Dictionary of Ham Radio Terms

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A
AC : Alternating Current

AF : Abbreviation for Audio Frequency. AF is in the range 20Hz to 20 000Hz

AFC : Automatic Frequency Control - used to prevent drift in FM receivers

AGC : Automatic Gain Control - a feedback system to reduce fading by automatically adjusting gain

ALC : Automatic Level Control - a feedback system in the transmitter output amplifier used to prevent overload.

 Ampere :(A) The unit used for measurement of current. Usually abbreviated to Amps

Amplitude : the height of a wave from the average or median position.

AMSAT : The name for amateur radio satellite organizations world-wide, but in particular the Radio Amateur Satellite Corporation.

Analog (also analogue): a continuously varying signal.

 Antenna: a device to either radiate radio signals or to revieve them from another station.

Antenna Switch " A switch used to change the output of a transceiver from one antenna to another.

Antenna Tuner : A device used to match the output impedance of a transmitter to that of an antenna.

Amplifier : A device that is used to increase voltage, current or power.

AMTOR : A specialised form of RTTY protocol. An acronym for AMateur Teleprinting Over Radio or AMateur Teletype over Radio.

ARDF : Amateur Radio Direction Finding

ARRL : The American Amateur Radio League - the national ham radio association for the USA

APRS : Automatic Position Reporting System.

 Attenuator : A resistive device to reduce the amplitude or power of a signal.

ATV : Amateur Television - "moving picture" ham TV transmissions.

B
Balun : A passive electronic device that converts between balanced and unbalanced electrical signals using some form of electromagnetic coupling.

Balanced Line : parallel conductors at equal and opposite potentials. Neither conductor is at ground potential.

Bandpass (also Passband): the range of frequencies that a certain filter allows to pass.

Base Station : A ham station that has a fixed location

 Bandpass Filter : a filter designed to pass a certain range of frequencies.

Band : The portions of the Electromagnetic Spectrum that are allocated to ham radio operators.

 Beacon : A station that transmits signals either continuously or on a timed basis, for location and propagation purposes.

BFO : Beat Frequency Oscillator. An oscillator that is mixed with an incoming signal to produce an Audio Frequency (AF tone for CW reception.

Boat Anchor : A slang term used to describe obsolete ham radio gear - often applied to old transceivers

BNC : A coaxial connector commonly used with VHF/UHF equipment.

BPSK : (Binary Phase Shift Keying). A digital modulation method for transmitting data.

Bureau (also Burro) : An organization set up to process QSL cards between amateurs.

C
Callsign A unique identifier for each radio amteur throughout the world

Capacitor : A passive electronic component composed of two conducting plates separated by a dielectric (insulating material).

CLOVER : A PSK mode that allows full duplex communications.

CNDX : Abbreviation for Conditions

Coaxial Cable : Cable that has a central conductor and an outer shield as the second conductor. Known as coaxial because the cable is cylindrical and the conductors share the same central axis.

Conductor : A material through which electricity flows easily.

CQ : Request for contact - specifically "calling any operator"

CTCSS : Continuous Tone-Coded Squelch Syatem - a sub audible tone that is frequently used on repeaters. The signal "opens" the repeater for use.

Current : The flow of electicity through a conductor - usually associated with electron movement, but current is actually the transfer of charge between atoms.

CW : Continuous wave - used in morse code transmissions.

CW Abbreviations Used by CW operators to reduce the length of transmissions by shortening words or phrases to a 2 or three letter code.

D
dB : Decibel - the ratio of two power measurements.

dBd : dB relative to a dipole. Also known as dBD

dBi : dB relative to a theoretical isotropic (point) source.

 dBm: The power compared to a 1 milliwatt (1mW) source, expressed in decibels (dB)

dBo : Optical gain. An unofficial term used by some amateurs working with transmission of data using light.

 De or DE : "this is" or "from" - for example an operator may use VL2TK de VK4ZW .......

Dipole : An antenna with two sides, usually of equal length.

 Dish : A highly directional antenna, parabolic in shape. Often used at microwave frequencies.

Domino EX : a digital mode that uses a variant of MFSK known as IFK for transmission of information.

DTMF Dual Tone Multi Frequency - the allocation of a unique tone to each button on an appliance (made up of two frequencies - high and low) that allows a computer to recognize the tone.

Dummy Load : An artificial antenna that does not radiate. used when alligning transceivers.

Duplex : Transmit and receive are on two different frequencies - often use in repeaters with a shift (difference) of 600Hz.

DXCC : DX Century Club

DX : Distance or distant station

E
'Earth : A circuit connection to a ground rod driven into the ground or system of wires buried below the surface of the ground.

