The late 19th and early 20th centuries were times of rapid growth in science and technology and a fascinated public eagerly absorbed every new announcement and discovery. Many sought to experiment and duplicate the works of inventors and scientists of the day, perhaps hoping to find riches in some new invention of their own. Home shops and chemistry labs were common place and it seemed everyone was dabbling in the new technologies in one way or another. One of those technologies that captured the imagination of many was the idea of wireless communication. Experimenters with "wireless" became the first Amateurs as they, like Marconi (who claimed himself to be an Amateur), worked to improve the sensitivity and range of their home built stations. There were no laws governing the transmission of signals in the earliest days. (As wireless communication, knowing no borders, quickly evolved into chaos it soon became evident that both National and International regulations would be necessary.)

Amateur radio, like other technological endeavors has it's share of terminology, acronyms, and slang. It draws from a rich heritage and long history; a history longer than wireless communication itself. Many of the terms and procedures used today date back to pre-wireless days, being adopted from land line telegraph practice and carried over by telegraph operators dabbling in Amateur Radio; after all, it was wireless telegraphy then.
 

SOME COMMON TERMS

AM: Amplitude Modulation. Intelligence (audio, video, data, etc.) is impressed on a carrier (radio signal) for transmission by varying the carrier's amplitude. The modulating process actually causes the intelligence to be contained in mirror image "sidebands" which reside just to either side of the carrier. This method is used by AM broadcast stations and aircraft two-way radio. It was the earliest form of wireless voice transmission. An AM voice signal typically occupies about 6 KHz of radio spectrum.

American Morse Code: See Code.

ARES: Amateur Radio Emergency Service. Founded in 1935 by, and operating under the auspices of, the ARRL, the ARES is a national organization of volunteer amateur radio operators who provided their services to serve the public, particularly during emergencies.

ARRL: The American Radio Relay League. Founded in 1914 by Hiram Percy Maxim (of Maxim automobile and silencer fame) the "League" is a non-profit national organization of Radio Amateurs. Maxim felt a need for a national organization to represent Amateurs in those turbulent times. With the then limited range of amateur stations Maxim thought the organization of a radio relay network of amateur stations which could "relay" messages from one amateur station to another, greatly extending their effective communication range, would be a good rallying point around which to form such an organization, hence, the name. (It's still the only national organization we have representing us, especially in Washington D.C.)

Base Station: Amateur slang term borrowed from the commercial radio services. The FCC defines a Base Station as a station licensed in a mobile radio service operating from a fixed location. Since the Amateur Service is not a "mobile radio service" (though it permits  mobile operation) there is no such thing as a "base station" in amateur radio. The term is used as a euphemism for Fixed Station and seems to be in common use on VHF phone.

Break: A procedure signal used to interrupt or break into an existing conversation or to tell another station to go ahead, as in "over". Also used in traffic handling as a separator between major portions of formal traffic such as between the address, message text, and signature. On land line telegraph break meant to interrupt a sending operator.

Break-in: CW station operation in which the sending station can hear received signals between the dots and dashes he is sending. Also called "QSK" (see Q-Signals).

Cavity: Special filter which is essentially a short, resonant, very low loss transmission line inside of a closed cylindrical container. It is most commonly used as a filter at the input and output of a repeater to allow the use of a common antenna and feed line for both receive and transmit. Usually assembled in groups of four to six and collectively called a duplexer.

Channel: Amateur slang term borrowed from other radio services. Euphemism for frequency. Most radio services operate on specific frequencies designated by the FCC that are often called channels.  The most familiar are probably TV channels and Class D C.B. channels (11 meters). These frequencies must be held to within tight tolerances. For example Class D transmitters must be within 0.005% of the designated channel frequency; AM broadcast stations must remain within + or - 20 cycles per second of their designated frequency. The purpose is to insure proper station operation (particularly with users having no technical knowledge) and to minimize interference between users.

Amateur Radio has no designated channel frequencies but rather has designated frequency bands. The Amateur is expected to have sufficient knowledge and skill to limit emissions to within those specified band limits and may use any frequency between the limits consistent with permissions of the Rules and Regulations. It is for this reason that Amateur Radio has the most efficient utilization of frequency spectrum of all the radio services.

The VHF amateur bands have been "channelized" to a degree by the Voluntary Band Plans which recommend specific frequencies for FM and FM repeater use.

