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Standing-Wave Current vs Traveling-Wave Current
There seems to be mass confusion even among the gurus on
this newsgroup as to the difference between standing-wave current, as exists on a 1/2WL dipole, vs traveling-wave current, as exists on a terminated antenna like a rhombic. I have prepared two EZNEC files that should run on the free demo version of EZNEC as well as on the commercial edition. These two files clearly show the difference in the two types of currents. The standing-wave example is designed to illustrate standing-wave current. All of the forward energy is reflected at the open end of the wire. The total current displayed by EZNEC is the sum of the forward and reflected currents which are close to equal. The traveling-wave example is designed to illustrate traveling-wave current. Most of the forward energy is dissipated in the load resistor rather than being reflected. The total current displayed by EZNEC is the sum of the forward and reflected currents with the reflected current minimized to a negligible value. Each EZNEC file consists of a 1/4WL wire run horizontal one foot above ground at 4 MHz. In the standing-wave file, the wire is open and unterminated. In the traveling-wave file, the wire is terminated to ground by its characteristic impedance. To view EZNEC's tabulated current at each of the 18 segments along the 1/4WL, simply click on "Load Dat". The standing-wave file is: http://www.w5dxp.com/StndWave.EZ The traveling-wave file is: http://www.w5dxp.com/TravWave.EZ In the following results (directly from EZNEC) please note the almost constant phase reported for the standing-wave current vs the continuously changing phase reported for the traveling-wave current. Here are the values of current at each segment for the standing-wave example as reported by EZNEC: EZNEC+ ver. 4.0 standing wave 12/18/2007 9:11:33 AM --------------- LOAD DATA --------------- Frequency = 4 MHz Load 1 Current = 0.9974 A. at -0.01 deg. Load 2 Current = 0.9874 A. at -0.02 deg. Load 3 Current = 0.9703 A. at -0.03 deg. Load 4 Current = 0.9461 A. at -0.04 deg. Load 5 Current = 0.915 A. at -0.05 deg. Load 6 Current = 0.8773 A. at -0.06 deg. Load 7 Current = 0.8332 A. at -0.07 deg. Load 8 Current = 0.783 A. at -0.08 deg. Load 9 Current = 0.7271 A. at -0.08 deg. Load 10 Current = 0.6659 A. at -0.09 deg. Load 11 Current = 0.5999 A. at -0.09 deg. Load 12 Current = 0.5295 A. at -0.10 deg. Load 13 Current = 0.4553 A. at -0.10 deg. Load 14 Current = 0.3777 A. at -0.10 deg. Load 15 Current = 0.2974 A. at -0.10 deg. Load 16 Current = 0.2148 A. at -0.11 deg. Load 17 Current = 0.1307 A. at -0.11 deg. Load 18 Current = 0.0447 A. at -0.11 deg. Here are the values of current at each segment for the traveling-wave example as reported by EZNEC: EZNEC+ ver. 4.0 traveling wave 12/18/2007 9:18:19 AM --------------- LOAD DATA --------------- Frequency = 4 MHz Load 1 Current = 0.9992 A. at -3.12 deg. Load 2 Current = 0.9983 A. at -8.11 deg. Load 3 Current = 0.9977 A. at -13.08 deg. Load 4 Current = 0.9972 A. at -18.05 deg. Load 5 Current = 0.9970 A. at -23.02 deg. Load 6 Current = 0.9970 A. at -27.99 deg. Load 7 Current = 0.9973 A. at -32.96 deg. Load 8 Current = 0.9978 A. at -37.92 deg. Load 9 Current = 0.9985 A. at -42.87 deg. Load 10 Current = 0.9993 A. at -47.82 deg. Load 11 Current = 1.0000 A. at -52.75 deg. Load 12 Current = 1.0010 A. at -57.67 deg. Load 13 Current = 1.0030 A. at -62.58 deg. Load 14 Current = 1.0040 A. at -67.48 deg. Load 15 Current = 1.0050 A. at -72.36 deg. Load 16 Current = 1.0060 A. at -77.23 deg. Load 17 Current = 1.0070 A. at -82.09 deg. Load 18 Current = 1.0080 A. at -86.97 deg. -- 73, Cecil http://www.w5dxp.com |
Standing-Wave Current vs Traveling-Wave Current
Cecil Moore wrote:
There seems to be mass confusion even among the gurus on this newsgroup as to the difference between standing-wave current, as exists on a 1/2WL dipole, vs traveling-wave current, as exists on a terminated antenna like a rhombic. I have prepared two EZNEC files that should run on the free demo version of EZNEC as well as on the commercial edition. These two files clearly show the difference in the two types of currents. Heavily clip....... The standing-wave file is: http://www.w5dxp.com/StndWave.EZ The traveling-wave file is: http://www.w5dxp.com/TravWave.EZ clip..... Hi Cecil, I tried the files and they work well. Congratulations on a clever use of zero resistance loads. I have not seen that technique used before but it certainly allows for a good EZNEC demonstration. EZNEC is a great program. 73, Roger, W7WKB |
Standing-Wave Current vs Traveling-Wave Current
Roger wrote:
