Near as I can tell from the video, that little white box is just a little white box. The Lexan box that guy is leaning on appears to have a much larger antenna in it, and that's what the cable plugged into the BlackBerry is plugged in to.
The guy even says "The _goal_ is to get it down to a box this size". That information seems to be missing from the blog post.
The guy even says "The _goal_ is to get it down to a box this size". That information seems to be missing from the blog post.