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#1
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Roy Lewallen wrote:
A single conductor doesn't have a characteristic impedance -- it's the impedance between the two conductors of a transmission line. You can measure a characteristic impedance between, say, a coil and ground, but its value depends on the spacing between the two. If the coil is tilted with respect to the ground, the impedance of this two-conductor system will change with the position along the coil. Roy: I understand what you are saying. But the derivation of Characteristic Impedance in the Corum Bros. paper depends only on the coil dimensions and number of turns; it is independent of any relationship to other conductors or groundplanes. I also note that ON4AA's inductance calculator predicts the "Characteristic impedance of n=0 sheath helix waveguide mode at design frequency" based purely on the coil geometry. The maths is a bit beyond me (trying to solve Maxwell's equations for a solenoidal helix), but seems to bear analogy to the derivation of the characteristic impedance of a waveguide. I'm inclined to try to understand it better, because it's this derived Characteristic Impedance, along with the axial Velocity Factor, that generates the reactance values which seem such a good match to experimental and modelled results. Regards, Steve G3TXQ |
#2
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steveeh131047 wrote:
I'm inclined to try to understand it better, because it's this derived Characteristic Impedance, along with the axial Velocity Factor, that generates the reactance values which seem such a good match to experimental and modeled results. Steve, you will find some old-fashioned concepts here based on the lumped-circuit model rather than the distributed network EM wave reflection model. One can easily disprove the assertion that a single wire in free space doesn't have a characteristic impedance by asking the question: Does a single electromagnetic wave traveling through free space (without a wire) encounter a characteristic impedance? If so, why doesn't a single wave traveling through a wire in free space encounter a characteristic impedance? Of course, the ratio of the electric field to the magnetic field, whatever that turns out to be, is the characteristic impedance of a single wire in free space. It, like the characteristic impedance of free space, seems to be a few hundred ohms. There are lots of old wives tales asserted by the gurus on this newsgroup. One must be careful what one accepts as technical fact. "A single conductor doesn't have a characteristic impedance." is a preposterous assertion. If free space itself has a characteristic impedance, what are the chances that a single wire in free space would not have a characteristic impedance??? Zero, at best??? :-) Some will say: "Where is the return path for the current?" I will respond: Where is the return path for the "current" arriving from the Sun that can be captured by a solar panel? Good Grief! -- 73, Cecil, IEEE, OOTC, http://www.w5dxp.com |
#3
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On Apr 23, 10:07*am, Cecil Moore wrote:
steveeh131047 wrote: I'm inclined to try to understand it better, because it's this derived Characteristic Impedance, along with the axial Velocity Factor, that generates the reactance values which seem such a good match to experimental and modeled results. Steve, you will find some old-fashioned concepts here based on the lumped-circuit model rather than the distributed network EM wave reflection model. One can easily disprove the assertion that a single wire in free space doesn't have a characteristic impedance by asking the question: Does a single electromagnetic wave traveling through free space (without a wire) encounter a characteristic impedance? If so, why doesn't a single wave traveling through a wire in free space encounter a characteristic impedance? Of course, the ratio of the electric field to the magnetic field, whatever that turns out to be, is the characteristic impedance of a single wire in free space. It, like the characteristic impedance of free space, seems to be a few hundred ohms. There are lots of old wives tales asserted by the gurus on this newsgroup. One must be careful what one accepts as technical fact. "A single conductor doesn't have a characteristic impedance." is a preposterous assertion. If free space itself has a characteristic impedance, what are the chances that a single wire in free space would not have a characteristic impedance??? Zero, at best??? :-) Some will say: "Where is the return path for the current?" I will respond: Where is the return path for the "current" arriving from the Sun that can be captured by a solar panel? Good Grief! -- 73, Cecil, IEEE, OOTC, *http://www.w5dxp.com Cecil, reference you comment that a straight wire does NOT have a characteristic impedance, this is one place where you misunderstanding things. A charge rests on the surface and when it is radiating it instantly is removed from the surface by the displacement current in coordination with the applied current. If the radiator is not a full wave length there is no surface for a displacement current to exist thus the direction of charge is not elevated away from the surface but continuing the parallel to the surface direction which is the