QRN - Interference from non-human sources (such as static buzz or lightning)
QRO - High transmit power. ("Just flipped on the amplifier, so I'm QRO now!")
QRP - Low transmit power--usually means 5 watts or less ("I'm on battery so I'm running QRP here tonight!")
Note: Some hams delight in seeing how far their signals go with very low power. For some of these
folks, it's almost an obsession! A person who often uses low power will commonly refer to themselves
as a "QRP'er" proudly. There are many full-time QRP stations, most commonly on CW (morse code).
QRT - Stop transmitting, or a way of saying that you are going off the air ("I'm going QRT for dinner.")
QRU - Do you have any traffic or messages for me? (Normally used only for traffic or message nets)
QRV - I'm ready. (for traffic or messages--again normally only for nets)
QRX - Please wait a minute, or please stand by.
QRZ - Most commonly used as a question "Who is calling me?" (see bonus info below)
QSB - Signals are fading in and out. Usually applies only to HF (shortwave) operation.
QSL - Acknowledged. (often just "Roger!"). As a question, used to request confirmation from the other station.
QSO - Commonly used to describe a radio conversation between hams. ("We had a nice long QSO tonight!")
QSY - Change frequency or channel. ("Please QSY to 146.52 simplex!")
QTH - Your present location or your home. ("My QTH is Morgan Hill, California.")
Bonus info: In order to make communications more clear, hams almost always
pronounce the letter "z" as "zed" rather than "zee". This follows the common
pronunciation used by English speakers in Britain, New Zealand, Australia, etc.
It avoids spoken confusion with other letters of the alphabet, such as the
letter "c". So, the spoken "QRZ" is almost universally pronounced "Q R Zed?".