I tried the files and they work well. Congratulations on a clever use of zero resistance loads. I have not seen that technique used before but it certainly allows for a good EZNEC demonstration. It's a way to "measure" the current without disturbing the current. Do you see how the EZNEC current has a reference phase and thus is a "snapshot" in time? Do you see how traveling-wave current travels and standing- wave current just appears to stand there? Since EM waves cannot just stand there and must necessarily move at the speed of light, a standing-wave is just an artifact of superposition (a magical illusion for some). It has no stand-alone existence aside from its forward and reverse component EM waves that indeed do travel at the speed of light (adjusted for velocity factor). EZNEC is a great program. Yes indeed, like the Smith Chart, it is a great antenna tool. I've been a satisfied customer for 20 years, since I first purchased ELNEC. ELNEC and EZNEC have been great tutors for me. If someone doesn't want to buy it, the free demo version of EZNEC available from http://www.eznec.com is quite a free lunch and although limited to 20 segments, is very useful on wire dipoles and monopoles and learning how they work. -- 73, Cecil http://www.w5dxp.com |
Standing-Wave Current vs Traveling-Wave Current
On Tue, 18 Dec 2007 09:33:23 -0600, Cecil Moore
wrote: There seems to be mass confusion even among the gurus on this newsgroup as to the difference between standing-wave current, as exists on a 1/2WL dipole, vs traveling-wave current, as exists on a terminated antenna like a rhombic. :-) Confusion appears to be selective here, and not to be found generally in the remainder of the group. For instance, in the quote above, we are introduced to two antennas THAT ARE NEVER AGAIN EMPLOYED, AS EXPLICITLY INFERRED, AS THE BASIS OF COMPARISON! In short, the author immediately dismissing these practical antennas, never again approaches the problem as described above. The solution to this confusion appears to be of no true concern. So, what's the problem? No question follows in the remainder of the post, only statements. No statements illustrate the difference between any antennas that are the source of the presumed confusion. The original model wires draped 1/200th wavelength above ground are certainly not to be confused with conventional rhombic, nor dipoles. Diligent readers would back away from this dead horse. Modeling a rhombic is not outside the art of the practitioner, only one practitioner for whom the data does not support the premise for these antennas (quickly discarded as I have pointed out). Four 4 wavelength wires built into a symmetric diamond, one source at 22MHz, one load, and the whole model is described. As a variation, put it in free space, test; repeat with it 65 feet above ground, test. As another variation, load with a matched R, test; load with an open/short, test. What monumental results follow from all results? 65 feet above ground we observe: w/Rl = 816 Ohms: I magnitude declines end-to-end due to radiation; I magnitude varies insignificantly seg-to-seg (1%); I phase varies ~160-~100 degrees per 10 segments; I phase inverts every 10 segments. w/Rl = 1e9 Ohms: I magnitude declines end-to-end due to radiation; I magnitude varies seg-to-seg (~10%-~40%); I phase varies ~160-~100 degrees per 10 segments; I phase inverts every 10 segments. In free space we observe: w/Rl = 816 Ohms: I magnitude declines end-to-end due to radiation; I magnitude varies insignificantly seg-to-seg (1%); I phase varies ~160 degrees per 10 segments; I phase inverts every 10 segments. w/Rl = 1e9 Ohms: I magnitude declines end-to-end due to radiation; I magnitude varies seg-to-seg (~5%-~25%); I phase varies ~160 degrees per 10 segments; I phase inverts every 10 segments. All variations support the notion of traveling and standing wave antennas (unless, of course, some novel re-definition of terms is injected into the debate). The presumption of traveling waves is well defined in the current data when placing a "matched load" on the antenna-as-transmission line is performed. The presumption of standing waves is well defined in the current data when the "matched load" is opened on the antenna-as-transmission line. What does not conform to well tailored expectations? The phase swings under all conditions are well defined, extensive, and repeat with regularity. Further, we can also observe how ground's proximity, even with a substantial height against wavelength begins to intrude into current dynamics. We can then proceed into where confusion might reside (it not being found in these antennas): GROUND. Yes, the death embrace of the original models with GROUND profoundly skews the data. I would note that there is the usual crafting of the original post to insure plausible deniability. In short, the reader is left to be astonished by the data (corrupt as it is, given the tantalizing premise of Rhombics and Dipoles being so confusing to the crowd of readers) and to then be lead further away from that initial dismissal of those antennas, only to be drawn back to them through Byzantine extrapolations and copious mathematical "proofs." As always, fun. I doubt anything new in the technical vein will follow, so I look forward to the parade that is sure to fill this thread. 73's Richard Clark, KB7QHC |
