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Old June 11th 10, 03:06 PM posted to rec.radio.amateur.antenna
Cecil Moore Cecil Moore is offline
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First recorded activity by RadioBanter: Aug 2006
Posts: 572
Default Question about "Another look at reflections" article.

On Jun 10, 10:04*pm, lu6etj wrote:
For this discussion would be relevant the results corresponding to
sixth column of your article using a quarter wave line.
They a 0 - 8 - 22 - 50 - 88.9 - 128 and 200 W (190 W the last one
with Spice TL simulation).


I'm sorry, Miguel, using a "quarter wave line" is a mistake. You
should be using a lossless 1/8WL line. The results in my article are
based on a 1/8WL (45 deg) lossless line, NOT on a 1/4WL (90 deg) line.
*Please re-run your Spice simulation using a 1/8WL line* and report
back to us. When the line is 1/8WL long, the reflected wave arrives
back at Rs 90 degrees out of phase with the forward wave and cos(90) =
0, so the interference term is zero and all the reflected power is
dissipated in the source resistor. For the special case where
cos(A)=0, i.e. the interference term is zero, the power density
equation reduces to: Prs = Pfor + Pref + 0

Nowhere in my article did I use a 1/4WL line so please don't say that
your Spice results disagree with my chart. It is perfectly
understandable that your 1/4WL results do not agree with my 1/8WL
results.
--
73, Cecil, w5dxp.com