Q-Codes

QRM   Man made noise, adjacent channel interference 
QRN   Static noise 
QRO   Increase power 
QRP   Reduce power 
QRT   Shut down, clear 
QSL   Confirmation, often refers to confirmation cards exchanged by hams 
QSO   Conversation 
QSX   Standing by on the side 
QSY   Move to another frequency 
QTH   Address, location 

Example uses of the codes: 

  Use                    Meaning
  ---------------------  ------------------------------------------------
  Going QRT              Switching off now 
  Receiving QRM          Getting interference from another station 
  Having QRN trouble     Having static trouble. 
  That was a quick QSO!  That was a quick chat! 
  QSY to channel...      Go to channel... 
  What's your QTH?       What's your location?