A ham radio operator is issued a call sign by the FCC, after he or she passes a licensing exam. The call sign is used to identify the person operating the radio, whenever transmitting on ham frequencies. Since 1934, west of the Mississippi, call signs that start with “K” are issued, and east of the Mississippi, call signs that start with “W” are issued. If you listen to music on the radio in the car or at home, you will occasionally hear the station announce “This is KMPS” or “You’re listening to WKRP” (or some other combination of letters) – this is their call sign, also issued by the FCC. Since the station is a business, their call-sign is a slightly different format, but the idea is the same. People who talk on certain frequencies have to identify themselves with a call sign. When you get your license, you’ll get your own call-sign!
If you’re willing to pay a few dollars extra, you can get a call-sign with letters and numbers that you choose, called a “vanity call sign.” And depending on the level of license that you choose to get, they will be anywhere from four to six characters long. If you are able to get the “Extra” license, you can get a call sign with four, five, or six characters. Having a “General” license will allow you to use five or six characters, and the “Technician” license will allow you to use six. If you prefer, you can keep the original six-character that you are issued by the FCC, regardless of what additional licenses you may get later. Here are some fun possibilities, combining different characters: N0HOW, K1SS, K0RN, W0MAN, WA5HME, and KN1TTR. When it’s your turn, you choose!
Do you want to look up a call sign? You can do that here: http://www.qrz.com/.
If you’re looking for more details, you could also try the FCC database directly: http://wireless2.fcc.gov/UlsApp/UlsSearch/searchLicense.jsp.