The following "Q signals" are common in Amateur communications. The list is far from exhaustive, but knowing just these few can increase the understanding of exchanges between radio amateurs.

Q-Signal	Meaning	Example Of Use
QRL	ARE YOU BUSY?	QRL? (Is this frequency in use?)
QRM	IS MY SIGNAL BEING INTERFERED WITH?	UR RST IS 599 WITH QRM (your signal is Readability 5, Strength 9, and Tone 9 with interference)
QRN	ARE YOU TROUBLED BY STATIC?	UR RST IS 579 WITH QRN (your signal is Readability 5, Strength 9, and Tone 9 with static)
QRP	SHALL I DECREASE TRANSMITTER POWER?	I AM RUNNING QRP 5 WATTS (I am running low power 5 watts)
QRQ	SHALL I SEND MORE QUICKLY?	PSE QRQ (Please speed up)
QRS	SHALL I SEND MORE SLOWLY?	PSE QRS (Please slow down)
QRT	SHALL I STOP SENDING?	I HAVE TO GO QRT NOW (I have to stop now)
QRU	HAVE YOU ANYTHING FOR ME?	I AM QRU (I have nothing more to say)
QRV	ARE YOU READY?	DO YOU QRV ON 20 MTRS? (Do you operate on 20 meters)
QRX	WHEN WILL YOU CALL AGAIN?	PSE QRX (Please standby until I call)
QRZ	WHO IS CALLING ME?	QRZ? (Who is calling me?)
QSB	ARE MY SIGNALS FADING?	UR 569 WITH QSB (Your signal is Readability 5, Strength 6, and Tone 9 with fading - signal strength up and down during the transmission)
QSL	CAN YOU ACKNOWLEDGE RECEIPT?	PSE QSL VIA THE BURO (Please send me your QSL card by mail via the QSL bureau)
QSO	CAN YOU COMMUNICATE WITH ... DIRECT?	TNX FOR THE QSO (Thanks for this radio contact)
QSP	WILL YOU RELAY TO ... ?	PSE QSP MY NEW CALL TO BILL (Please tell bill that my new call sign is ....)
QST	GENERAL CALL TO ALL AMATEURS!	QST QST QST (General call preceding message addressed to all Amateurs and ARRL members. Also the name of the monthly magazine published by the ARRL for all Radio Amateurs)
QSY	SHALL I CHANGE FREQUENCY?	PSE QSY UP 5 AND CALL ME (Please increase your frequency by 5 Kilohertz and call me)
QTH	WHAT IS YOUR LOCATION?	MY QTH IS LOS ANGELES (The location of my station is Los Angeles)