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"Richard Clark" wrote in message ... On Fri, 05 Nov 2004 13:57:16 -0600, Cecil Moore wrote: The combined effort to suppers the ideas of Kraus and Balanis is getting Darn spellchecker. "suppers" should be "suppress". more ridiculous with each passing day. It can no longer be explained by ignorance. Blame the spellchecker? C'mon, Richard. That's a cheap shot beneath even you, I thought. |
"Richard Clark" wrote in message ... On Fri, 05 Nov 2004 07:45:16 GMT, Richard Clark wrote: So much for theories of Rr being modified by loading. I would appreciate other effort in kind to correct any oversights I've made Hi All, Nothing to offer? I didn't think so. :-) Well, to enlarge the dialogue (but still reject those who prefer to change the topic to what they CAN prove), any -ahem- "explanations?" 73's Richard Clark, KB7QHC Did you say something, Richard? |
"Richard Clark" wrote in message ... On Fri, 05 Nov 2004 10:45:57 -0800, Jim Kelley wrote: I have a question. Can you express the mathematical and/or physical relationship between Rr and antenna gain? It would sure help to clarify the point you were trying to make. Hi Jim, I would have thought someone else could, given the bandwidth of discussion in making the current taper shorter and the constant current section longer. Testing does not bear their facile relationship out however, and for the topic of a short antenna (otherwise, why are we talking about loading coils?) it would seem that antenna gain is immutable over several octaves below a quarterwave length. Of course, I coulda done something wrong. I did use a commonly available design. I did use a commonly available modeler. I even may have done the wrong thing in choosing a design that could be evaluated for free. Perhaps I erred in providing the cogent details of construction. It took all of 20 minutes to accomplish (far less time than that expended in theories of current-in/current-out). These technical hurdles appear to have set the bar too high for my work's refutation in kind. I appreciate that "it's hard work!" ;-) To answer your question, if you just abandon the perfect load, then you stand to achieve a higher gain. If you shorten the antenna, then you stand to achieve a higher gain. There is no change in Rr with the addition of Xl. Hence the mathematical relationship for an antenna shorter than quarterwave would be suggested as: gain ~ 1/Rr gain ~ 1/Xl Rr Z Don't take this gain to the bank however. 73's Richard Clark, KB7QHC Oh... This is about gain? No wonder I'm confused about the subject. |
"Roy Lewallen" wrote in message
... I'm sorry, but I can't make any sense out of your response, so I'm unable to answer your question. Roy Lewallen, W7EL Richard does that a lot, doesn't he? Richard Clark wrote: On Fri, 05 Nov 2004 13:06:40 -0800, Roy Lewallen wrote: What makes you think that the Rr isn't changing? Hi Roy, With what? I have offered a very ascetic report of very simple actions from very simple terms. You have chosen to change those terms to fit your own answer (I do not choose to put this into the context of a perfect world). Please offer effort in kind, or point out what error I've made instead of what error I might have made if something were changed from my model. 73's Richard Clark, KB7QHC |
On Sat, 06 Nov 2004 02:34:32 GMT, "Frank"
wrote: Regarding Richard's comments "Assuming the same currents". Not sure I understand, since the feed-point current varies with constant power Hi Frank, That is quite simple. The file VERT1.EZ has as a source, a constant current generator - a fact I pointed out in the summary of my results. Your presumption of constant power is a natural one for the sake of common discussion, but it is not even the default source for EZNEC. [However, having said that, a curiosity of program design has found that the concept of a "new file" has been orphaned. Any time the application is opened, it is opened with LAST.EZ and I cannot recall upon initial acquisition if EZNEC ever started with a blank slate. Given that you cannot have less than 1 wire nor 1 source, then there is on way to force a blank file. Hence the concept of a default resides in the last file opened.] In other words, each and every iteration of antenna, irrespective of its presumed or actual Rr or drivepoint Z had the same current applied to it, 1 Ampere. Now, if ANY resistance had changed, it then follows that the POWER would have changed too (which presents us with that puzzle confused by the expression V=I/R. that came out of the blue) at a linear rate (1² = 1). Note, a doubling of drivepoint Z by the addition of a load does not result in 3dB gain over the former design. I have seen I * I * R bandied about as an "explanation" and yet at least 3dB is remarkably absent in the results. What R is this that everyone speaks of? Certainly not the real component of drivepoint Z. What about the Rr that must've changed? Copper loss absorb it? Ground loss? As I offered, I must've done something wrong, taken the wrong turn, interpreted the modeler in error, -ahem- not read the help file.... I will bet it was that last one - which only reveals no one has. ;-) [aside] So, Wes, I will amend my ways and delve into that treasure of knowledge before returning your work in kind (no point in retread effort) sometime tomorrow morning. [to the audience] C'mon folks, this has to be an especially simple resolution - I'm glad that so many are just as flummoxed (even Reg is uncharacteristically silent in this regard :-) 73's Richard Clark, KB7QHC |
