Not So Pointy

This is a picture of the wire antenna (a solid) generated by rotating the area below (10/x)^(1/2) about the x-axis.

Such a antenna so shaped, will hopefully have a \(E=\cfrac{V}{d^2}.x\) profile along its length and so all energy fed into it is radiated off.  Close to 100% efficiency.

But under normal circumstances what happened to the rest of the energy? A good guess is that the signal in the antenna not radiated, bounces up and down the wire and generates echos and noise.  If it is possible to attain higher efficiency, there should also be a corresponding reduction in noise.