Have you ever wondered about the J-Pole antenna and been intimidated by it trying to figure out how it works? There is a principle that you should always keep in mind when looking analytically at any antenna for the electromagnetic spectrum: they are all merely dipoles in disguise!
When you hunt around on the web you will find all sorts of crazy discussions and truly funky analyses concerning the J-Pole. For example, consider the very nice-looking web page published on Ham Universe on the J-Pole and its dimensions. Most of it is perfectly fine but, like most of them, has a slight inaccuracy. In this case, it is the dimension D describing the distance between the legs of the J in the J-Pole. This article would have you believe that there is a precision distance it should be when in fact, the closer the legs of the J are to each other, the better the antenna will perform.
I made an animation video to analytically unmask the J-Pole antenna showing that his TRUE identify is none other than the dipole. Run time is only 3 minutes.