Need help storing special characters like ° (degrees)

Whenever I insert a geographical coordinate in database or even in
textfile after submit, for example 15°16'18''
it ends op like 15°16'18''. =E9, =E0, =E7, =E8, ... ends up funny too.=
It
shows ok when displayed on webpage. But it is hardly readable in
database or in textfile.
I've created 3 different tables with 3 different collations
(utf8_unicode_ci, latin1_bin, latin_swedish_ci) each with 3 fields
(varchar with the 3 different collations) 9 posibilities. All with the
same result. When I input via phpMyAdmin it works fine: I see
15°16'18'' in all the tables and all the columns. So it must be
somthing I do or don't do when submitting the information. When I
ouput the contents of the $_POST to a textfield it also shows 15=C2
°16'18'' on linux (cli) en wordpad on windows. Shows ok in notepad.
I've tried changing the http-equiv=3D"Content-Type", using
stripslashes(strip_tags(trim(urldecode(on the post-variables))))
Problem is I have to do test on the contents of the fields (once they
are in database) so for example for geographical coordinates I want to
find '°' and not '°'.

Help,

Pugi!