Morse code's prosigns — the procedural signals that control conversation flow on CW radio — are a complete communication protocol built into the code itself, and understanding them explains why Morse operators can communicate efficiently without ever speaking or establishing rules in advance
The previous articles on this site covered Morse code as assistive technology, its history and connection to digital communication, its modern survival (SOS, aviation, amateur radio), and the timing structure. This article addresses Morse code prosigns and Q codes — the procedural shorthand that makes Morse radio communication function as a structured exchange rather than a stream of letters.
What prosigns are: meta-communication in Morse
Prosigns (procedural signals) are Morse code combinations that convey communication control information — not message content, but instructions about the conversation itself.
Prosigns are sent as single characters (two letters transmitted without the normal inter-letter space between them) to distinguish them from regular letter pairs. A prosign is not "A-R" — it's "AR" fused into a single unit.
Key prosigns:
AR (end of message): signals that the transmitted message is complete and the sender is awaiting a reply. In voice radio, this is "over." When written, it's sometimes shown as + or ^ since there's no standard letter representation.
SK (end of contact / signing off): signals that the contact is ending completely. In voice radio, this is "out." Unlike AR ("I'm done with this transmission, reply when ready"), SK means "I'm done with the entire conversation and going off the air."
BK (break / invitation for the other station to transmit): mid-message invitation for the other station to interject. Useful in longer transmissions where you want to check the other station is still receiving before continuing.
KN (only the named station is invited to reply): a directed "over" — used when multiple stations are on frequency and you want only the specific station you've been talking to respond, not others.
K (general invitation to transmit): like KN but broader — any station that heard the transmission may respond. Used when calling CQ (a general call looking for any station to respond).
Q codes: the international shorthand that predates emoji
Q codes are three-letter codes beginning with Q that provide internationally standardized meanings in a single short transmission — originally developed for telegraphy and later adopted by radio communications.
Q codes were designed to work across language barriers — a German operator and an English operator who don't share a language can communicate common operational messages through Q codes without needing to translate full sentences.
Essential Q codes for CW (Morse) operation:
QRM: interference from other stations ("Is there interference from other stations?" / "There is interference from other stations")
QRN: interference from static (atmospheric noise) ("Are you troubled by static?" / "I am troubled by static")
QRO: increase power ("Shall I increase power?" / "Increase power")
QRP: reduce power or use low power ("Shall I decrease power?" / "Decrease power") — in modern amateur radio, QRP specifically refers to low-power operation (typically 5W or less), and "QRP operation" is a recognized style of minimalist amateur radio
QSB: signal fading ("Are my signals fading?" / "Your signals are fading")
QSL: confirm receipt ("Can you acknowledge receipt?" / "I confirm receipt") — QSL cards (paper confirmation cards sent between operators after a contact) are a longstanding ham radio tradition
QSY: change frequency ("Shall I change to another frequency?" / "Change to another frequency")
QTH: location ("What is your location?" / "My location is...")
The complete Morse QSO (contact) structure
A typical Morse amateur radio contact (QSO) follows a structured sequence:
- CQ CQ CQ DE W1ABC K — "CQ" (general call / "seek you"), the calling station's callsign, "K" (open to any reply)
- W1ABC DE G3XYZ G3XYZ K — responding station identifies itself, invites the caller to reply
- G3XYZ DE W1ABC UR 599 599 BK — signal report (599 = strength 5, tone 9, speed 9 on the standard RST scale), BK to pass transmission
- W1ABC DE G3XYZ UR 578 578 QTH LONDON BK — return signal report, location
- Further exchange of information (name, antenna, equipment, weather)
- G3XYZ DE W1ABC 73 SK — "73" (conventional sign-off meaning "best regards," one of the oldest ham radio abbreviations), SK to end contact
This entire structured exchange takes about 2-3 minutes on CW at typical amateur speeds (around 20 words per minute) — considerably more information-dense per minute than a voice contact would be, partly due to the procedural shorthand.
The RST system: signal reporting in Morse
RST (Readability-Strength-Tone) is the signal quality reporting system used in Morse contacts:
- R (Readability): 1-5 scale, how readable the signal is (1=unreadable, 5=perfectly readable)
- S (Strength): 1-9 scale, signal strength (1=barely perceptible, 9=extremely strong)
- T (Tone): 1-9 scale, the quality of the CW tone (1=rough/buzzy, 9=pure, clean tone)
"599" is the perfect report — the signal is perfectly readable, extremely strong, and has a perfect pure tone. In contest operation, 599 is often sent as a formality even when the signal isn't truly perfect, because contests prioritize speed over detailed assessment.
How to use the Morse Code Translator on sadiqbd.com
- Encode full text: paste any text to see the Morse equivalent — useful for learning the code, creating educational content, or preparing a transmission
- Decode received Morse: paste the dot-dash sequence to decode it — useful when you've received written Morse and need to read it without memorizing the chart
- For prosigns: prosigns like AR and SK are typically entered and displayed as their two-letter forms; be aware they're transmitted fused without the inter-letter space, which the translator may or may not represent
Frequently Asked Questions
Why is "73" used as a Morse sign-off when it's a number, not a Q code? 73 is one of the original telegraph abbreviations from the American Morse code era — a numerical code meaning "best regards" or "my compliments" in the early numbered phrase books used by telegraph operators. The Phillips Code (and similar systems) assigned numbers to common phrases for speed. The specific origin of 73 for "best regards" is documented in 19th-century telegraph codebooks. Unlike Q codes (which start with Q and were formally standardized), 73 is a legacy abbreviation that survived the telegraph era into modern amateur radio. "88" (love and kisses) is another example of the same system.
Is the Morse Code Translator free? Yes — completely free, no sign-up required.
Try the Morse Code Translator free at sadiqbd.com — convert any text to Morse code and back instantly.
