Here are definitions for some of the more common GMRS, ham radio, and R3EMCOMM Radio Network terms.
10 Codes – Or Ten-codes, officially known as ten signals, are brevity codes used to represent common phrases in voice communication, particularly by law enforcement and in Citizens Band (CB) radio transmissions. Avoid using them as they are not universal (also see Code Words).
Amateur or “Ham” Radio – Uses the radio frequency spectrum for purposes of non-commercial exchange of messages, wireless experimentation, self-training, private recreation, radiosport, contesting, and emergency communications. Amateur Radio Operators are required by the Federal Communications Commission to be licensed, which requires passing a written, technical exam (Wikipedia).
AC – Short for Alternating Current, where the current (or electrical flow) constantly reverses direction. Your home’s electrical system uses alternating current (as opposed to DC, or Direct Current).
Band – A group or range of radio frequencies, such as “Citizen’s Band,” “FM Band,” or “GMRS” Band.
Bandwidth – A measure of the width of a range of frequencies, measured in hertz (cycles per second).
Base Station – A non-handheld radio setup for use at home or office with a 12-volt DC power supply that plugs into a 120-volt AC power outlet.
CB – Short for “Citizens Band.” A type of low-power “Personal Radio Service,” as designated by the Federal Communications Commission.
Channel – A narrow span of frequencies assigned for the operation of television, radio, or other broadcast stations.
Citizen Responder – A layperson (someone who does not have special or advanced medical training or skill) who recognizes an incident or emergency and decides to act. The Citizen Responder is often the first and most crucial link in the emergency response system. An effective Citizen Responder is trained to recognize certain types of medical and non-medical emergencies and how to react appropriately to the emergency.
Coax or Coaxial Cable – A type of transmission line, used to carry high-frequency electrical signals with low loss. It has an inner conductor surrounded by a tubular insulating layer, surrounded by a tubular conducting shield. Many coaxial cables also have an insulating outer sheath or jacket.
Code RED – An emergency-notification system used by many Public Service agencies to send public safety and alert messages by text and voice messages to your wired or cellular phone in the event of a local emergency, evacuation, or disaster. Typically, you must “Opt-in” to these systems in order to receive these messages.
Code Words – Secret words or phrases used as code names or passwords, or words and abbreviations that may have evolved over time and that may have confusing or conflicting meanings. Avoid using them as they are not universal.
CTCSS Tone – FRS and GMRS radios frequently have provisions for using sub-audible tone squelch (CTCSS and DCS) codes, filtering out unwanted chatter from other users on the same channel. Also, see PL Tone.
dB – Short for “decibel,” a dB is a unit of measurement often used with antennas and cables to express the amount of gain or loss. Every 3 dB of antenna gain increases the power fed into it by 100%. An antenna with a 6 dB gain would increase the power fed into it by 400%. Conversely, a cable with a 3 dB loss would lose 50% of the power fed into it. A cable with a 6 dB loss would lose 75% of the power fed into it.
DC – Short for “Direct Current,” where the current (or electrical flow) constantly flows in just one direction. All computers and radios use DC power, although some may be equipped with an AC to DC power converter.
Directional Antenna – An antenna that sends and receives most of its signal in one direction. A TV antenna on a rooftop is an example of a directional antenna.
Disaster – A serious disruption occurring over a short or long period of time that causes widespread human, material, economic or environmental loss which exceeds the ability of the affected community or society to cope using its own resources (Wikipedia).
Duplex – Refers to a radio that transmits on one frequency and receives on another frequency, with a small offset between them to prevent the two signals from interfering with each other. Duplex is most often used for radio-to-repeater communications.
Dual-band – A type of radio capable of using both VHF and UHF frequency bands. Many Handie Talkie radios, especially those favored by the Ham Radio community, are dual-band radios.
Emergency – A situation that poses an immediate risk to health, life, property, or environment. Most emergencies require urgent intervention to prevent a worsening of the situation, although in some situations, mitigation may not be possible and agencies may only be able to offer palliative care for the aftermath (Wikipedia).
Emergency Alert System or EAS – A national public warning system commonly used by state and local authorities to deliver important emergency information, such as weather and AMBER alerts, to affected communities. EAS participants – radio and television broadcasters, cable systems, satellite radio, television providers, and wireline video providers – deliver local alerts on a voluntary basis, but they are required to provide the capability for the President to address the public during a national emergency. Note that cell phones typically receive Alerts sent through the WEA system instead of the EAS system.
