Ham Radio Jargon, Abbreviations and Terminology

This is an informal listing of Ham Jargon -- The opinions of AC6V Only.
Not to be used as a definitive source.
Caveat Lector. Reader Beware! Applies as in all things.

AGC - Automatic Gain Control. A feedback voltage in the receiver circuit to prevent fading

ALC - Automatic level control. A feedback voltage in the transmitter's output amplifier used to prevent amplifier overload. Also used as feedback from a linear amplifier back to the exciter to prevent overdriving.

alligator - A repeater that transmits further than it can receive, big mouth, small ears! Also used in reference to a repeater timer timeout. If you talk on the repeater too long, an internal timer will cut you off, and jargon for this is "The alligator got you!" Also in contesting circles to refer to a station (usually running high power and under noisy receive conditions) whose transmit signal is greater than their receive capability.

amateur radio - A non-commercial radio service as set by a recognized cognizant government agency. In the USA, amateur radio is defined under part 97 of the FCC Rules and Regulations - See URL: Part 97

amateur service: a radio communication service for the purpose of self-training, intercommunication and technical investigations carried out by amateurs, that is, duly authorized persons interested in radio technique solely with a personal aim and without pecuniary interest.

ampere (A) : the basic unit of electrical current. Current is a measure of the electron flow through a circuit per unit of time. 6.24 x 10^18 electrons moving past a point in one second, equals one ampere. Abbreviated as amps.

AMTOR - Amateur Teleprinter Over Radio. A version of RTTY. - See URL: AMTOR Also used commercially as SITOR (Simplex Teleprinter Over Radio).

antenna tuner: Impedance-matching device that matches the antenna system input impedance to the transmitter, receiver, or transceiver output impedance.

appliance operator : Hams who neither build nor experiment with radio equipment, but merely operate commercial equipment, perhaps without understanding how it all works.

ARC - Amateur Radio Club. Military Designation for Avionics (Aviation Radio Composite)

ARRL - American Radio Relay League , the national amateur radio organization in the USA - See URL: ARRL

ASCII - American Standard Code for Information Interchange. The ASCII 7-bit code represents 128 characters including 32 control characters.

ASR - Automatic send-receive. An RTTY terminal mode that allows message composition while receiving text from the another station.

auroral propagation - Propagation above 30 MHz by means of refraction by highly ionized regions around the Earth’s poles. See URL: Propagation

autopatch - (Repeater Term) a device that interfaces a repeater to the telephone system to permit repeater users to make telephone calls. Often just called a "patch."

AVC - Automatic Volume Control - A feedback scheme to level out the receiver audio volume.

AWG - American Wire Gauge - standard for describing the diameter of wire by which the wire size increases as the gauge number decreases.

B - Battery -- in early radio, batteries were the prime source of power - The A battery provided the filament voltage, the B battery furnished the B+ or the Voltage to the plates of the tubes, and the C battery provided the grid-bias voltage to the tubes.

balanced line: A feed line with two conductors having equal but opposite voltages, with neither conductor at ground potential.

balanced modulator: a mixer circuit used in a single-sideband suppressed-carrier transmitter to combine a voice signal and the RF carrier. The balanced modulator isolates the input signals from each other and the output, so that only the sum and the difference of the two input signals reach the output. The original carrier signal and the audio signal are suppressed.

balun - balance to unbalance , a device used to couple a balanced antenna to an unbalanced feed line (e.g., dipole to coax)

band - a range of frequencies allotted for a particular use (e.g., 20 Meter Band) See Ham bands

bandpass - range of frequencies permitted to pass through a filter or receiver circuit.

band-pass filter: a circuit that passes a range of frequencies and attenuates signals above and below this range

base -- a radio station located at a fixed location as opposed to a mobile. Used to identify the control location in a network of radio stations.

base loading - A loading coil at the bottom of an antenna to achieve a lower resonant frequency.

beacon: A station that transmits one-way signals for the purpose of navigation, homing, and propagation condition determination. See URL: Beacons

Benton Harbor Lunch Box - A portable transceiver made by Heathkit Co. Band choices were 2, 6, or 10 meters - AM operation.

BFO - Beat frequency oscillator. Used to mix with the incoming signal to produce an audio tone for CW reception. A BFO is needed to copy CW and SSB signals.

