GMRS capable handheld radio The General Mobile Radio Service (GMRS) is a land-mobile UHF radio service in the United States available for short-distance two-way communications to facilitate the activities of an adult individual who possesses a valid GMRS license, as well his or her immediate family members, including a spouse, children, parents, grandparents, aunts, uncles, nephews, nieces, and in-laws (47 CFR 95.179). Immediate relatives of the GMRS system licensee are entitled to communicate among themselves over the general area of their residence or during recreational group outings, such as camping or hiking. Image File history File linksMetadata Size of this preview: 284 Ã 598 pixel Image in higher resolution (792 Ã 1668 pixel, file size: 894 KB, MIME type: image/jpeg) GMRS capable radio. ...
Image File history File linksMetadata Size of this preview: 284 Ã 598 pixel Image in higher resolution (792 Ã 1668 pixel, file size: 894 KB, MIME type: image/jpeg) GMRS capable radio. ...
This article is about the radio frequency. ...
GMRS radios are typically handheld portable devices much like Family Radio Service (FRS) radios, and share some frequencies. Mobile and base station-style radios are available as well, but these are normally commercial UHF radios 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. The Family Radio Service is an improved walkie talkie system authorized in the United States. ...
Recreational, toy and amateur radio walkie talkies A walkie-talkie or two-way radio is a hand-held portable, bi-directional radio transceiver. ...
Although the introductory paragraph (as taken from the FCC website) would seem to exclude communications with others that are not part of one's immediate family, the license actually extends privileges of the primary licensee to include communications with the licensee's immediate family members, and authorizes immediate family members to use the licensees station(s) to conduct the activities of the licensee. Additionally, the FCC rules for GMRS state: "A GMRS license authorizes a GMRS station to transmit messages to other GMRS stations at any geographical location within or over the territorial limits of any area where radio services are regulated by the FCC". This means that GMRS licensees are also allowed to communicate with other licensees in the wider GMRS community. Futher, the FCC has clarified that GMRS licensees are allowed to communicate with FRS users on those frequencies that are shared between the two services. Other countries have personal radio services with somewhat similar characteristics, but technical details and operating conditions vary according to national rules. Interstitial Frequencies
There are 7 "interstitial" channels shared with Family Radio Service, and 8 channels exclusively for GMRS. GMRS use requires an FCC license in the US, and licensees are permitted to transmit at up to 50 watts on GMRS frequencies (although 1 to 4 watts is more common), as well as have detachable antennas. GMRS licensees are also able to use the first 7 FRS frequencies (the "interstitial" frequencies), but at the lower 5 watt maximum power output, for a total of 15 channels. Radios programmed for GMRS may also use repeater systems. 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 The FCCs official seal. ...
The watt (symbol: W) is the SI derived unit of power, equal to one joule per second. ...
The watt (symbol: W) is the SI derived unit of power, equal to one joule per second. ...
Recently, hybrid FRS/GMRS consumer radios have been introduced that have 22 channels, instead of the 14 channels associated with FRS. On this type of radio, only channels 8-14 are strictly license-free FRS channels: Transmitting on all channels above channel 14 requires a license, and transmitting on the shared FRS/GMRS channels 1-7 also requires a license if, as is the usual case, the effective radiated power of the radio is greater than 500 milliwatts (1/2 watt). It is the responsibility of the radio user to read and understand all applicable rules and regulations regarding GMRS. The requirement for GMRS licensing in the USA is not followed by many users of these frequencies. Nonetheless, there are over 80,000 GMRS licensees. Reports of GMRS enforcement are encouraging. However, enforcement against individuals is rare, if ever attempted. This has led to a lot of consternation among the "non-bubble-pack" segment of the GMRS user population, who have significantly more expensive equipment, and have paid approximately $80 for a license. Online communities such as www.gmrs.net.tc and http://www.popularwireless.com are working to solve this problem by 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 (talk-around) mode only utilizes the 'Lower Freq' values. A simplex communication system is one where all signals flow in one direction. ...
| Name | Lower Frequency (MHz) | Upper Frequency | Motorola convention | Icom F21-GM convention | Notes | | "550" | 462.550 | 467.550 | Ch. 15 | Ch. 1 | | | "575" | 462.575 | 467.575 | Ch. 16 | Ch. 2 | | | "600" | 462.600 | 467.600 | Ch. 17 | Ch. 3 | | | "625" | 462.625 | 467.625 | Ch. 18 | Ch. 4 | | | "650" | 462.650 | 467.650 | Ch. 19 | Ch. 5 | Use not permitted near the Canadian border. | | "675" | 462.675 | 467.675 | Ch. 20 | Ch. 6 | Nationwide emergency and road information calling. Nationally recognized coded squelch for 675 emergency repeater operation is 141.3 Hz. | | "700" | 462.700 | 467.700 | Ch. 21 | Ch. 7 | Use not permitted near the Canadian border. | | "725" | 462.725 | 467.725 | Ch. 22 | Ch. 8 | | 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. The Family Radio Service is an improved walkie talkie system authorized in the United States. ...