On Fri, 5 Nov 2004 22:06:42 -0600, "John Smith"
wrote: C'mon, Richard. That's a cheap shot beneath even you, I thought. Hi John, Your exposure to cheap shots is clearly shallow. ;-) 73's Richard Clark, KB7QHC |
I'd be glad to help clarify any confusion, but I can't for the life of
me figure out what the confusion is about. Regarding EZNEC's sources, you have the option of using a constant-current source, constant-voltage source, or having a fixed power applied to the model. If a fixed power level is chosen, multiple sources will have the same ratio of voltages and currents as you've specified. For example, if your model has two sources, one of 1 amp and the other 2 amps, and you choose a fixed power level, the current from the second source will always be twice the current from the first (and at the specified relative phase), but both will be modified as necessary to produce the total power you specified. Fixed power is selected in the Options menu. While the relative source currents (2 amps and 1 amp in the example) are saved with the model, the Options menu choices aren't. They're applied to all models. Changes you make in the Options menu remain effective until you end the program. If you choose "Save as Default" from the Options menu, the current settings will remain in effect even after you end the program, until you change them. I don't personally use a fixed power level very often, since I'm more often interested in things like currents on wires relative to a source, so it's convenient for me to set the source to 1 amp. The fixed power level is useful whenever you need an absolute value of voltage or current, though, or want to see how the voltage, current, or load power dissipation changes as you modify the model. It can be helpful in understanding radiation resistance, by illustrating the relationship among feepoint power, current, and resistance. Just what is it that's confusing about radiation resistance and EZNEC results? Richard's EZNEC results are exactly what I'd expect, and they're consistent with theory. (I'm talking about established theory found in textbooks, not ones cooked up by people who don't understand basic principles or common nomenclature.) The small gain change due to the ground reflection reaction to altered current distribution was admittedly a surprise, but it makes perfect sense after a moment's thought. If someone can summarize what seems to be wrong, I'll do my honest best to explain it. Is the problem that the gain doesn't go up with Rr? Of course it doesn't, in the nearly lossless antennas of Richard's models. Why should it? I tried to explain why in my earlier posting, but I'll try again if that's what the problem is. Roy Lewallen, W7EL Richard Clark wrote: On Sat, 06 Nov 2004 02:34:32 GMT, "Frank" wrote: Regarding Richard's comments "Assuming the same currents". Not sure I understand, since the feed-point current varies with constant power Hi Frank, That is quite simple. The file VERT1.EZ has as a source, a constant current generator - a fact I pointed out in the summary of my results. Your presumption of constant power is a natural one for the sake of common discussion, but it is not even the default source for EZNEC. [However, having said that, a curiosity of program design has found that the concept of a "new file" has been orphaned. Any time the application is opened, it is opened with LAST.EZ and I cannot recall upon initial acquisition if EZNEC ever started with a blank slate. Given that you cannot have less than 1 wire nor 1 source, then there is on way to force a blank file. Hence the concept of a default resides in the last file opened.] In other words, each and every iteration of antenna, irrespective of its presumed or actual Rr or drivepoint Z had the same current applied to it, 1 Ampere. Now, if ANY resistance had changed, it then follows that the POWER would have changed too (which presents us with that puzzle confused by the expression V=I/R. that came out of the blue) at a linear rate (1² = 1). Note, a doubling of drivepoint Z by the addition of a load does not result in 3dB gain over the former design. I have seen I * I * R bandied about as an "explanation" and yet at least 3dB is remarkably absent in the results. What R is this that everyone speaks of? Certainly not the real component of drivepoint Z. What about the Rr that must've changed? Copper loss absorb it? Ground loss? As I offered, I must've done something wrong, taken the wrong turn, interpreted the modeler in error, -ahem- not read the help file.... I will bet it was that last one - which only reveals no one has. ;-) [aside] So, Wes, I will amend my ways and delve into that treasure of knowledge before returning your work in kind (no point in retread effort) sometime tomorrow morning. [to the audience] C'mon folks, this has to be an especially simple resolution - I'm glad that so many are just as flummoxed (even Reg is uncharacteristically silent in this regard :-) 73's Richard Clark, KB7QHC |
