Topband: Maximum size of capacitance top hat?

[George Stewart, VK5ALS]

Hi Topbanders,

Just picking up on a point that Tom, W8JI made in the thread currently
running on "Short, Fat Vertical":

"More capacitance at the top is a good idea, SO LONG AS YOU DON'T MOVE THE
CURRENT MAXIMA PAST THE CENTRE OF THE RADIATOR".

Does this apply more to the situation where the antenna is in a "T" or
inverted "L" configuration or can one visualize a capacity top hat in the
same way with regard to the current distribution?

I have been working on the premise that the bigger a capacity top hat the
better and that the physical constraints will be the final determinate.

For a vertical that is 2" in diameter and 40 foot tall what is likely to be
the point at which this would happen?

I have constructed, but not put into use yet, a top hat made of 8 spokes
consisting of telescoping sections of aluminium tube that have an average
diameter of 3/4" with an aluminium wire joining the perimeter. This top hat,
if fully extended, will have a DIAMETER of around 20 feet. Will this amount
of capacity come anywhere near being so large as to cause the current maxima
to go past the centre of the radiator?

Wishing you all a blessed Christmas,

George, VK5ALS

ggstewart at adam.com.au