The Q code

The Q code is a standardised 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. 

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: 

  • QRA: What is the name of your station?
  • QRB: What is your distance from my station?
  • QRG: What is my exact frequency?
  • QRH: Does my frequency vary?
  • QRI: How is the tone of my transmission? (1 = good, 2 = variable, 3 = bad)
  • QRJ Are you receiving me badly? I cannot receive you.
  • QRK How do you read my signals? (1 = bad, 5 = Excellent)
  • QRL Are you (this frequency) busy?
  • QRM Is my transmission interfered with? (1 = Nil, 5 = Extremely)
  • QRN Are you troubled by statics? (1 = Nil, 5 = Extremely)
  • QRO Shall I increase transmitter power?
  • QRP Shall I decrease transmitter power?
  • QRQ Shall I send faster? (... WPM)
  • QRR Are you ready for automatic operation?
  • QRS Shall I send more slowly? (... WPM)
  • QRT Shall I stop transmission?
  • QRU Do you have more for me? I don't have more for you.
  • QRV Are you ready?
  • QRW Shall I inform ... that you are calling him on ... kHz?
  • QRX When will you call me again? I will call you again in ... minutes/hours.
  • QRY What is my turn?
  • QRZ Who are calling me?
  • QSA What is the strength of my singals? (1 = poor, 5 = very good)
  • QSB Are my signals fading?
  • QSD Is my keying defective?
  • QSK Can I break in between your signals in your transmission?
  • QSL Can you confirm the contact with a receipt?
  • QSO Can you communicate with ... directly or by relay?
  • QSP Will you relay to...?
  • QSV Shall I transmit a series of V's on this frequency?
  • QSX Will you listen to ... on ... kHz?
  • QSY Shall I change to transmission on another frequency? (...kHz)
  • QSZ Shall I send each word more then once?
  • QTC How many messages have you to send?
  • QTH What is your position?
  • QTR What is the correct time?