Richard Clark wrote:
Cecil Moore wrote: Darn spellchecker. "suppers" should be "suppress". Blame the spellchecker? Yep, it changed "supress" to "suppers". -- 73, Cecil http://www.qsl.net/w5dxp ----== Posted via Newsfeeds.Com - Unlimited-Uncensored-Secure Usenet News==---- http://www.newsfeeds.com The #1 Newsgroup Service in the World! 100,000 Newsgroups ---= East/West-Coast Server Farms - Total Privacy via Encryption =--- |
John Smith wrote:
"Oh...This is about gain?" Don`t think so. This is about unequal currents into and out of an antenna loading coil. The effect a loading coil has on received signals is due at least in part to its effect on radiation resistance versus total (radiation + loss) resistance. If you increase radiation resistance as comared with loss resistance you increase effective radiated power. Directive gain has nothing to do with loss. Here is Terman`s comment on gain in Note 2 on page 870 of his 1955 edition: "Directive gain depends entirely on the distribution in space of radiated power. The power input to the antenna, the antenna losses, or the power consumed in a terminating resistance have nothing to do with directive gain. Such factors are taken into account in terms of the power gain of the antenna which is defined as the ratio of the power input to the comparison antenna required to develop a particular field strength in the direction of maximum radiation, to the power input that must be delivered to the directional antenna to obtain the same field strength in the same direction. Unless otherwise specified the comparison antenna is a lossless isotropic radiator." Best regards, Richard Harrison, KB5WZI |
Roy Lewallen wrote:
This is indeed an interesting result, even though it's small. As a dipole or monopole gets shorter than a resonant length, the current distribution changes from sinusoidal to triangular. Actually, it just moves to a straighter portion of the sinusoidal curve. The cosine curve from 75 degrees to 90 degrees does resemble a triangle but it is not a straight line. Assuming a triangle from 75 deg to 90 deg is a simplified shortcut that introduces almost a 1% error at 82.5 deg. -- 73, Cecil http://www.qsl.net/w5dxp ----== Posted via Newsfeeds.Com - Unlimited-Uncensored-Secure Usenet News==---- http://www.newsfeeds.com The #1 Newsgroup Service in the World! 100,000 Newsgroups ---= East/West-Coast Server Farms - Total Privacy via Encryption =--- |
Roy Lewallen wrote:
Under those conditions, the phase of the current is nearly constant along the wire, so the fields from the various parts of the antenna add together in phase at a distant point broadside to the wire. And remember, that's the net current, i.e. the current in the standing wave. It, as a net stand alone entity, is not flowing anywhere. It is merely the phasor sum of two traveling waves traveling in opposite directions. The phase of the forward current and the phase of the reflected current are changing in the normal traveling wave manner. But since their phases are rotating in opposite directions, their net phasor sum results in very little phase shift. In fact, Kraus shows zero phase shift for the standing wave current on an infinitesimally thin wire. -- 73, Cecil http://www.qsl.net/w5dxp ----== Posted via Newsfeeds.Com - Unlimited-Uncensored-Secure Usenet News==---- http://www.newsfeeds.com The #1 Newsgroup Service in the World! 100,000 Newsgroups ---= East/West-Coast Server Farms - Total Privacy via Encryption =--- |
Almost 1%! Holy moly!
You're correct that the distribution is only approximately triangular. But since a difference between a full quarter sine wave and a true triangular distribution results in less than a 0.5 dB difference in field strength, a 1% difference between a true triangular distribution and the end of a sine wave will make a difference in gain, efficiency, or feedpoint impedance that would be entirely negligible and in fact impossible to measure. For that matter, the current distribution on a wire of finite diameter isn't really a sine wave anyway, but a close approximation (although very possibly not within 1%). So the current distribution on a short antenna is triangular for any practical purpose. Roy Lewallen, W7EL Cecil Moore wrote: Roy Lewallen wrote: This is indeed an interesting result, even though it's small. As a dipole or monopole gets shorter than a resonant length, the current distribution changes from sinusoidal to triangular. Actually, it just moves to a straighter portion of the sinusoidal curve. The cosine curve from 75 degrees to 90 degrees does resemble a triangle but it is not a straight line. Assuming a triangle from 75 deg to 90 deg is a simplified shortcut that introduces almost a 1% error at 82.5 deg. |
Wes Stewart wrote:
for the extremely short antennas that were (are) the subject of the "shootout" business, the current actually increases between the ends of the inductor. Heh, heh, the helix feature in EZNEC shows the same thing. So here's a question for all the "constant current" gurus. How can the current in the middle of the loading coil be a greater magnitude than the current at either end? Hint: it happens all the time in distributed networks. I can design an antenna with a loading coil that has one amp at one end and zero amps at the other end. The forward current and reflected current are simply 180 degrees out of phase at the end where the net current is zero and thus a current node (minimum) is developed. A naive person would say one amp is flowing into one end and zero amps is flowing out the other end. But standing wave current doesn't flow. This is W8JI's basic mistake in his explanation on his web page. The standing wave current is an artifact caused by the superposition of two traveling waves, traveling in opposite directions at the speed of light. For a 1/4WL antenna, there is a standing wave current antinode at the feedpoint and a standing wave current node at the tip of the antenna. -- 73, Cecil http://www.qsl.net/w5dxp ----== Posted via Newsfeeds.Com - Unlimited-Uncensored-Secure Usenet News==---- http://www.newsfeeds.com The #1 Newsgroup Service in the World! 100,000 Newsgroups ---= East/West-Coast Server Farms - Total Privacy via Encryption =--- |
Roy Lewallen wrote:
Almost 1%! Holy moly! Aren't you the same Roy Lewallen who raked me over the coals for using a simplified shortcut? (The devil made me do it. :-) -- 73, Cecil http://www.qsl.net/w5dxp ----== Posted via Newsfeeds.Com - Unlimited-Uncensored-Secure Usenet News==---- http://www.newsfeeds.com The #1 Newsgroup Service in the World! 100,000 Newsgroups ---= East/West-Coast Server Farms - Total Privacy via Encryption =--- |
On Sat, 06 Nov 2004 00:05:49 -0600, Cecil Moore
wrote: Yep, it changed "supress" to "suppers". An expensive Bank Shot.... |
I hope most readers can tell the difference between an approximation or
simplification that we understand and that produces negligible and unmeasurable errors, from one that's based on invalid premises and leads to major errors. Roy Lewallen, W7EL Cecil Moore wrote: Roy Lewallen wrote: Almost 1%! Holy moly! Aren't you the same Roy Lewallen who raked me over the coals for using a simplified shortcut? (The devil made me do it. :-) |
Now I understand the confusion. I am not using EZNEC, and am not familiar
with the program. My analysis is written in NEC code. I do have access to some graphical results with the use of NEC-Win Pro, but have taken the NEC output file and imported it to an Excel spread sheet (NEC-Win Pro's simplified data entry formats do not recognize cards such as 'GH" and "GM" so am forced to resort to direct code entry). For a constant power input I therefore have to read the input impedance results, then calculate the required "Peak" Voltage for the desired power -- note that NEC requires all voltages and currents to be peak values. If anybody is interested I have uploaded the models to my wife's business web site (she will probably kill me when she finds out!). The models show the current distribution of two 84" monopoles; one of which is loaded with a 6" long, 12 turn helix, of 2.5" diameter. The other is unloaded. The ground is defined as "Perfect". The input power is set at 100 W. Just looking at the curves led me to the (mostly) wrong conclusion (verified with numerical integration of the Excel data) that the Integral of I(z)dz is a constant. The results are posted at www.carolyns-creations.com/ve6cb Regards, Frank "Roy Lewallen" wrote in message ... I'd be glad to help clarify any confusion, but I can't for the life of me figure out what the confusion is about. Regarding EZNEC's sources, you have the option of using a constant-current source, constant-voltage source, or having a fixed power applied to the model. If a fixed power level is chosen, multiple sources will have the same ratio of voltages and currents as you've specified. For example, if your model has two sources, one of 1 amp and the other 2 amps, and you choose a fixed power level, the current from the second source will always be twice the current from the first (and at the specified relative phase), but both will be modified as necessary to produce the total power you specified. Fixed power is selected in the Options menu. While the relative source currents (2 amps and 1 amp in the example) are saved with the model, the Options menu choices aren't. They're applied to all models. Changes you make in the Options menu remain effective until you end the program. If you choose "Save as Default" from the Options menu, the current settings will remain in effect even after you end the program, until you change them. I don't personally use a fixed power level very often, since I'm more often interested in things like currents on wires relative to a source, so it's convenient for me to set the source to 1 amp. The fixed power level is useful whenever you need an absolute value of voltage or current, though, or want to see how the voltage, current, or load power dissipation changes as you modify the model. It can be helpful in understanding radiation resistance, by illustrating the relationship among feepoint power, current, and resistance. Just what is it that's confusing about radiation resistance and EZNEC results? Richard's EZNEC results are exactly what I'd expect, and they're consistent with theory. (I'm talking about established theory found in textbooks, not