observed as "end effect" If the concept of a bounce back of charge was maintained then the amount of charge must also change as time revolves around a full period where eventually the charge totally reaches the scource when the bouncing around coincided with a period. Thus if the charge is in "standing wave" form the impedance changes during every circuit of the charge back to the source and that can never be. Characteristic impedance is that seen only with a closed anti resonant point or in other words at the point of equilibrium which is represented by a period. Looking at things from a different angle, when the time varying field becomes a constant which is then the application of DC then you have a tesla coil where the spark or energy and thus radiation is parallel to the conductor and where the period covered by over shoot, a one time event, where radio radiation is shown by the area of the curve during the time of that event. Best regards Art |
#4
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On Apr 23, 11:16*am, Art Unwin wrote:
On Apr 23, 10:07*am, Cecil Moore wrote: steveeh131047 wrote: I'm inclined to try to understand it better, because it's this derived Characteristic Impedance, along with the axial Velocity Factor, that generates the reactance values which seem such a good match to experimental and modeled results. Steve, you will find some old-fashioned concepts here based on the lumped-circuit model rather than the distributed network EM wave reflection model. One can easily disprove the assertion that a single wire in free space doesn't have a characteristic impedance by asking the question: Does a single electromagnetic wave traveling through free space (without a wire) encounter a characteristic impedance? If so, why doesn't a single wave traveling through a wire in free space encounter a characteristic impedance? Of course, the ratio of the electric field to the magnetic field, whatever that turns out to be, is the characteristic impedance of a single wire in free space. It, like the characteristic impedance of free space, seems to be a few hundred ohms. There are lots of old wives tales asserted by the gurus on this newsgroup. One must be careful what one accepts as technical fact. "A single conductor doesn't have a characteristic impedance." is a preposterous assertion. If free space itself has a characteristic impedance, what are the chances that a single wire in free space would not have a characteristic impedance??? Zero, at best??? :-) Some will say: "Where is the return path for the current?" I will respond: Where is the return path for the "current" arriving from the Sun that can be captured by a solar panel? Good Grief! -- 73, Cecil, IEEE, OOTC, *http://www.w5dxp.com Cecil, reference you comment that a straight wire does NOT have a characteristic impedance, this is one place where you misunderstanding things. A charge rests on the surface and when it is radiating it instantly is removed from the surface by the displacement current in coordination with the applied current. If the radiator is not a full wave length there is no surface for a displacement current to exist thus the direction of charge is not elevated away from the surface but continuing the parallel to the surface direction which is the observed as "end effect" If the concept of a bounce back of charge was maintained then the amount of charge must also change as time revolves around a full period where eventually the charge totally reaches the scource when the bouncing around coincided with a period. Thus if the charge is in "standing wave" form the impedance changes during every circuit of the charge back to the source and that can never be. Characteristic impedance is that seen only with a closed anti resonant point or in other words at the point of equilibrium which is represented by a period. Looking at things from a different angle, when the time varying field becomes a constant which is then the application of DC then you have a tesla coil where the spark or energy and thus radiation is parallel to the conductor and where the period covered by over shoot, a one time event, where radio radiation is shown by the area of the curve during the time of that event. Best regards Art Cecil, You based your proof of a magnetic wave in a vacuum but it is an accelerating charge which obviously must have mass, that is radiation ala the particle. If you have a Tesla set up in a vacuum the speed of the particle/spark/ light is the approximation of the speed of light.( I say approximation since I am using the metric of Earth's vacuum and not that of the Universe) The velocity factor is the true ratio of the mismatch with the travel of a electric current on Earth with all its relavent factors and comparing it to the speed of light in the average metric of vacuum of the Universe. Bottom line is particles are part of radiation as is light, "waves" are not involved other than a bevy of particles separated by a fraction of a period. Art |
#5
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On Apr 23, 12:22*pm, Art Unwin wrote:
