General Mobile Radio Service
It requires a license in the United States, but some GMRS compatible equipment can be used license-free in Canada.
The United States permits use by adult individuals who possess a valid GMRS license, as well as their immediate family members.
[citation needed] GMRS licensees are allowed to establish repeaters to extend their communications range.
[5] GMRS license holders are allowed to communicate with FRS users on those frequencies that are shared between the two services.
Prior to July 31, 1987, the FCC issued GMRS licenses to non-individuals (corporations, partnerships, government entities, etc.).
Theoretically, the range between two hand-held units on flat ground would be about one or two miles (about 1.5–3 km).
A GMRS repeater with an antenna mounted high above the surrounding terrain can extend the usable range to 20 miles or more (30+ km) depending on height.
Higher power does not give much increase in range although it may improve the reliability of communication at the limits of line-of-sight distance.
[14] The 467 MHz interstitial frequencies have a power limit of 500 milliwatts ERP,[15] and only hand-held portable units may transmit on these channels.
With the exception of FRS channels 8 through 14, GMRS licensees may use higher power radios with detachable or external antennas.
Conditions: Effective February 16, 1999, the GMRS rules have been amended and one may operate on any of the primary or interstitial channels shown in section 95.1763.
Additionally receivers and transmitters may drift over time or temperature so the bandwidth is further constrained to prevent interference to the adjacent channel.
There was also a Class B Citizens Radio Service which used a different set of 461 MHz channels and was limited to five watts output.
In 2010 the U.S. Federal Communications Commission (FCC) proposed removing the individual licensing requirement.
[17] 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.
Generally these services have strict technical standards for equipment to prevent interference with licensed transmitters and systems.
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.
GMRS equipment that is approved for use in the United States will not communicate with PMR446 radios due to using different frequency ranges.
[22] As of November 1, 2024 it now has this added to the operations tab: "In other words, repeaters may not be linked via the internet—an example of an “other network” in the rules—to extend the range of the communications across a large geographic area.
