K5PRT.COM Amateur Radio Glossary of Terms

Pete Theer, 191 FM 2313, Kempner, Texas 76539-8672 USA

Glossary of Common Amateur Radio Terms

* Click on the letters below to go directly to that section of this page:

A - B - C - D - E - F - G - H - I - J - K - L - M
N - O - P - Q - R - S - T - U - V - W - X - Y - Z

A

ACC - ACCessory (A socket in the back of a radio).

Adjacent Channel Interference - When a receiver is tuned to a specific frequency and interference is received from a nearby frequency.

Advanced - Intermediate level of Amateur Radio license. No longer issued.

AES - Amateur Electronic Supply - Equipment Vendor (WEBSITE)

AF - Audio Frequency.

AFC - Automatic Frequency Control. Automatically compensates for frequency drift.

AFSK - Audio Frequency Shift Keying.

AGC - Automatic Gain Control. Automatically optimizes receiver gain by adjusting the gain for different input signal levels to maintain a constant output.

AGWPE - PC software that allows a computer sound card to emulate a TNC for packet operation.

ALC - Automatic Limiting Control. Limits RF drive level to power amplifier during transmit to prevent distortion.

AM - Amplitude Modulation. Voice transmission system in which a steady carrier is amplitude modulated by information resulting in upper and lower sidebands surrounding a carrier.

Amplifier, HF Power - Device connected between the transmitter and antenna which amplifies the RF power output without changing the signal's characteristics.

AMSAT - Radio AMateur SATellite Corporation. (WEBSITE)

AMTOR - AMateur Teleprinting Over Radio. A form of radio teletype (RTTY).

ANF - Automatic Notch Filter.

ANL - Automatic Noise Limiter. Eliminates impulse and static noise peaks.

ANT - ANTenna.

Antenna Ground System - Term used for an RF reference potential for some types of antennas. Most unbalanced or asymmetrical antennas need a good RF ground.

Antenna Impedance - The impedance of an antenna at its resonance. Although an antenna's impedance fluctuates with the frequency of operation, an antenna should be 50 Ohms for most transceivers.

Antenna Matching - When the antenna's impedance at resonance is at optimum performance for your transmitter output circuit.

Antenna Relay - Electromechanical device that can be used to switch an antenna remotely, typically from transmitter to receiver.

Antenna Tuner - Device used to match an antenna to the output impedance of a transmitter.

APC - Automatic Power Control. Current limiting of a power amplifier to prevent damage to the finals in high SWR conditions.

APRS - Automatic Position Reporting System. In conjunction with a GPS (Global Positioning System) and TNC (Terminal Node Controller) provide position reporting.

ARC - Amateur Radio Club.

ARDS - Amateur Radio Disaster Services (WEBSITE)

ARES - Amateur Radio Emergency Service. A public service organization of the ARRL. (WEBSITE)

ARISS - Amateur Radio on the International Space Station. (WEBSITE)

ARRL - American Radio Relay League. The national association for amateur radio in the U.S. (WEBSITE)

ASCII - American Standard Code for Information Interchange. A seven unit digital code for the transmission of teleprinter data. (made up of 0's & 1's)

AT - Antenna Tuner

ATT - ATTenuator. A network designed to reduce the amplitude of a signal.

ATV - Amateur TeleVision (FSTV, SSTV)

Auto Patch - Used in repeater operation for telephone interconnect.

Auto Tuner - Antenna tuner which automatically senses the mismatch between the transmitter and antenna and does the necessary matching with minimal user intervention.

Auxiliary Station - Radio system that is part of an RF control link, often used for control of a remote repeater station. (more info)

Average Power - Power measured on a standard power meter.

Aviation Headset - Combination earphones and attached boom mounted microphone.

AX.25 - Amateur version of the X.25 communication protocol. X.25 supports "store and forward" messaging and insures delivery of ASCII text by retransmitting packets in the event an acknowledgment is not received from the destination.

Azimuth Pattern - Graphical description of the power intensity of radiation from an antenna as a function of the horizontal angle (at a specified elevation angle) around an antenna.

Azimuth Plot - Graphical representation of signal strength from an antenna as a function of horizontal angle around the antenna center. It is made a particular elevation angle, often the angle with the maximum response.

B

Backscatter - Form of ionospheric propagation via the E and F layers of the atmosphere allowing stations to hear other stations within the skip zones.

Balanced Load - A termination in which each of the two terminals is at the same potential above ground.

Balanced Modulator - Mixer or modulator in which at least one of the input signals is canceled at the output following generation of the desired modulation or mixing products.

Balun - A simple transformer used to change an unbalanced input to a balanced output. Part of an antenna system that provides the transition between a balanced antenna such as as center fed dipole and an unbalanced transmission line such as coaxial cable. (more info)

Band - A range of frequencies.

Bandwidth - Frequency needed for a particular type of emission.

Bank - Memory bank.

Baseloading - Shortening the physical length of a vertical antenna by substituting an inductance at the base for part of the lower section of the antenna.

Bazooka - A type of wire antenna.

BBS - Bulletin Board System - Combination of software and PC hardware that accepts packet messages for use by multiple users to receive messages at a later time by request.