On Apr 23, 11:16*am, Art Unwin wrote: On Apr 23, 10:07*am, Cecil Moore wrote: steveeh131047 wrote: I'm inclined to try to understand it better, because it's this derived Characteristic Impedance, along with the axial Velocity Factor, that generates the reactance values which seem such a good match to experimental and modeled results. Steve, you will find some old-fashioned concepts here based on the lumped-circuit model rather than the distributed network EM wave reflection model. One can easily disprove the assertion that a single wire in free space doesn't have a characteristic impedance by asking the question: Does a single electromagnetic wave traveling through free space (without a wire) encounter a characteristic impedance? If so, why doesn't a single wave traveling through a wire in free space encounter a characteristic impedance? Of course, the ratio of the electric field to the magnetic field, whatever that turns out to be, is the characteristic impedance of a single wire in free space. It, like the characteristic impedance of free space, seems to be a few hundred ohms. There are lots of old wives tales asserted by the gurus on this newsgroup. One must be careful what one accepts as technical fact. "A single conductor doesn't have a characteristic impedance." is a preposterous assertion. If free space itself has a characteristic impedance, what are the chances that a single wire in free space would not have a characteristic impedance??? Zero, at best??? :-) Some will say: "Where is the return path for the current?" I will respond: Where is the return path for the "current" arriving from the Sun that can be captured by a solar panel? Good Grief! -- 73, Cecil, IEEE, OOTC, *http://www.w5dxp.com Cecil, reference you comment that a straight wire does NOT have a characteristic impedance, this is one place where you misunderstanding things. A charge rests on the surface and when it is radiating it instantly is removed from the surface by the displacement current in coordination with the applied current. If the radiator is not a full wave length there is no surface for a displacement current to exist thus the direction of charge is not elevated away from the surface but continuing the parallel to the surface direction which is the observed as "end effect" If the concept of a bounce back of charge was maintained then the amount of charge must also change as time revolves around a full period where eventually the charge totally reaches the scource when the bouncing around coincided with a period. Thus if the charge is in "standing wave" form the impedance changes during every circuit of the charge back to the source and that can never be. Characteristic impedance is that seen only with a closed anti resonant point or in other words at the point of equilibrium which is represented by a period. Looking at things from a different angle, when the time varying field becomes a constant which is then the application of DC then you have a tesla coil where the spark or energy and thus radiation is parallel to the conductor and where the period covered by over shoot, a one time event, where radio radiation is shown by the area of the curve during the time of that event. Best regards Art Cecil, You based your proof of a magnetic wave in a vacuum but it is an accelerating charge which obviously must have mass, that is radiation ala the particle. If you have a Tesla set up in a vacuum the speed of the particle/spark/ light is the approximation of the speed of light.( I say approximation since I am using the metric of Earth's vacuum and not that of the Universe) The velocity factor is the true ratio of the mismatch with the travel of a electric current on Earth with all its relavent factors and comparing it to the speed of light in the average metric of vacuum of the Universe. Bottom line is particles are part of radiation as is light, "waves" are not involved other than a bevy of particles separated by a fraction of a period. Art When students perform an experiment to proove the laws of Nature it really does belittle seeing is believing. To change the statistics of what we are seeing which is the situation on Earth, this alludes the"relative" term of Einstein, then to bring what we deduced by seeing by the conversion of weight to mass. This correction thus brings in to focus what Einstein meant by relativity because it depends on the gravitational pull relative to what part of the Universe the experiment was performed. What we term as Classical physics is the behavior of the Universe and the laws that govern it. Thus mass is the carrier of potential energy where decay is synonamous with the break off of a particle which contains a portion of the potential energy where the brake off is the decelleration of the partical when it enters a different gravitational field and thus turns to kinetic energy and where this change is seen as light i.e Kinetic energy that is transformed to heat which also governs light. Thus when considering a perfect conductor ie zero resistance which is also a measure of the datum level of zero movement of electrons within mass there is zero movement within mass to affect the passage of current and thus the current travels at the speed of light. When temperature in not at the datum level it is the movement of electron within mass that provides the resistance to current flow and thus we have what is known as the "velocity factor", and it is the circular movement of displacement current which is also a movement of current flow that applies what we know as displacement current. Thus there is a Universal law of nature because all things revolve about the relative movement of particles compared to that of a static particle which if the change is instantaneous we have what Hawkings calls the BIG BANG. All of the above emphasises where all the participants of this thread are argueing about the same problem but from different relative positions within the Universe Lesson. All scientific debate is correlated to the whole of the Universe and not the metric datum of vacuum as represented by the size of a arbitrary fieldwithin the Universe This is what is meant by CLASSICAL PHYSICS. Enuff said. Art Unwin |
