Ham Radio General Class Practice Test

What does it mean when a CW operator sends "CL" at the end of a transmission?

1. Keep frequency clear

2. Operating full break-in

3. Listening only for a specific station or stations

4. Closing station

The correct answer is: Closing station

When a CW operator sends "CL" at the end of a transmission, it signifies "Closing station." This is a common practice in Morse code communications, indicating that the operator is finished transmitting and is closing their communication for the time being. It serves as a courteous signal to other operators that the frequency is now available for others to use and that the operator will no longer be actively listening or transmitting on that frequency. This usage of "CL" helps maintain order and clarity in communication, ensuring that others know the operator has concluded their contact. It encourages effective frequency management and prevents overlapping communications, which can hinder propagation and clarity. The other options refer to different aspects of operating procedures in amateur radio. For example, "Keep frequency clear" involves ensuring that the frequency remains open for other users; "Operating full break-in" pertains to a mode of operation where an operator can hear incoming signals while transmitting; and "Listening only for a specific station or stations" indicates a selective listening practice where the operator is only monitoring for specific calls. Each of these has distinct meanings and use cases in amateur radio but does not correlate directly with the message conveyed by sending "CL."