Standing-Wave Current vs Traveling-Wave Current
On Tue, 18 Dec 2007 12:53:06 -0800, Richard Clark
wrote: We can then proceed into where confusion might reside (it not being found in these antennas): GROUND. Yes, the death embrace of the original models with GROUND profoundly skews the data. Hi All, Well, I find there is more technical content to dissect in at least one dead horse. Let's look at the "traveling wave" model and see what it has to offer in the cold harsh light of reality. Right off the bat with its performance: -23.74dB What could possibly account for all this loss? The "load?"? Instead of tossing the load, let's toss ground and put this corpse in free space. It's performance: -0.30dB I don't know how any math error like this could be used to validate a model, but the efficiency as an antenna that hugs ground so vigorously hardly measures up to either a dipole or a rhombic. On the plus side, confusion certainly offers many vendors an income, and suckers are born every minute who would love a low noise antenna. However, what happened to the currents when we discarded ground? Well, the pristine constant current of the former model plunges right down the toilet of expectations (while performance shot through the ceiling at the same time - one has to wonder what was confusing about this?). Phase change? That cute 90 degrees formerly nudged and cosseted onto center stage has now been nailed to the floor with no more total variation than 2.15 degrees. Hard to imagine how a transmission line could so thoroughly rape its inventor. Turning to the "standing wave" model, would it be instructive how a ground free performance might similarly fare? Right off the bat with its performance: -1.69dB it would seem a stretch to find any more efficiency (and shows how that traveling wave model really sucks). However, without ground for completeness' sake: -0.28dB However, what happened to the currents when we discarded ground? Well, roughly the same 2 degree shift we found when the "traveling wave" model split the sheets with ground, but beyond that, an almost identical current taper and phase lock-down found with the "traveling wave" model free of ground (or in comparison to itself close to ground). So, is there any substantial difference between the two models once ground's death grip is released? I will leave that question for tea-leaf analysis, because engineers would have buried this dead horse long ago. ***** Irony meter pegged ***** I would like to point out that the only things changed with these original models was a switch from 2D to 3D analysis to reveal total loss; and a switch from the ground offered to free space. I look forward to Cecil, once again, impeaching his own evidence (and typically without once mentioning the data). I am sure I have sunken to new lows and once I am exposed for what I am (an English major), vindication will taste sweeter than wine. (may as well steal that thunder too) 73's Richard Clark, KB7QHC |
Standing-Wave Current vs Traveling-Wave Current
On Tue, 18 Dec 2007 17:42:00 -0800, Richard Clark
wrote: Let's look at the "traveling wave" model and see what it has to offer in the cold harsh light of reality. Right off the bat with its performance: -23.74dB What could possibly account for all this loss? The "load?"? Hi All, Being one to never leave too many unanswered questions (Cecil merely questions questions); I poured 100W into the original model (the only change made was from constant I/E to constant P). In fact, the proximity of ground allowed 99.38 watts to be absorbed by the load! How much reaches the load once this dead horse wrenches free from ground's death grip and is allowed to ascend the stairway to heaven? 0.4982 watts You heard it here first. ;-) And, yes, another change (2 total) was made to the ground offered to make it, instead, free space. Who knows, maybe the "traveling wave" model is for a new matching device for greater load efficiency. Unfortunately it would be best suited for 80M speakers. 73's Richard Clark, KB7QHC |
Standing-Wave Current vs Traveling-Wave Current
Richard Clark wrote:
Let's look at the "traveling wave" model and see what it has to offer in the cold harsh light of reality. Right off the bat with its performance: -23.74dB What could possibly account for all this loss? The "load?"? You are wasting your time. The entire purpose of the model is to illustrate the phase shift in the traveling wave current - absolutely no other purpose. So how do you explain the phase shift in the current which is obviously traveling wave current? -- 73, Cecil http://www.w5dxp.com |
Standing-Wave Current vs Traveling-Wave Current