Bird - nickname for satellite. Also a brand name of a high-end, high quality directional wattmeter.

birdie - Spurious signals produced in a receiver - usually a product of mixed intermediate frequencies within the radio.

bleeder resistor: a large-value resistor connected across the filter capacitor in a power supply to discharge the filter capacitors when the supply is turned off.

block diagram: a drawing using rectangles to represent major sections of electronic circuits. The diagram shows signal flow and the function of the sections.

BNC - Coax connector commonly used with VHF/UHF equipment -- Bayonet Niell-Concelman (standard connector type used on COAX cable, named for its inventors).\

birdie: A false or spurious signal in a receiver inadvertently produced by the receiver’s circuitry.

boat anchor - antique ham equipment -- So named because of weight and size. See BoatAnchors

bootlegger - Someone, usually not a Ham but a wannabe, making up a callsign, one usually not in the callbook, and getting on the air. Sometimes it is someone who already bought a radio, took the test and flunked, and then gets on the air anyway.

bounce - reflections of a radio wave off of an object, (e.g., the ionosphere or the moon)

breadboard - Early experimenters used a wood board or bread board to lay out circuits. Now used to describe an experimental layout on whatever media -- like PC boards.

break - (Repeater Term) used to interrupt a conversation on a repeater to indicate that there is an emergency or urgent message. If non-urgent, simply interject your callsign.

break break (Repeater Term) used to intercede in an existing conversation with emergency communications.

broadcasting: transmissions intended for the general public. Broadcasting is prohibited on the Amateur Radio Bands, other than QST's which of are of interest to all Amateur Stations, example W1AW code practice transmissions.

bureau - International Amateur organizations set up to process QSL cards between countries. Provides an inexpensive way to send and receive QSL cards - See URL: Bureaus

C- Battery -- in early radio, batteries were the prime source of power - The A battery provided the filament voltage, the B battery furnished the B+ or Voltage to the plates of the tubes, and the C battery provided the grid-bias voltage to the tubes.

calling frequency: A defacto standard frequency where stations attempt to contact each other. Example -- 146.52 is the USA National FM simplex calling frequency See Calling Frequencies

capacitor: an electronic component composed of two or more conductive plates separated by an insulating material. A capacitor stores energy in an electric field.

carrier - a pure continuous radio emission at a fixed frequency, without modulation and without interruption. Several types of modulation can be applied to the carrier, See AM and FM. See URL: Modulation Modes

carrier-operated relay (COR) - (Repeater Term) circuitry that causes the repeater to transmit in response to a received signal.

CC&R's - Covenents, Conditions, and Restrictions - an extensive set of rules drawn up by homeowner's associations and their lawyers which, among other things, typically restrict or completely prohibit a homeowner from having most forms of antennas on their property.

center loading - A loading coil at the center of an antenna to achieve a lower resonant frequency

channel - (Repeater Term) the pair of frequencies (input and output) used by a repeater.

chassis ground: the common connection for all parts of a circuit that connect to the negative side of the power supply.

chirp - Changes in the carrier frequency of a CW transmitter, resulting in a chirping sound

closed repeater - (Repeater Term) a repeater whose access is limited to a select group (see open repeater).

cloud warmer - an antenna which radiates most of the transmitted energy nearly straight up.

coax, coaxial cable A type of wire that consists of a center wire surrounded by insulation and then a grounded shield of braided wire. The shield minimizes electrical and radio frequency interference. 50-ohm and 72 ohm characteristic impedances are typical. See Coax Types

color code: a system in which numerical values are assigned to various colors. Colored stripes are painted on the body of resistors and other components to show their value. See Color Code

condenser - Old term for capacitor - basic unit is farads, which is generally too large so usually expressed in microfarads or picofarads. An electronic component composed of two or more conductive plates separated by an insulating material. A capacitor stores energy in an electric field.

controller: (Repeater Term) the control system within a repeater -- usually includes turning the repeater on-off, timing transmissions, sending the identification signal, controlling the auto patch and CTCSS encoder/decoder.

control operator - (Repeater Term) the Amateur Radio operator designated to "control" the operation of the repeater, as required by FCC regulations.

copy -- indication of how well communications are received. "I have a good copy on you"
also used as a question, as in "did you copy" - understand all"

copying -- used to indicate one is monitoring as in "I was copying the mail" which means
I was listening in on the conversation

core: the material used in the center of an inductor coil, where magnetic fields is concentrated.

courtesy beep - (Repeater Term) an audible indication that a repeater user may go ahead and transmit, usually resets the timer

coverage - (Repeater Term) the geographic area that the repeater provides communications.

