Q–Codes have been around since around the beginning of the 20th century and consist of 3 letters, starting, surprisingly enough, with the letter Q. They are a short–hand method of relaying information, rather than sending and receiving longer sentences. Q–Codes are very effective at relaying the information they represent, so effective in fact, that they have made it into spoken conversations (think QSO, QSL, QSB, etc.)

The following table lists the more commonly encountered Q–Codes.

Q-Code Question Reply Comment
QRL Are you busy? I am busy. More commonly used to check to see if a frequency is in use.
QRM Am I being interfered with? I am being interfered with: 1 — 5 QRM is man–made interference.
QRN Are you troubled by static? I am troubled by static: 1 — 5 QRN is naturally occuring interference.
QRO Should I increase transmitter power? Increase transmitter power.
QRP Should I decrease transmitter power? Decrease transmitter power. Also used to indicate low power (5W or less) operation.
QRQ Should I sent faster? Send faster. (WPM)
QRS Should I send more slowly? Send more slowly. (WPM)
QRT Should I stop sending? Stop sending. Also used to indicate a station is going off the air.
QRV Are you ready? I am ready. Also used to indicate that a station is on the air.
QRZ Who is calling me? You are being called by …
QSB Are my signals fading? Your signals are fading.
QSL Can you acknowledge receipt? Acknowledging receipt. QSL Cards anyone?
QSO Can you communicate with …? I can communicate with … direct (or by relay through …) Commonly used to indicate an amateur radio contact on the air.
QST Is there a message for hams? Here is a message for hams. Now you know why the most popular ARRL magazine is called QST.
QSY Should I transmit on another frequency? Transmit on another frequency (…kHz or MHz) Also used to indicate that the operator is changing frequency, usually to avoid QRM.
QTH What is your position (location)? My position (location) is …