Which Q signal indicates that you are changing frequency?

The Q signal 'QSY' means 'change frequency' or 'I am changing frequency.' It is commonly used on the air when operators decide to move to a clear frequency to avoid interference or shift to another band. Looking at the other options, 'QRU' means 'I have nothing for you', 'QSL' means 'I acknowledge receipt', and 'QRZ' asks 'Who is calling me?'. A helpful mnemonic for QSY is to think of the 'Y' as a fork in the road, prompting you to move to a new frequency.