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#61
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On Sun, 24 Aug 2003 12:22:34 +0100, "Ian White, G3SEK"
wrote: [*] Well-known to some college students in the USA, perhaps? I'd never heard of him, but Dan's summary suggests this book might be worth looking for. Hi Ian, Any university student in course work relating to Transmission lines would have a copy. It comes from a successful line of tutorials known as "Schaum's Outlines." Chipman also discusses the relevancy of the characteristic Z of a source to SWR, which is tucked away in the unread part. ;-) 73's Richard Clark, KB7QHC |
#62
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On Sun, 24 Aug 2003 11:26:00 -0500, "William E. Sabin"
sabinw@mwci-news wrote: Richard Clark wrote: To date their best argument is you cannot possibly know that value (for any of a variety of reasons, unrelated to simply sitting down at the bench and measuring an actual value). In short, institutionalized ignorance, embraced with a mystic missionary zeal, is their crowing logic. The problem lies in the difficulty of measuring or calculating Zs, especially for signals that have large variations in amplitude, such as SSB. There is no institutionalized ignorance, just a lot of skepticism regarding the reliability of the analysis methods and the measurement methods. Bill W0IYH Hi Bill, If the best that skeptics can offer to methods described and data obtained are "it's not important" or "the time is not justified going there;" then that is not a particularly high bar of excellence in reasoning and remains thinly veiled institutionalized ignorance. Or call it intellectual glaciation, the insurmountable obstacles plea as argument defending naysaying is frayed and time worn. This is all "special engineering olympics" caliber justification. Perhaps the correspondents who enter into these debates should have their handicaps posted somewhere so the odds makers could weigh the risks of following such gold medal champions. 73's Richard Clark, KB7QHC |
#63
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"Richard Clark" wrote in message ... Chipman also discusses the relevancy of the characteristic Z of a source to SWR, which is tucked away in the unread part. ;-) 73's Richard Clark, KB7QHC Richard, There used to be a Dr. Chipman who taught a fields/waves course at the University of Toledo (OH) in the 60s. Do you know if it is the same guy? Tam/WB2TT |
#64
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#66
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#67
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"Dr. Slick" wrote in message om... (Tdonaly) wrote in message ... You know, Garvin, if you can't even tell the numerator from the denominator, you're in sad shape. Maybe you should stick to playing your guitar and doodling. 73, Tom Donaly, KA6RUH Maybe you should stick to your all-night wanking sessions... Slick one word --- blisters |
#68
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"Dr. Slick" wrote in message om... [s]**2 = [(ZL - Zo*) / (ZL + Zo)]**2 the "power reflection coefficent". Note the squares. yes, please do note the squares.... and remember, just because [s]**2 = [(ZL - Zo*) / (ZL + Zo)]**2 does NOT mean that s = (ZL - Zo*) / (ZL + Zo) this is the one big trap that all you guys that like to use power in your calculations fall into. just because you know the power doesn't mean that you know squat about the voltage and current on the line. you can not work backwards. that is why it is always better to work with voltage or current waves and then in the end after you have solved all those waves you can always calculate power if you really need to know it. |
#69
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Peter O. Brackett wrote:
s11 is a reflection coefficient that has the special condition that a2 must be equal zero. When a2 is not equal zero, the s11 reflection coefficient and the apparent reflection coefficient (rho) are not the same. No! The scattering paramters, e.g for a two-port the s11, s12, s21 and s22 are all parameters fixed by the network and are not dependent upon either the independent or dependent variables! i.e. b1 = s11*a1 + s12*a2, and b2 = s21*a1 + s22* a2. I'm sorry, Peter, but you probably misunderstood me. s11 cannot possibly be the same as 'rho' when a2=100 watts. s11 = b1/a1 when a2=0. b1 is equal to something else if a2 is not zero. rho = Sqrt(Pref/Pfwd) These do NOT have to be the same values. That's all I was saying. -- 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! =----- |
#70
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Peter O. Brackett wrote:
Only the "electricals" the v and I are "real"! The "waves" the a and b are just different manifestations of v and i as viewed through and instrument [reflectometer] using a, perhaps arbitrary, reference impedance, or matrix transformation. Sorry Cecil. :-) Sorry Peter, quantum physics disagrees with you. It's the electrons, photons, and virtual photons that are real. :-) -- 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! =----- |
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