Electromagnetic Waves : The waves emitted by an antenna, having two dimensions, electric and magnetic.

EHF : Extremely High Frequency - from 30GHz to 300GHz

EME : Earth Moon Earth - bouncing a signal off the moon to a remote station that would not normally be accessible.

EMF : Electromotive Force - Voltage.

EMI : Electromagnetic Interference.

eQSL : Electronic QSL - a website for sending and receiving QSL's online.

F
Feedline : The wire or cable that joins a transmitter or receiver to an antenna. Also known as a transmission line.

Filter : An electric circuit (often called a network) that allows certain frequencies to pass but rejects (attenuates) other unwanted frequencies.

FM (Frequency Modulated or Frequency Modulation): The shape of the carrier signal is changed (modulated) by the frequency of another signal, usually the voice of the operator.

Frequency: The number of complete waves that pass a reference point per second. Expressed in Hertz (Hz)

Frequency Shift Keying: A digital mode in which the signal is broken int "chunks". Each chunk is then shifted in frequency slightly above or below the central carrier.

 Fuse : A device that self destructs when too much current passes through it - used for circuit protection.

G
Gain : How much more effective an antenna is as a radiator than a half wave dipole

Ground : A direct connection from electrical equipment to the Earth - often achieved by driving a conducting spike into the ground, and connecting equipment to it.

GMT : Greenwich Mean Time - the time at Greenwich UK. Also known as zulu and UTC.

G-TOR (Golay - TOR) : A digital FSK mode that offers faster transfer rate than PACTOR. Rarely used by ham radio operators.

H
''' Harmonic : Multiples and sub multiples of the frequency of a reference equation

Hellschreiber (Hell) : Adigital mode for sending and receiving text using facsimile (fax) technology.

Henry :(H) The unit for inductance

Hertz : Hz - The unit of measure for frequency.

HF : High Frequency. Frequencies in the range 3MHz to 30MHz.

High Pass Filter : A filter designed to pass high frequency signals.

HT : Handheld Transceiver or HandiTalkie. Usually refers to transceivers that operate in the 2m and  70cm amateur bands.

I
IFK : Incremental Frequency Keying a variant of MFSK

Ionosphere : a region in the atmosphere that contains ionised gasses that refract (bend) radio waves and direct them back to earth.

 Inductance : A measure of how well a coil stores energy in the form of a magnetic field.

 Interface: usually refers to a circuit used to connect the soundcard of a computer to a transceiver to allow digital modes to be used.

Insulator : A substance through which electricity does not pass easily - known as a dielectric in capacitors

IRLP Internet Radio Linking Project. A method of linking cross-world linking of repeaters so that very basic equipment can be used to communicate with hams in other countries.

ITU : International telecommunication Union. The international organisation set up to standardise and regulate radio communications.

J
JOTA : Jamboree On The Air - an annual event in which scouts worldwide can communicate with each other and radio amateurs using ham radio equipment.

K
K : The symbol use in CW (morse) and digital modes for "please respond" or "any station respond".

Kilohertz : one thousand Hertz (Hz) or one thousand cycles per second.

L
LPDA : Log Periodic Dipole Array. A multiband Antenna

M
Microphone : A device that converts voice into electrical signals.

Mode : The way electromagnetic waves are changed so that transmission of information is possible.

Morse Code The code used by CW operators instead of voice communications

N
NB: Narrow band. Also noise Blanker

NBFM : Narrow band FM

Negative : no, incorrect

Negative copy : unsuccessful transmission

Negative Feedback A process in which a portion of the amplifier output is returned to the input, 180 degrees out of phase with the input signal.

Negative Offset : Used in repeater systems where the the repeater input frequency is lower than the output frequency.

 Net : a scheduled on on air meeting of amateurs - often run and controlled by clubs.

NiCad : Nickel Cadmium, generally refers to a type of rechargeable battery

NiMH : Nickel Metal Hydride, generally refers to a newer type of rechargeable battery

NPN : A type of transistor that has a layer of P-type semiconductor material sandwiched between layers of N-type semiconductor material.

NVIS : near-vertical-incidence-skywave, a propagation mode where signals are reflected back down from directly overhead. Useful for relatively short-distances, overcoming the limitations of the usual "skip-zone" distance"

O
Ohm : ($$ \Omega$$) The unit for resistance

OM : Abbreviation meaning Old Man

OSCAR : Orbiting Satellite Carrying Amateur Radio

OCF : Off Centre Fed Dipole. A dipole that has sides of unequal length. These are multiband wire antennas

P
PACTOR : An FSK mode that combines packet and AMTOR technologies.

Period : the time it taks in seconds for a complete wave to pass a reference point.

