Dr. Slick wrote:
Cecil Moore wrote: Pz-/Pz+ = |rho|^2 and take the square root of each side. And this shows us that if [rho] is greater than one, the reflected power will be greater than the incident power. Maybe, or maybe the equation assumes Z0 is not complex. I don't know the assumptions. Which leads to another question. Can the index of refraction for a material be complex? To the best of my knowledge, there's no mention of complex indices of refraction in _Optics_. ... most of the literature has rho=[gamma]. Where gamma is the complex reflection coefficient, and rho is only the magnitude. That is the convention I use. Unfortunately, it is not universal and may even be old-fashioned, like me. :-) -- 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! =----- |
Cecil Moore wrote:
wrote: My gosh, you work hard to find disagreement. In my sentence above, please update "there are NET reflections" with "there may be NET reflections". Shirley, you can understand that the first statement is an absolute- exclusive and the second statement is a conditional-inclusive and are logically opposite statements, one false and the other true. That is the beauty of reading for disagreement; you can always justify the disagreement. If readers spent just a small fraction of their effort interpreting for agreement instead, discussion would flow so much more smoothly. Interpreting an exclusive statement as an inclusive statement is logically invalid. To read for agreement, the reader examines statements in context and ignores the minor inconsistencies that the author has made in the prose. Taking each statement out of context and examining it individually will provide a myriad of opportunities for finding disagreement, if that is the objective. Sometimes, there are net reflections existing where there is no impedance discontinuity. Excellent. Agreement. Nope, not agreement. Your absolute statement was false. My conditional statement is true. There it is again; searching for disagreement. If you had said 'sometimes', your statement would have been true instead of false. And is that not exactly what I did with my clarification to the original sentence? Are you sure that you do not read with the intent of maximizing disagreement? ....Keith |
wrote:
And is that not exactly what I did with my clarification to the original sentence? Thanks for correcting your error. -- 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! =----- |
Keith wrote:
"---it is this cyclical variation in energy flow which prompted power dudes to invent three phase lines in which energy flow does not vary cycillaly, power is constant." It`s true the wires are shared by multiple phases which peak 120-degrees apart in the 3-phase case. This distributes power flow more evenly with respect to time and reduces peak loads since the phases never coicide. Tesla figured this out 100 years ago. Coincidences of incident and reflected waves are very different from the cyclical variations of a-c. Incident and reflected waves have cyclical voltages and currents. As the reflected wave is just a delayed incident wave, the period is the same for both. In those line spots where the total reflected voltage is 180-degrees different in phase from the incident wave, the net voltage is always zero during the cycle if the reflection is complete on a lossless line. The power is not zero at points where the voltage is always zero because the voltages that add to zero are not zero. In the lossless line, these voltages are full strength, as are the currents at a current null, some 90-degrees away in space from the voltage null on the line. Fact is, both the forward power and the reflected power would measure the same at any point along the line. The wave action has been observed and documented for more than a century. The explanations withstand all arguments, so far. Something new will be needed to replace the ancient wave theory to win acceptance. Keith`s zero power at zero null spots won`t persuade. The power appearing to null is not the whole story when there are forward and reflected powers, each having electric and magnetic fields with phase differences all around. Best regards, Richard Harrison, KB5WZI |
W5DXP wrote: wrote: W5DXP wrote: Jim Kelley wrote: Nodes and zero crossings aren't necessarily the same thing. They are for standing waves on lossless unterminated lines, by definition. Zero crossings are not unique to standing wave patterns, therefore nodes and zero crossing aren't necessarily the same thing. What are you claiming crosses zero at a node in a standing wave pattern? 73 de ac6xg |
Cecil Moore wrote: To the best of my knowledge, there's no mention of complex indices of refraction in _Optics_. Born and Wolf has a chapter on the Optics of Metals. Chapter 13.1 is called Wave Propagation in a Conductor. In it, they use a complex wave number, complex dielectric constant, complex phase veloctity, and a complex refractive index. 73, Jim AC6XG |
Jim Kelley wrote:
Zero crossings are not unique to standing wave patterns, therefore nodes and zero crossing aren't necessarily the same thing. A zero crossing exists at a node in a lossless unterminated transmission line. If they were the same thing there wouldn't need to be two different names, would there? -- 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! =----- |
Jim Kelley wrote:
Cecil Moore wrote: To the best of my knowledge, there's no mention of complex indices of refraction in _Optics_. Born and Wolf has a chapter on the Optics of Metals. Chapter 13.1 is called Wave Propagation in a Conductor. In it, they use a complex wave number, complex dielectric constant, complex phase veloctity, and a complex refractive index. Yep, also found it in _Optics_ under "Waves in a Metal". -- 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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