Richard Clark wrote:

Hi Jim,

Wouldn't it be clearer (as you are one who complains of the lack of
clarity) to simply call this "useful purpose" as Zen?

Hi Richard,

You don't like it much, do you. I suggest not dishing out so much of
it then.

I don't know about you, but I learned about the utility of 'points' in
my geometry and mathematics classes. Data is, for example, often
obtained by accumulating an array of them.

For the problem at hand (antennas) Kraus uses c = w/k, not dw/dk.
Naturally, he was interested in the velocity with which field lines
move across a point - the speed at which the wave propagates.
VF = v sub p over c, not v sub g over c.


The second part of your
question is unintelligible to me.


As is your response.

You probably intended that as a clever retort.

Throwing equations over the transom doesn't make
them explanations.

Had I not 'thrown', you would likely have desired to know what I was
talking about. It was as concise a presentation as I could conjure in
30 seconds. Equations do offer the advantage of illustrating the
point without leaving much need for semantic interpretation.

73, ac6xg