On Tue, 18 Dec 2007 17:42:00 -0800, Richard Clark
wrote: On Tue, 18 Dec 2007 12:53:06 -0800, Richard Clark wrote: We can then proceed into where confusion might reside (it not being found in these antennas): GROUND. Yes, the death embrace of the original models with GROUND profoundly skews the data. Hi All, Well, I find there is more technical content to dissect in at least one dead horse. Let's look at the "traveling wave" model and see what it has to offer in the cold harsh light of reality. Well first, mea culpa's to the readership in using Cecil's models (never a good idea as they did not attend the question he introduced whereas mine did). However, moving on to the nut of my copping a plea. I had not noticed that Cecil drove his wires into MiniNEC ground - something I have never done in all my modeling. So, my "changes," as reported, were faithful, but very much unbalanced the implicit return path through that MiniNEC ground. Being the good analyst, I then considered my previous work in an even colder, harsher light of brutal reality. What I did was to replace that ground path with a wire symmetrical to the 60 footer and then raised the assembly an inch. Right off the bat with its performance: -23.74dB -42.04dB What could possibly account for all this loss? The "load?"? And through a follow-up last time, the same conclusion. The transmission line apparent load for a 100W constant power consumes 99.25 watts Instead of tossing the load, let's toss ground and put this corpse in free space. It's performance: -0.30dB -42.20dB I don't know how any math error like this could be used to validate a model, but the efficiency as an antenna that hugs ground so vigorously hardly measures up to either a dipole or a rhombic. On the plus side, confusion certainly offers many vendors an income, and suckers are born every minute who would love a low noise antenna. Now it enjoys nearly 20dB less noise than before my mistake. However, what happened to the currents when we discarded ground? Well, the pristine constant current of the former model plunges right down the toilet of expectations (while performance shot through the ceiling at the same time - one has to wonder what was confusing about this?). Phase change? That cute 90 degrees formerly nudged and cosseted onto center stage has now been nailed to the floor with no more total variation than 2.15 degrees. Hard to imagine how a transmission line could so thoroughly rape its inventor. The current is still not constant (the original model must rely on a poor return path to accomplish this). The phase does vary by 90 degrees. As modified, the current slope reveals this is no longer a traveling wave antenna (but it never was anyway). This can be remedied by shifting the last load (the apparent transmission line load) to 750 Ohms. This, of course, improves nothing in performance. Turning to the "standing wave" model, would it be instructive how a ground free performance might similarly fare? Right off the bat with its performance: -1.69dB -21.43dB it would seem a stretch to find any more efficiency (and shows how that traveling wave model really sucks). However, without ground for completeness' sake: -0.28dB -21.12dB However, what happened to the currents when we discarded ground? Well, Not enough to discuss. roughly the same 2 degree shift we found when the "traveling wave" model split the sheets with ground, but beyond that, an almost identical current taper and phase lock-down found with the "traveling wave" model free of ground (or in comparison to itself close to ground). So, is there any substantial difference between the two models once ground's death grip is released? I will leave that question for tea-leaf analysis, because engineers would have buried this dead horse long ago. Well, after sifting my own tea-leaves (one has to wonder how this escaped the intrepid author's scrutiny) - no not much difference after all. Transmission lines are pretty robust when designed correctly. However, neither bear any resemblance to the original post's mention of rhombic or dipole antennas; and my models of those clearly discard Cecil's confusion over his named currents by using conventional designs of conventional antennas. After all, who ever heard of a traveling wave transmission line? [This is probably the only point Cecil could ever hope to argue as he would immediately seize on the opportunity to force that term into the canon.] ***** Irony meter pegged ***** I would like to point out that the only things changed with these original models was a switch from 2D to 3D analysis to reveal total loss; and a switch from the ground offered to free space. I look forward to Cecil, once again, impeaching his own evidence (and typically without once mentioning the data). I am sure I have sunken to new lows Having beaten Cecil in the game of analysis, even to my own, I must be pond scum by now. and once I am exposed for what I am (an English major), vindication will taste sweeter than wine. (may as well steal that thunder too) Imagine, I got to the wine decanter first too! :-) 73's Richard Clark, KB7QHC |