BCD - Binary Coded Decimal. Decimal numbers represented in binary code. (0s and 1s)

BCI - BroadCast Interference.

BFO - Beat Frequency Oscillator.

Bias Supply - A power supply designed to provide the usually low current negative DC voltage required by the control grid of a vacuum tube.

Binocular Core - Dual ferrite core structure often used in RF transformers.

Bleeder Resistor - A resistor placed across the filter capacitors in a power supply so that they will have a discharge path when equipment is turned off. This prevents lethal voltages from lurking in an otherwise non-operating power supply. NEVER trust them to work.

Bluetooth -Portable short range communications technology often used to connect headsets to communications devices like cellular phones.

BNC - Bayonet Neill-Concelman. A type of antenna connector commonly used on HT's. Built like a type N connector, but smaller.

Bonding - Interconnecting via low resistance conductors, particularly of separate ground points to avoid potential between them.

Boom - Structure that forms the support for multiple individual elements on a beam antenna.

BPL - 1. Brass Ponders League: An ARRL Club for CW traffic net operators. 2. Broadband over Power Lines: Providing Internet Access over power lines. (More Info)

Broadband - System or antenna that can operate over a wide band of frequencies.

Bug - Semi-Automatic Telegraph key. Device that mechanically forms "dots" while sending morse code. No longer in common use.

Busy Lockout - Inhibits transmit on a frequency in use.

C

Call Sign - Sequence of letters and numbers used to identify amateur radio operators and issued by the FCC.

CAP - Civil Air Patrol. Volunteer affiliate of the U.S. Air Force. (WEBSITE)

Carbon Mic - Microphone element in which a diaphragm is pushed against a cup of carbon granules by acoustic pressure from speech.

Carrier - An unmodulated transmitted signal.

Carrier Frequency Offset - (Carrier Shift) Distance between Mark and Space of the RTTY or similar transmissions.

CB - Citizen's Band - A US radio service having 40 assigned channels in the former Amateur 11 Meter band. Available to US citizens for personal or business use under strict power and antenna limitations. (More Info)

CBR - Cross Band Repeater. A repeater which receives incoming signals and re-transmits them on different bands. (e.g. receives in the 440 mHz band and re-transmits on 144 mHz.

CCW - Counter ClockWise.

Center fed Zepp - common name for a balanced antenna in a dipole configuration and fed with low loss open wire or window line to allow operation on multiple bands.

CH - CHannel. Sequence of memory positions where a frequency and related information is stored.

Circular Polarization - Electromagnetic propagation mode in which the polarization, rather than being Vertical or Horizontal linear polarization, rotates as the wave moves from the source.

CI-V - Icom computer Control Interface allowing multiple radio control simultaneously.

Clarifier - A control on a transceiver to allow the receive frequency to be shifted from the transmit frequency by a small amount. On some radios called "RIT".

Coax - Coaxial Cable.

Coaxial Cable - Transmission line type used for radio and data transmission. Consists of a single center conductor surrounded by a dielectric (often polyethylene or foam polyethylene, but sometimes air). The dielectric is then by a tubular conductor that may be flexible raid or tubing. In operation, the properly applied and terminated signal exists only between the conductors.

Coil Choke Balun - A multi-turn coil in a length of coaxial cable intended to provide an inductive reactance ands thus reduce currents flowing on the outside of the shield.

Colpitts Oscillator - Classic oscillator circuit in which the feedback is provided by a signal from a portion of the tuned circuit set by a voltage divider.

Common Mode Currents -Currents that flow on both sides of a circuit at the same time, such as result from not having a balun on a coax fed dipole. The other side of the circuit is usually some kind of ground. This type of connection is sometimes intentionally used for signaling on a balanced telephone line, but is generally undesired in Amateur Radio systems.

Control Operator - The person responsible for the proper operation of a licensed radio station. This person may be a licensee or a person with appropriate license privileges designated by the licensee. The control operator has broad authority to take any action deemed necessary to insure that the station is being operated within FCC regulations per the terms of the license.

Conversion - Number of IF circuits in a receiver.

CPO - Code Practice Oscillator.

CPU - Central Processing Unit.

CQ - Radio communication term used to call for any station.

CRT - Cathode Ray Tube. Vacuum tube based video display.

CTCSS - Continuous Tone Coded Squelch System. Adds a continuous sub-audible low frequency tone to a transmitted carrier. Receivers set to the same low frequency tone can decode the signal.

Current Balun - A transformer or choke designed to force the currents on the two leads of a transmission line to be equal and opposite.

CW - 1. Carrier Wave (morse code) 2. ClockWise.

CW Filter - Used to narrow passband to improve reception of CW in crowded band conditions.

D

Data Communications - Transfer of data between two or more locations.

dBd - Unit of RF power in decibels compared to a dipole antenna.

dBi - Unit of RF power in decibels compared to an isotropic antenna.

dBm - Decibels measure, 1 mW with a load impedance of 600 Ohms (0dBm = 1 mW)

DC - Direct Current.

DC Ground - A connection point directly to a chassis or battery ground to prevent build-up of hazardous DC voltage.

