Dave, Thanks a million for the help. That's exactly the formula that I have
been searching for.
It is correct and plugs into basic very nicely. Now I can continue with my
xmission line
matching and find values that yield acceptable matches with the help of W4RNL's
fine
tutorial on the subject. 73 Dallas W3PP

From: Leeson[SMTP:leeson@earthlink.net]
Sent: Wednesday, August 04, 1999 9:02 AM
To: Dallas Carter
Subject: SWR from R,X,Zo
Here's the formula derivation for SWR from known R, X and Zo:
Reflection coefficient refl = sqrt[((RZo)^2 +X^2)/((R+Zo)^2 +X^2)]
SWR = (1+refl)/(1refl)
You can combine these two formulas into one for SWR
SWR = {1+sqrt[((RZo)^2 +X^2)/((R+Zo)^2 +X^2)]}/
{1sqrt[((RZo)^2 +X^2)/((R+Zo)^2 +X^2)]}
Try this out with various values for which you know the SWR to be sure
I've gotten all the details right. For example,
For R = Zo, X = 0, refl = 0 and SWR = 1
For R = 0, X = Zo, refl = 1 and SWR = infinity
For R = X = Zo, refl = 0.45 and SWR = 2.62
Give this a try...
73 de Dave Leeson, W6NL/HC8L
leeson@nova.stanford.edu

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