This is just a bigger version of previous coax antenna.
http://www.zero13wireless.net/foro/showthread.php?t=3964
http://www.digdice.com/2008/03/30/small-coax-omni-antenna-for-wifi/
There is no info available about gain or anything els.
Used coax is RG-213
On site also suggest some sort of franklin dipole :
I thing that this design will be fun to test.
May be will work ? What you thing ?