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Old August 29th 03, 04:15 AM
Richard Clark
 
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On Thu, 28 Aug 2003 21:01:54 -0500, W5DXP
wrote:

Richard Clark wrote:
To put it ironically, the challenge I offer is deliberately incoherent
to give that math a deliberate solution that is other than the result
of simple addition or subtraction.


So how do you get the reflections in a single source system to be
incoherent?


Hi Cecil,

Two reflective interfaces with an aperiodic distance between.

The cable (or any transmission line) falls in between. So does most
instrumentation to measure power. All fall prey to this indeterminacy
(unless, of course, it is made determinant through the specification
of distance, which it is for the challenge). As I offered, this
challenge is not my own hodge-podge of boundary conditions, it was
literally drawn from a standard text many here have - hence the quote
marks that attend its publication by me. I am not surprised no one
has caught on, I also pointed out this discussion is covered in the
parts of Chapman that no one reads. Whatchagonnado?

The example of the challenge serves to illuminate (pun intended) the
logical shortfall of those here who insist that a Transmitter exhibits
no Z, or that it is unknowable (to them, in other words), or that it
reflects all power that returns to it (to bolster their equally absurd
notion that the Transmitter does not absorb that power). Chapman is
quite clear to this last piece of fluff science - specifically and to
the very wording. Engineers and scientists simply converse with the
tacit agreement that the source matches the line when going into the
discussion of SWR (and why Chapman plainly says this up front on the
page quoted earlier). This is so commonplace that literalists who
lack the background (and skim read) fall into a trap of asserting some
pretty absurd things. It follows that for these same literalists, any
evidence to the contrary is anathema, heresy, or insanity - people
start wanting to "help" you :-P

Ian grasped at the straw that the discussion simply peters out by the
steady state and wholly disregards the compelling evidence (and
further elaboration of Chapman to this, but he lacks another voice,
the same Chapman, to accept it) with a forced mismatch at both ends of
the line. It is impossible to accurately describe the power delivered
to the load without knowing all parameters, the most overlooked is
distances traversed by the power (total phase in the solution for
interference). I put the challenge up to illustrate where the heat
goes (the line); and it is well into the steady state, as I am sure no
one could argue, but could easily gust
"t'ain't so!"
At least I saved them from the prospect of strangling on their own
spit sputtering "shades of conjugation." [Another topic that barely
goes a sentence without being corrupted with a Z-match
characteristic.]

Using this example for the challenge forces out the canards that the
source is adjusting to the load (in fact, the challenge presents no
such change in the first place) and dB cares not a whit what power is
applied unless we have suddenly entered a non-linear physics. None
have gone that far as they have already fallen off the edge earlier.

Now, be advised that when I say "accurately" that this is of concern
only to those who care for accuracy. Between mild mismatches the
error is hardly catastrophic, and yet with the argument that the
Transmitter is wholly reflective, it becomes catastrophic. The lack
of catastrophe does not reject the math, it rejects the notion of the
Transmitter being wholly reflective. This discussion in their terms
merely drives a stake through their zombie theories.

I would add there has been another voice to hear in this matter. The
same literalist skim readers suffer the same shortfall of perception.
We both enjoy the zen-cartwheels so excellently exhibited by the drill
team of naysayers. ;-)

73's
Richard Clark, KB7QHC