The quake-json.php doesn't have any iconv() to change from the USGS UTF8 to another character set.
Try changing wxquake.php include("top.php");
to $useUTF8 = true;
include("top.php");
and that will cause the entire page to be rendered in UTF8 (and automatically change any language-LL.txt, language-LL.js to UTF8 for this page also).