Event – Non-urgent, non-life threatening fires, accidents, road closures, weather, animal control issues, power outages, suspicious activities, meetings, fundraisers, parties, and sponsored community activities are just some examples of reportable events for an R3EMCOMM Radio Network program.
Falcon – A radio operator who is located at a high vantage point where they can more easily spot smoke, fire, or First Responder activity and report it to the R3EMCOMM Radio Network community via radio.
FM – Short for “Frequency Modulation,” a type of low-noise, high-fidelity radio transmission. For this reason, most music is broadcast over FM radio.
FRS – Family Radio Service. A type of low-power “Personal Radio Service,” as designated by the Federal Communications Commission. These are the common, retail “blister-pack” walkie-talkie type radios sold at Wal-Mart, Best Buy, Home Depot, and others. FRS radios are low-powered, Handie Talkies only, have non-detachable antennas, and cannot transmit to Repeaters. The FRS service does not require a license to operate.
First Responder – Professionally-trained individuals from the Office of Emergency Services, Police, Fire, Sheriff’s Office, Highway Patrol, National Guard, Search and Rescue, EMT, Ambulance, or Medivac are some examples of people whose job it is to respond to events, emergencies and disasters to save lives, prevent property damage and protect the community.
Frequency – The number of occurrences of a repeating event per unit of time. In radio terms, the frequency of a radio wave is expressed in Hertz. One (1) Hertz = 1 cycle per second.
Gain – The amount by which an antenna might increase the signal fed to it. Also, see “dB.”
GMRS – General Mobile Radio Service. Operating within the UHF frequency band between 462 to 467 MHz, GMRS is a popular type of “Personal Radio Service,” established by the Federal Communications Commission. Mainly because of its higher power limits and thus greater potential to cause interference at a distance, this service requires a GMRS license to operate.
Ham – Also known as an Amateur Radio Operator. The term’s origins are debated, but some believe it was originally a derogatory term used by experienced telegraph operators to diss “ham-fisted” or less-experienced radio operators.
Handie Talkie – Also known as a Walkie Talkie, portable radio, or “HT,” a Handie Talkie is a type of self-contained, battery-operated, two-way radio that can be easily carried and used.
Hertz – This is the unit of measurement of the frequency of radio waves. One (1) Hertz = 1 cycle per second; 1,000 Hertz = 1 kilohertz or kHz; 1,000,000 Hertz = 1 Megahertz or 1 MHz. The AM Broadcast band operates at frequencies between 525 kHz and 1,606 kHz. The FM Broadcast band operates at frequencies between 88 MHz and 108 MHz.
HF – Short for “High Frequency,” A range of radiofrequency waves between 3 and 30 megahertz (MHz). HF bands have the potential for the longest range up to thousands of miles and are popular with “short-wave listeners” and Amateur Radio operators for this reason.
HT – A Handheld radio, aka handheld transceiver or Handie-Talkie.
kHz – A frequency abbreviation for “kilohertz,” or 1,000 Hertz (1 Hz = 1 cycle per second).
Mag Mount – A type of mount used with mobile antennas that hold the antenna to the top of a vehicle using a magnet.
MHz – A frequency abbreviation for “megahertz,” or 1,000,000 Hertz.
Mobile – A (usually) non-handheld “mobile” radio for use in a vehicle on 12V DC battery power. These radios are normally connected to a vehicle’s 12-volt battery electrical system and a vertical “whip” antenna mounted outside the vehicle. Mobile radios can also be used at home or office with an external 12-volt power supply and an outdoor antenna.
Mother Hen – An R3EMCOMM Radio Network operator who can monitor and use multiple forms of communication including GMRS, Ham Radio, Scanners, Pagers, Internet, and phone services to look out for their community and do any “heavy lifting” in case messages need to be relayed in or out of the community, or over long distances to call for help or to summon aid.
MURS – Multi-use Radio Service. Operating at 151 to 154 MHz, a type of low-power “Personal Radio Service,” similar to Citizens Band, established by the Federal Communications Commission in 2000.
R3EMCOMM Radio Network – An all-volunteer group of concerned Citizen Responders dedicated to promoting community safety in the neighborhoods of Culpeper, Madison, Orange, and Rappahannock counties through the use of simple, easy-to-use, two-way radios and radio repeaters.
NMO – Short for “New Motorola,” a type of popular, threaded mobile antenna connector that attaches an antenna to a magnetic base that is usually placed on the outside of a vehicle.
Net – A regular, typically weekly radio “round table,” where radio users can check in and talk to each other. Usually, nets are moderated and directed by one or more persons who are designated as the “Net Control” operator.