ones cooked up by people who don't understand basic principles or common nomenclature.) The small gain change due to the ground reflection reaction to altered current distribution was admittedly a surprise, but it makes perfect sense after a moment's thought. If someone can summarize what seems to be wrong, I'll do my honest best to explain it. Is the problem that the gain doesn't go up with Rr? Of course it doesn't, in the nearly lossless antennas of Richard's models. Why should it? I tried to explain why in my earlier posting, but I'll try again if that's what the problem is. Roy Lewallen, W7EL Richard Clark wrote: On Sat, 06 Nov 2004 02:34:32 GMT, "Frank" wrote: Regarding Richard's comments "Assuming the same currents". Not sure I understand, since the feed-point current varies with constant power Hi Frank, That is quite simple. The file VERT1.EZ has as a source, a constant current generator - a fact I pointed out in the summary of my results. Your presumption of constant power is a natural one for the sake of common discussion, but it is not even the default source for EZNEC. [However, having said that, a curiosity of program design has found that the concept of a "new file" has been orphaned. Any time the application is opened, it is opened with LAST.EZ and I cannot recall upon initial acquisition if EZNEC ever started with a blank slate. Given that you cannot have less than 1 wire nor 1 source, then there is on way to force a blank file. Hence the concept of a default resides in the last file opened.] In other words, each and every iteration of antenna, irrespective of its presumed or actual Rr or drivepoint Z had the same current applied to it, 1 Ampere. Now, if ANY resistance had changed, it then follows that the POWER would have changed too (which presents us with that puzzle confused by the expression V=I/R. that came out of the blue) at a linear rate (1² = 1). Note, a doubling of drivepoint Z by the addition of a load does not result in 3dB gain over the former design. I have seen I * I * R bandied about as an "explanation" and yet at least 3dB is remarkably absent in the results. What R is this that everyone speaks of? Certainly not the real component of drivepoint Z. What about the Rr that must've changed? Copper loss absorb it? Ground loss? As I offered, I must've done something wrong, taken the wrong turn, interpreted the modeler in error, -ahem- not read the help file.... I will bet it was that last one - which only reveals no one has. ;-) [aside] So, Wes, I will amend my ways and delve into that treasure of knowledge before returning your work in kind (no point in retread effort) sometime tomorrow morning. [to the audience] C'mon folks, this has to be an especially simple resolution - I'm glad that so many are just as flummoxed (even Reg is uncharacteristically silent in this regard :-) 73's Richard Clark, KB7QHC |
As mentioned in an earlier post. I have analyzed an 84" monopole, at 21.3
MHz, with and without loading coils. To view the graphical results of current distribution go to www.carolyns-creations.com/ve6cb These data are placed without comment, since I cannot intelligently add to the ongoing arguments of current distribution. Regards, Frank "Cecil Moore" wrote in message ... Wes Stewart wrote: for the extremely short antennas that were (are) the subject of the "shootout" business, the current actually increases between the ends of the inductor. Heh, heh, the helix feature in EZNEC shows the same thing. So here's a question for all the "constant current" gurus. How can the current in the middle of the loading coil be a greater magnitude than the current at either end? Hint: it happens all the time in distributed networks. I can design an antenna with a loading coil that has one amp at one end and zero amps at the other end. The forward current and reflected current are simply 180 degrees out of phase at the end where the net current is zero and thus a current node (minimum) is developed. A naive person would say one amp is flowing into one end and zero amps is flowing out the other end. But standing wave current doesn't flow. This is W8JI's basic mistake in his explanation on his web page. The standing wave current is an artifact caused by the superposition of two traveling waves, traveling in opposite directions at the speed of light. For a 1/4WL antenna, there is a standing wave current antinode at the feedpoint and a standing wave current node at the tip of the antenna. -- 73, Cecil http://www.qsl.net/w5dxp ----== Posted via Newsfeeds.Com - Unlimited-Uncensored-Secure Usenet News==---- http://www.newsfeeds.com The #1 Newsgroup Service in the World! 100,000 Newsgroups ---= East/West-Coast Server Farms - Total Privacy via Encryption =--- |
Cecil Moore wrote:
