73 - "Best regards"
Alternating Current (AC) - Electrical current that flows in both directions, first in one and then in the other. The direction changes at the rate of the power's frequency. For example, for 120V household current in the United States, this frequency is 60 Hz, or 60 times per second.
Amateur Radio Emergency Service (ARES) - A volunteer group of amateur radio operators providing emergency communications
Amateur radio operator - Someone who is authorized or licensed to operate an amateur radio station.
Amateur radio station - A station licensed to operate on amateur radio frequencies, including any necessary equipment enabling amateur communication.
Ammeter - A tool which measures the current in a circuit.
Amplitude modulation (AM) - A transmit method which combines a signal, such as someone's voice going into a microphone, with a RF (radio frequency) carrier.
Antenna - A device that receives, and possibly transmits, radio frequency energy.
Antenna switch - A device which permits switching between antennas. For example, one could have multiple antennas hooked up to a transceiver and switch between them based on which antenna is best for the operating mode desired.
Antenna tuner - A device which works to present 50 ohms to the transceiver. This can, for example, allow a multiband antenna with primary frequency of 80 meters to work on 40 meters if the antenna is designed to do so, but the antenna doesn't quite match at 50 ohms when working on 40 meters.
Balun - Balanced to unbalanced. This device allows connecting a balanced load to an unbalanced source, such as a dipole antenna to a coax cable.
Band plan - The voluntary partitioning of a band to help avoid interference between modes
Beacon station - A station that transmits to help with understanding how far amateur radio signals are propagating (travelling) and/or to aid with navigation.
Beam antenna - An antenna which focuses its energy and reception in one direction. Because it is directional, it must be rotated so it is aimed in the direction of a desired signal.
Call sign - A series of unique letters and numbers which identifies a person holding an amateur radio license.
Capacitance - The measurement of a capacitor's ability to store energy in an electric field.
Capacitor - An electronic component which stores energy in an electric field.
Closed repeater - A repeater which is not open for general use.
CQ - "Calling any station." Used when calling over high-frequency (HF) bands in an attempt to find other amateur radio operators.
CTCSS - Continuous tone coded squelch system. CTCSS tones are used on amateur radio repeaters to either restrict access or to aid with squelching when no communications are occurring by requiring a sub-audible tone when transmitting into the repeater.
DE - The Morse code abbreviation of, "this is."
Digipeater - A store-and-forward digital repeater which receives a digital communication (a data packet) and then transmits it on the same frequency.
Direct current (DC) - Electrical current that flows in only one direction.
Dual band antenna - An antenna designed to be used on two different amateur radio bands.
Dummy load - A device used in place of an antenna to help with testing transmitting equipment without sending an over-the-air signal by converting the radio energy to heat.
Duplexer - A device used to allow an antenna to transmit and receive on two different frequencies simultaneously.
DX - Distance. Often used to indicate someone is contacting distant radio stations, typically in other countries.
Elmer - An amateur radio operator who mentors other amateur radio operators or future amateur radio operators.
Emergency - A serious situation where lives or property are in danger.
Emergency traffic - Messages related to emergency situations, often containing requests for supplies or assistance, or details pertaining to life and death situations.
Emission - The signal transmitted from an amateur radio station.
Eyeball QSO - Amateur radio operators meeting face-to-face.
Federal Aviation Administration (FAA) - The governmental group overseeing the nation's airspace, including imposing restrictions on tower height when located near airports.
Feed line (or feedline) - The cable used to connect an antenna to an amateur radio transceiver.
Field Day - An annual event held the forth full weekend in June designed to practice emergency communications and also help introduce amateur radio to the public. There is also a Winter Field Day the last full weekend in January.
Frequency - The rate of oscillation of a signal or alternating current, measured in Hertz (cycles per second).
Frequency coordination - To ensure minimal interference between repeaters, frequencies are coordinated. See Frequency coordinator.
Frequency coordinator - The individual or team that recommends repeater frequencies to help prevent interference with existing repeaters.
Frequency Modulation (FM) - A type of signal used to communicate using voice (phone) over most repeaters. This is also common in vehicle radios which tune FM stations.
Full quieting - A way of telling someone talking through a repeater that their signal is coming in clear into the repeater. It's called full quieting because if someone were to transmit into the repeater but not say anything, you would hear no static or other noise in the silence.
Gain - the measure, in decibels (dB), of how much an antenna increases the effective power radiated by an antenna, sometimes in a specific direction.
GMRS - General Mobile Radio Service
Ham - an amateur radio operator.
Hertz (Hz) - the unit of measure used to measure frequency in cycles per second.
HF - High Frequency (3 MHz to 30 MHz)
Holding the repeater - This is a way of saying whether or not your signal is making it into the repeater without cutting out. If your transmission is repeated without the repeater dropping you, such as due to a weak signal, "You are holding the repeater." If the repeater cuts in and out while you are transmitting into it, "You are not holding the repeater."
HT - Handie-talkie, a way to refer to handheld radios.
ITU - International Telecommunications Union
ITU Phonetics - A common way of giving individual letters using words, such as spelling CAT as Charlie Alpha Tango. Often used to give call signs when someone cannot understand you, such as similarly-sounding B and E and V.
Morse code - A code which represents an alphabet using a combination of long and short radio-frequency signals.
POTA - Parks On The Air