Net Control, Net Control Station or NCS – A communications station designated to manage net traffic and enforce communications discipline during a net.
Omnidirectional Antenna – A type of antenna which radiates equal radio power in all directions perpendicular to its long axis. A whip antenna on a handie talkie is an example of an omnidirectional antenna.
One-to-Many – A term used to describe transmissions where a radio signal broadcast from one transmitter can be received by many receivers. A TV or radio station, and most two-way radios, are typical examples of one-to-many transmission devices.
One-to-One – A term used to describe transmissions where a radio signal broadcast from one transmitter can be received by only one receiver. A cell phone is an example of a one-to-one device.
One-way Radio – A type of radio that can only receive and cannot transmit. AM/FM radios, police and fire scanners, weather radios, and pagers are examples of one-way radios, also known as “listen-only” devices.
Pager – A type of one-way radio used to receive short text and voice messages and alerts. Different models of pagers use frequencies in the VHF or UHF bands and can receive radio signals sent through repeaters.
PAN-PAN – The international standard urgency signal that someone aboard a boat, ship, aircraft, or other vehicle uses to declare that they have a situation that is urgent, but for the time being, does not pose an immediate danger to anyone’s life or to the vessel or vehicle itself.
Personal Radio Services – These are short-range, low-power radio communications using devices that operate much like walkie-talkies. Personal radio services include one- and two-way voice services, data services, and remote-control transmissions that operate the equipment. The most popular types of personal radio services are Citizens Band Radio Service, Family Radio Service, General Mobile Radio Service, Low-Power Radio Service, and Multi-Use Radio Service. Of these types of services, only General Mobile Radio Service requires an FCC license to operate (https://www.fcc.gov/consumers/guides/personal-radio-services-prs-keeping-touch).
PL Tone – A type of sub-audible tone used to prevent multiple signals using the same frequency from interfering with each other. Also, see CTCSS Tone.
Portable Radio – Also known as a Walkie Talkie, Handie Talkie or “HT,” a portable radio is a type of self-contained, battery-operated, two-way radio that can be easily carried and used.
Propagation – The varying ability of radio waves to travel in different directions through space or around obstacles, including the curvature of the earth, the air, weather, trees, buildings, etc.
PTT Button – The “Push-To-Talk” button on a Handie Talkie or microphone that is pressed in order to transmit.
Q-Codes – A standardized collection of three-letter codes all of which start with the letter “Q”, initially developed for commercial radiotelegraph communication and later adopted by other radio services, especially amateur radio. Avoid using them as they are not universal (also see Code Words).
Radio – A wireless communications device that uses radio waves to receive and transmit data and information. A cell phone is a specialized type of radio, as are many household devices such as garage door openers, TVs, WiFi routers, wireless cameras, and doorbells.
Repeater – A type of radio “relay” that receives transmissions sent on one frequency and then rebroadcasts those transmissions on another frequency. Used to extend the range of normal radio communications. A cell phone tower is a type of radio repeater.
RF – Short for “Radio Frequency.”
RX – Short for Receive” or “Receiver.” Many radios are “RX only” in that they can receive signals but not transmit them.
Safety Net – See Net
Scanner – A type of receive-only radio that can be set to “scan’ across a wide range of frequencies until it detects a radio transmission and then stops. Used mainly to monitor police, fire, and emergency frequencies.
Simplex – Direct, radio-to-radio communications without the use of a repeater. See Talk Around.
Squelch – A circuit function that acts to suppress the audio output noise of a receiver in the absence of a sufficiently strong desired signal.
Start-Up Tone – The audible tone or beep emitted by your radio when starting up to alert you that the device is functioning.
SWL – Short for Short-Wave Listening. Short Wave is another name for “High Frequency” or HF – a range of radiofrequency waves between 3 and 30 megahertz (MHz). Within these frequencies, short-wave listeners can receive radio transmissions from thousands of miles away.
Talk Around – Also known as Simplex, Talk Around denotes communications directly from one radio to another radio, without the use of a repeater to bridge between the two radios.
Two-way Radio – A type of radio that can transmit and receive (TX + RX). All Handie Talkies are examples of two-way radios.
TX – Short for “Transmit” or “Transmitter.” Many radios are “TX / RX” capable, meaning they can “transmit” and “receive.”