DCS - Digital Coded Squelch. A selective calling system.

Deviation - a measurement for an FM signal of the maximum carrier frequency changes either side of the carrier frequency during modulation.

Differential Mode Circuit - The circuit formed by two conductors in which the current leaves on one and returns on the other - the typical desired circuit.

Diplexed - Circuitry that can process two signals without combining them.

Dipole - A simple common type of wire antenna, usually center fed with coaxial cable.

Direct Conversion Receiver - Receiver architecture in which signals are mixed directly to audio. The Local Oscillator is at the receive frequency and thus there are no IF amplifier stages, just audio amplifier stages.

Directivity - Measure of how much of the energy from an antenna is radiated in a particular direction.

Director - Element(s) on a Yagi in front of the driven element. (see Yagi)

Distress Call - Signals a life-threatening situation. Most commonly referring to an SOS or Mayday call.

Distress Frequency - A frequency or channel specific for use in distress calling. RadioTelephone Distress frequencies are: 2.182 MHz and 156.8 MHz. Survival craft use 243 MHz. Maritime frequencies are the same, while general aviation frequency is 121.5 MHz.

Downlink - (opposite of uplink) The frequency that a repeater or satellite transmits on to a user.

DRM - Digital Radio Mondiale. High Definition digital transmission system used by commercial shortwave broadcast stations.

DSP - Digital Signal Processing. Used to improve the signal to noise ratio for cleaner and more legible communications. Fairly new to ham radio.

DTCS - Digital Tone Coded Squelch. (see DCS)

DTMF - Dual Tone Multi-frequency. (touch-tone) Used to transmit/receive numeric information such as phone number, PIN, remote radio control commands, etc.

DualWatch - To receive two signals simultaneously.

Dummy Load - A non-radiating 50 Ohm load connected to a transmitter to replace an antenna for testing purposes.

Duplex - A mode of operation in which the transmit and receive frequencies are different.

Duplexer - A device which divides transmit and receive signals.

Duty Cycle - The ratio of transmit to receive time.

DX - Distant station, usually in another country.

DXCC - DX Century Club. An ARRL award for verified contacts with 100 countries or more. (More Info)

DX'Pedition - Trip to a foreign land to "be DX".

Dynamic Mic - Microphone element in which the diaphragm is tied to a coil of wire surrounding a permanent magnet.

Dynamic Range - Ratio of the strongest to the weakest signal that a system can respond to within a specified level of distortion.

E

Earth Grounding System - Set of usually buried conductors often arranged radially and in combination with metal (ground) rods driven into the soil. Designed to provide a low resistance ground connection for systems or equipment.

EAS - Emergency Alert System - superceded the EBS in 1994. (WEBSITE)

EBS - Emergency Broadcast System. A system where at first an alert tone is transmitted, followed by specific instructions regarding the receivable frequency in case of a national or local emergency. Superceded in 1994 by the EAS Emergency Alert System. (More Info)

EEPROM - Electrically Erasable Programmable Read Only Memory.

EIA - Electronic Industries Association.

Electrolysis - Electrochemical process in which a current through a solution between electrodes of different metals results in the transfer of molecules of one material into the solution and then often to the other electrode. This is the process by which electroplating is performed. It also can happen if two dissimilar metals are in contact in the presence of water.

Electrolytic Capacitor - Kind of high capacitance capacitor used in power supply filters and other applications. Unlike many capacitors, the positive terminal is marked and must be connected to the positive terminal. The electrolyte is generally a liquid or semi-liquid paste material from which it gets its name.

Elevation Pattern - Graphical description of the power intensity of radiation from an antenna as a function of the angle in a specified vertical plane from horizon to horizon.

EME - Earth-Moon-Earth (bouncing signals off the moon and back to earth.)

EMF - Electro-Motive Force - Voltage

EMI - Electro-Magnetic Interference (Often called RFI - Radio Frequency Interference.)

EMI Sleeves - Ferrite Beads or tubes slipped over wires to insert inductance with the intent of attenuating unwanted high frequency signals.

Emission - Transmission of a signal.

Enameled copper wire - Wire in which the insulation is a thin coating of enamel. Often used for inductors, transformers or electromagnets.

Encryption - Transmitting cryptic form so that only certain people understand what has been sent.

EOC - Emergency Operation Center.

EPROM - Electrically Programmable Read Only Memory.

Extra - Highest level of Amateur Radio license. All privileges.

F

Fading - Signal reduction due to atmospherics.

Fahnstock clip - Metal spring clip shaped like the letter "R" with a small loop at the center. Often used for connection of antenna and ground leads in early radio equipment.

FCC - Federal Communications Commission. Regulates wireless communications in the U.S.

Feed Impedance - The resistance and sometimes reactance as seen at the connection point of an antenna.

Feed Point - Part of an antenna at which connections are made. The connections are usually to a transmission line that runs from the antenna to the radio equipment.

FFT - Fast Fourier transform. Digital technique to interchange frequency and time domain data.

Field Day - Annual ARRL sponsored operating event in which temporary amateur radio stations are set up (usually in a public place) to communicate with as many stations as possible. (More Info)

Filter - A circuit designed to pass only the desired frequency(ies).