CQ - calling any amateur radio station, may be sent in CW, phone or some digital modes

critical angle - The angle at which a radio signal is refracted in the ionosphere. Lower angles generally result in greater distance transmissions.
critical frequency: the highest frequency at which a vertically incident radio wave will return from the ionosphere. Above the critical frequency radio signals pass through the ionosphere instead of returning to Earth.

crystal - a piezoelectric device that tends to resonate at a frequency dependent on its material, dimensions, and temperature

crystal filter - A network of piezoelectric crystals used to obtain high rejection of unwanted signals.

crystal oscillator: a device that uses a quartz crystal to keep the frequency of a transmitter constant.

CSCE - Certificate of Successful Completion of Examination (U.S.), a certificate certifying a person has successfully passed one or more of the amateur radio license examinations

CTCSS - (Repeater Term) abbreviation for continuous tone-controlled squelch system, a series of subaudible tones that some repeaters use to restrict access. See CTCSS Codes

cutoff frequency - The frequency at which a filter will begin to reject signals.

CW - Continuous Wave, see carrier. In truth a continuous wave is an unmodulated, uninterrupted RF wave. However in common usage refers to Morse code emissions or messages which is an interrupted wave. See URL: Modulation Modes

cycles (cps) term used for measuring frequency prior to the term Hertz replaced it - hence kc, Mc, etc.

dB - Decibel (1/10 of a Bel); unit for the ratio of two power measurements. - See URL: decibel

desense (desensitization): the reduction of receiver sensitivity due to overload from a nearby transmitter.

detector - the stage in a receiver in which the modulation (voice or other information) is recovered from the RF signal. Called a discriminator in FM

deviation - The change in the carrier frequency of a FM transmitter produced by the modulating signal.

deviation ratio - the ratio between the maximum change in RF-carrier frequency and the highest modulating frequency used in an FM transmitter. Also see modulation Index.

digipeater - A store-and-forward digital repeater which will receive and transmit a data packet on the same frequency.

dip meter - or grid dip meter -- a device used to determine the resonant frequency of an electronic circuit

diplexer - A frequency splitting and isolation device. Typically used to couple two transceivers to a single or dual band antenna , thus allowing one to receive on one transceiver and transmit on the other transceiver. Typical application 2M and 440MHz transceivers into a dual band antenna for satellite work. Thus typically an isolation device for use on 2 or more different bands.
dipole - the basic antenna consisting of a length of wire or tubing, open and fed at the center. The entire antenna is ½ wavelength long at the desired operating frequency. This antenna often used as a standard for calculating gain, dBd.

director - an element in front of the driven element in a Yagi or Quad and some other directional antennas.

doubling -- (Repeater Term) On a repeater if two stations transmit simultaneously, the signals mix in the repeater's receiver and results in a raspy signal. FM has a characteristic whereby the stronger signals "captures" and over-rides the weaker one.

double-pole, double-throw (DPDT) switch - switches two different circuit lines to two different points.
double-pole, single-throw (DPST) switch - switches two different circuit lines on or off.

DPSK - Differential Phase Shift Keying; a form of BPSK where only data transitions are transmitted.

D-region - D-layer: The lowest region of the ionosphere found approximately 25 to 55 miles above Earth; it fades away quickly after sunset and sometimes does not form at all on short winter days. The main impact of the D-layer on radio propagation is to absorb energy from signals passing through it. -- See URL: Propagation

dropping out - (Repeater Term) a repeater requires a minimum signal in order to transmit, when a signal does not have enough strength to keep the repeater transmitting, it "drops out"

DSP - Digital Signal Processing - allows for filtering, noise reduction, audio equalization, etc

DTMF - (Repeater Term) abbreviation for dual-tone multi-frequency, the series of tones generated from a keypad on a ham radio transceiver (or a regular telephone). Uses 2-of-7 or 2-of-8 tones; often referred to by Bell's trademark Touchtone. See DTMF Tones

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

dummy load - a device which substitutes for an antenna during tests on a transmitter. It converts radio energy to heat instead of radiating energy. Offers a match to the transmitter output impedance.

duplex - (Repeater Term) a communication mode in which a radio transmits on one frequency and receives on another (also see full duplex, half duplex, and simplex)

duplexer - (Repeater Term) a device used in repeater systems which allows a single antenna to transmit and receive simultaneously. Thus typically for isolation on a system on the same band.

