Just a guess he when I create a table in Access I can specify field
width for my entries. Is it possible the field width in your DBF file
is set to some default value that is comparitively low?

I just tested this by saving some Excel text as a DBF (DBase IV
format). The only database program I have on this computer is Access,
so I opened the DBF file using Access and found the file width to be 9
characters- but I couldn't alter the field width because Access had
attached the data rather than import it. Do you have software that can
alter the field width?