Code: In amateur radio "code" generally refers to the International Morse Code. Adopted world wide in the early 1900's for all commercial international communication, amateurs too adopted its use. There are many other versions of the Morse Code such as the American Morse Code (used extensively on American land line telegraph circuits and by early American wireless stations) and the Continental Code (used extensively on European land line telegraph circuits) which is nearly identical to, and the basis from which, the International Morse Code was developed. The American Morse Code is legal on the Amateur bands but stations must identify using the International Morse Code. (Morse purists argue that there is only one Morse Code and that the others should not be called "Morse" codes at all!)

The term code is sometimes used to refer to codes used in digital modes such as ASCII (American Standard Code for Information Interchange) or Baudot (a five level code used for some radio teletype operation). It can also refer to computer programming "code".

Continental Morse Code: See Code.

Copy: As a noun: Written or recorded communication sent by another station such as traffic which has been received and written down.

As a verb: Hearing or understanding what is being sent.

Used routinely on CW the term is also quite convenient on phone and is less formal than a Q-Signal. Common usage would be: "do you copy?", "how copy?", or simply "copy?" when inquiring as to how well one's signal was being received. This term is often misused on phone by those that do not clearly understand its meaning. Experienced operators in-the-know cringe when they hear some one say "do you have a copy?" and their minds cannot help but wonder: "a copy of what?".

Crossband: Operating by transmitting on one band and listening on another.

CW: Abbreviation for Continuous Wave. Often also used to designate operation using the International Morse Code. Before the invention of the vacuum tube high frequency signals could only be generated as damped waves. An oscillatory circuit (tuned antenna circuit) was excited by a spark repeatedly discharging a capacitor into the oscillatory circuit setting up an oscillation that was radiated by the antenna. The oscillation quickly dampened as the energy was radiated requiring a rapid continuous succession of sparks to keep the semblance of a continuous signal.  These spark discharges occurred at a rate of tens to hundreds of times per second creating a continuous string of damped waves which were turned on and off by a telegraph key. They also made it easier to hear the signals with the simple receivers of the time by, in effect, producing audible modulation, however bad it might have sounded! With the invention of the vacuum tube it became possible to create a truly continuous wave of constant amplitude. It was far more efficient and amateurs quickly adopted continuous waves as fast as they could afford the then expensive short lived vacuum tubes. Spark transmission was eventually banned in all radio services. A high speed CW signal can occupy up to 0.1 KHz of radio spectrum, slower code occupies proportionately less.

Decibel: One tenth of a Bel, the Bel being a relative comparison of sound levels on a logarithmic scale named after Alexander Graham Bell of telephone fame and, coincidentally, named by himself. While the Bel is seldom if ever used, the decibel is used extensively in electronics to compare the relative magnitudes of two or more signal levels (such as voltages, currents, powers, etc.) without having to compare actual signal values. Amplifier gain is often specified in dB and antenna gain is virtually always specified in such. Because the decibel is calculated using a logarithm it easily covers a very large range. 60dB for example represents a voltage or current ratio of 1,000 to 1 or a power ratio of 1,000,000 to 1. There are some commonly heard and used values that are quite useful. 3dB represents a voltage or current ratio of 0.707 or 1.414 and a power ratio of 2 or 1/2. If an antenna feed line has a 3dB loss it means only half the transmit power put into it will appear at the antenna end. Likewise, only half the signal power intercepted by the antenna will reach the receiver. Some other useful values are 6dB = 1/2 or 2 times voltage or current and 1/4 or 4 times power; 10dB = 1/10 or 10 times power; and 20 dB = 10 times or 1/10 voltage or current and 100 or 1/100 times power.

Diplex: The simultaneous reception or transmission of two signals over a single feed line or antenna. The term diplexer is often applied to the small VHF/UHF "signal splitters" used to connect two radios for different bands to a single feed line/multiband antenna. During W.W.II the term was applied to special filters that allowed up to several radios on different frequencies to share an antenna. The term originated in the 1800s when inventors found a way to simultaneously send or receive two messages over a single telegraph wire. It's development  preceded Duplex operation.

Diplexer: See Diplex.