Firmware - Operating instructions for microprocessors that are stored in non-volatile memory. It remains there even when power is turned off

Fist - refers to the quality of a CW operators sending skill.

FISTS - Club promoting the use of the CW transmission mode. (WEBSITE)

FM - Frequency Modulation.

FM Capture Effect - The ability of an FM signal that is stronger than others on the same channel to completely take over the channel to the exclusion of the weaker signals.

Frequency Counter - Test instrument that measures and displays the frequency of signals or repetition rate of pulses.

Front to Back Ratio - Ratio of relative power transmitted from the front of an antenna to that transmitted from the rear.

FSK - Frequency Shift Keying.

FSTV - Fast Scan TV - Graphics (and audio) communication using TV broadcast signals. Requires a wide bandwidth.

Full Duplex - An operating mode which transmits and receives on different frequencies at the same time, as a telephone communication.

G

Gamma Match - Kind of impedance matching arrangement in which a rod is used to tap into one side of a dipole antenna element to allow attachment of coaxial cable to the appropriate impedance point of the antenna. Often used in directional arrays (yagis).

General - Most common level of Amateur Radio License. Some privileges on all bands.

Grid Square - Geographical location. Entire globe is divided into grid squares.

Ground Plane - A type of omni-directional vertically polarized antenna.

Ground Wave - Electrical wave traveling directly from the transmitter to the receiving station without bouncing off the ionosphere.

Grounding - Electrical connection to the earth.

Guy Ropes - Ropes used to support a tower or mast.

Guy Wires - Wires used to support a tower or mast.

H

Half Wave Dipole - Antenna approximately a half wavelength long, usually fed by connections to each side of the center. Often used as an antenna itself, it is also a reference standard for other antennas.

Hamfest - Informal scheduled gathering of Amateur Radio Operators. Often includes presentations, workshops, exam sessions and a flea market. (More info)

Harmonic - Multiple of a fundamental frequency.

Heterodyne - Term for signals at the output of a mixing or modulating process.

HF - High Frequency - 3 to 30 MHz range signals (normally 1.8 MHz (160 meter) band is also included.

HF Bands - Amateur bands in the region of the RF spectrum from 3 to 30 MHz. There are bands at approximately 80, 30, 20, 17, 15, 12 and 10 meters in this region. (More Info)

Home Call Area - Of the 10 FCC Regions in the U.S., the one in which you resided upon issuance of your Amateur Radio license. For years, the FCC required licensees to change callsigns when they moved to a different call area. This requirement is no longer in effect.

Horizontally Polarized Antennas - Antennas in which the electric field lines are horizontal. This is generally the case for dipole or yagi antennas, for example, with horizontal elements.

HPF - High Pass Filter

HRO - Ham Radio Outlet - Equipment Vendor (WEBSITE)

HT - Handie-Talkie. Hand Held Radio (used in lieu of walkie-talkie to distinguish licensed hams from CB'ers.)

Hz - Hertz (cycles per second)

I

IARU - International Amateur Radio Union. Association of national Amateur Radio organizations to represent Amateur Radio before the International Telecommunications Union (ITU). (WEBSITE)

IC - Integrated Circuit. A single structure containing multiple active devices that perform a function such as operational amplifier (OpAmp), a number of logic gates or a microprocessor.

IDC Connector - Connector intended for use on flat "ribbon" type cables.

IF - Intermediate Frequency. Internally converted frequency for amplification and other signal processing.

IF Shift - A function that electronically shifts IF frequency from a center frequency (usually to eliminate interference).

IMD - Inter-Modulation Distortion - Distortion within circuits made with upper and lower adjacent channel signals.

Impedance Transformation - Changing the voltage to current ratio of a signal in a circuit. Can be done with a transformer or by making use of the transformational property of mismatched transmission lines.

IP - Internet Protocol

Inverter - A device that converts DC into typically 60Hz AC.

Inverted V - A dipole wire antenna in which the center is higher than the two ends.

IOTA - Islands On The Air - Program of the RSGB to promote operation from islands. (WEBSITE)

IRC - International Reply Coupon. Available at the Post Office and widely accepted worldwide (but not universally) for return postage for QSL cards.

J

K

Key - Device used to manually send morse code. Also called a straight key.

Keyer - Device used to send morse code more accurately. Automatically and electronically forms dots and dashes.

kHz - KiloHertz - 1 kHz = 1000 cycles per second

KW - Kilowatt - 1000 watts.

kWh Meter - Device used to measure electrical consumption over time. Often used by power companies to establish usage for billing purposes.

L

L Network - Two element, generally passive network, with one series element and one shunt element. The circuit diagram resembles an "L".

Ladder Line - Type of balanced 2 wire transmission line in which the wires are separated and spacing is maintained by distinct insulators. Also called open wire line.

LF - Low Frequency. 30 to 300 kHz range signals.

Landline - A dedicated leased or dial-up telephone line, often used to provide control connectivity to a remote repeater station.

Li-Ion - Lithium Ion - Type of rechargeable battery which has better capacity than Ni-Cad (Nickel-Cadmium), Ni-MH (Nickel-Metal Hydride), etc., no memory effect after repeated non-full charge/discharge cycles.

