LinkBack Thread Tools Search this Thread Display Modes
Prev Previous Post   Next Post Next
  #2   Report Post  
Old March 5th 08, 01:00 AM posted to rec.radio.amateur.antenna
external usenet poster
 
First recorded activity by RadioBanter: May 2007
Posts: 492
Default The Rest of the Story

On Mar 4, 3:36*pm, Cecil Moore wrote:
After discovering the error on Roy's web page at:

http://eznec.com/misc/Food_for_thought.pdf

I have begun a series of articles that convey "The Rest
of the Story" (Apologies to Paul Harvey). Part 1 of
these articles can be found at:

http://www.w5dxp.com/nointfr.htm


Looks good. And well presented. There is only one small problem
with the analysis.

When the instantaneous energy flows are examined it can be seen
that Prs is not equal to 50 W plus Pref.

Taking just the second example (12.5 ohm load) for illustrative
purposes...

The power dissipated in Rs before the reflection arrives is
Prs.before = 50 + 50cos(2wt) watts

The reflected power at the source is
Pref.s = 18 + 18cos(2wt) watts

But the power dissipated in Rs after the reflection arrives is
Prs.after = 68 + 68cos(2wt-61.9degrees) watts

Prs.after is not Prs.before + Pref, though the averages do sum.

And since the energy flows must be accounted for on a moment by
moment basis (or we violate conservation of energy), it is the
instantaneous energy flows that provide the most detail and
allow us to conclude with certainty that Prs.after is not
Prs.before + Pref.

The same inequality holds for all the examples except those
with Pref equal to 0.

Thus these examples do not demonstrate that the reflected power
is dissipated in the source resistor.

...Keith
 
Thread Tools Search this Thread
Search this Thread:

Advanced Search
Display Modes

Posting Rules

Smilies are On
[IMG] code is On
HTML code is Off
Trackbacks are On
Pingbacks are On
Refbacks are On


Similar Threads
Thread Thread Starter Forum Replies Last Post
Now for the rest of the story! [email protected] General 2 April 28th 06 04:39 PM
Now for the rest of the story! [email protected] Policy 2 April 28th 06 04:39 PM
Now for the rest of the story! [email protected] General 5 April 26th 06 03:23 PM
Now for the rest of the story! [email protected] Policy 5 April 26th 06 03:23 PM
WTD: Paul Harvey Rest of the Story broadcasts from Sep 1 thru 6 AM Broadcasting 0 November 8th 05 05:41 AM


All times are GMT +1. The time now is 10:22 PM.

Powered by vBulletin® Copyright ©2000 - 2025, Jelsoft Enterprises Ltd.
Copyright ©2004-2025 RadioBanter.
The comments are property of their posters.
 

About Us

"It's about Radio"

 

Copyright © 2017