LinkBack Thread Tools Search this Thread Display Modes
Prev Previous Post   Next Post Next
  #25   Report Post  
Old August 27th 03, 04:04 PM
W5DXP
 
Posts: n/a
Default

Roy Lewallen wrote:
Hm, this has me puzzled.


:-) Good one, Roy. :-)

Assuming a purely real Z0, you're taking the
square roots of two purely real quantities, each of which can have two
values, and speaking of a phase angle between them. Where in the process
did they pick up phase information? Or do you just mean when one is the
negative of the other? If so, how do you tell -- each has two roots,
that is, Sqrt(Pfwd*Z0) can be either positive or negative, and so can
Sqrt(Pfref*Z0). How do you know when one is the negative of the other?


V^2/Z0=P is a well known equation (so is I^2*Z0=P). These are *RMS* values.
So the RMS voltage is V = Sqrt(Pfwd*Z0). Root Mean Square AC voltages are
equivalent to DC voltages in power dissipation and are generally considered
to be positive values because they are the sum of squared terms. We can turn
those RMS voltages into phasors by adding the phase angles. When Vfwd+Vref = Vmax,
Vfwd and Vref are in phase (at the SWR voltage maximum point). When Vfwd+Vref = Vmin,
Vfwd and Vref are 180 degrees out of phase (at the SWR voltage minimum point).
Vmax/Vmin = VSWR. Please feel free to pull my leg again anytime. :-)
--
73, Cecil http://www.qsl.net/w5dxp



-----= Posted via Newsfeeds.Com, Uncensored Usenet News =-----
http://www.newsfeeds.com - The #1 Newsgroup Service in the World!
-----== Over 100,000 Newsgroups - 19 Different Servers! =-----


 
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
Re-Normalizing the Smith Chart (Changing the SWR into the same load) Dr. Slick Antenna 98 August 30th 03 03:09 AM
Length of Coax Affecting Incident Power to Meter? Dr. Slick Antenna 140 August 18th 03 08:17 PM


All times are GMT +1. The time now is 12:16 AM.

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