Lid - An "inept" radio operator.

Linear Amplifier - see Amplifier.

LCD - Liquid Crystal Display. Type of display system in which the light transmission is changed from transparent to opaque with the application of voltage.

Loaded Dipole - Electrical half wavelength antenna shortened by the substitution of lumped series inductance or shunt capacitance in place of antenna length.

Loading Coil - An inductance inserted into an antenna that lowers it's resonant frequency allowing for a shorter antenna.

Log - Recording of Amateur Radio contacts. No longer mandatory by FCC, but required for contesting.

Logger - Person who assists the operator of a contest or event by recording the contact details.

LPF - Low Pass Filter.

LSB - Lower Side Band

M

Magic Band - Refers to the 6 Meter band (50-54 MHz) due to the unpredictable propagation. During band "openings" you can "work the world" with just 10 watts or less.

Marine HF radio channels - Frequency channels assigned by international agreement for use by recreational or commercial vessels beyond the range of coastal VHF operation. There are channels assigned near 2, 4, 6, 8, 11, 13, 17 and 22 MHz.

MARS - Military Affiliate Radio System (More Info)

MCW - Modulated Continuous Wave (Morse Code) - Telegraphy in which a steady carrier is transmitted accompanied by amplitude or frequency modulated code characters. (A CPO through a microphone)

Memory Bank - A set of memory channels organized into a group.

Memory Effect - Rechargeable batteries such as Ni-Cad and Ni-MH types may be temporarily getting less capacity as a result of repeated non-full charge/discharge cycles. It is called so since rechargeable batteries lose capacity as if "memorizing" wrong full-capacity level at less than full charge. Li-Ion batteries are free from this effect.

MF - Medium Frequency. 300 kHz to 3 MHz range signals.

MHz - Mega-Hertz. 1 MHz = 1 Million cycles per second

MIC - MICrophone.

Mobile - Operating an Amateur Radio from a vehicle.

Modulation - Method of adding information to a radio frequency carrier.

Molex Connector - Nylon supported two or more pin connector often used for power connections.

Moonbounce - see EME.

MOSFET - Metal Oxide Semiconductor Field Effect Transistor. A type of active solid state device often used as an amplifier or switch.

Multiband Trap Antennas - Antennas in which parallel resonant circuits, called traps, are used to isolate certain sections to operate only on some frequencies. This results in antennas which can operate on multiple bands. (more info).

N

N type connector - Coaxial cable connector family particularly suited for UHF operation up to full legal amateur power levels, featuring low loss, constant impedance and waterproof operation.

NAQCC - North American QRP CW Club. Club promoting and encouraging QRP operation and CW proficiency on the ham bands. Life Membership is free (WEBSITE)

NB - Noise Blanker

NBFM - Narrow Band FM

Negative resistance characteristic - Action of a material or device in which increased current results in reduced voltage drop. Often found in materials in the plasma state, such as within a lightning arc.

Ni-Cad - Nickel-Cadmium (battery)

Ni-MH - Nickel-Metal Hydride (battery)

NMO - Short name for New MOtorola antenna mount. Kind of screw-on mobile antenna mounting arrangement that provides a coaxial connection.

Notch Filter - Sharp and narrow rejection filter for elimination of interfering signals.

Novice - Past entry level Amateur Radio License . No Longer Issued.

NR - Noise Reduction. DSP feature reduces unwanted signal noise.

NTS - National Traffic System - An ARRL organized structure of local, regional and national networks designed to deliver radiograms anywhere in the U.S.

NWS - National Weather Service

O

OCF - Off Center Fed wire antenna (sometimes called a windom).

Offset Frequency - Frequency difference between transmit and receive.

Ohm's Law - Formula for basic electronic calculation (I=E/R)

Omnidirectional - An antenna that radiates well in all directions in one or more planes.

OSC - Oscillator

Oscilloscope - see Scope.

P

PA - Power Amplifier

Paddle - Device used to send morse code with an electronic keyer.

Panadapter - Oscilloscope for monitoring a band of frequencies.

Parasitic Suppresser - Designed to absorb sufficient energy to suppress unwanted VHF parasitic Oscillations in a high voltage HF amplifier.

Parawatch - (see Dualwatch)

PBT - PassBand Tuning. A function to electronically reduce receiver interference by narrowing the IF bandwidth.

PEP - Peak Envelope Power. RF power at maximum amplitude.

Phone Patch - Device that interconnects a radio system to commercial phone lines. This allows a call from a distant station to be completed to anyone within telephone range.

Pileup - The situation in which a large number of stations are trying to call the same (DX) station on the same frequency.

Pilot Streamer - Column of ionized air which progresses downward at speeds of about 100 mph and establishes a path for a return lightning strike.

Plate Tank - A resonant circuit at a vacuum tube amplifier's output frequency that is used to couple energy from the high impedance plate or anode circuit to an antenna load.

Plate Transformer - Voltage step-up device that provides the high voltage to be rectified and filtered to supply a vacuum tube amplifier's plate circuit.