Standing-Wave Current vs Traveling-Wave Current
Richard Clark wrote:
On Tue, 18 Dec 2007 17:42:00 -0800, Richard Clark wrote: On Tue, 18 Dec 2007 12:53:06 -0800, Richard Clark wrote: We can then proceed into where confusion might reside (it not being found in these antennas): GROUND. Yes, the death embrace of the original models with GROUND profoundly skews the data. Hi All, Well, I find there is more technical content to dissect in at least one dead horse. Let's look at the "traveling wave" model and see what it has to offer in the cold harsh light of reality. Well first, mea culpa's to the readership in using Cecil's models (never a good idea as they did not attend the question he introduced whereas mine did). However, moving on to the nut of my copping a plea. I had not noticed that Cecil drove his wires into MiniNEC ground - something I have never done in all my modeling. So, my "changes," as reported, were faithful, but very much unbalanced the implicit return path through that MiniNEC ground. Being the good analyst, I then considered my previous work in an even colder, harsher light of brutal reality. What I did was to replace that ground path with a wire symmetrical to the 60 footer and then raised the assembly an inch. Right off the bat with its performance: -23.74dB -42.04dB What could possibly account for all this loss? The "load?"? And through a follow-up last time, the same conclusion. The transmission line apparent load for a 100W constant power consumes 99.25 watts Instead of tossing the load, let's toss ground and put this corpse in free space. It's performance: -0.30dB -42.20dB I don't know how any math error like this could be used to validate a model, but the efficiency as an antenna that hugs ground so vigorously hardly measures up to either a dipole or a rhombic. On the plus side, confusion certainly offers many vendors an income, and suckers are born every minute who would love a low noise antenna. Now it enjoys nearly 20dB less noise than before my mistake. However, what happened to the currents when we discarded ground? Well, the pristine constant current of the former model plunges right down the toilet of expectations (while performance shot through the ceiling at the same time - one has to wonder what was confusing about this?). Phase change? That cute 90 degrees formerly nudged and cosseted onto center stage has now been nailed to the floor with no more total variation than 2.15 degrees. Hard to imagine how a transmission line could so thoroughly rape its inventor. The current is still not constant (the original model must rely on a poor return path to accomplish this). The phase does vary by 90 degrees. As modified, the current slope reveals this is no longer a traveling wave antenna (but it never was anyway). This can be remedied by shifting the last load (the apparent transmission line load) to 750 Ohms. This, of course, improves nothing in performance. Turning to the "standing wave" model, would it be instructive how a ground free performance might similarly fare? Right off the bat with its performance: -1.69dB -21.43dB it would seem a stretch to find any more efficiency (and shows how that traveling wave model really sucks). However, without ground for completeness' sake: -0.28dB -21.12dB However, what happened to the currents when we discarded ground? Well, Not enough to discuss. roughly the same 2 degree shift we found when the "traveling wave" model split the sheets with ground, but beyond that, an almost identical current taper and phase lock-down found with the "traveling wave" model free of ground (or in comparison to itself close to ground). So, is there any substantial difference between the two models once ground's death grip is released? I will leave that question for tea-leaf analysis, because engineers would have buried this dead horse long ago. Well, after sifting my own tea-leaves (one has to wonder how this escaped the intrepid author's scrutiny) - no not much difference after all. Transmission lines are pretty robust when designed correctly. However, neither bear any resemblance to the original post's mention of rhombic or dipole antennas; and my models of those clearly discard Cecil's confusion over his named currents by using conventional designs of conventional antennas. After all, who ever heard of a traveling wave transmission line? [This is probably the only point Cecil could ever hope to argue as he would immediately seize on the opportunity to force that term into the canon.] ***** Irony meter pegged ***** I would like to point out that the only things changed with these original models was a switch from 2D to 3D analysis to reveal total loss; and a switch from the ground offered to free space. I look forward to Cecil, once again, impeaching his own evidence (and typically without once mentioning the data). I am sure I have sunken to new lows Having beaten Cecil in the game of analysis, even to my own, I must be pond scum by now. and once I am exposed for what I am (an English major), vindication will taste sweeter than wine. (may as well steal that thunder too) Imagine, I got to the wine decanter first too! :-) 73's Richard Clark, KB7QHC Cecil's decanter has too much lead in the glass. 73, Tom Donaly, KA6RUH |
