Review of codes transmitted at the end of a session
Ending CW Transmission Sessions: Proper Use of Procedural Signals
Every individual exchange (turn) or completed QSO in Morse code telegraphy finishes with a specific procedural signal (prosign). Over time, using these codes becomes second nature; however, mastering them correctly early on is essential to maintaining clear, collision-free operating practices.
Key Distinction: There is a fundamental difference between a single transmission/turn (Over) and a complete contact (QSO). A single QSO generally consists of several back-and-forth overs.
1. Procedural Signals Ending Transmissions
| Code | Meaning | Correct Operational Context |
|---|---|---|
| AR | End of Transmission (No specific station invited). | Sent concatenated at the end of a general CQ call or when answering a station calling CQ or QRZ. |
| K | End of Turn. Over to you! | Sent at the end of a regular turn during an exchange. Invites any listening station to respond. |
| KN | Over Specifically to You. | Sent at the end of a turn when inviting only the named station to reply. Outside stations must stand by. |
| BK | Break-In / Break. | Not concatenated. Used for rapid, back-and-forth exchanges without re-transmitting callsigns on every turn. |
| SK | Final End of Contact (End of QSO). | Sent concatenated at the conclusion of a contact. Signals to other listening stations that the frequency is clear. |
| SK CL | End of QSO + Closing Station. | Sent when shutting down the station, indicating that no further calls will be answered. |
| AR K / AR KN / AR SK | Incorrect redundant combinations. | DO NOT USE! Combining these prosigns is grammatically redundant and considered poor operating practice. |
2. The Traditional „DIT DIT“ CW Final Sign-off
At the very end of a Morse code contact, after the formal SK prosign has been exchanged, operators regularly send two final dits spaced slightly apart (sounding like E E or DIT... DIT).
While not an official ITU or IARU procedural code, this friendly exchange is an iconic on-air tradition — the ham radio equivalent of a casual „bye-bye“ or „take care“.
