies (the "interstitial" GMRS frequencies) with a few limitations. Specifically, they may be used as long as one-way pages are not transmitted, communications are limited to voice, and transmission power (ERP) does not exceed 5 watts (FCC Code §95.29, section f). This allows GMRS users to transmit on a total of 15 channels. FRS channels 8 through 14 are not available for GMRS use; use of these frequencies requires an FRS transceiver, or a hybrid transceiver operating under FRS rules.

Hybrid FRS/GMRS consumer radios have been introduced with 22 channels, instead of the 14 channels associated with FRS. On this type of radio, transmitting on shared FRS/GMRS channels 1-7 requires a license if using more than 0.5 watt. Channels 8-14 are strictly license-free FRS channels. Transmitting on GMRS-only channels 15-22 requires a license. It is the responsibility of the radio user to read and understand all applicable rules and regulations regarding GMRS. These hybrid radios are often referred to as "bubble pack" radios, since they are often packed in a plastic shell, for hanging on a display shelf. The massive sales of these radios have led to the term "bubble-pack pirates", persons who use GMRS without a license.

Effective September 28, 2017, FCC revised the definition of the FRS service. FRS operation is now permitted with up to 2 watts on the shared FRS/GMRS channels. The FCC will not grant type acceptance for hybrid radios that would exceed the limits for the FRS service on the FRS channels. Current "hybrid" FRS/GMRS radios will not require a GMRS license for power up to 2 watts, but FRS radios will still not be permitted to use the input frequencies of GMRS repeaters. Any radio exceeding the limits of the new FRS service will be classified as a GMRS radio.

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 one half 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 one half watt and the unit is certified for FRS operation. Only two makers of hybrid FRS/GMRS radios (Garmin and Motorola) presently sell radios that will operate on the GMRS repeater channels; the common "22 channel" radios cannot be used with GMRS repeaters. The Icom IC-F21GM is a solely-GMRS radio that will also work with repeaters. FRS rules permit only 2.5 kHz (Narrowband FM) frequency deviation on the FRS shared channels. GMRS uses ±5 kHz deviation on the GMRS channels.

Effective September 30, 2019, it becomes unlawful in the USA to import, manufacture, sell or offer to sell radio equipment capable of operating under both GMRS and FRS. 47 CFR § 95.1792

New GMRS/FRS Frequency chart effective September 28, 2017.

Notes (1) Shared FRS and GMRS simplex. (2) Shared FRS and GMRS simplex, GMRS repeater output. (3) GMRS repeater input.

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Frequency chart

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

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.

GMRS radio channels in the table below use 5 kHz deviation and 25 kHz channel bandwidth although some "bubble pack" combo FRS/GMRS radios utilize 2.5 kHz deviation. For best compatibility of audio level, 5 kHz deviation should be used when communicating with GMRS equipment. The 4-digit decimal GMRS frequencies (shared FRS 1-7/ICOM 9-15) are spaced 12.5 kHz from the (ICOM 1-8) GMRS frequencies, and may receive interference from other nearby stations. It may be advisable to utilize 12.5 kHz narrow-band (NFM) in congested areas, or avoid their use as a last resort.

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.

This third set of frequencies are for FRS use only and are not part of the General Mobile Service. They are included here to show the remaining interstices of the 467 MHz frequency band.

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History

The predecessor to GMRS was named Class A Citizens Radio Service when it was rolled out in the 1960s. Tube type transceivers were used, and transmitter 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 1987, 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; General Mobile Radio Service or GMRS.

In 2010 the U.S. Federal Communications Commission (FCC) proposed removing the individual licensing requirement. In 2015, the FCC ruled to keep the license requirement, but to remove the regulator fee for licensing. Adopted on May 20, 2015, the ruling would be in effect after a 90-day notification period to Congress; the fee will not be eliminated before August 18, 2015. The fee for a 5-year license was $90.00, with the regulatory fee portion of the license at $5 per year (or $25 for the 5-year life of the license). After the notification period, the fee for a 5-year license was to become $65.00. The change became effective on September 3, 2015.

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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. 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 446 MHz known as PMR446, as well as a 69-channel low-power LPD433 which is shared with the ISM band. GMRS equipment that is approved for use in the United States will not communicate with PMR446 radios due to using different frequency ranges.

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See also

• Family Radio Service
• Multi-Use Radio Service

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References

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External links

• FCC: GMRS Specifications and U.S. licensing information
• FCC FRS Band Plan
• Example nonprofit GMRS Repeater
• MyGMRS.com Repeater Directory

Source of the article : Wikipedia