DXer - An Amateur radio operator who actively pursues contacting distant and rare Amateur Radio stations. Also applied to Short Wave Listeners.

DXCC - Award offered by ARRL for contacting and confirming 100 or more different countries first introduced in 1937. DXCC is copyright ARRL and its use here is printed with permission of the ARRL. See DXCC

DXpedition - Radio expedition to remote and rare locations -- See Current DX Operations

dynamic range: How well a receiver can handle strong signals with overloading; any measure of over 100 decibels is considered excellent.

earth ground - a circuit connection to a ground rod driven into the earth
Echolink Uses a network protocol called VoIP (Voice over IP). This program allows worldwide connections to be made between stations, from computer to station, or from computer to computer. There are more than 96,000 registered users in 128 countries worldwide! URL: EchoLink

Edison Effect - Thomas A. Edison discovered the electron flow from a glowing cathode to an anode in an evacuated glass bulb and was called the 'Edison-effect' This led to the development of the vacuum tube.

E-layer: The region of the ionosphere found approximately 55 to 90 miles above Earth; it fades away a few hours after sunset. The main impact of the E-layer on radio propagation is to absorb energy from signals passing through it, although sporadic-E propagation makes possible distant communications on frequencies above 30 MHz. See URL: Propagation

elephant - a repeater that receives further than it can transmit, big ears, small mouth!

elmer - a mentor; an experienced operator who tutors newer operators See URL: ELMERS

EME - Earth-Moon-Earth; using the moon as a passive reflector to establish a signal path; moonbounce. - See URL: EME

emission mode - the form of a radio emission, such as AM, FM, or single sideband - See URL: Modulation Modes

EMP - Electromagnetic pulse; a extremely high-energy magnetic field. Such as the current flow caused by a lightning strike or nuclear explosion.

ether - Old theory for the medium once believed to conduct radio waves. The existence of the ionosphere is first discovered by the English physicist, Appelton in 1924.

F-layer: The region of the ionosphere found approximately 90 to 400 miles above Earth and which is responsible for most long distance propagation on frequencies below 30 MHz. During the daytime (especially in summer), solar heating can cause the F-layer to split into two separate layers, the F1-layer and the F2-layer. See URL: Propagation

far field of an antenna - that region of the electromagnetic field surrounding an antenna where the field strength as a function of angle (the antenna pattern) is essentially independent of the distance from the antenna. In this region (also called the free-space region), the field has a predominantly plane-wave character. That is, locally uniform distributions of electric field strength and magnetic field strength are in a plane perpendicular to the direction of propagation.

Farnsworth - a method of sending Morse code characters. Example characters are sent at 13 words per minute but the spacing is adjusted so that the overall code speed is 5 words per minute.

fax - facsimile, a digital mode for transmitting images - See URL: Modulation Modes

FCC - Federal Communications Commission, the governmental body in the U.S. which regulates the radio spectrum See URL: FCC

field day - Amateur Radio activity in June to practice emergency communications.

field strength meter - a test instrument used to show the presence of RF energy and the relative strength of the RF field.

filter - A circuit or device that will allow certain frequencies to pass while rejecting others.

final - The last transmission by a station during a contact. Also the last amplifying stage of a radio transmitter.

first personal - first name - CB jargon that has crept into Ham jargon - old timers shudder

fist - early spark transmitters showered the operator with sparks - so Marconi's key lever was lengthened and the padded end was beaten with the 'fist' of the operator to send dots and dashes. Also a CW ops' reference to another ops' keying characteristic

flutter - Rapid variation in the signal strength of a station, usually due to propagation variations.

