On Mar 16, 11:39*pm, Owen Duffy wrote:
Hi Tom,

K7ITM wrote :

...

I'm sorry...perhaps I don't understand your notation. *Don't you

I am taking a convention that the sense of currents in segments is from
bottom to top. That means that I defined all segments in order from bottom
to top.

My notation ~= is to mean approximately equal.

Does that clarify things?

Cheers
Owen

Yes--and then if they were exactly equal, would that not imply only
transmission line current on the stub? Obviously, they are exactly
equal if you simply connect the ends of the elements together...but
that isn't what gets us to in-phase currents at the centers of each
element (in the case of the symmetrical 3 element design; or the base
current in the bottom quarter wave in phase with the center current in
the top half wave...), and (nearly) equal currents at those current
maxima. To the extent that the currents A and D in your diagram
differ, there is common-mode or "antenna" current on the stub.

Cheers,
Tom