PL-259 - (misnamed UHF) Male coaxial cable connector commonly used to connect HF antennas to radios.

PLL - Phase Locked Loop. Circuit to synthesize the different frequencies a radio will operate on.

Pocket Beep - Beeping function (usually of an HT) when a specific signal is received.

Polar Orbit - Satellite orbit that passes over the North and South poles.

Potentiometer - (pot) Variable resistor in which the total resistance remains constant while resistance between end points is varied.

Prefix - The first half of a callsign, usually made up of 1 or 2 letters followed by a number. Letters after the number are called the suffix.

Priority Watch - Reception mode in which a selected frequency is periodically checked even when radio is tuned to another frequency.

PS - Power Supply

PSK31 - Popular keyboard-to-keyboard amateur digital transmission system. Phase Shift Keying at 31 Hz bandwidth.

PTO - Permeability Tuned Oscillator - A Variable Frequency Oscillator (VFO) in which the frequency change is accomplished via an inductor with a movable slug rather than via a variable capacitor. Usually much more linear than a VFO.

PTT - Push-To-Talk

PWR - Power

Q

Q Signals - Set of 3 letter codes specific to Ham Radio beginning with "Q" to speed CW communications. (similar to police "10" codes). (e.g. QTH = "location", QRZ = "Who is calling me?", QSB = "atmospheric fading", QRM = "interference", QRN = "static". Download complete list HERE.

QSL Card - Post Card (usually 3.5x5") sent to a station confirming a radio contact. "The final courtesy of a QSO is a QSL".

QRP - Low power, usually 5 watts or less.

Quad Antenna - Multi-element beam antennas based on square loops approximately one wavelength in circumference.

R

Radials - Horizontal counterpoise elements of a vertically polarized antenna, sometimes buried to act as a low resistance path to ground. (more info)

Radiation Resistance - That part of the total resistance of an antenna that results in radiation. The remainder generally results in loss of applied power as heat.

Rag Chew - Have a long, drawn out conversion (usually over 30 minutes).

RAM - Random Access Memory.

Rat Killing - refers to doing other things besides talking on the radio (i.e.: "well, I'm going back to my rat killing").

RCV - Receive

RCVR - Receiver

Receiver - Device which receives signals over the air.

Reflected Power - Non-radiated power dissipated as heat when a transmitter is mismatched to the antenna or load.

Reflector - Element(s) on a Yagi behind the driven element (see Yagi).

Repeater - Radio System which simultaneously receives (usually weak) incoming signals and re-transmits them (usually at higher power) for extended communication area. Usually placed at high geographical location for access by VHF/UHF HT's and mobiles.

Resistive Divider - Two resistor circuit used to reduce an applied voltage.

Resonant Circuit - A circuit in which the inductive and capacitive reactances are equal and cancel, leaving just the resistive part of the circuit.

Rig - Another name for radio.

RIT - A control on a transceiver to allow the receive frequency to be shifted from the transmit frequency by a small amount. On some radios called a "Clarifier".

RF - Radio Frequency Energy.

RF Ground - Connection of radio equipment to earth ground to eliminate hazards from RF exposure and reduce RFI.

RFI - Radio Frequency Interference.

RIT - Receiver Incremental Tuning. Fine tuning the receive frequency without changing the displayed or memory frequency.

RMS Voltmeter - Alternating current (AC) voltmeter to read the "Root Mean Square" voltage level.

ROM - Read Only Memory

Rotary Inductor - Kind of variable inductor in which a sliding contact is moved along the coil as it is rotated.

Rotator - Motorized device to rotate a directional antenna.

RSGB - Radio Society of Great Britain (British Equivalent of ARRL.) (WEBSITE)

RS-232 - EIA standard defining a serial computer connection arrangement. The standard specifies pin-outs for a 25-pin (DB25) and 9-pin (DB9) subset, signal relations, voltage levels and maximum cable lengths.

RST - Readability (1-5), Strength (1-9), Tone (1-9). A method of reporting how well a station can be heard. (e.g. 599, 579, 458)

RTTY - Radio TeleTYpe. Keyboard to keyboard transmission mode originally conducted between special teletype machines. Now one of many modes that are frequently sent with a PC and a sound card.

Rubber Duck - Flexible antenna for an HT.

RX - Receive

S

S Line - A line of transmitters (32S), receivers (75S), amplifiers and other accessories offered by the Collins Radio Company from 1958 to 1975.

S Meter - Signal Strength meter for a receiver. Basic calibration is in S units, from 1 (faint, barely perceptible) to 9 (strongest signal). There is often an additional scale above S9 calibrated in decibels (db).

S-Unit - Unit of measure on S-Meters. Each S-Unit is intended to represent a factor of 2 in input voltage at the receiver antenna terminals. ("S" stands for Strength)

S/N - Signal to Noise ratio .

Salt Mine - Generic term for place of employment.

SAR - Search And Rescue

SB Line - A line of transceivers (SB10x), transmitters (SB40x), receivers (SB30x), amplifiers (SB2xx) and other accessories (SB6xx) offered by the Heathkit Radio Company in the 60's and 70's. (considered the "poor man's Collins" because of the similarities and much lower cost)

Scan - Continually sweeping frequencies looking for active signals.