Standing-Wave Current vs Traveling-Wave Current
Richard Clark wrote:
As modified, the current slope reveals this is no longer a traveling wave antenna (but it never was anyway). This can be remedied by shifting the last load (the apparent transmission line load) to 750 Ohms. Duhhhhhhhh! When you changed the conditions, you changed the characteristic impedance. The reason for your confusion is obvious below. This, of course, improves nothing in performance. This is not a performance issue. This is a current phase issue. The purpose for the existence of that EZNEC file is to illustrate traveling-wave current - nothing else. After all, who ever heard of a traveling wave transmission line? Who indeed? Richard, FYI, a transmission line terminated in its characteristic impedance *IS* a traveling wave transmission line. Do you understanding the meaning of a "flat" transmission line? A flat transmission line *is* a traveling wave transmission line. Here is one modeled in EZNEC. Download and click on "Load Dat". http://www.w5dxp.com/stub514R.EZ Why is the ignorance level about traveling waves so high on this newsgroup? It's the result of those inadequate lumped circuit models. -- 73, Cecil http://www.w5dxp.com |
Standing-Wave Current vs Traveling-Wave Current
Tom Donaly wrote:
Cecil's decanter has too much lead in the glass. Tom, why haven't you calculated the phase shift from Vfor1 to Vfor2 in the following example? --43.4 deg 600 ohm line--+--10 deg 100 ohm line--open Vfor1--|--Vfor2 Assume that 100v at 0 deg is incident upon the open at the end of the stub. I get Vfor2 = 100v at -10 deg and Vfor1 = 143.33v at -46.6 deg. Looks like the phase shift is 36.6 degrees after all. Please feel free to prove me wrong. -- 73, Cecil http://www.w5dxp.com |
Standing-Wave Current vs Traveling-Wave Current
On Wed, 19 Dec 2007 22:11:23 GMT, Cecil Moore
wrote: This is a current phase issue. The Rhombic antenna shows phase variation for every configuration. The Rhombic is, by the way, a traveling wave antenna, and your own topic selection. The Rhombic antenna does not support your thesis. Absolutely no correspondence (other than my own for a non-antenna) has been offered to assault my data. So, the bottom line is that EZNEC faithfully models both traveling wave antennas, and resonant lines; and no one here is surprised about that. Still confused? You don't seem to be particularly motivated with this issue at all - it must be a humbling experience for you to have introduced this in terms of a real antenna that refuses to toe any of your absurd propositions. Clever crafting only makes your theories ever simpler to blow away. I wait for your next joke, that one was too easy! :-) |
Standing-Wave Current vs Traveling-Wave Current
Richard Clark wrote:
The Rhombic antenna does not support your thesis. Of course it does, Richard. The rhombic is a traveling- wave antenna. Unlike a 1/2WL dipole, its current phase changes with distance from the feedpoint. We certainly have an EZNEC 1/2WL dipole model but I don't think EZNEC comes with a rhombic model. Do you happen to have one? If not, I'll be glad to whip one out. I guarantee the results will be no different from the 1/4WL terminated wire that I presented previously. -- 73, Cecil http://www.w5dxp.com |
Standing-Wave Current vs Traveling-Wave Current
Richard Clark wrote:
The Rhombic antenna does not support your thesis. On the contrary, I just whipped out an EZNEC rhombic without taking any special care. I copied it out of The ARRL Antenna Book, 20th edition, page 13-13. I only installed ten zero ohm loads, but clicking on "Load Dat" clearly shows the phase shift in the traveling wave current along the wire. http://www.w5dxp.com/rhombic.EZ Sorry, a rhombic won't run on the free demo version of EZNEC. -- 73, Cecil http://www.w5dxp.com |
Standing-Wave Current vs Traveling-Wave Current
On Wed, 19 Dec 2007 23:06:58 GMT, Cecil Moore
