Q code

From Wikipedia, the free encyclopedia

The Q code is a standardized collection of three-letter message encodings, all starting with the letter "Q", initially developed for commercial radiotelegraph communication, and later adopted by other radio services, especially amateur radio. Although Q codes were created when radio used Morse code exclusively, they continued to be employed after the introduction of voice transmissions. To avoid confusion, transmitter call signs have often been limited to restrict ones starting with "Q" or having an embedded three-letter Q sequence. The codes in the range QAA-QNZ are reserved for aeronautical use; QOA-QOZ for maritime use, and QRA-QUZ for all services.

Contents

[edit] Early developments

The original Q codes were created, circa 1909, by the British government as a "list of abbreviations... prepared for the use of British ships and coast stations licensed by the Postmaster-General". The Q codes facilitated communication between maritime radio operators speaking different languages, so they were soon adopted internationally. A total of forty-five Q codes appeared in the "List of Abbreviations to be used in Radio Communications", which was included in the Service Regulations affixed to the Third International Radiotelegraph Convention. (This Convention, which met in London, was signed on July 5, 1912, and became effective July 1, 1913.)

The following table reviews a sample of the all-services Q codes adopted by the 1912 Convention:

First Twelve Q Codes Listed in the 1912 International Radiotelegraph Convention Regulations

Abbre-
viation.		 Question. Answer or Notice.
QRA What ship or coast station is that? This is ____.
QRB What is your distance? My distance is ____.
QRC What is your true bearing? My true bearing is ____ degrees.
QRD Where are you bound for? I am bound for ____.
QRF Where are you bound from? I am bound from ____.
QRG What line do you belong to? I belong to the ____ Line.
QRH What is your wave length in meters? My wave length is ____ meters.
QRJ How many words have you to send? I have ____ words to send.
QRK How do you receive me? I am receiving well.
QRL Are you receiving badly? Shall I send 20 ...-. for adjustment? I am receiving badly. Send 20 ...-. for adjustment.
QRM Are you being interfered with? I am being interfered with.
QRN Are the atmospherics strong? Atmospherics are very strong.

[edit] Later usage

Over the years, modifications were made to the original Q codes to reflect changes in radio practice. In the original international list, QSW/QSX stood for "Shall I increase/decrease my spark frequency?", however, spark-gap transmitters were banned in the United States in the 1920s, rendering the original meaning of those Q codes obsolete. Other Q codes have been introduced, especially those for amateur radio usage.

Some Q codes are also used in aviation, in particular QNH and QFE, referring to certain altimeter settings. These codes are used in radio conversations with air traffic control as unambiguous shorthand, where safety and efficiency are of vital importance. A subset of Q codes is used by Dade County, Florida law enforcement, one of the few instances where Q codes are used in ground voice communication.

Many military and other organizations that use Morse code have adopted additional codes, including the Z code used by most European and NATO countries. The Z code adds commands and questions adapted for military radio transmissions. For example, "ZBW 2" — change to backup frequency number 2 — or "ZNB abc" — my checksum is abc, what is yours? In most military Morse code transmissions, freeform text is strictly forbidden, and all communication must be accomplished using three-letter abbreviations, the Q and Z code.

Used in their formal "question/answer" sense, the meaning of a Q code varies depending on whether or not the individual Q code is sent as a question or an answer. For example, the message "QRP?" means "Shall I decrease transmitter power?", and a reply of "QRP" means "Yes, decrease your transmitter power". This structured use of Q codes is fairly rare and now mainly limited to amateur radio and military morse code (CW) traffic networks.

[edit] Amateur radio

Selected Q codes were soon adopted by amateur radio operators. In December, 1915 the American Radio Relay League began publication of a magazine titled QST, named after the Q code for "General call to all stations". In amateur radio, the Q codes were originally used in Morse Code transmissions to shorten lengthy phrases and were followed by a Morse code question mark (– – ––– ––– – – ) if the phrase was a question. In voice communications, the Q code is commonly used as shorthand nouns, verbs and adjectives making up phrases. For example, an amateur radio operator will complain about QRM (man-made interference), or tell another operator that there is "QSB on the signal"; "to QSY" is to change your operating frequency.

