On Fri, 25 Jan 2008 19:33:41 GMT
Owen Duffy wrote:

Roger Sparks wrote in
:

On Fri, 25 Jan 2008 05:32:33 GMT
Owen Duffy wrote:

Roy Lewallen wrote in news:13pirk5h1cpt4f5
@corp.supernews.com:

Owen Duffy wrote:
Roger Sparks wrote in
:

... The reader can
also see that more power is present on the transmission line than
is delivered to the load.

The notion that "power is present" is a different one.

Owen

...
Nothing mysterious was hinted with the words "power is present".

As I finished writing the post, I wanted to call attention to the
assumption that the reflected power is true power and adds to the
amount of energy "stored" on the transmission line. But "stored" is
a word that implies static conditions, and static conditions are not
found on a transmission line. So I substituted "present" for "stored.

Roger,

If you were wanting to mean "stored", perhaps it is energy that is stored
(over a non-zero length of line) rather than power. In that sense, energy
is "present" on the line, and the load may store energy (only if it has
reactive elements, and irrespective of whether it looks resistive at its
terminals).

Owen

I think everyone agrees that energy is stored on a transmission line in the sense that energy enters at time one and does not exit until some time later at time two.

It is important to be aware that the time shape of the energy package is preserved on a transmission line. The time shape information is contained in the power term for every instant of passing time.

I can understand why many hesitate to think of power as being "stored" on a transmission line, because at best, such storage is dynamic and fleeting. Thinking of power being "present" on a transmission line is better than "stored" because the concept of a time component is not lost.

--
73, Roger, W7WKB