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## [antennaware] RE: SWR from R,X,Zo

 To: [antennaware] RE: SWR from R,X,Zo ludal@dmv.com (Dallas Carter) Wed, 4 Aug 1999 11:09:14 -0400
 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[((R-Zo)^2 +X^2)/((R+Zo)^2 +X^2)] SWR = (1+refl)/(1-refl) You can combine these two formulas into one for SWR SWR = {1+sqrt[((R-Zo)^2 +X^2)/((R+Zo)^2 +X^2)]}/ {1-sqrt[((R-Zo)^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 -- FAQ on WWW: http://www.contesting.com/antennaware-faq.html Submissions: antennaware@contesting.com Administrative requests: antennaware-REQUEST@contesting.com Problems: owner-antennaware@contesting.com
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