For those familiar with Unix: The search engine is a Perl script, and it knows about the regular expressions known by Perl. The exception are wildcards . and .*, which are replaced by the shell-like ? and * (Joe ham understands them). The script adds an escape character before a . so you can use dots in email address searches. See man perlre for more information.

Some examples:

• Callsign: oh?lzb
  oh7lzb in any region.
• Callsign: oh[1-3]lzb
  lzb in regions 1-3.
• Callsign: oh[1-3,7]lzb
  lzb in regions 1-3 tai 7.
• Callsign: oh*b
  All callsigns which end with a b.
• Callsign: *lz*
  All callsigns, which include the string lz. Note the difference:
• Name: eik
  All names, which include the string eik. Asterisks are not required here!
• Email: @*hut.fi
  All hams studying in the Helsinki University of Technology (who have their email addresses in the database). The address sven@hut.fisknet.no would also match ... but:
• Email: ^hannikainen@*hut.fi$
  ^ matches the beginning of a string and $ the end, so the email address must begin with hannikainen@ ja end with hut.fi. When searching for a callsign, ^ and $ are added around the expression by the script!

Confused enough?