Duplex: Means simultaneous transmission and reception. In radio the transmitting and receiving frequencies must be different or the station operating duplex would only "hear" itself. Repeaters operate duplex, repeater users do NOT. While repeater users do transmit and receive on two different frequencies (the frequency separation between receive and transmit is called the "offset"), they do not do it simultaneously. In the commercial two-way radio business this is called half duplex. The term "duplex" originated during the 1800s when inventors found a way to simultaneously send and receive two different telegraph messages over a single wire at the same time. In fact, the telegraphers are still one up on radio. They went on to develop Quadraplex (effectively the combination of Diplex and Duplex operation) which allowed the simultaneous transmission and/or reception of two messages at the same time over a single wire, effectively doubling the line capacity of a single wire.

Duplex Operation: A radio station, using a separate receiver and transmitter, operating by simultaneously transmitting on one band while receiving on another. (This type of operation on the amateur bands is limited by FCC regulation.) A common mode for stations operating on the amateur radio satellites.

Duplexer: A special filter, usually made up of four or more resonant cavities, which allow a repeater transmitter and receiver to share a common feed line and antenna. Extensively used by amateur and commercial repeaters.

DSB: Double Sideband. A form of amplitude modulation in which the carrier is suppressed and only the sidebands are transmitted. It requires the same spectrum space as conventional AM but eliminates heterodynes and is much more power efficient. To be received properly it requires a special detector. It can be tuned with a single sideband receiver as an SSB signal would be tuned because the receiver filters out one sideband turning it into an SSB signal before detection. However this "wastes" the power in one sideband effectively halving the transmitter power.

FM: Frequency Modulation. Intelligence (audio) is impressed on a carrier for transmission by shifting its frequency. This mode is used by FM broadcast stations, television sound, public safety radios, business radios, Amateurs, and others. An FM broadcast station occupies 200 KHz and TV sound 90 KHz of radio spectrum. See NBFM.

Fixed Station: The FCC defines a fixed station as a station installed at a fixed, or particular, location. The most common type of amateur station.

Formal Traffic: See "Traffic".

Frequency: The frequency of an alternating current is the number of cycles completed by the alternating current in one second.

Full Break-in: Term sometimes used to distinguish between a station operating "break-in" and a station operating  "Semi Break-in". See "Break-in".

Gain: In relation to antennas it refers to the signal strength advantage a given antenna has over a standard reference antenna such as a dipole or the theoretical "isotropic radiator". Antenna gain increases received signal strength as well as transmitted signal strength. In general, the gain figures quoted by manufactures for their antennas are half truths, deceptions, and out right lies. Never buy an antenna on the strength of advertised gain.

Gain is also an expression for the amplification which takes place in an amplifier. It may be expressed as a multiple of the input or expressed in decibels.

HF: High Frequency (band). Frequencies between 3.0 and 30 MHz.

ID: Identify. Station identification.

Informal Traffic: Messages handled informally on behalf of others without the benefit of a preamble. See "Traffic".

Land Line: Slang for telephone.

International Morse Code: See Code.

LF: Low Frequency (band). Frequencies between 30 KHz and 300 KHz.

MAYDAY: 'Phone distress call. Derived from the French m'aider (help me). This call is internationally used in all radio services. For CW see SOS.

Meter: Standard metric unit of length. Approximately 39.4 inches or 3 1/3 feet; a bit over a yard.

In the early days of wireless before accurate frequency measurement and control were available signal wavelengths were used extensively and frequency was never mentioned. With the advent of much more precise crystal frequency control the use of frequency  rather than wavelength became common place and the use of wavelength was relegated to identifying frequency bands by their nominal wavelength which it still does quite conveniently today.

This is probably one of the most mispronounced terms heard on VHF. One frequently hears expressions like "2 meter", "10 meter", "11 meter", etc. when referring to amateur bands. Given that the expression actually refers to an amateur band by designating the nominal wavelength of signals on the band, clearly, when the wave length is greater than one meter the term is plural and an "s" must be affixed such as "2 meters", "10 meters", etc.,. Anything less is just plain bad English and demonstrates that the user simply doesn't understand the true meaning or origin of the term. The exception, of course, is when the term "meter" is used as an adjective where it carries the tense of the noun it modifies such as 2 meter beam or 10 meter transmitter. The next time you hear someone say "2 meter" will you be able to avoid thinking "2 meter what?"?

Also an indicating device such as voltmeter, ohmmeter, S-meter, etc.

