A Q signal followed by a ? asks a question. A Q signal without the ?
answers the question affirmatively, unless otherwise indicated.

QRA QRG QRH QRI QRK QRL QRM QRN QRO QRP QRQ QRS QRT QRU QRV QRW QRX QRZ QSA QSB QSD QSG QSK QSL QSM QSO QSP QSV QSW QSX QSY QSZ   QTA QTB QTC QTH QTR QTV QTX QUA

What is the name of your station?  What's my exact frequency?  Does my frequency vary?  How is my tone?(1-3)  What is my signal intelligibility?(1-5)  Are you busy?  Is my transmission being interfered with?  Are you troubled by static?  Shall I increase transmitter power?  Shall I decrease transmitter power?  Shall I send faster?  Shall I send slower?  Shall I stop sending?  Have you anything for me? (Answer in negative.)  Are you ready?  Shall I tell...you’re calling him?  When will you call again?  Who is calling me?  What is my signal strength? (1-5)  Are my signals fading?  Are my signals mutilated?  Shall I send...messages at a time?  Can you work breakin?  Can you acknowledge receipt?  Shall I repeat the last message sent?  Can you communicate with...direct?  Will you relay to...?  Shall I send a series of V's?  Will you transmit on...?  Will you listen for ...on...?  Shall I change frequency?  Shall I send each word/group more than once?  (Answer, send twice or ...)  Shall I cancel number...?  Do you agree with my word count?(Answer negative.)  How many messages have you to send?  What is your location?  What is your time?  Shall I stand quard for you...?  Will you keep your station open for further communicationwith me?  Have you news of...?