frequency - the rate of oscillation (vibration). Audio and radio wave frequencies are measured in Hertz. (cycles per second)

frequency coordinator - (Repeater Term) an individual or group responsible for assigning frequencies to new repeaters without causing interference to existing repeaters

FSK Frequency-shift keying. Modulating the transmitter by using the RTTY data signal to shift the carrier frequency. Mark and Space. See URL: Modulation Modes

full-break in (QSK) - allows a station to break into the communication without waiting for the transmitting station to finish.

full duplex - a communications mode in which a radios can transmit and receive at the same time by using two different frequencies (see "duplex" and half duplex)

full quieting -- (Repeater Term) a phenomenon on FM transmissions where the incoming signal is sufficient to engage the receiver limiters - thus eliminating the noise due to amplitude fluctuations.

full-wave bridge rectifier - a full-wave rectifier circuit that uses four diodes and does not require a center-tapped transformer. Converts AC to DC
full-wave rectifier - a circuit basically composed of two half-wave rectifiers. The full wave rectifier allows the full ac waveform to pass through; one half of the cycle is reversed in polarity. This circuit requires a center-tapped transformer. Converts AC to DC
fuse - a thin metal strip mounted in a holder. When excessive current passes through the fuse, the metal strip melts and opens and protects the circuit. Fuses are rated in amperes and voltage and time to activate - fast blow or slow blow.

gallon - slang for transmitter output power -- legally either 1000 watts CW or 1500 watts PEP

gain, antenna - an increase in the effective power radiated by an antenna in a certain desired direction, or an increase in received signal strength from a certain direction. This is at the expense of power radiated in, or signal strength received from, other directions.

GCR - General Certification Rule. Most award sponsors allow GCR in lieu of actually wanting to see your cards. You need to have the cards! GCR usually means getting the signatures of two witnesses who certify that you possess the cards and that the information you state on the application is correct.

GOTA - Get on the Air -- A category in the annual ARRL Field Day event. The GOTA station may be operated by Novice, Technicians or generally inactive hams under their existing operating privileges, or under the direction of a Control Operator with appropriate privileges, as necessary. Non-licensed persons may participate under the direct supervision of an appropriate control operator.See URL: ARRL FIELD DAY

gray line - a band around the Earth that separates daylight from darkness. It is a transition region between day and night. One of the many types of propagation paths.

great circle route - The shortest path by radio between any two points on Earth.

green stamp - U.S. dollar bill sent along with a QSL card (instead of an IRC) to offset postage costs of a return card.

grid dip meter -- Test Equipment that causes a meter decrease (dip) when near resonant circuits

ground-plane antenna - a vertical antenna built with the central radiating element one-quarter-wavelength long and several radials extending horizontally from the base. The radials are slightly longer than one-quarter wave, and may droop toward the ground.

ground wave propagation - radio waves that travel along the surface of the earth, even beyond the horizon. See URL: Propagation

half duplex - (Repeater Term) a communications mode in which a radio transmits and receives on two different frequencies but performs only one of these operations at any given time (see "duplex" and "full duplex")

half-wave dipole - the basic antenna consisting of a length of wire or tubing, open and fed at the center. The entire antenna is ½ wavelength long at the desired operating frequency.
half-wave rectifier - a circuit that allows only half of the applied ac waveform to pass through it.

hand-held - (Repeater Term) a small, lightweight portable transceiver small enough to be carried easily; also called HT (for Handie-Talkie, a Motorola trademark).

hang time - (Repeater Term) the short period following a transmission that allows others who want to access the repeater a chance to do so; a courtesy beep sounds when the repeater is ready to accept another transmission.

hamfest - ham festival, a social and commercial event at which hams meet to buy, sell, and swap equipment - See URL: HamFests

handle - A radio operator’s name. Kinda unnecessary -- just say the name is. But lotsa old timers use handle.

harmonic - a signal at a multiple of the fundamental frequency. Also a slang term for the children of an Amateur.

HDX - Half-duplex. A communication system in which stations take turns transmitting and receiving.