MF: Medium Frequency (band). Frequencies between 300 KHz and 3.0 Mhz. The 160 meter band (1.8 to 2.0 Mhz) is an MF band though we usually think of it, and refer to it, as an HF band.

Mic.: Abbreviation for microphone.

Mike: Microphone.

Microwaves: Technically, frequencies between 225 MHz and 100 GHz. The frequency range is divided into bands with letter designations such as the "L", "S", and "X" bands. Amateurs have frequency assignments in some of these bands such as the L and S bands which are being used by Amateur satellites. The letter band designations are considered unofficial (not international) and were likely assigned during or before W.W.II with the development of radar which first utilized such high frequencies. Amateurs frequently refer to frequencies between the 225 Mhz and 1000 MHz as UHF and those above 1000 MHz as "microwaves".

Mobile: An amateur station designed and/or capable of being operated while in motion. Note that this type of station would include not only the ubiquitous radio-in-a-vehicle but also the hand held radio or walkie-talkie. The FCC no longer requires the identification of mobiles as such, however, when it serves a purpose, amateurs sometimes attach unofficial designators to their call sign such as "aeronautical mobile", "balloon mobile", "train mobile", etc. There is one, sometimes misused, "official" designator: MM, for Maritime Mobile (sometimes phonetically pronounced "mickey mouse"). A maritime station is defined as a station outside of country territorial limits and is used by amateur stations operating on the high seas. Note that this is not simply a boat on the water. Mobiles on rivers, lakes, and the Great Lakes are NOT Maritime Mobiles. If desired, one could attach an unofficial designator such as "marine mobile" if it would have some significance to the person or persons being communicated with.

Mode: Type of signal or modulation being used. Permissible modes for the amateur service are defined by the FCC in Part 97 of the FCC rules and regulations for the Amateur Service. Common modes are CW (designated A1), AM (designated A3), and Single Sideband (designated A3J). There are many others. Amateurs have great flexibility in choice of modes and new ones are still being added.

Morse Code: Though a few changes were made early on, as known today it is essentially the code proposed and used by Samuel Morse when he developed the telegraph. While the International Morse Code long ago replaced the "American Morse Code" on the amateur bands the code can still be legally used as long as stations identify using the International Code. There used to be a few operators on the air using the American Morse Code; there could still be.

NBFM: Narrow Band Frequency Modulation. A narrow bandwidth form of FM used by Amateurs and nearly all FM two way radio services. An NBFM signal typically occupies 15 KHz of radio spectrum.

"Personal": CB slang for "name". Not used in Amateur radio but occasionally heard from newcomers.

'Phone: Voice operation. A contraction of "telephone" adopted when amateurs started experimenting with voice transmissions in the early 1900's to distinguish such from CW operation.

Phonetic (alphabet): A standardized list of words, each starting with a different letter of the alphabet. Phonetics were intended for use during periods of difficult copy on Phone were it was felt that spelling out traffic using standardized readily recognized words would be more effective than trying to receive less familiar words that might be in a message. There are a number of phonetic alphabets. The amateur fraternity uses the ICAO alphabet, the same one used by pilots and the military. Example: A=Alpha, B=Bravo, C=Charlie,...X=Xray, Y=Yankee, Z=Zulu. The phonetic alphabet is never used on CW. It has found much use on phone where the low audio quality of phone leads to many letters, and even words, being difficult to communicate, especially in call signs and formal message handling. For example, the letters B, C, D, E, G, P, T, V, and Z all sound about the same when pronounced on phone. Using phonetics the call sign N8LT might be articulated as November 8 Lima Tango. Sometimes other "non official" phonetics are used with call signs: because they seem to work better under difficult conditions (such as November 8 London Tokyo); when the operator cannot remember the correct phonetics; or just to be cute like a pilot with the call W8HFH who might use W8 High Flying Ham. (Which, incidentally, may not satisfy the FCC for identification purposes.)

Portable (station): FCC definition of a fixed station operating at a location other that the one indicated on its station license.

This is perhaps the most misused term heard on VHF. Note that the term "portable" when affixed to the end of a call sign does NOT refer to the type of radio being used but to the type of station being operated. A portable station can weigh several tons, require mains power, and use a giant antenna structure. A hand held radio is NOT a portable station unless it cannot be operated while in motion such as when it is attached to a permanently mounted antenna, operated form an external power supply, or both. Otherwise it's a mobile station.

