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#411
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Analyzing Stub Matching with Reflection Coefficients
On Apr 27, 7:28 am, Cecil Moore wrote:
Keith Dysart wrote: Okay, so you can't find anything to point at that is wrong with the model. What is wrong with the model is that it doesn't work in reality. Hmmm. Having a complete inability to articulate any issues with the model, you are, none-the-less, convinced that it does not work in 'reality'. Hmmm. Of course I claimed no such thing; you do need to read more carefully. And you have conveniently neglected the other example which was presented right beside for which 4 times the "reflected power" was dissipated by the source. These two completely different results call into question the nature of "reflected power". No, they call into question the validity of the model. The reflected energy is there and can be dissipated by a circulator load. The fact that zero energy is dissipated in a source is prima facie evidence of destructive interference and a "redistribution of energy in a direction that allows constructive interference". But then what is the fact that 4 times the energy is dissipated in the source prime facie evidence of? Good explanations explain all the observations, not just the supporting ones. ....Keith |
#412
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Analyzing Stub Matching with Reflection Coefficients
Keith Dysart wrote:
Hmmm. Having a complete inability to articulate any issues with the model, you are, none-the-less, convinced that it does not work in 'reality'. Hmmm. I have been articulating issues with the model for weeks now and I am just about articulated out. We are repeating the same things over and over and unless you take time out to comprehend interference, there's no reason to continue. The fact that zero energy is dissipated in a source is prima facie evidence of destructive interference and a "redistribution of energy in a direction that allows constructive interference". But then what is the fact that 4 times the energy is dissipated in the source prime facie evidence of? Of *total constructive interference* in the source, of course. I already answered that question days ago. It is futile to try to communicate with someone who refuses to listen. Here are the power intensity equations governing the power dissipated in the two sources in the previous two examples. Thevenin equivalent if P1 = P2: Pdis = P1 + P2 - 2*SQRT(P1*P2) = 0 *Total Destructive Interference* as defined by Hecht in "Optics", 4th edition, page 388. Norton equivalent if P1 = P2: Pdis = P1 + P2 + 2*SQRT(P1*P2) = 4*P1 *Total Constructive Interference* as defined by Hecht in "Optics", 4th edition, page 388. Until you learn to recognize interference when it is staring you in the face, you are going to continue to make the same mistakes over and over. Forward and reflected energy is alive and well and obeys the conservation of energy principle. That you cannot figure out where the photonic energy goes during a wave interference event is not my problem. Hints about destructive interference: www.mellesgriot.com/products/optics/oc_2_1.htm "Clearly, if the wavelength of the incident light and the thickness of the film are such that a phase difference exists between reflections of p, then reflected wavefronts interfere destructively, and overall reflected intensity is a minimum. If the two reflections are of equal amplitude, then this amplitude (and hence intensity) minimum will be zero." Note that "intensity" is *power density* in watts/unit-area. "In the absence of absorption or scatter, the principle of conservation of energy indicates all 'lost' reflected intensity will appear as enhanced intensity in the transmitted beam. The sum of the reflected and transmitted beam intensities is always equal to the incident intensity. This important fact has been confirmed experimentally." http://micro.magnet.fsu.edu/primer/j...ons/index.html "... when two waves of equal amplitude and wavelength that are 180- degrees out of phase with each other meet, they are not actually annihilated. All of the photon energy present in these waves must somehow be recovered or *redistributed in a new direction*, according to the *law of energy conservation* ... Instead, upon meeting, the photons are *redistributed to regions that permit constructive interference*, so the effect should be considered as a *redistribution* of light waves and photon energy rather than the spontaneous construction or destruction of light." emphasis mine -- 73, Cecil http://www.w5dxp.com |
#413
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Analyzing Stub Matching with Reflection Coefficients
Cecil Moore wrote:
Keith Dysart wrote: Certainly the model I described is linear. Is there some other fault in the model that makes it sufficiently incorrect to be unusable? Yes, it doesn't model a class-C amplifier. Cecil, I heard a rumor that the FCC does not like people to inject class-C type pulses directly into an antenna from the output of an amateur transmitter. Perhaps that rumor is just an urban legend, however, and non-linear outputs are welcome. 8-) 73, Gene W4SZ |
#414
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Analyzing Stub Matching with Reflection Coefficients
Gene Fuller wrote:
I heard a rumor that the FCC does not like people to inject class-C type pulses directly into an antenna from the output of an amateur transmitter. Perhaps that rumor is just an urban legend, however, and non-linear outputs are welcome. The subject is modeling a class-C source, Gene, not filtering a class-C source. We all know how to filter a class-C source. Do you have a model for a class-C source? -- 73, Cecil http://www.w5dxp.com |
