Q codes are three-letter abbreviations that started in Morse code and are now used on voice too. Sent with a question mark, a Q code asks a question; without one, it is a statement.
| Code | As a question | As a statement |
|---|---|---|
| QRL | Is the frequency in use? | The frequency is in use. |
| QRM | Is there interference? | There is interference (usually from other stations). |
| QRN | Are you troubled by static? | I am troubled by static / atmospheric noise. |
| QRO | Shall I increase power? | Increase power. |
| QRP | Shall I decrease power? | Decrease power; also means low-power operating. |
| QRQ | Shall I send faster? | Send faster. |
| QRS | Shall I send more slowly? | Send more slowly. |
| QRT | Shall I stop sending? | I am stopping transmission / closing down. |
| QRV | Are you ready? | I am ready. |
| QRX | When will you call me again? | Wait; I will call you again. |
| QRZ | Who is calling me? | You are being called by… |
| QSB | Are my signals fading? | Your signals are fading. |
| QSL | Can you acknowledge receipt? | I acknowledge receipt; also a confirmation card. |
| QSO | Can you communicate with…? | A contact (conversation) between stations. |
| QSY | Shall I change frequency? | Change to another frequency. |
| QTH | What is your location? | My location is… |
The Technician pool asks about QRM, QSY and similar codes, and the General and Extra pools go further with CW procedures. Learning the dozen codes above covers most of what you will hear on the air.