The FCC no longer requires identification of portable amateur stations as such however the practice is still in common usage and serves to inform other stations that the transmitting station is not operating from its assigned location on the station license. On voice the word portable is added after the call sign followed by the call area in which the station is located if that call area is other than the one in the call sign. Thus a portable station from Michigan operating in Wisconsin, Indiana, or Illinois might identify as N8LT portable 9. In non voice modes the call sign would be given as N8LT/9. (That's a fractional bar not a "slash".)

Procedure Signal: A special code character, group of characters, (or on phone, word) used to represent a complete thought. On phone "Clear" is a procedure signal or proword. Procedure signals expedite communications and reduce errors and misunderstandings.

Prosign: Procedure signal used on CW. Often used prosigns on CW include signs for end of message, end of transmission, break, from, go ahead designated station only, and invitation to transmit (go ahead anybody).

Proword: Procedure signal (word) used on phone; the voice equivalent of a prosign.

Push-To-Talk (PTT): Radio system that requires the pressing and holding of a spring loaded button, lever, or switch to place a radio in transmit; the release of which causes the radio to return to the receive mode. The most common example is the push-to-talk microphone supplied with every radio which allows push-to-talk operation.

When a push-to-talk microphone is placed on the seat of a vehicle it will activate by wedging itself between the seats, between the seat and back rest, or between the seat and someone's backside. This leads to embarrassing broadcasts of conversations in the car.

A Q-signal immediately followed by a question mark becomes a query rather than a declaration. For example, QSL means "I confirm receipt of your message" but QSL? means "do you confirm receipt of my message?". QSL is probably the most abused Q signal used. Note that it does NOT mean yes, I agree, you are correct, affirmative, or any other such thing. It's use should be reserved for message and information handling.

While developed specifically for morse code use, some Q-signals are convenient in phone operation and have crept into use. Also, some Q signals are sometimes used in conversation with more loosely defined meanings than the formal ones, for example:

QRM: Interference from another radio station.
QRN: Natural interference such as static from atmospherics and electrical equipment.
QRO: High power operation.
QROp: Low power operation greater than 5 watts output.
QRP: Low power operation, usually 5 watts output or less. (10 watts input or less in the old days.)
QRPp: Very low power operation.
QRT: Sometimes used on phone to indicate an operator is going to shut down his station. On CW, CL (for closing station) is also used.
QSL: As a verb: Referring to the process of sending and receiving written confirmation of a contact via QSL Card. As a noun: A QSL card.
QSO: A contact or conversation with another station.

"Radio Check": CB term not used in Amateur radio.

Radio Teletype (RTTY): The practice of linking teletype machines by radio rather than telegraph lines to provide low cost flexible long distance communications. This method of communication was extensively used by the military, government, news services, and, of course, Radio Amateurs. In fact it's still popular today though the clanking, rumbling, shaking, oil throwing teletype machine has largely given way to the soft whir of a computer hard drive and glare of the proverbial "glass eye". (And taken a lot of the fun out of it too.)

"Reading the Mail": Slang. Listening to Amateur communications without being a participant.

Receiver: Selects, demodulates, and amplifies transmitted signals. Also a telegraph instrument.

Relay: As a verb: An operator passing on or relaying a message received from one station, to another (as used in the name of the ARRL, the American Radio RELAY League). As a noun: An electromechanical telegraph instrument used to "relay" telegraph line signals to local telegraph instruments. Today, an electromechanical switch of many different forms used in numerous electrical and electronic applications.

Repeater: A station designed to automatically re-transmit signals received on its input frequency. Repeaters are usually placed in highly advantageous locations such as hill and mountain tops with very high antennas, low loss feed lines, large gain antennas, and significant power output, in short, locations which give them the greatest possible range. Though the primary purpose is to extend the range of mobiles by, in effect, giving the mobile station the receive and transmit capabilities of the repeater, it does the same for any station using it, and thus can greatly extends the range of any VHF station with a lesser installation.

The term "repeater" was first used for a telegraph instrument  invented to extend the practical 200 to 300 mile limit of the typical telegraph line by automatically "repeating" the signals into the start of another line. Repeater circuits were developed that could repeat signals in both directions between two lines just as radio repeaters repeat both ends or directions of contacts today.

