Ham Amateur Radio Technician Practice Exam 2026 – The Complete All-in-One Guide to Exam Success

The prosign that is used to indicate the end of a formal message when using CW (Continuous Wave) is "AR." In Morse code, "AR" (.-. -.) signifies the conclusion of a message, effectively instructing the receiving operator that the transmission has ended and that they may respond. This is an important convention in CW operations as it helps ensure clarity in communication, signaling to the other station that no further information will follow in that transmission.

Other prosigns, while commonly used in amateur radio, serve different purposes. "SK" (... -.-) typically indicates the end of a contact or that a station is going QRT (turning off), but it may not signify the end of a formal message in the same way that "AR" does. "CQ" is a call to all stations, inviting any operator to respond, and "QRZ" is used to ask who is calling, thus not applicable to the context of ending a formal message.