{"id":736,"date":"2026-03-25T11:34:14","date_gmt":"2026-03-25T10:34:14","guid":{"rendered":"https:\/\/www.i8zse.it\/en\/?page_id=736"},"modified":"2026-03-25T11:34:56","modified_gmt":"2026-03-25T10:34:56","slug":"glossary","status":"publish","type":"page","link":"https:\/\/www.i8zse.it\/en\/radio\/glossary\/","title":{"rendered":"Glossary"},"content":{"rendered":"
\n
\n

A glossary of technical and uncommon terms<\/p>\n

 <\/p>\n

\n

A<\/h3>\n

ATU (Antenna Tuning Unit)<\/strong> \u2013 A device that matches the impedance between the transmitter and the antenna to minimize SWR.<\/p>\n

\n

B<\/h3>\n

Balun<\/strong> \u2013 A device that converts between a balanced line (e.g., dipole) and an unbalanced line (e.g., coaxial cable). The name comes from balanced to unbalanced<\/em>.<\/p>\n

Band plan<\/strong> \u2013 A conventional subdivision of frequencies allocated to amateur radio by emission type (CW, SSB, digital, etc.).<\/p>\n

Beacon<\/strong> \u2013 An automatic radio station that transmits identification and test signals to monitor propagation conditions.<\/p>\n

Blocking dynamic range<\/strong> \u2013 A parameter indicating a receiver’s resistance to strong signals on nearby frequencies without degrading reception of weak signals.<\/p>\n

Booster<\/strong> \u2013 An additional power amplifier used to increase a transmitter’s output power.<\/p>\n

\n

C<\/h3>\n

CAT (Computer Aided Transceiver)<\/strong> \u2013 A control protocol that allows a computer to manage a transceiver’s functions (frequency, mode, etc.).<\/p>\n

Choke<\/strong> \u2013 An inductor used to block common mode currents on a coaxial cable, often made by winding the cable around a toroid.<\/p>\n

Collinear<\/strong> \u2013 A vertical antenna composed of multiple in-phase sections that compress the radiation lobe, increasing gain.<\/p>\n

CW (Continuous Wave)<\/strong> \u2013 A transmission mode used for telegraphy (Morse code).<\/p>\n

\n

D<\/h3>\n

dBd<\/strong> \u2013 Decibels relative to a dipole. A unit of antenna gain referenced to an ideal dipole (0 dBd = 2.15 dBi).<\/p>\n

dBi<\/strong> \u2013 Decibels relative to an isotropic radiator. A unit of antenna gain referenced to a theoretical isotropic antenna.<\/p>\n

DDS (Direct Digital Synthesis)<\/strong> \u2013 A technique for generating variable frequency signals with high precision.<\/p>\n

Dielectric<\/strong> \u2013 The insulating material in coaxial cables between the center conductor and the shield.<\/p>\n

Discone<\/strong> \u2013 A wideband antenna, typically used for reception, with low gain but extensive coverage.<\/p>\n

DSP (Digital Signal Processing)<\/strong> \u2013 Technology that filters and processes signals through software.<\/p>\n

\n

E<\/h3>\n

EIRP (Effective Isotropic Radiated Power)<\/strong> \u2013 The effective power an antenna radiates relative to an isotropic radiator.<\/p>\n

EME (Earth-Moon-Earth)<\/strong> \u2013 Communication that uses the Moon as a passive reflector (moonbounce).<\/p>\n

EMI (Electromagnetic Interference)<\/strong> \u2013 Disturbance caused by electromagnetic radiation.<\/p>\n

E\u2011sporadic (Sporadic E)<\/strong> \u2013 An anomalous propagation phenomenon that reflects VHF signals from ionization clouds in the ionospheric E layer.<\/p>\n

\n

F<\/h3>\n

Feed<\/strong> \u2013 The radiating element positioned at the focus of a parabolic dish.<\/p>\n

Field day<\/strong> \u2013 An event where amateur radio operators operate in the field, often using portable equipment.<\/p>\n

FT8<\/strong> \u2013 A weak-signal digital mode, highly efficient for long-distance contacts with low power.<\/p>\n

\n

G<\/h3>\n

Ground plane<\/strong> \u2013 A vertical antenna that uses a ground plane (radials) to create the image of the radiating element.<\/p>\n

\n

H<\/h3>\n

Homebrewing<\/strong> \u2013 The do-it-yourself construction of radio equipment.<\/p>\n

Horn<\/strong> \u2013 A horn antenna, used in microwave bands for its linearity and signal cleanliness.<\/p>\n

\n

I<\/h3>\n

IARU (International Amateur Radio Union)<\/strong> \u2013 The international federation of national amateur radio societies.<\/p>\n

IMD (Intermodulation Distortion)<\/strong> \u2013 A measure of transmitter linearity.<\/p>\n

IQ<\/strong> \u2013 In-phase and Quadrature signals. A digital representation of a radio signal.<\/p>\n

\n

K<\/h3>\n

Keyer<\/strong> \u2013 A device that automatically generates dots and dashes in CW from paddles.<\/p>\n

Kp<\/strong> \u2013 The planetary geomagnetic activity index, used to assess propagation stability.<\/p>\n

\n

L<\/h3>\n

Ladder line<\/strong> \u2013 A balanced transmission line with two parallel conductors separated by insulating spacers.<\/p>\n

LNB (Low Noise Block)<\/strong> \u2013 A low-noise converter mounted at the focus of satellite dishes for reception.<\/p>\n

\n

M<\/h3>\n

MDS (Minimum Discernible Signal)<\/strong> \u2013 The lowest signal level detectable by a receiver.<\/p>\n

