A Q signal followed by a ? asks a question. A Q signal without the ? answers the question affirmatively, unless otherwise indicated. 
QRA--What is the name of your station? 
QRG--What's my exact frequency? 
QRH--Does my frequency vary? 
QRI--How is my tone? (1-3) 
QRK--What is my signal intelligibility? (1-5) 
QRL--Are you busy? 
QRM--Is my transmission being interfered with? 
QRN--Are you troubled by static? 
QRO--Shall I increase transmitter power? 
QRP--Shall I decrease transmitter power? 
QRQ--Shall I send faster? 
QRS--Shall I send slower? 
QRT--Shall I stop sending? 
QRU--Have you anything for me? (Answer in negative) 
QRV--Are you ready? 
QRW--Shall I tell ______ you're calling him? 
QRX--When will you call again? 
QRZ--Who is calling me? 
QSA--What is my signal strength? (1-5) 
QSB--Are my signals fading? 
QSD--Is my keying defective? 
QSG--Shall I send ______ messages at a time? 
QSK--Can you work breakin? 
QSL--Can you acknowledge receipt? 
QSM--Shall I repeat the last message sent? 
QSO--Can you communicate with ______ direct? 
QSP--Will you relay to ______? 
QSV--Shall I send a series of V's? 
QSW--Will you transmit on ______? 
QSX--Will you listen for ______ on ______? 
QSY--Shall I change frequency? 
QSZ--Shall I send each word/group more than once? (Answer, send twice or ______) 
QTA--Shall I cancel number ______? 
QTB--Do you agree with my word count? (Answer negative) 
QTC--How many messages have you to send? 
QTH--What is your location? 
QTR--What is your time? 
QTV--Shall I stand guard for you ______? 
QTX--Will you keep your station open for further communication with me? 
QUA--Have you news of ______?