#6
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Art Unwin wrote:
You based your proof of a magnetic wave in a vacuum but it is an accelerating charge which obviously must have mass, that is radiation ala the particle. The accelerating charges are slow-moving electrons. The RF current moves at the speed of light in the (conductive) medium. Therefore, the RF current is associated with photons emitted by the electrons. Photons have zero rest mass and zero electric charge. Photons are the particles associated with RF waves. -- 73, Cecil, IEEE, OOTC, http://www.w5dxp.com |
#7
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On Apr 23, 3:22*pm, Cecil Moore wrote:
Art Unwin wrote: You based your proof of a magnetic wave in a vacuum but it is an accelerating charge which obviously must have mass, that is radiation ala the particle. The accelerating charges are slow-moving electrons. The RF current moves at the speed of light in the (conductive) medium. Therefore, the RF current is associated with photons emitted by the electrons. Photons have zero rest mass and zero electric charge. Photons are the particles associated with RF waves. -- 73, Cecil, IEEE, OOTC, *http://www.w5dxp.com Cecil there you go again with the idea that zero mass and zero energy is something that can exist which some have termed as "photons" Point to the laws of nature that support that notion. At one time it was the same as a particle without mass. Presence science now state that particular particle does have mass which is why the World spent millions for the CERN project. Your technical expertise is built on the state of science 50 years ago and you are now building a castle on sand or excuses to justify your unwillingness to embrace change. It took 7 days to build the Universe by the initial expenditure of kinetic energy which embraces the laws of nature and the concept of a cycle or equilibrium. Remember the words" let there be light" which aligns with energy expenditure upon mass ie everything starts with the expenditure of energy upon or from mass it is not a chicken or egg analogy. And it is expenditure of energy upon mass that makes it a particle unconnected to all mass around it such that the particle is unbound and cannot be absorbed by another state. Lets face it, Adam and Eve knew nothing regarding equilibrium and the notion of frequency or period. All the work had been completed way belong that came upon the scene,, which is why religeon exists as the sole explanation of who and what was and is in charge with respect to the laws of nature. Again it is impossible for something to exist without mass. Art |
#8
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Art Unwin wrote:
Cecil there you go again with the idea that zero mass and zero energy is something that can exist which some have termed as "photons" Point to the laws of nature that support that notion. It's part of the standard model, Art, with which I am not about to disagree. http://en.wikipedia.org/wiki/Standard_Model -- 73, Cecil, IEEE, OOTC, http://www.w5dxp.com |
#9
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On Apr 23, 3:22*pm, Cecil Moore wrote:
Art Unwin wrote: You based your proof of a magnetic wave in a vacuum but it is an accelerating charge which obviously must have mass, that is radiation ala the particle. The accelerating charges are slow-moving electrons. The RF current moves at the speed of light in the (conductive) medium. Therefore, the RF current is associated with photons emitted by the electrons. Photons have zero rest mass and zero electric charge. Photons are the particles associated with RF waves. -- 73, Cecil, IEEE, OOTC, *http://www.w5dxp.com You are quoting the aproach of the bookswhere it is acknowledged that radiationn cannot fully be explained For me I am quoting an alternative that does provide the explanation. If current moves at the speed of light within the Universe ( the speed of light relative to Earth is slower which creates delay compared to the former. Insertion of Plank's constant I believe is a metric that represents the ratio of that delay) it imparts the same speed to a static particle when impacted, where the acceleration is determined by Newton's law u.t +f.t sq/2. Since the particle is static the "u.t" portion equals zero and f.t.sq/2 is the acceleration from zero to that of the speed of current of the particle, which is a measure of the expended kinetic energy that creates the initial format of radiation. I state again without mass there can be no acceleration.Period Regards Art |
#10
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![]() "Art Unwin" wrote in message ... I state again and again, and again, adding bafflegab and gobbledygook with every iteration... I love it art, how much deeper can you go with this? |
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