#415
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Analyzing Stub Matching with Reflection Coefficients
Cecil Moore wrote:
Gene Fuller wrote: I heard a rumor that the FCC does not like people to inject class-C type pulses directly into an antenna from the output of an amateur transmitter. Perhaps that rumor is just an urban legend, however, and non-linear outputs are welcome. The subject is modeling a class-C source, Gene, not filtering a class-C source. We all know how to filter a class-C source. Do you have a model for a class-C source? Cecil, The original topic was the *output* of an amateur transceiver, e.g., as seen by a transmission line. Sorry I did not catch the thread redefinition toward the inner workings of such a device. That move could open up infinite opportunity for more arguments. 8-) 73, Gene W4SZ |
#416
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Analyzing Stub Matching with Reflection Coefficients
Gene Fuller wrote:
Sorry I did not catch the thread redefinition toward the inner workings of such a device. Apology accepted. The crux of what we have been discussing for days, if not weeks, is what does a model of the active, dynamic volcano of energy, i.e. the source, look like? -- 73, Cecil http://www.w5dxp.com |
#417
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Rotational speed
Cecil Moore wrote: Cecil Moore wrote: Jim Kelley wrote: Rotational speed has nothing to do with direction of travel. I assumed that the "same rotational speed" implies the same direction. The reason I assumed that is this assertion by W7EL. "This is the total current. It has magnitude and phase like any other phasor, and the same rotational speed as its components." The total current, as graphed by Kraus and displayed by EZNEC *DOES NOT* have the same rotational speed as its components. It is obvious that Roy meant the same direction when he said "same rotational speed". I'm sure you're in a better position to know that than Roy is. ac6xg |
#418
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Rotational speed
Jim Kelley wrote:
Cecil Moore wrote: Cecil Moore wrote: Jim Kelley wrote: Rotational speed has nothing to do with direction of travel. I assumed that the "same rotational speed" implies the same direction. The reason I assumed that is this assertion by W7EL. "This is the total current. It has magnitude and phase like any other phasor, and the same rotational speed as its components." The total current, as graphed by Kraus and displayed by EZNEC *DOES NOT* have the same rotational speed as its components. It is obvious that Roy meant the same direction when he said "same rotational speed". I'm sure you're in a better position to know that than Roy is. It's a matter of logic, Jim. We know that the forward current and reflected current phasors are rotating in opposite directions. Kraus and EZNEC say that the phase angle of the current on a 1/2WL dipole changes by only 2 degrees, end to end. Therefore, contrary to what Roy asserted, the total current does NOT have the same rotational speed as its components. That was Roy's mistake in using total current to try to measure phase shift through a coil. One cannot use total current phase on a standing wave antenna to determine any valid measurement concerning phase shift through a coil. But since the phase information is preserved in the total current amplitude, it can be used to estimate phase shift through the coil. Roy said, "What I measured was a 3.1% reduction in magnitude from input to output, with no discernible phase shift." From this, for a base-loaded coil we can estimate the phase shift through the coil to be arccos(.969) = 14.3 degrees With no discernible phase shift we can estimate that there was no decrease in current from end to end for either the forward current or reflected current. -- 73, Cecil http://www.w5dxp.com |
#419
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Rotational speed
Cecil Moore wrote: We know that the forward current and reflected current phasors are rotating in opposite directions. Kraus and EZNEC say that the phase angle of the current on a 1/2WL dipole changes by only 2 degrees, end to end. Therefore, contrary to what Roy asserted, the total current does NOT have the same rotational speed as its components. Due to the shape of the North American elk's esophagus, even if it could speak, it could not pronounce the word lasagna. Cliff Claven |
#420
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Rotational speed
Jim Kelley wrote:
Cecil Moore wrote: We know that the forward current and reflected current phasors are rotating in opposite directions. Kraus and EZNEC say that the phase angle of the current on a 1/2WL dipole changes by only 2 degrees, end to end. Therefore, contrary to what Roy asserted, the total current does NOT have the same rotational speed as its components. Due to the shape of the North American elk's esophagus, even if it could speak, it could not pronounce the word lasagna. The technical content of your posting is noted. Roy can easily verify that EZNEC disagrees with his assertion that "the total current has the same rotational speed as its components". The total current has hardly any rotational speed at all, i.e. 2 degrees of rotation end-to-end in 180 degrees of a 1/2WL dipole. -- 73, Cecil http://www.w5dxp.com |
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