Mesh<\/strong> \u2013 A parabolic reflector made of wire mesh to reduce wind loading.<\/p>\n

Mixing dynamic range<\/strong> \u2013 A parameter evaluating the impact of phase noise on receiving weak signals adjacent to strong ones.<\/p>\n

MUF (Maximum Usable Frequency)<\/strong> \u2013 The highest frequency that can be used for a given path via ionospheric propagation.<\/p>\n

\n

O<\/h3>\n

Offset<\/strong> \u2013 A type of parabolic dish with the focus shifted away from the center, so the feed does not obstruct the reflector.<\/p>\n

OM (Old Man)<\/strong> \u2013 Slang term for an amateur radio operator.<\/p>\n

\n

P<\/h3>\n

Panadapter<\/strong> \u2013 A real-time graphical display of the radio spectrum.<\/p>\n

Paddle<\/strong> \u2013 An electronic key for CW transmission.<\/p>\n

PLL (Phase Locked Loop)<\/strong> \u2013 A circuit that locks an oscillator’s phase to a reference for stable frequency generation.<\/p>\n

POTA (Parks On The Air)<\/strong> \u2013 An activity that awards contacts made from national parks.<\/p>\n

Prime focus<\/strong> \u2013 A type of parabolic dish with the feed located at the center, in front of the reflector.<\/p>\n

\n

Q<\/h3>\n

QFH (Quadrifilar Helix)<\/strong> \u2013 A four-wire helical antenna used for satellite reception with circular polarization.<\/p>\n

QRP<\/strong> \u2013 Low power, generally understood as less than 10 watts on HF.<\/p>\n

QSO<\/strong> \u2013 A radio contact between two amateur stations.<\/p>\n

\n

R<\/h3>\n

Radiantismo<\/strong> \u2013 The activity carried out by amateur radio operators (Italian term for amateur radio practice).<\/p>\n

ROS (Rapporto di Onde Stazionarie)<\/strong> \u2013 SWR. The ratio between forward and reflected power on a transmission line.<\/p>\n

\n

S<\/h3>\n

SDR (Software Defined Radio)<\/strong> \u2013 Radio defined by software, where most signal processing occurs digitally.<\/p>\n

Shack<\/strong> \u2013 An amateur radio station and its set of equipment.<\/p>\n

SFI (Solar Flux Index)<\/strong> \u2013 The solar flux index at 10.7 cm, an indicator of solar activity.<\/p>\n

SOTA (Summits On The Air)<\/strong> \u2013 An activity that awards contacts made from mountain summits.<\/p>\n

Speech processor<\/strong> \u2013 A circuit that enhances voice intelligibility during transmission.<\/p>\n

SSB (Single Side Band)<\/strong> \u2013 A modulation mode used for voice transmission.<\/p>\n

SWR (Standing Wave Ratio)<\/strong> \u2013 See ROS.<\/p>\n

\n

T<\/h3>\n

TCXO (Temperature Compensated Crystal Oscillator)<\/strong> \u2013 A crystal oscillator with temperature compensation for improved stability.<\/p>\n

Trap<\/strong> \u2013 A resonant circuit that electrically isolates a section of an antenna.<\/p>\n

Troposcatter<\/strong> \u2013 Propagation via tropospheric scatter, extending range beyond line-of-sight.<\/p>\n

\n

U<\/h3>\n

Unun<\/strong> \u2013 An impedance matching device for unbalanced lines (unbalanced to unbalanced).<\/p>\n

\n

V<\/h3>\n

VFO (Variable Frequency Oscillator)<\/strong> \u2013 An oscillator with variable frequency for tuning the receiver or transmitter.<\/p>\n

VOX (Voice Operated Transmission)<\/strong> \u2013 A function that automatically activates transmission upon detecting voice.<\/p>\n

\n

W<\/h3>\n

WARC<\/strong> \u2013 The amateur bands of 30m, 17m, 12m, added after the World Administrative Radio Conference.<\/p>\n

Waterfall<\/strong> \u2013 A graphical display showing the radio spectrum over time.<\/p>\n

\n

Y<\/h3>\n

Yagi<\/strong> \u2013 A directional antenna consisting of a driven element, a reflector, and one or more directors.<\/p>\n

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A glossary of technical and uncommon terms   A ATU (Antenna Tuning Unit) \u2013 A device that matches the impedance between the transmitter and the antenna to minimize SWR. B Balun \u2013 A device that converts between a balanced line (e.g., dipole) and an unbalanced line (e.g., coaxial cable). The name comes from balanced to […]<\/p>\n","protected":false},"author":1,"featured_media":0,"parent":575,"menu_order":38,"comment_status":"closed","ping_status":"closed","template":"","meta":{"footnotes":""},"class_list":["post-736","page","type-page","status-publish","hentry"],"yoast_head":"\nGlossary - I8ZSE<\/title>\n<meta name=\"robots\" content=\"index, follow, max-snippet:-1, max-image-preview:large, max-video-preview:-1\" \/>\n<link rel=\"canonical\" href=\"https:\/\/www.i8zse.it\/en\/radio\/glossary\/\" \/>\n<meta property=\"og:locale\" content=\"en_GB\" \/>\n<meta property=\"og:type\" content=\"article\" \/>\n<meta property=\"og:title\" content=\"Glossary - I8ZSE\" \/>\n<meta property=\"og:description\" content=\"A glossary of technical and uncommon terms   A ATU (Antenna Tuning Unit) \u2013 A device that matches the impedance between the transmitter and the antenna to minimize SWR. 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