wrote: I don't think EZNEC comes with a rhombic model. Do you happen to have one? With that, I can tell you didn't read anything in this thread. That's OK, the topic was a snooze from the first paragraph. If not, I'll be glad to whip one out. I guarantee the results will be no different from the 1/4WL terminated wire that I presented previously. And this proves you didn't read anything in this thread. But, your comment was a good laugh! You are already several postings shy of results already here. As the Red Queen informed Alice, "You have to run awful fast just to keep up in one place." When that dawns on you (sorry, but you will have to read the posting), it will probably expose me for what I am (scum of the earth? or is it wine sipping Liberal Arts major this week?). Looking forward to your damage control. :-) |
Standing-Wave Current vs Traveling-Wave Current
On Wed, 19 Dec 2007 17:50:53 -0600, Cecil Moore
wrote: The "traveling wave" antenna clearly shows standing waves. This is just too, too easy! :-) |
Standing-Wave Current vs Traveling-Wave Current
On Wed, 19 Dec 2007 17:11:41 -0800, Richard Clark
wrote: On Wed, 19 Dec 2007 17:50:53 -0600, Cecil Moore wrote: The "traveling wave" antenna clearly shows standing waves. This is just too, too easy! :-) I've just discovered that this "copy" from the ARRL The ARRL Antenna Book, 20th edition, page 13-13. must be quite a departure from reality. In outer space? Well, I trust Cecil hasn't mislaid his glasses once again, performed another math error, or tried to use his car keys to get into the house; but when we substitute his former 1/200th wavelength above ground, this antenna clearly exhibits a SWR of 1.33. Of course, it can be jimmied back into outer space in an effort to suppress evidence of standing waves, but like the Ghost of Christmas Past, those chains will still rattle poor ol' Cec'. (Will he give Cratchit the day off?) Cecil's clever crafting can always be mined for simple problems. Pay dirt every time. Now that I have been exposed for what I am, I can full well expect a lump of coal the size of West Virginia in my stocking. I'm going to need a larger mantle. :-( 73's Richard Clark, KB7QHC |
Standing-Wave Current vs Traveling-Wave Current
Richard Clark wrote:
Cecil Moore wrote: The "traveling wave" antenna clearly shows standing waves. This is just too, too easy! :-) Too bad for you the threaded newsreader shows that the only thing I wrong above was "clearly shows". It also shows that you wrote the rest. Any idiot can falsify a posting. -- 73, Cecil http://www.w5dxp.com |
Standing-Wave Current vs Traveling-Wave Current
On Wed, 19 Dec 2007 19:33:22 -0600, Cecil Moore
wrote: Any idiot can falsify a posting. Well, are the standing waves falsified? This is a "traveling wave" antenna, is it not? Presumably any idiot can figure that one out. This, of course, has already been answered by me in another posting. Perhaps you want to look under the bed for idiots there too. ;-) I don't mind being called an idiot, it elevates me in this thread! |
Standing-Wave Current vs Traveling-Wave Current
On Wed, 19 Dec 2007 19:33:22 -0600, Cecil Moore
wrote: Richard Clark wrote: Cecil Moore wrote: The "traveling wave" antenna clearly shows standing waves. This is just too, too easy! :-) Too bad for you the threaded newsreader shows that the only thing I wrong above was "clearly shows". It also shows that you wrote the rest. Any idiot can falsify a posting. 73's Richard Clark, KB7QHC |
Standing-Wave Current vs Traveling-Wave Current
Roger wrote:
Congratulations on a clever use of zero resistance loads. I am probably missing something, but why not just show the currents and phase in the 'View Antenna' window ? |
Standing-Wave Current vs Traveling-Wave Current
4nec2 wrote:
Roger wrote: Congratulations on a clever use of zero resistance loads. I am probably missing something, but why not just show the currents and phase in the 'View Antenna' window ? Maybe I am missing something. I can not get a numeric record of the phase and current in the "View Antenna" window. I am using version 4.0. |
Standing-Wave Current vs Traveling-Wave Current
4nec2 wrote:
Roger wrote: Congratulations on a clever use of zero resistance loads. I am probably missing something, but why not just show the currents and phase in the 'View Antenna' window ? For current phase, EZNEC does not display the same absolute phase as the "Load Dat" function reports. That would appear to be a bug in the EZNEC GUI software. I'm glad you asked that question. Perhaps W7EL can tell us why EZNEC does not display the same current phase as it reports in the "Load Dat" function. EZNEC seems to display the current amplitude correctly but it is unclear exactly what EZNEC is displaying when the current phase box is selected. That's why I used the "Load Dat" feature. Here is a graphic using the "View Antenna" window for the EZNEC files TravWave.EZ and StndWave.EZ. http://www.w5dxp.com/eznec.jpg Looking at TravWave.EZ with the current phase turned off, the current displayed is indeed the amplitude of the current up and down the wire which is essentially a constant RMS magnitude. But with the current phase turned on, the display does not display the same phase reported by "Load Dat". It displays a cosine function