Hertz - the standard unit used to measure frequency (one Hertz equals one complete cycle per second)

"hi hi" is the Morse equivalent of a laugh as in Morse it sounds like someone chuckling ("hehhehhehheh hehheh"). That is ditditditdit dit dit --- or dot dot dot dot dot dot. You really have to listen to it sent in Morse to appreciate its laugh like sound. It is most commonly used in CW (Morse Code), but has carried over to voice as well. Many CW expressions have carried over to voice -- such as 73 (Best Regards) and 88 (love and Kisses), etc. The origin probably dates back before radio to the telegraph days. And since Hams used Morse long before voice became practical-- the sound of the Morse characters HI HI was used to resemble a laugh sound. In some sense it is equivalent of a smiley. It's onomatopoeic -- that is the naming of a thing or action by a vocal imitation of the sound associated with it (as buzz, hiss) The definitive answer might be found in the "Dodge's The Telegraph Instructor Manual" circa 1850 to 1900. However, I have never been able to find a copy of this document. Wish I could as it would help to see the transitions from telegraph to radio usage.So that is my best guess -- based on what old time telegraphers have told me

high-pass filter - a filter designed to pass high frequency signals, while blocking lower frequency signals.

hop - communication between stations by reflecting the radio waves off of the ionosphere.

horizontally polarized wave - an electromagnetic wave with its electric lines of force parallel to the ground.

IARU - International Amateur Radio Union - worldwide ham radio organization whose members consist of the official radio society from each participating country. See IARU

ID -- Identification, as announcing station callsign at intervals specified by Part 97 of the FCC Rules and Regulations.

IF - Intermediate Frequency -- Intermediate frequency, resultant frequency from heterodyning the carrier frequency with an oscillator, mixing incoming signals to an intermediate frequency enhances amplification, filtering and the processing signals. Desirable to have more than one IF.

impedance: The opposition to the flow of electric current and radio energy; it is measured in ohms (symbol is Z). For best performance, the impedance of an antenna, the feedline, and the antenna connector on a radio should be approximately equal.

inductance - a measure of the ability of a coil to store energy in a magnetic field.

inductor - an electrical component usually composed of a coil of wire wound on a central core. An inductor stores energy in a magnetic field.

input frequency - (Repeater Term) the frequency of the repeater's receiver (and your transceiver's transmitter).

intermod - Short for "intermodulation," this means false or spurious signals produced by two or more signals mixing in a receiver or repeater station.

intermodulation distortion (IMD -- (Repeater Term) the unwanted mixing of two strong RIF signals that causes a signal to be transmitted on an unintended frequency.

ionosphere - The electrically charged region of the Earth’s atmosphere located approximately 40 to 400 miles above the Earth’s surface that refracts radio signals.

IRC - International Reply Coupon: A coupon that can be purchased at post offices which can be exchanged in foreign countries for return postage for a surface mail letter to the country that issued the coupon. See IRC's

IRLP Radio Linking Project. Uses a network protocol called VoIP (Voice over IP). There are now nearly 800+ repeaters around the world connected by the internet through the Amateur radio internet radio linking project, 24 hours per day, 7 days a week. URL: IRLP

ITU - International Telecommunications Union, the body which specifies worldwide guidelines concerning the use of the electromagnetic spectrum for communications purposes. See ITU

J antenna (J pole) - a mechanically modified version of the zepp (zeppelin) antenna. It consists of a half-wavelength radiator fed by a quarter-wave matching stub. This antenna does not require the ground plane that ¼-wave antennas do to work properly.

JOTA - Jamboree on the Air -- an annual event in which about 500,000 Scouts and Guides all over the world make contact with each other by means of amateur radio. See URL: ARRL JOTA

K- index - A measure of the Earth’s magnetic field as measured at Boulder, Colorado. Propagation conditions improve with lower measurement numbers. See URL: Propagation

kerchunking - activating a repeater without identifying or modulating the carrier.

key - (noun) any switch or button, usually refers to a telegraph or Morse code key

keyer - Electronic device for sending Morse Code semi-automatically; connects to a key (see above). Dits are sent by pressing one paddle of the key, dahs sent by pressing the other one paddle.

key up - (Repeater Term) to turn on a repeater by transmitting on its input frequency.

ladder line -- an open wire transmission line -- 600, 450 ohm characteristic impedances are typical.

lid - a poor operator, one who does not follow proper procedures or sends sloppy morse code.