Scan Edge - Start or End frequencies for a scanning range.

Schedule 40 PVC - Poly-vinyl chloride pipe with thicker walls than some other types. Popular material often used as antenna structural support or insulator.

Schematic - Semi-pictorial record of the circuits in a radio.

Scope - Short for oscilloscope. Test instrument that displays voltage as a function of time on a television like display screen (CRT).

Scratch Pad Memory - Temporary frequency memories for quick access.

Screwdriver - Type of motorized mobile multi-band HF antenna.

SDR - Software Defined Radio. Radio system in which the majority of processing is performed in a PC using special software that defines the radio's functionality.

Secondary coupling - In lightning environment, transformer-like electro-magnetic coupling between powerful cloud-to-earth lightning strikes and nearby above ground wires and cables. Typically creates above ground surges in those wires.

Selectivity - Indicates how well a receiver can distinguish close signals.

Self Supporting - Not requiring guy wires to remain vertical.

Semi-Duplex - A mode of operation in which transmit and receive is accomplished on different frequencies alternatively.

Sensitivity - Indicates how weak a signal a receiver will pick up.

Service Entrance Panel - Device generally located immediately behind the kWh meter that provides mains fusing for the electric service wires. It then distributes the electrical load to a number of separately fused electrical circuits for customer equipment.

SET - Simulated Emergency Test.

Set Mode - An operational mode used for radios to set less frequently used control features.

Silent Key - A deceased Amateur Radio Operator.

Simplex - An operational mode in which transmit and receive frequencies are the same.

SK - Silent Key or Straight Key.

SKCC - Straight Key Century Club. Club promoting the use of Hand Keys for CW communications. (WEBSITE)

SkyWarn - An organization of trained volunteer storm spotters for the National Weather Service. (WEBSITE)

SMA - Sub-Miniature "A" connector usually used on HT's for the antenna.

SMIRK - Six Meter International Radio Klub - promoting the use of the 6 Meter band. (WEBSITE)

SMT - Surface Mount Technology. Method of mounting minuscule components on circuit boards without leads.

SO-239 - Female antenna connector used on most HF radios. (Mates the PL-259)

Solar Cycle - 11 year cycle of intense sunspot activity. High activity = good DX propagation, low activity = poor DX propagation. (more info)

Solder Lug - Electrical connection device that has a toothed hole to fit under a machine screw or nut. It includes a protrusion with one or more holes designed for as a place for wires to be soldered.

Solid State - circuitry containing no vacuum tubes.

SP - Speaker.

Speaker-Mic - Optional accessory for an HT containing both a small speaker and a microphone.

Splatter - Undesired emissions resulting from overdriving an amplifier or modulator, causing distortion.

Split - An operational mode in which the transmit and receive frequencies are different.

SQL - Squelch. A function muting the audio output for set conditions.

SSB - Single Side Band. Transmission system in which the carrier and one sideband are not transmitted, but inserted in the receiver.

SSTV - Slow Scan TV - Graphic communication using narrow bandwidth, usually still images.

Straight Key - (see Key)

Sunspots - Area on the sun's surface responsible for radiation that increases ionization level and consequently long distance propagation via the ionosphere.

Superheterodyne - Classic receiver architecture in which an incoming signal is beat (or heterodyned) with a signal generated in the local oscillator (LO) to translate the incoming signal to an intermediate frequency for processing. The receive frequency is changed by moving the LO to shift a different incoming frequency to the same IF. This allows the same circuit elements to process signals of different frequencies providing consistency of operation and performance.

Swishing - Term for changing the frequency of a transmitter while it is keyed.

SWL - Short Wave Listener.

SWOT - Side Winders on Two - Club promoting SSB transmissions on the 2 Meter band. (WEBSITE)

SWR - Standing Wave Ratio - Measurement of forward vs. reflected power output during transmit.

T

T Match - A kind of double Gamma Match that provides a balanced connection to an antenna. (see Gamma Match)

TCXO - Temperature Compensated Crystal Oscillator. Heated Crystal Oscillator for better frequency stability.

Telnet - Remote terminal protocol that's fundamental to the operation of the internet protocol (IP).

Temperature Coefficient - amount a component value changes as a function of change in temperature.

Ten-Ten -(10-10 or 10-X) Club promoting the use of the 10 Meter band. (WEBSITE)

Technician - Current Entry Level Grade of Amateur Radio License with primary privileges above 50 MHz. (some limited privileges on HF)

TNC - Terminal Node Controller - Device which groups characters into packets, generates modem tones and implements the X.25 protocol used for various digital modes of transmission.

Tolerance - Amount the value of a component can be different than nominal value and still be considered "good".

Toploading - Shortening the physical length of a vertical antenna by substituting an inductance at the top in place of additional height.

TOT - Time Out Timer - Time limiting function for continued repeater or other operations.

Traffic - Messages sent by radio.

Traffic Net - scheduled meeting of Amateur Radio Operators at particular time and frequency for the purpose of sending and receiving traffic.

Transceiver - Combined Transmitter and Receiver in one unit. Often some components are used in both functions.

