US amateur lookup and vanity availability, derived from the ULS extract
Class and state are optional — they add the §97.19 eligibility
check (group vs. class, and the residency gate on regions 11–13).
Use ? as a wildcard in the suffix pattern.
The search enumerates the legal call space and subtracts what is taken, so
never-issued call signs show up too.
Every call scored two ways. Dit units —
the full length in Morse at standard timing, counting a dit as 1, a dah as 3,
the gap inside a character as 1 and the gap between characters as 3.
Voice — how it holds up spoken through noise.