Roger (R): Phonetic for Received. A procedure signal. In effect, I have received your last transmission.  On CW it is simply the letter R. It does NOT mean yes; I agree; you're right; affirmative; or any other such thing. Informal equivalent to QSL. (In contests one often hears CW stations sending QSL to confirm receipt of contest exchange information; which is nuts when you consider "QSL" is 10 times more work to sent than the much faster "R". Imagine sending "QSL" a few hundred or thousand times! Then, many phone operators do the same thing. "Que-ess-el" or "roger"? You decide.

RTTY: See Radio Teletype.

S-Meter: Signal strength meter. A meter in receivers (and transceivers) which indicates relative signal strength of received signals. Increasingly, the "meter" is becoming a bar graph in the display (unfortunately). S-meters are typically calibrated from 0 (sometimes 1) to 9 and above 9 in dB to 50 or 60 at full scale. The digits from 0 to 9 are called "S-units". This is a takeoff from the pre-meter days when signal strength reports were based on the judgment of the radio operator and were rated on a scale of S-1 to S-9 (still used on CW), S-1 being barely perceptible and S-9 meaning extremely strong. The calibrations above S-9 are in decibels above S-9. Years ago most manufacturers  calibrated their S-meters so that S-9 represented a signal strength of 50 or 100 microvolts at the receiver antenna terminals. Since receiver sensitivity tends to vary from band to band this was an approximation at best. "S" meters have always been notoriously inaccurate, especially in solid state equipment where manufactures have given up all pretense of meaningful readings. The only thing you can be sure of today is that a higher reading means a stronger signal. Don't even attempt to compare S-meter readings between two different radios! the S-meters in FM radios are nearly useless (partly due to the nature of FM receivers) working over only a small portion of the received signal strength range.

S-meters began to appear after the adoption of the superhetrodyne receiver and the incorporation of automatic volume control. By the end of W.W.II they were standard equipment on all but the least expensive shortwave receivers.

Shack: Location of an amateur radio station. Today it may literally be a "shack",  closet, or space in a basement, living room, or corner of a bedroom (quite common). The term dates from the very early days of radio when those that could afford it built a small shack in the back yard to house their often large (many pieces of equipment), noisy (crackling spark gaps and sometimes whining motors and generators), smelly (ozone from the arcing spark gap and sparking motor/generator brushes), dangerous (very high voltages on fully exposed wiring and equipment), sloppy (chemical rectifiers that routinely boiled over and batteries containing spillable acid which generated explosive gases while being recharged), amateur station. Perhaps, for some, the house was never an option.

SHF: Super High Frequency. Frequencies between 3GHz and 30 GHz (1 GHz = 1000 MHz.).

"Slash": Computereze slang for the fractional bar. Evidently invented by computer people who didn't know what the symbol was properly called.

SOS (with a bar over the letters): Some times claimed to stand for "Save Our Ship" or "Sink Or Swim" it is in reality an unfortunate misunderstanding of the CW distress signal. Like other CW prosigns the distress call has no printed character equivalent. To describe such code characters in print they are often shown as a combination of letters with a bar above them meaning "sounds like the group of barred letters run together". The letters SOS where chosen to illustrate the sound of the code distress signal, however, other letter groups such as VMS, IWB, VGI, SMB, IJS, or even STMS (all letter groups with bars over them) would have been just as valid. Tragically, this misunderstanding is so universal that a properly sent distress signal on CW would likely have a far poorer chance of being understood than the improper use of the letters SOS!

SSB: Single Sideband. A form of amplitude modulation in which the carrier and "other" sideband are suppressed. It's more efficient than AM, occupies only 1/2 the spectrum space, and eliminates the potential of annoying heterodynes on crowded bands. On the other hand, transmitters are more costly, receivers more complex, and precise tuning is required. First used by the telephone on long distance telephone circuits. An SSB signal typically occupies about 2.5 KHz of radio spectrum.