Phonetic Alphabet Specific, easily identfiable, non-confusable words are used instead of the letters of the alphabet.

 Pi pad  : one of the possible configurations used in Attenuators

Power : The rate of energy consumption. Calculated by multiplying voltage by  current, P = VI

Propagation : How well a signal is transferred from the sending station to the receiving station.

 PSK : Phase Shift Keying - a digital mode.

Q
Q Code Three letter codes used instead of sentences or phrases.

 Q of a circuit The quality factor of a resonant circuit - the ratio of stored power to dissipated power in the Reactance and Resistance of the circuit.

QRM : Man made noise. Can be used to indicate noise interfering with an amateur station or an amateur station interfering with other spectrum users.

QRN : Electromagnetic noise from natural sources interfering with amateur transmissions.

QRP : Low power operations - usually understood to mean power at or below 5 watts.

QRPp : Very low power operation - at or below 1 Watt.

QSL : Confirmation of receipt of transmission

R
 Repeater : A transceiver - often comprised of separate transmitted and receiver linked by controlling hardware. A repeater picks up a radio signal and re-transmits it, allowing weak stations to be heard from further away than normally possible.

RSGB : Radio Society of Great Britain - national amateur radio organisation of UK.

RSQ code Used to describe the readability, strength and quality of digital modes.

 RST code Used to describe the readability, strength and tone of voice or CW transmissions.

RSV code used to describe the readability, stength and video quality of SSTV transmissions

RX : Abbreviation for receive or receiver

S
Skip : Skip is a radio phenomenon in which signals are reflected or refracted by the atmosphere and return to earth in unexpected places, far away from the normal reception zones. In between transmitter and receiver there is a zone where no transmissions can be heard

Skip Distance : The shortest distance, for a fixed frequency, between transmitter and receiver.

Skip Zone : The distance between the point of no reception and the closest point of reception.

SSB : Single Sideband. A transmission mode used mainly in the HF bands.

SSTV : Slow Scan Television - still picture ham transmissions.

Standing Wave: The vector sum of two waves - in ham radio, this most usually refers to the forward and reflected waves in a feedline

SWR : Standing Wave Ratio. The ratio of the height of a standing wave on a transmission line to the height of an adjacent node.

T
THROB : An MFSK digital mode based on tone pairs.

TOR (Teleprinting Over Radio): Used in three disgital modes; AMTOR, PACTOR and G-TOR.

 T pad  : one of the possible configurations used in Attenuators

 Transmission Line : Also known as feedline.

TX : Abbreviation for transmit or transmission

U
UHF : Ultra High Frequency. Frequencies in the range 300MHz to 3 000MHz

V
 Volt : (V) The unit of electric potential difference (Voltage) between two points.

VA : Volt Amperes - measure of apparent power.

VAC : Volts Alternating Current.

Varactor Diode : a component whose capacitance varies as the reverse bias voltage is changed.

VCO : Voltage-controller oscillator

VFO : Variable Frequency Oscillator

Velocity Factor : the speed at which radio waves travel in a particular feedline, expressed as a percent of the speed of light

VHF : Very High Frequency. Frequencies in the range 30MHz to 300MHz

VIS : Vertical Interval Signaling. Digital encoding of the transmission mode in the vertical sync portion of an SSTV image.

 VLF : Very Low Frequency 3 - 30 KHz

VMOS : Vertical metal-oxide semiconductor

VOX : Voice Operated Transmit

VSWR : Voltage standing wave ratio

VXO : Variable crystal oscillator

W
WARC : World Administrative Radio Conference. Run by the International telecommunication Union.

WARC Bands : Agreed to at the 1979 WARC, they consist of the 30m ( 10.100Mhz - 10.150MHz), 17m (18.086MHz - 18.186MHz) and 12m (24.890MHz - 24.990MHz) amateur bands.

Wavelength : The distance in metres between corresponding points on a wave.

WIA : Wireless Institute of Australia. The national organisation for Australian hams.

WSPR : Weak Signal Propagation Reporter.

WSJT : Weak Signal Joe Taylor - named after Joe Taylor who wrote the software.

X
XCVR : Transceiver

XTAL : Crystal

XYL : Wife of an amateur operator

Y
Yagi : A directional antenna consisting of a dipole and two additional elements, a slightly longer reflector and a slightly shorter director. Invented in 1926 by Hidetsugu Yagi and Shintaro Uda.

YL : Abbreviation for Young lady

Z
Zero Beat : one or both of two signals are adjusted so that they are identical and in phase.

Zulu : (z) Time compared to GMT. Also known as UTC

0-9
30: End of message

73: Goodbye

88: Love and Kisses