| Name | Frequency (MHz) | Motorola convention | Icom F21-GM convention | Notes | | "5625" or "FRS 1" | 462.5625 | Ch. 1 | Ch. 9 | | | "5875" or "FRS 2" | 462.5875 | Ch. 2 | Ch. 10 | | | "6125" or "FRS 3" | 462.6125 | Ch. 3 | Ch. 11 | | | "6375" or "FRS 4" | 462.6375 | Ch. 4 | Ch. 12 | | | "6625" or "FRS 5" | 462.6625 | Ch. 5 | Ch. 13 | | | "6875" or "FRS 6" | 462.6875 | Ch. 6 | Ch. 14 | | | "7125" or "FRS 7" | 462.7125 | Ch. 7 | Ch. 15 | | Note: PRSG and 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 but you are more likely to attract attention on more frequencies. You can make the travel tone system work by setting one or more of your base-station frequencies to the 141.3 Hz tone. Remember when people use a Travel Tone, they don't necessarily go alone. Some groups have been pushing FRS channel 1 as an emergency/calling channel. FRS radios operate with very little power and FRS in urban areas is nothing but congested anarchy.
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 ordered reallocated 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. Repeaters began to proliferate in the 1980s after the prevalence of unlicenced operations in the Class D Citizens Band made HF CB radios unusable in many applications. In the United States, the Office of Management and Budget (OMB) has produced a formal definition of metropolitan areas, which are organized around county boundaries. ...
A typical CB base station. ...
HF or Hf might be an acronym or abbreviation for: High frequency Radio hafnium, a chemical element the chemical formula for Hydrofluoric acid Historisk-filosofisk fakultet, abbr. ...
GMRS in Canada In Canada, hand-held GMRS radios up to 2 watts have been approved for use since September 2004. Typically these are dual FRS and GMRS units, with fixed antennas, and operating at 2 watts on GMRS and 0.5 watts on the FRS-only channels. A licence is not required in Canada for operation at 2 watts on the GMRS channels. Mobile units (permanently mounted in vehicles), base stations and repeaters are not currently permitted on the GMRS channels in Canada. Two GSM mobile phone base stations disguised as trees in Dublin, Ireland. ...
See also Ham radio station with modern solid-state transceiver featuring LCD display and DSP capabilities Ham radio station with vintage vacuum tube gear featuring separate transmitter, receiver and power supply Amateur radio, often called Ham radio, is a hobby and public service enjoyed by about 6 million people throughout the world. ...
The Family Radio Service is an improved walkie talkie system authorized in the United States. ...
The Multi-Use Radio Service (MURS) is a small two-way radio service consisting of five frequencies in the VHF spectrum. ...
External links Amateur and hobbyist Amateur radio • Amateur radio repeater • Citizens' band radio • Family Radio Service General Mobile Radio Service • Mobile rig • Multi-Use Radio Service • PMR446 • UHF CB (Australia) A two-way radio is simply a radio that can both transmit and receive (a transceiver). ...
Ham radio station with modern solid-state transceiver featuring LCD display and DSP capabilities Ham radio station with vintage vacuum tube gear featuring separate transmitter, receiver and power supply Amateur radio, often called Ham radio, is a hobby and public service enjoyed by about 6 million people throughout the world. ...
An Amateur radio repeater is an electronic device that receives a weak or low-level amateur radio signal and retransmits it at a higher level or higher power, so that the signal can cover longer distances without degradation. ...
A typical CB base station. ...
The Family Radio Service is an improved walkie talkie system authorized in the United States. ...
Mobile surveillance camera watching over passengers in a taxicab A mobile rig (or automobile rig) is a class of communications system that is midway between a base station (building-mounted) and portable (body mounted). ...
The Multi-Use Radio Service (MURS) is a small two-way radio service consisting of five frequencies in the VHF spectrum. ...
Alan 456r PMR446 (Personal Mobile Radio, 446 MHz) is a radio frequency part of the UHF range that is open without licensing for personal usage in most members of the European Union. ...
UHF CB is a licence-free citizens band radio service authorised by the government of Australia in the UHF 477MHz band. ...
Aviation (aeronautical mobile) Air traffic control • Aircraft emergency frequency • Airband • Mandatory frequency airport • Single Frequency Approach • UNICOM Air Traffic Control Towers (ATCTs) at Amsterdams Schiphol Airport (Netherlands) Air traffic control (ATC) is a service provided by ground-based controllers who direct aircraft on the ground and in the air. ...
The aircraft emergency frequency is a frequency used on the aircraft radio band reserved for emergency communications for aircraft in distress. ...
Note: This article title may be easily confused with AirBand The airband or air band is the band of frequencies used for radio communication in aviation. ...
An airport with a mandatory frequency (MF), mandatory traffic advisory frequency (MTAF) or air/ground radio (A/G) is an airport which does not have a control tower but still requires arriving and departing airport to communicate with other aircraft or a radio operator on a published frequency. ...
In aviation, a Single Frequency Approach (SFA) is a service for a military single-piloted turbojet aircraft to use a single UHF frequency during their landing approach. ...