UHF – Short for “Ultra High Frequency,” A range of radiofrequency waves between 300 megahertz (MHz) and 3 gigahertz (GHz). For amateur radio communications, this typically means 420 to 450 MHz, often referred to as the “440” or “70-centimeter” band. At 462 to 467 MHz, the frequencies used by GMRS are within the UHF frequency band.
VHF – Short for “Very High Frequency,” A range of radiofrequency waves between 30 megahertz and 300 megahertz (MHz). For amateur radio communications, this typically means 144 to 148 MHz, often referred to as “144” (the frequency) or “2-meter” (the wavelength in meters).
Walkie Talkie – See Handie Talkie.
Watt – A unit of power measurement. In radio, each doubling of signal watts equals a doubling of power. For instance, 10 watts equals two times the power of 5 watts, 20 watts equals four times the power of 5 watts, and forty watts equals 8 times the power of 5 watts.
Weather Radio – A type of one-way radio used to receive severe-weather announcements and other emergency-warning alerts. Many can be programmed to receive alerts specific to your ZIP Code using Specific Area Message Encoding, or S.A.M.E. technology.
Wireless Emergency Alerts or WEA System – The Wireless Emergency Alerts system, also known as Amber Alerts, is a nationwide public safety system that allows people who own compatible mobile devices to receive geographically targeted, text-like messages alerting them of imminent threats to safety in their area. Unlike CodeRED, which is an “Opt-in” system, the WEA system is an “Opt-out” system, meaning you must manually disable this feature in your cell phone or else you will receive WEA alerts. Unlike the EAS Alert System, the WEA system does not broadcast alerts through TV, radio, or cable systems although they often share the same alerts. Keep in mind that there’s no way for you to disable or opt out of Presidential alerts.
Yagi or Yagi Antenna – A type of “Directional Antenna,” which sends and receives most of its signal in one direction. Named after one of its inventors, Hidetsugu Yagi. Outdoor TV antennas are good examples of Yagi antennas.
Zone – A grouping of related channels. A programmable radio may have one or more related channels, grouped together in a “Zone.” For example, you could have a radio with a zone named “GMRS.” You would then first select that zone to access those channels. In that zone, all of your radio’s GMRS channels could be grouped together to make them easier to find.
73 – Meaning “Best Regards,” a popular abbreviation commonly used in Amateur Radio, and most frequently in Morse code, to signal “Goodbye.”
Other Radio Lingo and Code Words
Affirmative – Yes
Break, Break, Break! – An interruption to an existing transmission to communicate an urgent message.
Code Blue – For a non-crucial incident.
Code Yellow – For a non-dangerous incident that still requires an immediate response.
Code Red – For a dangerous or serious incident that requires an immediate response.
Come In? – Asking another party to acknowledge they can hear you.
Emergency, Emergency, Emergency! – Distress call, only to be used when there is an imminent danger to life and immediate assistance is required.
Go Ahead – I am ready for your message.
I Spell – The next word will be spelled out using the International Phonetic Alphabet.
Negative – No.
Out – Conversation is finished, no answer is required or expected.
Over – Message finished, inviting others to respond if needed
Phonetic Alphabet – The Ham Radio Phonetic Alphabet is used to identify amateur radio call sign letters instead of saying the letter itself.
Radio Check – What’s my signal strength? Can you hear me?
Read You Loud And Clear – Your transmission signal is good, I can hear you fine.
Roger So Far – Confirming part way through a long message that you’ve understood the message so far.
Roger That – Message received and understood.
Say Again – Repeat your last message.
Say All Before/After – Repeat all before/after a certain phrase or word if you didn’t catch part of the message.
Stand By – Wait for a short period and I will get back to you.
Wait Out – Delay is longer than I expected, I’ll get back to you as soon as possible.
Wilco – Abbreviation for “I will comply” which means the listener will complete the task that’s been asked of them.
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R3EMCOMM is a “not-for-profit,” all-volunteer community service organization. Members are not reimbursed for their membership or for services provided to the community. All of the community radio equipment we furnish is provided at or below our out-of-pocket cost, and our general support services are offered free of charge. Radio acquisition, programming, and training workshops are provided by our members free of charge. Unpaid volunteer assistance may be available if you or your neighbors need help installing their equipment at home. Donations to R3EMCOMM to sustain our efforts are gratefully accepted but are not required nor expected.
FRS, GMRS, Ham Radio, and/or the R3EMCOMM Radio Network are NOT a replacement for Emergency Services such as Police, Fire, the Sheriff’s Office, or 911. Programs like the R3EMCOMM Radio Network are intended as a backup communications solution when traditional means of communication are inoperable or when “all else fails.”