Amateur Radio Glossary

www.arrl.org/ham-radio-glossary

* balun - device to couple a balanced load to an unbalanced source, or vice versa
  (contraction for balanced to unbalanced)

* band - a group of adjacent frequencies in the electromagnetic spectrum

* baud - unit of information transfer rate, signals/sec.

* beam antenna - a directional antenna. A beam antenna must be rotated to provide
  coverage in different directions

* capacitance - a measure of the ability of a capacitor to store energy in an
  electric field (capacitance = E/coulomb)

* coaxial cable - coax = A type of feed line with one conductor inside the other

* dipole - a basic antenna used by radio amateurs. It consists of a length of wire
  (or tubing), opened and fed at the center. For a half-wave dipole, the entire
  antenna is 1/2 wavelength long at the desired operating frequency

* digipeater - a packet-radio station used to retransmit signals that are
  specifically addressed to be retransmitted by that station

* D-Star - a type of digital packet-radio

* dual-band antenna - an antenna designed for use on two different Amateur Radio
  bands

* duplex operation - receiving on one frequency and transmitting on a different
  frequency (see simplex operation)

* Elmer - an individual who acts as an advisor or mentor to a newly licensed amateur

* emission - the transmitted signal from an amateur station

* feed line - the wires or cable used to connect a transmitter, receiver or
  transceiver to an antenna

* frequency - the rate at which a vibration occurs that constitutes a wave, for
  example in an electromagnetic field (as in radio waves and light), usually
  measured per second

* grid square - a way of dividing up the surface of the Earth, a shorthand
  means of describing your general location, using two letters (the field) and
  two numbers (the square), as in FN31 (grid square measures 1° latitude by
  2° longitude)

* ground connection - a connection made to the earth for electrical safety. This
  connection can be made inside (to a metal cold-water pipe) or outside (to a
  ground rod)

* ground-wave propagation - the method by which radio waves travel along the
  Earth's surface

* harmonics - signals from a transmitter or oscillator occurring on whole-number
  multiples (2×, 3×, 4×, etc.) of the desired operating frequency

* impedance - the opposition to electric current in a circuit. Impedance includes
  factors other than resistance, and applies to alternating currents

* inductance - a measure of the ability of a coil to store energy in a magnetic
  field (inductance = voltage/(rate of change of current)

* ionosphere - a region of electrically charged (ionized) gases high in the
  atmosphere

* modem - short for modulator/demodulator. A modem modulates a radio signal to
  transmit data and demodulates a received signal to recover transmitted data

* modulate - to vary the amplitude, frequency, or phase of a radio-frequency signal

* modulation - the process of varying an RF carrier in some way (the amplitude or
  the frequency, for example) to add an information signal to be transmitted

* oscillator - a circuit that generates electromagnetic signals

* packet radio - a system of digital communication whereby information is broken
  into short bursts. The bursts ("packets") also contain addressing and
  error-detection information

* prosign - procedural signal, one or two letters sent as a single character.
  Amateurs use prosigns in CW contacts as  a short way to indicate the operator's
  intention, e.g. AR for "End of Message" or K for "Go Ahead" (the prosign is sent
  as one character)

* Q signals - three-letter symbols beginning with Q. Used on CW to save time and
  to improve communication. Some examples are QRS (send slower), QTH (location),
  QSO (ham conversation) and QSL (acknowledgment of receipt)

* QRL? - ham radio Q signal meaning "Is this frequency in use?"

* QRQ - request to send faster

* QRS - request to send the code at a slower speed

* QRZ? - "Who is calling me?"

* QSL card - a postcard that serves as a confirmation of communication between
  two hams

* quad antenna - an antenna built with its elements in the shape of four-sided
  loops (also called a cubical quad antenna)

* receiver - a device that converts radio waves into signals we can hear or see

* repeater station - an amateur station that automatically retransmits the signals
  of other stations

* resistance - the ability to oppose an electric current (resistance = E/I)

* RF burn - a burn produced by coming in contact with exposed RF voltages

* RF carrier - a steady radio frequency signal that is modulated to add an
  information signal to be transmitted. For example, a voice signal is added to
  the RF carrier to produce a phone emission signal

* shack - the room where an Amateur Radio operator keeps his or her station
  equipment

* sidebands - the sum or difference frequencies generated when an RF carrier is
  mixed with an audio signal. Single-sideband phone (SSB) signals have an upper
  sideband and a lower sideband. SSB transceivers allow operation on either
  USB or LSB

* simplex operation - receiving and transmitting on the same frequency (see
  duplex operation)

* skip zone - an area of poor radio communication, too distant for ground waves
  and too close for sky waves

* sky-wave propagation - the method by which radio waves travel through the
  ionosphere and back to Earth. Sometimes called skip, sky-wave propagation has a
  far greater range than line-of-sight and ground-wave propagation

* sunspot cycle - the number of sunspots increases and decreases in a predictable
  cycle that lasts about 11 years

* third-party communications - messages passed from one amateur to another on
  behalf of a third person

* transmission line - the wires or cable used to connect a transmitter or receiver
  to an antenna (also called feed line)

* terminal - a less expensive piece of equipment that can be used in place of a
  computer in a packet radio station

* transceiver - a radio transmitter and receiver combined in one unit

* transmitter - a device that produces radio-frequency signals

* wavelength - the distance a radio wave travels in one RF cycle (often abbreviated
  'lambda'). The wavelength relates to frequency. Higher frequencies have shorter
  wavelengths

* yagi antenna - the most popular type of amateur directional (beam) antenna. It
  has one driven element and one or more additional elements