cqCT

cqCT stands for "callsign query Call Sign Transmitter". It is a method used in amateur radio to query the identity of a transmitter when a signal is received, particularly in crowded or challenging signal conditions. When a station transmits cqCT, it is essentially asking any station that hears it to respond with their own callsign. This allows the receiving station to identify the source of the transmission.

The purpose of cqCT is to facilitate clear communication and identification. In amateur radio, proper callsign identification is crucial for legal operation and for building a contact log. By using cqCT, a station can proactively request this information without needing to establish a full two-way contact first. This is especially useful for short transmissions or when trying to identify a weak signal.

The use of cqCT is not a formal protocol but rather a convention adopted by some amateur radio operators. It is typically used on VHF and UHF bands where repeaters might be involved or when multiple stations are active on the same frequency. The brevity of the phrase makes it efficient for quick exchanges. Some operators may also use variations or follow-up phrases to clarify their intent, such as asking for a signal report or location.