The decrease (drop) in current across a loading coil installed in a standing-wave antenna does NOT in any way violate Kirchhoff's current law. True. One can imply from Kirchhoff's current law that there is no current decrease (drop) across a point. By 'point' I believe you are referring to what is commonly referred to as a node. Kirchoff's current law stipulates that charge may not accumulate at nodes. Therefore by definition, any feature of the system where charge accumulation needs to be considered is not a node. This makes sense since charge must accumulate on a surface (surface charge density) (coul / meter squared) or in a dielectric volume (volume charge density) (coul / meter cubed). Both concepts require some sort of area or volume which is inconsistant with the notion of a node. I don't know anyone who disagrees with that so any argument is just a straw man. Kirchhoff never said the current at one point in a network had to equal the current at another point in the network. The currents through two nodes connected in series, without branches, is identical. I think that fact was established before Kirchoff but it's certainly stipulated in circuit theory. Many patches have been added to the DC circuit model to try to adapt it to RF networks. Many? Seems to me that the concept of electric displacement introduced by Maxwell provides everything needed to extend DC theory all the way through classical electromagnetics. What am I missing? Some function after a fashion and some fail utterly. Like what? We all need to be able to recognize the difference. For EM waves, the E-field and H-field are often affected in the same way. Huh? Saying that the E-field voltage drops but the H-field current doesn't drop is simply nonsense. Saying the electric field voltage drops is nonsense. Voltage is the scalar potential defined as the electric potential difference between two points in space. The electric field is vector field, characterized as having a field strength in volts per meter dependant on spatial location, direction, and perhaps time. I don't understand what the term 'E-field voltage drop' could mean. Same with 'H-field current drop'. Likewise, saying that the H-field current flows and the E-field voltage doesn't flow is nonsense. H-field current flows? The field H (amps per meter), is the so called magnemotive field. It doesn't flow anymore than voltage flows through a resistor, and is associated with the generation of magnetic flux. The magnetic flux density, B, has the units of webers per meter squared and can be integrated over an arbitrary surface to evaluate the total magnetic flux passing through that surface. Magnetic flux is somewhat analogous to current but H is not at all. The E-field and H-field are usually inseparable. In the classical electromagnetic model, E & H are completely separable. They are coupled via Faraday's law, and Maxwell's so called displacement current. At steady state (DC) no coupling exists. When one field quantity _varies_ in time, so will the other in accordance with the curl equations. The coupling described by the time varying part of the curl equations only involves the time varying components. When determining the analysis method used to gather insight into a physical system, one of the first considerations is to determine if the time varying field components need to be considered, and if so, which ones. For example, analysis of a 60 Hz power supply choke, or electric motor, usually ignores the electric field in the air gap arising from the time varying magnetic flux density. It's not important in the gap, but is the driver of undesirable eddy currents in the core laminations. bart wb6hqk |
"Richard Clark" wrote in message ... On Fri, 5 Nov 2004 22:06:42 -0600, "John Smith" wrote: C'mon, Richard. That's a cheap shot beneath even you, I thought. Hi John, Your exposure to cheap shots is clearly shallow. ;-) 73's Richard Clark, KB7QHC Yes, Master. |
Roy Lewallen wrote:
I hope most readers can tell the difference between an approximation or simplification that we understand and that produces negligible and unmeasurable errors, from one that's based on invalid premises and leads to major errors. It follows that if you choose not to make an effort to understand a valid premise, according to you, it is still worthless. Do standing wave antennas possess standing waves? (no answer) Kraus and Balanis say "yes". Are those standing waves composed of forward and reflected waves? (no answer) Kraus and Balanis say "yes". Why does Kraus say that, for purposes of conceptual discussion, we can consider those waves to be equal? (no answer) If it's good enough for Kraus, why isn't it good enough for you? (no answer) Do you actually disagree with Kraus? (no answer) Why does Balanis state that standing wave antennas can be conceptually analyzed by representing the forward current as If and the backward current as Ib? (no answer) All I have done is follow Kraus' and Balanis' suggestions. You finding fault with that is amazing. Conceptual solutions are very often not quantitized. "The sun is the center of the solar system" is a conceptual solution and was not quantitized for many, many years. What I have been saying is based on what Kraus and Balanis wrote. There is no "major error" because it is just a concept akin to lossless lines and ideal inductors. And just how do you explain the fact that your very own EZNEC agrees with me when the loading is done by the helix method or the series stub method? Sacred cows die hard, huh? -- 73, Cecil http://www.qsl.net/w5dxp ----== Posted via Newsfeeds.Com - Unlimited-Uncensored-Secure Usenet News==---- http://www.newsfeeds.com The #1 Newsgroup Service in the World! 100,000 Newsgroups ---= East/West-Coast Server Farms - Total Privacy via Encryption =--- |
