I just realized that I never posted my ham (amateur radio) callsign, something which I meant to do as soon as I received confirmation. It’s:
N3JIM
If you want to know more about radio callsigns (both ham and broadcast), here’s some additional information. The leading “N” is one of the 4 letters assigned to United States radio operators. The other US identifiers are “K”, “W”, and “A”. (K and W are familiar to most people because of broadcast radio and TV station identifiers such as “WGBH” and “KXPR”.)
The “A” designator is a little different, because it’s partially assigned to the US — only “AAx” through “ALx” are for US operators. The rest of the A’s are assigned to about a dozen other countries large and small. See the Allocation of International Call Signs for the complete list.
Broadcast stations are identified by a 3- or 4 letter (only) code, typically Kaaa in the west or Waaa in the east. Ham call signs, at least in the US, include a single digit in the second or third position. The digit normally identifies the part of the country in which the operator was living when their license was granted. See the table “Geographic Region-based Numerals” at the bottom of the FCC Sequential Callsign Systems page. Because I’m in California, my digit should be “6″, but…
I really wanted a 1×3 call sign that ended with my name, “JIM”. The only one that was available when I got my license was N3JIM, so I took it, even though the “3″ would normally be used in Delaware, DC, Maryland or Pennsylvania.
I don’t know if I’d bother switching to K6JIM, N6JIM, or W6JIM if/when any of those came available. It’s probably not worth the trouble, and a few people are starting to recognize N3JIM when I announce. The only downside is occasionally explaining that I really am from California, not somewhere back east. 
