Hi Sub , that antenna is called Obluchatel , that antenna was tested a long time ago , please see the link below:
http://www.zero13wireless.net/foro/s...t=6057&page=11
In the page 11 of this post is the antenna , it´s a good antenna , but it´s to long for feeder.
Have you tested the " SRM " or the " TDJ13 circle ".
In the test the obluchatel was behind of the TDJ13.
We have designed a variatión of the TDJ13 for minimize the Kelvin´s effect , it´s the TDJ13 circle.
The new project have only 1.8mm front - end.
Excuseme my poor english.
Kind regards.