On Sat, 06 Nov 2004 10:25:30 -0600, Cecil Moore
wrote: "The sun is the center of the solar system" is a conceptual solution and was not quantitized for many, many years. And when it was, the "conceptual solution" was shown to be in error. The center of the solar system is a point about which the mass of the sun AND the planets all turn. The difference is miniscule but such differences being ignored would result in navigational errors in traversing the solar system - which is Roy's point about the significance of error being ignored where it is important. |
Bart Rowlett wrote:
The currents through two nodes connected in series, without branches, is identical. I think that fact was established before Kirchoff but it's certainly stipulated in circuit theory. Let's deal with concrete examples. Assume a lossless, unterminated transmission line. Because of the standing waves, the net current in that series loop varies from point. It is zero every 1/2WL and in between those zero points, it is at a maximum. That's all I was trying to say - that the series current in a distributed network with standing waves is not constant because it no longer can be considered a "circuit". It must be considered a network as it is an appreciable portion of a wavelength. The phases of the forward current and reflected current are rotating in opposite directions which causes their superposition magnitude to vary from minimum to maximum. The magnitudes of the forward and reflected traveling wave currents can be constant while their phasor sum varies as a standing wave sinusoid. Most of the stuff in this posting is a diversion away from the original argument which is: Does the current through a 75m bugcatcher vary from end to end? Since the net current is the standing wave current in a standing wave antenna, it is mostly standing wave current, not traveling wave current. Kraus even suggests that we can consider the forward current equal to the reflected current in a standing wave antenna for purposes of conceptual discussion which means the net current is not moving at all, i.e. not flowing into the bottom of the coil and out the top as assumed by W8JI on his web page. Balanis clearly states that a standing wave antenna can be analyzed based on the forward current and the backward current. Simulations with EZNEC using the helix option indicates that the net current is not the same at each end of a bugcatcher coil. Essentially the same result occurs using a series inductive stub. -- 73, Cecil http://www.qsl.net/w5dxp ----== Posted via Newsfeeds.Com - Unlimited-Uncensored-Secure Usenet News==---- http://www.newsfeeds.com The #1 Newsgroup Service in the World! 100,000 Newsgroups ---= East/West-Coast Server Farms - Total Privacy via Encryption =--- |
Richard Clark wrote:
Cecil Moore wrote: "The sun is the center of the solar system" is a conceptual solution and was not quantitized for many, many years. And when it was, the "conceptual solution" was shown to be in error. The center of the solar system is a point about which the mass of the sun AND the planets all turn. The difference is miniscule but such differences being ignored would result in navigational errors in traversing the solar system - which is Roy's point about the significance of error being ignored where it is important. Being such a nickpicker, why don't you object to the gross errors (50%) introduced by using the circuit theory math model on a distributed network problem? -- 73, Cecil http://www.qsl.net/w5dxp ----== Posted via Newsfeeds.Com - Unlimited-Uncensored-Secure Usenet News==---- http://www.newsfeeds.com The #1 Newsgroup Service in the World! 100,000 Newsgroups ---= East/West-Coast Server Farms - Total Privacy via Encryption =--- |
On Sat, 06 Nov 2004 12:07:47 -0600, Cecil Moore
wrote: Being such a nickpicker, why don't you object to the gross errors (50%) introduced by using the circuit theory math model on a distributed network problem? I Object to ALL of your raging inconsistencies. :-) |
Richard Clark wrote:
I Object to ALL of your raging inconsistencies. :-) But not to Roy's or Tom's. One wonders why. -- 73, Cecil http://www.qsl.net/w5dxp ----== Posted via Newsfeeds.Com - Unlimited-Uncensored-Secure Usenet News==---- http://www.newsfeeds.com The #1 Newsgroup Service in the World! 100,000 Newsgroups ---= East/West-Coast Server Farms - Total Privacy via Encryption =--- |
On Sat, 06 Nov 2004 13:52:03 -0600, Cecil Moore
wrote: I Object to ALL of your raging inconsistencies. :-) But not to Roy's or Tom's. One wonders why. Probably because you don't pay attention. Others certainly don't wonder. |
W5DXP wrote:
I'm chugging Franzia Merlot while cleaning my Colt Python .357 Magnum and Winchester 30-30 Lever-Action Carbine. :-) After shooting a rattler do you, Hollywood-fashion, put the weapon to your lips and blow the smoke out of the barrel? ;o) I'm not that primitive, Reg. I use commercial ammo with smokeless powder. -- 73, Cecil, W5DXP ========================================== Ah, I see, modern high-technology smokeless and odorless powders do not betray your postion to the rattler if you miss him first time. At night, have you tried infra-red telescopic sights? But by now rattle snakes must be becoming, like Bengal tigers and red indians, an endanged species. ;o) ---- Reg. |
