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#1
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Jim Kelley wrote:
Just cut the BS, Cecil. In order to prove your assertion you must first be able to describe how two co-linear, coherent waves that are 180 degrees out of phase at every point along their path and traveling in the same direction can under those circumstances at any time produce measureable energy. In addition, you must be able to measure it. Let me know when you do. It is an indirect measurement, Jim. Given the s-parameter equation, b1 = s11*a1 + s12*a2 = 0, s11 is not zero, a1 is not zero, s12 is not zero, and a2 is not zero. Although HP cannot measure those quantities either, they tell us that |s11*a1|^2 is in watts, e.g. 100 watts. They tell us that |s12*a2|^2 is in watts, e.g. 100 watts. When all energy is accounted for, it is obvious that those 200 watts are no longer in the direction of the source but have changed direction toward the load. This ain't rocket science. If reflections are eliminated toward the source by wave cancellation, the reflected energy is redistributed back toward the load just as explained on the Melles-Groit and FSU web pages. If it weren't headed for the source in the first place, they wouldn't say it was "REDISTRIBUTED". If 200 joules/sec disappear toward the source and there are only two directions in a transmission line, do you really want to tell us that you can't figure out in which direction those joules go? Do you need help from my 10 year old grandson? You clearly fail to understand the process defined by the wave reflection distributed network model. Until you are in a position to discredit that model, you are just blowing smoke. -- 73, Cecil http://www.w5dxp.com |
#2
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![]() Cecil Moore wrote: Jim Kelley wrote: Just cut the BS, Cecil. In order to prove your assertion you must first be able to describe how two co-linear, coherent waves that are 180 degrees out of phase at every point along their path and traveling in the same direction can under those circumstances at any time produce measureable energy. In addition, you must be able to measure it. Let me know when you do. It is an indirect measurement, Jim. :-) Sure thing. Like I said, let me know when you measure energy in the canceled waves. ac6xg |
#3
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Jim Kelley wrote:
Cecil Moore wrote: It is an indirect measurement, Jim. :-) Sure thing. Like I said, let me know when you measure energy in the canceled waves. Let me know when you figure out an explanation for the reversal of momentum in those reflected waves. So far, you have absolutely refused to provide any explanation. -- 73, Cecil http://www.w5dxp.com |
#4
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![]() Cecil Moore wrote: Jim Kelley wrote: Cecil Moore wrote: It is an indirect measurement, Jim. :-) Sure thing. Like I said, let me know when you measure energy in the canceled waves. Let me know when you figure out an explanation for the reversal of momentum in those reflected waves. So far, you have absolutely refused to provide any explanation. The momentum in reflected waves changes direction upon reflection. What part of that do you need to have explained? So, back to you. Let's hear more about your measurement of canceled waves. ac6xg |
#5
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Jim Kelley wrote:
The momentum in reflected waves changes direction upon reflection. What part of that do you need to have explained? What causes 100% reflection when the power reflection coefficient (reflectance) is only 0.5? -- 73, Cecil http://www.w5dxp.com |
#6
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Cecil Moore wrote:
Jim Kelley wrote: The momentum in reflected waves changes direction upon reflection. What part of that do you need to have explained? What causes 100% reflection when the power reflection coefficient (reflectance) is only 0.5? If you would just work the problem the hard way, you would see where you're misconception lies. Any given wave front will never reflect 100% from a surface which is only 50% reflective, no matter how vicious your insults become, how may URLs you cut and paste, or how furiously you wave your hands. But when you work the problem as has been suggested you will see how energy gets from source to load. It does not rely on macroscopic layman's explanations or mathematical shortcuts in order to get there. The only energy "lost" by partial reflection in the process is that which is reflected back toward the source or stored in the system during the transient period. The sum of all the partial reflections equals the energy stored in the system (less the portion of energy admitted to the load or reflected back to the source). After the transient period, no energy is reflected back to the source, and the energy entering the system from the source equals the energy existed the system through the load. I know that you understand the difference between potential and kinetic energy in mechanics. Please try to consider that the concepts are no less valid in electromagnetism. (Note that we even use the word 'potential' to describe voltage.) 73, ac6xg |
#7
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Jim Kelley wrote:
Any given wave front will never reflect 100% from a surface which is only 50% reflective, That's all you have to say, Jim, to defeat your argument. If you would stop refusing to perform a simple calculation involving my example at: http://www.w5dxp.com/thinfilm.GIF you would understand. When the internal (0.009801w) wave reflection arrives at t3 and interferes with the (0.01w) external reflection wave, what is the resulting reflected power back toward the source. When you calculate the results and realize that it is not 0.01 - 0.009801 watts, you will begin to understand the nature of interference. -- 73, Cecil http://www.w5dxp.com |
#8
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Jim Kelley wrote:
Cecil Moore wrote: Jim Kelley wrote: Just cut the BS, Cecil. In order to prove your assertion you must first be able to describe how two co-linear, coherent waves that are 180 degrees out of phase at every point along their path and traveling in the same direction can under those circumstances at any time produce measureable energy. In addition, you must be able to measure it. Let me know when you do. It is an indirect measurement, Jim. :-) Sure thing. Like I said, let me know when you measure energy in the canceled waves. At the risk of being both a dullard and messing up all the fun, does not every destructive interference have to be balanced by a constructive interference, which in turn leads to a condition of "Okey dokey?" A canceled wave needs a reinforced wave, and then nothing is lost, nothing is gained. - 73 de Mike N3LI - |
#9
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Michael Coslo wrote:
At the risk of being both a dullard and messing up all the fun, does not every destructive interference have to be balanced by a constructive interference, which in turn leads to a condition of "Okey dokey?" Yep, any destructive interference toward the source is exactly offset by constructive interference toward the antenna. If one takes time to calculate the component phasor voltages on both sides of a Z0-match located away from the source, the constructive and destructive interference is obvious. A canceled wave needs a reinforced wave, and then nothing is lost, nothing is gained. Exactly. The reflected energy that appears to be lost as destructive interference in the direction of the source when a Z0-match is achieved, is recovered in the forward wave as constructive interference energy traveling toward the antenna. -- 73, Cecil http://www.w5dxp.com |
#10
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![]() Michael Coslo wrote: At the risk of being both a dullard and messing up all the fun, does not every destructive interference have to be balanced by a constructive interference, which in turn leads to a condition of "Okey dokey?" A canceled wave needs a reinforced wave, and then nothing is lost, nothing is gained. - 73 de Mike N3LI - Hi Mike - One could suggest a number of different possible scenarios in which nothing is lost or gained. But an impossible scenario is one which violates thermodynamic principles. Another might describe phenomena which is not in accord with Maxwell's equations. One should therefore feel comfortable discarding any description which is inconsistent with both thermodynamics and Maxwell's equations. 73, ac6xg |
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