A
Amateur Radio: See Ham Radio.
APRS: Automatic Packet Reporting System. Used to send text messages and data (like GPS coordinates) over radio. aprs.org
AREDN: Amateur Radio Emergency Data Network. A high-speed data network over Ham frequencies for use in emergencies. arednmesh.org
ARES: Amateur Radio Emergency Service. ARRL's volunteer emergency communications arm, organized by Hams. arrl.org/ares
ARRL: American Radio Relay League. The national association for amateur radio in the US. arrl.org
B
Band: A range of radio frequencies. For example, common bands for HTs include 2 meter (VHF) and 70 cm (UHF).
Base Station: A radio setup installed permanently in a fixed location, typically with an external antenna for greater range.
Break: What you say to interrupt an ongoing conversation. Wait for a pause, then say "break" followed by your name.
C
Calling Frequency: A standard frequency that many users monitor, used to make initial contact before moving to another frequency.
Callsign: A unique identifier assigned by the FCC when you get your license. Required when transmitting on Ham and GMRS.
Channel: A specific frequency or frequency pair that a radio is tuned to.
CHIRP: Free software for programming frequencies and repeater settings into many Ham and GMRS radios. Download CHIRP
Clear: What you say when ending a conversation and leaving the channel open for others.
Contesting: Competitive events where Ham radio operators try to make as many contacts as possible in a set period. Helps build skills, test equipment, and connect with the global community.
Copy: Acknowledgment that you received and understood a transmission. Same as "Roger."
CTCSS: Continuous Tone-Coded Squelch System. See Privacy Tones.
D
Digital Modes: Methods of sending data (email, pictures, text) over radio instead of voice.
Directed Net: A structured net where all communication goes through the Net Control operator.
DMR: Digital Mobile Radio. A free and open source protocol for sending voice and data digitally over radio. Wikipedia
D-STAR: Digital Smart Technologies for Amateur Radio. ICOM's proprietary digital voice and data protocol. dstarinfo.com
Duplex: Communication using two frequencies: one to transmit, one to receive. Used with repeaters.
Dipole: A basic, effective antenna made of two equal-length wires fed in the center. Wikipedia
DX: Long-distance communication, often between continents.
E
EME: Earth-Moon-Earth, also called "moon bounce." Bouncing signals off the moon for extreme long-distance communication.
End Fed Half Wave: An HF antenna that's half a wavelength long, fed at one end. Doesn't require a tuner or ground.
F
Fox Hunt: A radio direction-finding activity where participants locate a hidden transmitter.
FRS: Family Radio Service. A license-free radio service with lower power and quality than GMRS. Avoid if you can.
FT8: A digital mode for long-distance, weak-signal communication using short 13-character messages. Popular for contesting.
Frequency: The number of complete wave cycles (from peak to peak) that pass a point in one second, measured in Hertz (Hz). In radio, frequency is usually given in Megahertz (MHz), representing millions of cycles per second.
G
GMRS: General Mobile Radio Service. A radio service with 22+ channels that requires a $35 license (no test). Great for beginners. FCC GMRS info
H
Ham Radio: Amateur radio. Requires passing a test to get licensed, but offers access to many frequencies and long-range communication.
HF: High Frequency (3-30 MHz). Can transmit hundreds or thousands of miles by bouncing signals off the atmosphere.
HT: "Handie Talkie" (but really "Handheld Transceiver"). A handheld portable radio.
J
J-Pole: A simple, popular omnidirectional antenna. Often homemade and gives modest gain.
JS8Call: A digital mode for keyboard-to-keyboard messaging over HF. js8call.com
L
LoRa: Long Range. A low-power radio protocol used by Meshtastic devices.
M
MeshCore: An open-source mesh networking protocol for encrypted off-grid text messaging using LoRa radios. meshcore.co.uk
Meshtastic: Devices that send text messages over the air without internet, cell service, or a Ham license. meshtastic.org
MHz: Megahertz. Unit of frequency (millions of cycles per second).