Balanis
clearly states that a standing wave antenna can be analyzed based on the forward current and the backward current. ================================ Who the heck is "Balony" Never heard of him or her. ---- Reg |
Reg Edwards wrote:
Balanis clearly states that a standing wave antenna can be analyzed based on the forward current and the backward current. ================================ Who the heck is "Balony" Never heard of him or her. ---- Reg That's because you never read. 73, Tom Donaly, KA6RUH |
Reg Edwards wrote:
Ah, I see, modern high-technology smokeless and odorless powders do not betray your postion to the rattler if you miss him first time. I would never kill a life form except in self defense or by accident. I was actually one of the older California hippies in the 70's, full of peace and free love. -- 73, Cecil http://www.qsl.net/w5dxp ----== Posted via Newsfeeds.Com - Unlimited-Uncensored-Secure Usenet News==---- http://www.newsfeeds.com The #1 Newsgroup Service in the World! 100,000 Newsgroups ---= East/West-Coast Server Farms - Total Privacy via Encryption =--- |
Reg Edwards wrote:
W5DXP wrote: I'm chugging Franzia Merlot while cleaning my Colt Python .357 Magnum and Winchester 30-30 Lever-Action Carbine. :-) After shooting a rattler do you, Hollywood-fashion, put the weapon to your lips and blow the smoke out of the barrel? ;o) I'm not that primitive, Reg. I use commercial ammo with smokeless powder. -- 73, Cecil, W5DXP ========================================== Ah, I see, modern high-technology smokeless and odorless powders do not betray your postion to the rattler if you miss him first time. At night, have you tried infra-red telescopic sights? But by now rattle snakes must be becoming, like Bengal tigers and red indians, an endanged species. ;o) ---- Reg. Rattlesnakes shouldn't mind being killed, since, after they die, they're immediately reincarnated as Republicans. Come to think of it,though, maybe they should mind after all. 73, Tom Donaly, KA6RUH |
Reg Edwards wrote:
Balanis clearly states that a standing wave antenna can be analyzed based on the forward current and the backward current. Who the heck is "Balony" Never heard of him or her. :-) Balanis is my Arizona State University professor who directed my thinking along these lines. He's the author of a textbook titled: "Antenna Theory, Analysis and Design" that has come to be a later reference than some of the Kraus, Jasik, Terman stuff. You can obtain a copy of his book on Amazon.com for only $119. A web search for "Constantine A. Balanis" turned up three pages of lists of web pages. -- 73, Cecil http://www.qsl.net/w5dxp ----== Posted via Newsfeeds.Com - Unlimited-Uncensored-Secure Usenet News==---- http://www.newsfeeds.com The #1 Newsgroup Service in the World! 100,000 Newsgroups ---= East/West-Coast Server Farms - Total Privacy via Encryption =--- |
Cecil Moore wrote:
I was actually one of the older California hippies in the 70's, full of peace and free love. Cecil - I'd like to see a picture, please. 73 - Lee H, NB7F |
Rattlesnakes shouldn't mind being killed, since, after they die, they're immediately reincarnated as Republicans. Come to think of it,though, maybe they should mind after all. 73, Tom Donaly, KA6RUH That says it all! Cecil, you are arguing with brainwashed liberals. I escaped from that crap, but it haunts me here, even on the radio internet waves. Viva Bush! Yuri da BUm |
Frank wrote:
Now I understand the confusion. I am not using EZNEC, and am not familiar with the program. . . You can download a free demo version of EZNEC from http://eznec.com. It's perfectly adequate for analysis of simple antennas with lumped loads, and gives you full graphics, the ability to fix the power level, and all the other features of the full EZNEC program with the single exception of a 20 segment limit. The demo version also includes the full EZNEC/EZNEC+/EZNEC pro manual, and there's no time limit on its use. Roy Lewallen, W7EL |
Lee Hopper wrote:
Cecil Moore wrote: I was actually one of the older California hippies in the 70's, full of peace and free love. I'd like to see a picture, please. A picture of the free love? -- 73, Cecil http://www.qsl.net/w5dxp ----== Posted via Newsfeeds.Com - Unlimited-Uncensored-Secure Usenet News==---- http://www.newsfeeds.com The #1 Newsgroup Service in the World! 100,000 Newsgroups ---= East/West-Coast Server Farms - Total Privacy via Encryption =--- |
Yuri Blanarovich wrote:
Cecil, you are arguing with brainwashed liberals. Well, I'm half liberal. I'm a social liberal so I disagree with Bush. I'm an economic conservative so I disagree with both Kerry and Bush. I voted Libertarian. -- 73, Cecil http://www.qsl.net/w5dxp ----== Posted via Newsfeeds.Com - Unlimited-Uncensored-Secure Usenet News==---- http://www.newsfeeds.com The #1 Newsgroup Service in the World! 100,000 Newsgroups ---= East/West-Coast Server Farms - Total Privacy via Encryption =--- |
I'm an economic conservative
So you are half OK :-) |
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