SWR: Standing Wave Ratio. When a transmission line is terminated in an impedance other than one equal to its characteristic impedance a variation in current and voltage develops along the length of the line. If the values of current or voltage were plotted on a graph they would form a line resembling a wave.  The voltage standing wave (VSWR) is the ratio of the maximum voltage on the transmission line to the minimum voltage on the line. Likewise the current standing wave ratio (ISWR) is the ratio of the maximum current in the line to the minimum current in the line. The VSWR and ISWR are equal so there is usually little need to specify which is being measured. The SWR is also equal to the ratio of the load impedance being fed by the line and the line's characteristic impedance. Thus a 50 ohm coaxial cable with a 2:1 SWR would be terminated in either a 100 ohm or 25 ohm load. Since the lowest possible SWR is 1:1 the ratio is obtained by dividing the highest number by the lowest number. A transmission line with a 1:1 SWR is called a flat line since the voltage and current are uniform over the length of the line and there are no maximums or minimums. Standing waves cause increased transmission line losses. Standing waves at VHF frequencies mean inefficiency and lost signals. VHF feed lines should always be 1:1.

    When working with antennas SWR is sometimes called the "swear" ratio.

Teletype (TTY): A teletype machine. Electromechanical keyboard/printer invented in the '20s to speed up the sending of messages by wire which were normally hand sent and received by telegraphers, typically using typewriters.

Traffic: Message(s) handled primarily on behalf of others. Especially Formal traffic meaning messages with a Preamble and "signature" or name of the sender.

Transceiver: Receiver and transmitter combined into a single unit. Technically to be a transceiver the transmitter and receiver must share a significant amount signal handling circuitry, not just an enclosure or power supply in which case it would more appropriately be called a receiver-transmitter. The line between the two is a gray one and Amateurs generally call any equipment with a receiver and transmitter in the same box a "transceiver". The term is also used for semiconductor devices designed to send and receive digital data over a line or cable. The term dates back at least to W.W.II.

Transmitter: Equipment to generate and amplify radio signals for transmission. Also a telegraph instrument which was used to send signals down a telegraph line which were originated by telegraph key on local circuits. Also name used for the telephone's microphone.

Twisted Pair: Telephone line. In ancient times indoor telephone wiring cable consisted of a pair of wires twisted together.

UHF: Ultra High Frequency. The band of frequencies between 300 and 3000 MHz.

VHF: Very High Frequency (band). The frequencies between 30 and 300 MHz.

VOX: Voice Operated Relay or Transmit. Radio automatically switches into the transmit mode when someone speaks into the transmitter microphone and switches back to receive when they stop. To work properly VOX must be properly adjusted, the user must develop certain speaking skills, and good microphone technique must be used. When used with a stand mounted microphone VOX can be very convenient, especially for net and traffic handling, since it leaves both hands free.

Left turned on and unattended VOX will also automatically transmit the sounds of barking dogs, screaming kids, hammers, saws, private conversations, etc. Always turn VOX off when leaving the rig, even if it's for only a moment, or when using the telephone or talking to someone that's present.

Wavelength: The distance in meters a radiated wave travels during the time required to complete one cycle. The speed of a radio wave can be taken as 300,000,000 meters (or 186,284 miles) per second (regardless of the frequency). The wavelength of a signal in meters is equal to 300 divided by the signals frequency in megahertz.

Work: Most commonly, meaning to contact another station. For example, if you were to successfully communicate with W1AW you might say you "worked" W1AW. Or you could also say you worked Connecticut (where the station is located), or even ARRL headquarters since W1AW is the ARRL headquarters station located in Newington, Connecticut.

Xmit: Transmit.

Xmitter: Transmitter.

73: A friendly informal signal between operators first used by land line telegraphers in the 1800s. It lives on in regular use today by amateurs on CW, phone, and other modes. It means "best regards". Unfortunately many phone operators often improperly pronounce it as seventy-threes (i.e., best regardses (the word "regards is plural", no "s" should be added). Or maybe they actually mean 3 3 3...64 more threes...3 3 3 = 70); or perhaps seven threes (i.e., 3 3 3 3 3 3 3) rather than the proper seventy-three, with no "s"?

The operating procedures used in amateur radio have much more in common with other radio services than most amateurs realize. There are many more terms in common usage, in addition to those listed above, that originated outside amateur radio. Amateur radio world wide has collectively adopted, modified (where necessary), and developed terms and procedures that serve it efficiently. Not to mimic others or to stand out from them but to facilitate efficient and effective world wide Amateur communication despite language and other barriers.

This list of terms is provided for information and amusement and is not necessarily a recommendation for their particular use. (Especially the slang.)