If you are new to radio and have been listening around on the bands, you’ve probably run into some conversations where stations use three-letter abbreviations as part of the conversation. These are known as “Q codes” and understanding them is an important part of being able to communicate effectively on the air. 

In this article, we’ll take a look at the origins of Q codes, where they are used and we’ll look at some of the more common ones that you are likely to come across while operating.

Origins of Q Codes

The origin of Q codes lies in the early days of CW (Continuous Wave - morse code) operation. They were originally developed by the British government, circa 1909, as a list of abbreviations for use by British ships and coastal stations, which at the time, were licenced by the Postmaster General. 

Because of their simplicity and ability to facilitate communication between operators potentially speaking different languages, they were included in the “list of abbreviations to be used in Radio Communications” produced at the Second International Radiotelegraph Convention held in London and were quickly adopted worldwide. A total of 45 Q codes were initially featured. 

Over the years, that original list of 45 Q codes has changed and evolved to match the evolving nature of radio practice and to fit the different requirements of different types of operators. By the 1970s, the “Post Office Handbook for Radio Operators” featured a list of over a hundred Q codes and their use has carried over into other modes/bands, such as SSB HF and - to a lesser extent - VHF/UHF.

So, why was this important? 

Despite the impressive speed displayed by some of the more experienced operators, CW is a relatively slow method of transmitting information, with the average speed being somewhere around 25 words per minute. Naturally, this leads to a desire for efficiency and brevity when transmitting, which Q codes help make possible. 

Q codes represent entire sentences, statements and/or questions, enabling operators to quickly convey or ask for specific information. While this is useful in day to day transmissions, it can be critical in an emergency, enabling an operator to make a full transmission significantly faster.

How and where are Q Codes used today?

These days Q codes aren’t confined solely to naval operation and are widely used in the aviation industry, the military and, of course, the amateur radio community. You’ll still find them in use in CW transmissions and their use is also very common in HF communications, particularly in competitions where operators are racing to get as many contacts as possible. Here again, they help operators keep transmissions short, succinct and help minimize any issues with the language barrier. 

You may also run into Q codes on VHF/UHF, particularly on simplex channels. For example, after responding to a CQ call on the 2m calling frequency, you may be asked to “QSY” to another frequency to free up the calling channel. Their use isn’t as widespread as on the HF bands, but sooner or later you will run into someone using them.

Common Q Codes on HF and 2m

Now that we know a little about the history of Q codes and the reasons for using them, let’s take a look at some of the more common ones you’ll come across on the air. 

“QRM” - Man-made interference

“QRN” - Natural interference

“QRT” - Signals that the sender is “closing down” and no longer accepting calls

“QRZ” - “Who is calling me?” or “you are being called by...” but is most often used to indicate that the station is ready to receive contact from another station at the end of a final over

“QSB” - Refers to a fading signal, which tends to occur in the early morning/evening due to propagation changes

“QSL” - Used at the end of an over to ask for acknowledgement of receipt. Essentially the amateur radio version of “do you copy?”

“QSO” - A QSO is a contact. This one is quite common to hear on repeaters, as other stations will often announce their callsign and ask “anyone around for a quick QSO?”

“QSY” - To change frequency. Most often used on 2m to move the conversation away from the calling channel

“QTH” - Refers to an operators location - “what is your QTH?” or “my QTH is…”

These are the more common Q codes and should be enough to get you started with understanding the exchange of information on the radio.

Should I use Q Codes in my QSO’s?

Yes! Feel free to do so, but try to avoid overuse - remember the aim is to have others understand you. Listen to how they are used by more experienced operators and pay attention to the context and social setting - 2m tends to be fairly relaxed and is almost always local, so you should keep jargon to a minimum. HF tends to be a little more formal (but still friendly) and using Q codes can help you make a successful contact where language difficulties would otherwise make it almost impossible. 

Where can I learn more?

 For a more extensive list as well as some additional historical and background information, you can take a look at the Wikipedia article located here or you can find the ITU document detailing the full list here (.pdf file).