Mobile Radio: A radio designed for vehicles, typically more powerful than an HT and using an external antenna.
Moon Bounce: See EME.
MR: Memory Recall. A radio mode for selecting from pre-programmed channels. See also VFO.
N
Net: An on-air radio meeting, usually held on a regular schedule.
Net Control: The person who runs a net, managing who speaks and when.
NOAA Weather: National weather service radio broadcasts on frequencies 162.40-162.55 MHz. weather.gov/nwr
NVIS: Near-Vertical Incidence Skywave. An HF technique for medium-range communication without repeaters.
O
Offset: The frequency difference between a repeater's receive and transmit frequencies.
Over: What you say when you're done talking but expect a response.
P
P25: A digital radio standard used by public safety agencies like fire and police. P25 makes extensive use of trunking.
PACE: Primary, Alternate, Contingency, Emergency. A framework for planning backup communication methods.
Packet Radio: A method of sending digital data over radio in small chunks called packets. Used by APRS and other digital modes.
Phonetic Alphabet: Standard words used to spell out letters clearly. (Alfa, Bravo, Charlie, Delta, etc.)
PL Tone: See Privacy Tones.
Priority: What you say to indicate urgent (but not life-threatening) traffic.
Privacy Tones: Sub-audible tones that filter out transmissions without the matching tone. Reduces chatter but is NOT encryption.
PTT: Push-to-Talk. The button you hold down to transmit.
R
RACES: Radio Amateur Civil Emergency Service. Government-activated Ham emergency communications. usraces.org
Random Wire Antenna: A simple HF antenna made from a length of wire that isn't tuned to a specific frequency. Requires a tuner to match the antenna to the radio.
Repeater: A radio that receives on one frequency and retransmits on another, usually from a high location to extend range.
Roger: Acknowledgment that you received and understood a transmission. Same as "Copy."
Rubber Duck: The short, basic antenna that comes stock with most HTs.
S
SDR: Software Defined Radio. A USB dongle that lets you listen to transmissions across the radio spectrum using a computer.
Simplex: Direct radio-to-radio communication without using a repeater.
Squelch: A setting that silences the radio until a signal strong enough to be heard comes through.
Signal Report: A rating of how well a transmission is being received, typically using the RST system (Readability, Strength, Tone).
Sitrep: Situation report. A structured update on current conditions, often used during emergencies.
T
Technician: The entry-level Ham license, requiring a 35-question multiple choice exam.
Traffic: Information or messages to be communicated over the radio.
Transceiver: A device that can both transmit and receive radio signals. All Ham and GMRS radios are transceivers.
Transmit: To send a radio signal. Only happens while holding the PTT button.
Trunking: A system where many users share a number of frequencies, managed by a computer.
Tuner: A device that matches your antenna to your radio for efficient transmission. Required for random wire antennas.
U
UHF: Ultra High Frequency (300-3000 MHz). Includes the 70 cm Ham band and GMRS frequencies.
V
VFO: Variable Frequency Oscillator. A radio mode for tuning to any frequency manually. See also MR.
VHF: Very High Frequency (30-300 MHz). Includes the 2 meter Ham band.
W
Watt: Unit of transmit power. More watts generally means more range, but terrain and antennas matter more.
Winlink: A system for sending and receiving email over Ham radio. winlink.org
WSPR: Weak Signal Propagation Reporter. A digital mode for testing propagation using very low power. wsprnet.org
Y
Yagi: A directional antenna that focuses signal in one direction for longer range.
Numbers & Symbols
3-3-3: An emergency comms protocol to check in on channel 3, every 3 hours, for 3 minutes.
73: Ham radio shorthand for "best regards." A friendly sign-off.
5-9: A perfect signal report meaning "loud and clear." The first number is readability (1-5), the second is signal strength (1-9). See Signal Reports for more.