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Old May 27th 10, 03:50 PM posted to rec.radio.amateur.antenna
lu6etj lu6etj is offline
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First recorded activity by RadioBanter: Jul 2006
Posts: 143
Default Question about "Another look at reflections" article.

On 25 mayo, 11:49, Cecil Moore wrote:
On May 24, 10:31*pm, lu6etj wrote:

Anyway, my question is about validity of the assertion that reflected
wave -in that example- IS ABSORBED by the pad. According to my simple
calculations this hipothesis, as I see it, it does not coincide with
my early learnings.


Miguel, let's switch your example over to an easier to understand
example. Assume an ideal signal generator equipped with a resistive
circulator load. Let's call such a device an SGCR, a Signal Generator
equipped with a Circulator and a Resistor. Assume that 100% of the
reflected energy is dissipated in the circulator load resistor (none
re-reflected) and none of the reflected energy reaches the source. So
here is the block diagram.

SGCR--------feedline--------load

That model should be easier to discuss than the pad attenuator model.
What do you think?
--
73, Cecil, w5dxp.com


Excuse me Cecil:

I am reading this newsgroup through Google groups web page and I just
realized that later replies to previous post are intercalated in the
thread, while I expected to see it always at the end of it, for that
reason I did not ACK before to it. (I hope yours be the only one, I
will review all thread tho chek for others).

In a early post I wrote = "of course if we insert a circulator to
separate both powers, generator now would see 1 ohm load, could
develope 1 W incident, 0 W reflected (Pn=1W) on circulator input, 0.36
W would be outputting on the other port to render 0.64 W (Pn) to the
load with 1 W Pf and 0,36 W Pr again"
Is this result OK for you?.

The thread advance toward more deeper issues since :), and now I have
been analizing all the matter because it quickly superceed my original
doubt. A few minutes ago had started to read your article (http://
www.w5dxp.com/energy.htm) and the Roy's one (http://eznec.com/misc/
Food_for_thought.pdf) and yesterday I have been reloading my old
"Transmission lines antennas and wave guides" from King, Mimno & Wing
to review the issue from that classical perspective.

I am interested in your optic analogy, I can imagine the load as a
partially reflecting surface, real part of it as absorbance
(transmittance if it was a radiator). line as a unidimensional medium
and reflection as the form of "redistribute energy" (is it OK?) and a
coherent light source for the voltage source, but I am still trying to
visualze the optical equivalent of source resistance and its job to be
a good analog, Also I am interested in check other values and
conditions in your other article (first part) with 45 degree line.

Thank you very much for your helping and inspiration.

73 - Miguel LU6ETJ