Transistor - Solid State replacement for vacuum tube.

Transmitter - Radio which sends a signal over the air.

Trap - Parallel resonant windings used to electrically isolate sections of an antenna to provide resonant operation on more than one frequency range.

Trimmer Capacitor - Small adjustable capacitor , generally screwdriver adjustable to set a calibration point as part of a system alignment.

Trimmer Potentiometer - Small adjustable resistor , generally screwdriver adjustable to set a calibration point as part of a system alignment.

TS - Tuning Steps - Incremental tuning steps.

TSQL - Tone Squelch - Squelch function using sub-audible tones, selective call.

TTL - Transistor-Transistor Logic. A family of logic gates found in many current lines of digital integrated circuits (ICs).

TVI - Television Interference.

TX - Transmit

U

UHF - Ultra-High Frequency - 300 MHz to 3 GHz range signals.

UHF connector - (misnamed before WWII for frequencies over 30 MHz) Coaxial cable connector commonly used to connect HF antennas to radios (PL-259 male, SO-239 female).

Unbalanced Feed Line - Transmission line, primarily coaxial cable, in which one conductor (the shield) is designed to be at ground potential.

Unmodulated Carrier - Steady transmitted RF signal carrying no information.

Uplink - opposite of downlink. Frequency on which the user transmits to a repeater or satellite.

UPS - Uninterruptable Power Supply. Power system in which the AC input is used to charge batteries which in turn power an inverter to provide clean AC in case of commercial AC power failure.

USB - 1. Upper Side Band. 2. Universal Serial Buss (in computers)

UTC - Universal Time Coordinate. Also called GMT (Greenwich Mean Time) and Zulu (military) time. Time at Greenwich, England at zero degrees longitude. Widely used in international radio communications.

UV Protection - Coating placed on plastics or other materials to prevent degrading by exposure to ultra-violet light from the sun.

V

Vacuum Relay - Electromechanical switching device in which the switch contacts are enclosed in an evacuated chamber, eliminating most contact oxidation, corrosion, burning and pitting.

Vacuum Tube Era - The time period during which most Amateur Radio equipment was constructed around vacuum tubes. Generally from the mid-20's to the early 80's.

Vacuum Variable Capacitor - Capacitor consisting of two electrodes, often concentric cylinders, in an evacuated glass envelope. One element is moved in and out with respect to the other.

Valve - European term for "vacuum tube"

Vanity Call - Callsign selected by a licensee instead of sequentially assigned by the FCC. (must be approved by the FCC)

Varactor Diode - A solid state two terminal device used in non-conducting mode. The capacitance between the terminals is changed by applying a different voltage between them resulting in a voltage variable capacitor.

VFO - Variable Frequency Oscillator. Allows the operator to change frequency freely.

VHF - Very High Frequency. 30 to 300 MHz range signals.

Voice Keyer - Device that can transmit pre-recorded voice transmissions, useful for calling CQ or during contest exchanges.

Voltage Doubler - A kind of power supply rectifier circuit in which a capacitor is charged during one part of the AC cycle and then placed in series with the input on another part to result in an output DC voltage approaching twice the peak value of the input waveform.

VOX - Voice Operated Transmit. A function which automatically puts the transmitter in transmit when you talk into the microphone.

VSC - Voice Scan Control or Voice Squelch Control.

W

Wall Wart - Small power supply unit for low power equipment with integral plug for standard AC wall outlet.

WARC - World Administrative Radio Conference.

WARC Bands - 12, 17, 30 and 60 Meter bands.

WAS - Worked All States - An ARRL award for verified contacts with at least one station in each of the 50 states. (More Info)

Weather Alert - When an NOAA or NWS station transmits alert signals.

White Noise - Noise with a flat spectrum that covers all frequencies. The 'hiss' you hear on a radio with no station present.

Wide Range Antenna Tuner - Antenna system matching device that can compensate for large impedance mismatches typically representing SWR of at least 10:1.

Windom - An Off Center Fed dipole antenna.

Window Line - similar to Ladder Line, but the spacing is maintained by a plastic coating with cutouts which look like windows.

WFM - Wideband FM

X

XMIT - Transmit

XTAL - Crystal. Device used to set a fixed frequency.

Y

Yagi - another name for a Beam antenna. A multi-element array in which one element (driven element) is directly connected to the transmission line and others are coupled through radiation. Named after one its Japanese inventors, Hidetsugu Yagi along with Shintaro Uda. Sometimes called the Yagi-Uda antenna, but most often shortened to "yagi".

Z

"Z" signals - 3 letter codes beginning with "Z" used only by MARS, in lieu of amateur "Q" signals, to speed CW communications. (see Q Signals)

Zener Diode - Two-terminal semiconductor device that has a well defined reverse breakdown voltage. By conducting at that voltage, it can serve as a voltage regulating device.

Zulu Time - Military designation for Greenwich Mean Time. see UTC.

Information on this page was compiled from various sources including books and websites, but primarily a document from Icom, Inc., and the "Hamspeak" column of QST, the ARRL's monthly magazine. This is a growing document and will be added to on a regular basis. To recommend a term for this page, email me using the CONTACT button below.