Inreply to cmacneill's comment on the rough vs. smooth surface, I would absolutely agree with him. Smooth surfaces tend to have laminar flow over the surface, this will still create a static buildup but it will not be concentrated at any particular point. A rough surface on the other hand will have a turbulent flow (more resistence), and yes this should create more of a potential then the smooth situation. The rough surface will also have areas where the charge accumulates doesn't flow evenly over the object.
Why did I rough'n up the omni, simple... I was at a loss and just tried what I did becuase I really didn't have an easier solution, static electricity can be a strange and unpredictable beast, and I am no expert, but this seemed to work for me.
In retrospect, I may have just gotten lucky. I do remember when this happened to me there was a post regarding it and it had a solution that sounds similar to tgrand's.
this is the other topic that had a possible solution, about half way down 1st page see Gerard's post.
http://forum.mikrotik.com/viewtopic.php ... 734&hilit=