limiter - (Repeater Term) a stage of an FM receiver that clips the tops of the FM signal thus makes the receiver less sensitive to amplitude variations and pulse noise.

linear - an amplifier used after the transceiver output. So named for its purity of amplification. Linear, in the mathematical sense, means that what comes out is directly proportional to what goes in. As far as linear amps go, if you double the input, the output is doubled and so on. This does not generate any additional frequency byproducts. If the amp is nonlinear, sums, differences and all combinations of those are generated also.

line-of-sight propagation - the term used to describe propagation in a straight line directly from one station to another.

local oscillator (LO) - a receiver circuit that generates a stable, pure signal used to mix with the received RF to produce a signal at the receiver intermediate frequency (IF).

long path - short path -- in degrees - the direct great signal bearing path between two locations. Long path is the reciprocal bearing.

lowfer - One who experiments at very low frequencies (typically 1750 Meters, which is 160-190 kHz and can be used under FCC Part 15).

low-pass filter - a filter that allows signals below the cutoff frequency to pass through and attenuates signals above the cutoff frequency.

LSB - Lower Side Band - See URL: Modulation Modes - the common single-sideband operating mode on the 40, 80, and 160 meter amateur bands.

magnetic mount or mag-mount - (Repeater Term) an antenna with a magnetic base that permits quick installation and removal from a motor vehicle or other metal surface.

MARS - Military Affiliate Radio System, military affiliated amateurs who provide free communications for overseas GIs and other Federal services. MARS operators are licensed under DOD. Established 1948.

matchbox - Normally called an Antenna Tuner. Impedance-matching device that matches the antenna system input impedance to the transmitter, receiver, or transceiver output impedance.

MCW - Modulated Continuous Wave, a fixed audio tone modulates a carrier, older method of sending Morse code - See URL: Modulation Modes

megacycles - million cycles per second. This terminology has been replaced by MegaHertz (MHz)

meteor scatter - ionized trails of meteors used as a reflecting media See URL: Propagation

mic (mike) - microphone - a device that converts sound waves into electrical energy.

mil 1/1000 of an inch. Also mill a special typewriter used by radio operators in copying messages

mixer - a circuit that takes two or more input signals, and produces an output that includes the sum and difference of those signal frequencies.

mobile - an amateur radio station installed in a vehicle - a mobile station can be used while in MOTION. A portable station is one that is designed to be easily moved from place to place but can only be used while stopped.

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

modulate - create a radio emission so that it contains information (voice, Morse code, music, binary, ascii)- See URL: Modulation Modes

modulation Index - (Repeater Term) the ratio between the maximum carrier frequency deviation and the audio modulating frequency at a given instant in an FM transmitter.

motorboating -- an undesirable low frequency feedback resulting in a motorboat sound on the audio

MUF - Maximum Usable Frequency, a measure of the highest frequency that will support transmissions off of the ionosphere.

MW - Medium Wave - 300 - 3000 kHz. Also used for the AM broadcast band - 530-1710 kHz

NCS - Net Control Station
near field of an antenna - the region of the electromagnetic field immediately surrounding an antenna where the reactive field dominates and where the field strength as a function of angle (antenna pattern) depends upon the distance from the antenna. It is a region in which the electric and magnetic fields do not have a substantial plane-wave character, but vary considerably from point-to-point.

negative feedback - the process in which a portion of the amplifier output is returned to the input, 180 degrees out of phase with the input signal. Improves linearity and reduces distortion.

negative offset - the repeater input frequency is lower than the output frequency.

net - A group of stations that meet on a specified frequency at a certain time. The net is organized and directed by a net control station, who calls the net to order, recognizes stations entering and leaving the net, and authorizes stations to transmit.

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

NODE - A remotely controlled TNC/digipeater - used as a connect point in packet radio.

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

NTS - National Traffic System - an amateur radio relay system for passing messages.

NTSC - National Television System Committee (NOT National Television Standards Committee) - USA and others TV Standards.

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" (See Skip Zone)

AMATEUR RADIO GLOSSARY JARGON, ABBREVIATIONS AND TERMINOLOGY

AMATEUR RADIO GLOSSARY
JARGON, ABBREVIATIONS AND TERMINOLOGY