Cecil, as an engineer of a few years experience you should know that a
scientist can never be allowed to build a bridge ... it will never be
finished because you can never close the flex seams that are used for
thermal expansion/contraction. While engineers finish the job by getting
close enough to walk/drive off.

In a more general tone for the general reader of the list. All
engineering/science deals with tolerances. Engineers accept close enough
to specifications. Scientists want to understand why another significant
digit after the decimal point is not relevant!! :-0

Deacon Dave, W1MCE

I've managed both engineers and applied scientists in my 40+ years of
engineering design. Both disciplines have much to offer.

+ + +

Cecil Moore wrote:

Tom Bruhns wrote:

Ah, we started out with exact geometric relationships that defined
precise points, and now we're down to 20% accuracy being OK.


Nope, we started out with a simple rule-of-thumb and here it is:

Originating the thread, alhearn wrote:

Why does the reactance peak occur slightly earlier than
half-wavelength?


I responded:

Since the monopole is purely resistive around 1/4WL and
around 1/2WL, i.e. the reactance is zero at those two
points, it is simply impossible for it to be be any
other way.


Sure looks like a simple relatively innocent rule-of-thumb to me.
Absolutely nothing said about exact geometric relationships that
define precise points. You then caused the thread to wander in
the direction of 0.0000000003 accuracy while I was thinking 20%.

I've looked back over my postings and I didn't explicitly state
what I was thinking. I thought it was implicit but I didn't explain my
differentiation between the value of maximum reactance for a dipole Vs
the value of maximum reactance for the SWR circle. My rule-of-thumb is
that they are close enough to being the same point, that for ballpark
conceptual visualization, they can be thought of as being the same point.
I apologize for not being clear on that point. It took me some time to
realize that extreme accuracy was the cornerstone of your argument
against my rule-of-thumb statements.