The following table gives the most common Q codes used in amateur radio:

Q Codes Commonly Used by Radio Amateurs

Code Meaning Sample use
QRG Exact frequency He's TX on a QRG of 14205 kHz
QRI Tone (T in the RST code) Your QRI is 9
QRK Intelligibility (R in the RST code) Your QRK is 5
QRL This frequency is busy. Used almost exclusively with Morse code, usually before transmitting on a new frequency
QRM Man-made interference There's another QSO up 2 kHz that's causing a lot of QRM
QRN Natural interference, e.g. static crashes The band is noisy today; There's a lot of QRN
QRO Increase power I need to QRO when propagation is poor.
QRP decrease power QRP 5 watts
QRQ increase speed Please send faster (opposite of QRS).
QRR temporarily unavailable/away, please wait I will be QRR 30 minutes./That station is QRR now.
QRRR Distress Distress call recommended by ARRL
QRS Send slower Please QRS, I'm new to Morse code
QRT Stop sending I've enjoyed talking to you, but I have to QRT for dinner now
QRV I am ready Will you be QRV in the upcoming contest?
QRX will call you again QRX @ 1500h
QRZ You are being called by ________. QRZ? You're very weak. (Only someone who has previously called should reply)
QSA Signal strength Your QSA is 5
QSB Fading of signal There's QSB on your signal
QSD Your keying is defective You are QSD, check your transmitter
QSK Break-in I can hear you during my transmission, you may QSK
QSL I Acknowledge receipt QSL your last transmission. Please QSL via the bureau (i.e. please send me a card confirming this contact).
QSM Repeat last message QRM drowned your last message out - please QSM
QSO A conversation Thanks very much for the QSO (Morse abbreviation: TNX QSO 73)
QSP Relay Please QSP this message to my friend
QST General call to all stations QST: Frequency allocations have changed
QSX I am listening on ... frequency I QSX 14200 to 14210 kilohertz
QSY Shift to transmit on ... Let's QSY up 5 kilohertz
QTA Disregard last message QTA, I didn't mean that
QTC Traffic Please stand by for the DX bulletin
QTH Location My QTH is South Park, Colorado
QTR Exact time QTR is 2000 Z

Some of these common usages vary somewhat from their formal, official sense. There are also a few unofficial and humorous codes in use, such as QLF ("try sending with your LEFT foot") and QSC ("send cigarettes", not the official meaning of "this is a cargo vessel"). In the question form, QNB?, is supposed to mean "How many buttons does your radio have?" A reply of the form QNB 45/15 means "45, and I know what 15 of them do." QRK is sometimes used to refer to the cost of something - "I would like an FT9000 but it is too much QRK".

QSK - "I can hear you during my transmission" - refers to a particular mode of morse code operating in which the receiver is enabled during the spaces between dots while transmitting. Some transceivers incorporate this function, sometimes referred to as full break-in as against semi-break-in in which there is a short delay before the transceiver goes to receive.

Some ham operators within the USA, particularly those travelling long distances, will monitor the National 2-meter FM calling frequency of 146.520 MHz while in their vehicles. If you see a vehicle on the road with a bumper-sticker, license plate or other sign that says QRZ 52? and a few extra antennas, that is what's happening. The reason QRZ is used instead of the more correct QSX is that QSX is not normally used in voice communications while QRZ is used extensively.

[edit] Aviation

Although the majority of the Q codes have slipped out of common use, several remain part of the standard ICAO radiotelephony phraseology in aviation.

[edit] Altimeter Setting

QNH 
sea level air pressure
QFE 
air pressure at airfield elevation
QSL 
used to verify time when communicating with TSC

e.g.

"Runway in use 22 lefthand, QFE 990 millibars."

"Request QNH"

[edit] Direction Finding

QDM 
Magnetic heading TO a station
QDR 
Magnetic heading FROM a station
QUJ 
True bearing TO a station
QTE 
True bearing FROM a station
QFU 
The Runway in use

e.g.

"QDM QDM QDM (callsign) request QDM"

"Runway 22 in use, QFU 22"

[edit] Radio Procedures

QSY 
To freecall another frequency. (This is not an official part of the standard phraseology any more but is still regularly heard)

[edit] External links

Retrieved from "http://en.wikipedia.org../../../q/_/c/Q_code.html"