UNICOM, or UNiversal Integrated COMmunication, is an air-ground communication facility operated by a private agency to provide private advisory station (PAS) service at uncontrolled aerodromes and airports with no Air Traffic Services (ATS) air-ground communication facility. ...
Land-based commercial and government mobile Business band • Base station • Mobile radio • Professional Mobile Radio • Radio repeater • Specialized Mobile Radio • Trunked radio system • Walkie talkie The business band is the name used by US scanner hobbyists who listen to Federal Communications Commission licensees using Industrial/Business pool frequencies. ...
Two GSM mobile phone base stations disguised as trees in Dublin, Ireland. ...
It has been suggested that this article or section be merged with Mobile radio telephone. ...
Professional Mobile Radio (also known as Private Mobile Radio (PMR) in the UK and Land Mobile Radio (LMR) in North America) are field radio communications systems which use portable, mobile, base station, and dispatch console radios and are sometimes based on such standards as MPT1327, TETRA and APCO 25 which...
A Radio Repeater is a combination of a radio receiver and a radio transmitter that receives a weak or low-level signal and retransmits it at a higher level or higher power, so that the signal can cover longer distances without degradation. ...
The Specialized Mobile Radio system (SMR) is a conventional two-way radio system, or trunked radio system, operated by a service in the 800 or 900 Mhz bands. ...
A trunked radio system is a radio system used to maximize available capacity in a two-way radio system, usually UHF. Groups of users are given a logical talkgroup to share for their communications, rather than a dedicated radio frequency. ...
Recreational, toy and amateur radio walkie talkies A walkie-talkie or two-way radio is a hand-held portable, bi-directional radio transceiver. ...
Marine (shipboard) 2182 kHz • Coast radio station • Marine VHF radio • Maritime mobile amateur radio The radio frequency of 2182 kilohertz (kHz) is the international calling and distress frequency for voice maritime communication (radio telephony) on the marine MF bands. ...
Coast radio station is a maritime radio station situated on shore which monitores radio distress frequencies and relays ship-to-ship and ship-to-land communications. ...
Portable VHF radio set Marine VHF radio is installed on all large ships and most motorized small craft. ...
Most countries amateur radio licences allow licensed operators to install and use radio transmission equipment while at sea. ...
Signaling / Selective calling CTCSS • Dual-tone multi-frequency • D-STAR • MDC-1200 • Push to talk • Quik Call I • Selcall In a conventional, analog two-way radio system, a standard radio has noise squelch or carrier squelch which allows a radio to receive all transmissions on a channel. ...
In telecommunications, squelch is a circuit function that acts to suppress the audio (or video) output of a receiver. ...
A DTMF telephone keypad Dual-tone multi-frequency (DTMF) signaling is used for telephone signaling over the line in the voice-frequency band to the call switching center. ...
// D-Star information Digital Smart Technology for Amateur Radio D-Star Radio is a digital HAM radio. ...
MDC, also known as MDC-1200 and MDC-600, is a low-speed Motorola two-way radio data system using audio frequency shift keying, (AFSK). ...
Push-to-Talk (PTT), also known as Press-to-Transmit, is a method of conversing on half-duplex communication lines, including two-way radio, using a momentary button to switch from voice reception mode to transmit mode. ...
Quik-Call I, also known as 2+2, is a selective calling method originally used in one-way paging receivers. ...
Selcall (selective calling) is a type of squelch protocol used in radio communications systems, in which transmissions are preceded by a brief burst of sequential audio tones. ...
System elements and principles Antenna • Audio level compression • Call sign • DC remote • Fade margin • Link budget • Rayleigh fading • Tone remote • Voting (diversity combining) A Yagi-Uda beam antenna Short Wave Curtain Antenna (Moosbrunn, Austria) A building rooftop supporting numerous dish and sectored mobile telecommunications antennas (Doncaster, Victoria, Australia) An antenna or aerial is an arrangement of aerial electrical conductors designed to transmit or receive radio waves which is a class of electromagnetic waves. ...
Audio level compression, also called dynamic range compression, volume compression, compression, limiting, or DRC (often seen in DVD player settings) is a process that manipulates the dynamic range of an audio signal. ...
Call sign can refer to different types of call signs: Airline call sign Aviator call sign Cosmonaut call sign Radio and television call signs Tactical call sign, also known as a tactical designator See also: International Callsign Allocations, Maritime Mobile Service Identity This is a disambiguation page — a navigational...
A current loop describes two different electrical signalling schemes. ...
In telecommunication, the term fade margin (fading margin) has the following meanings: A design allowance that provides for sufficient system gain or sensitivity to accommodate expected fading, for the purpose of ensuring that the required quality of service is maintained. ...
A link budget is the accounting of all of the gains and losses from the transmitter, through the medium (free space, cable, waveguide, fiber, etc. ...
Rayleigh fading is a statistical model for the effect of a propagation environment on a radio signal, such as that used by wireless devices. ...
A Motorola T-1300 series remote control is built in a telephone housing. ...
Diversity Combining is the technique applied to combine the multiple received signals of a diversity reception device into a single improved signal. ...
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