when the actual phase function is a straight sloping line varying from 0 degrees at the feedpoint to -90 degrees at the load resistor. What EZNEC is actually displaying associated with phase is unclear, confusing, and misleading. StndWave.EZ has the same unclear display for phase. The current amplitude is the correct cosine function but the current phase is misleading. The "Loads Dat" function says the phase varies from 0 degrees at the feedpoint to -0.11 deg at the open end of the wire, i.e. virtually no change at all in phase up and down the wire. Yet EZNEC displays a cosine function for the current phase the meaning of which is unclear. To answer your question, EZNEC does not display phase when the current phase box is selected. It is unclear to me exactly what EZNEC is displaying when the current phase box is selected. -- 73, Cecil http://www.w5dxp.com |
Standing-Wave Current vs Traveling-Wave Current
Roger wrote:
Maybe I am missing something. I can not get a numeric record of the phase and current in the "View Antenna" window. I am using version 4.0. You do get a *graphic* record of the current amplitude in the "View Antenna" window. It is unclear exactly what is displayed when the current phase box is selected. You do NOT get a numeric record in the View Antenna window. For a numeric record, you must use the "Loads" and "Load Dat" feature. -- 73, Cecil http://www.w5dxp.com |
Standing-Wave Current vs Traveling-Wave Current
Cecil Moore wrote:
Here is a graphic using the "View Antenna" window for the EZNEC files TravWave.EZ and StndWave.EZ. http://www.w5dxp.com/eznec.jpg Sorry, the graphic only contains information about TravWave.EZ Looking at TravWave.EZ with the current phase turned off, the current displayed is indeed the amplitude of the current up and down the wire which is essentially a constant RMS magnitude. But with the current phase turned on, the display does not display the same phase reported by "Load Dat". It displays a cosine function when the actual phase function is a straight sloping line varying from 0 degrees at the feedpoint to -90 degrees at the load resistor. What EZNEC is actually displaying associated with phase is unclear, confusing, and misleading. StndWave.EZ ... Please ignore what I said about StndWave.EZ To answer your question, EZNEC does not display phase when the current phase box is selected. To be more clear. EZNEC does not display the same phase as reported by the "Loads" feature. -- 73, Cecil http://www.w5dxp.com |
Standing-Wave Current vs Traveling-Wave Current
Roger wrote:
4nec2 wrote: Roger wrote: Congratulations on a clever use of zero resistance loads. I am probably missing something, but why not just show the currents and phase in the 'View Antenna' window ? Maybe I am missing something. I can not get a numeric record of the phase and current in the "View Antenna" window. I am using version 4.0. In all versions, the View Antenna display shows the currents only graphically and not numerically. There are three ways to find the numerical value of current at a particular segment: 1. Click the Currents button at the left of the main window. This gives the currents at all segments. 2. Insert a zero ohm load at the segment of interest and click Load Dat to see its current. 3. Insert a zero volt voltage (not current) source at the segment of interest and click Src Dat to see its current. Roy Lewallen, W7EL |
Standing-Wave Current vs Traveling-Wave Current
Roy Lewallen wrote:
1. Click the Currents button at the left of the main window. This gives the currents at all segments. 2. Insert a zero ohm load at the segment of interest and click Load Dat to see its current. Why doesn't EZNEC accurately plot those currents on the antenna display? -- 73, Cecil http://www.w5dxp.com |
Standing-Wave Current vs Traveling-Wave Current
On Thu, 20 Dec 2007 15:04:36 -0600, Cecil Moore
wrote: accurately And this cry in the wilderness from someone who can prove fundamental principles with +/-40% error. ;-) |
Standing-Wave Current vs Traveling-Wave Current
Cecil Moore wrote:
Roger wrote: Maybe I am missing something. I can not get a numeric record of the phase and current in the "View Antenna" window. I am using version 4.0. You do get a *graphic* record of the current amplitude in the "View Antenna" window. It is unclear exactly what is displayed when the current phase box is selected. Although one can get a current amplitude plot vs length from EZNEC, it seems impossible to get a current phase plot vs length. That's probably why so many people are confused. Click on "Currents" and transfer that data to EXCEL to make things a lot clearer. -- 73, Cecil http://www.w5dxp.com |
Standing-Wave Current vs Traveling-Wave Current
Cecil Moore wrote:
Cecil Moore wrote: Here is a graphic using the "View Antenna" window for the EZNEC files TravWave.EZ and StndWave.EZ. http://www.w5dxp.com/eznec.jpg Sorry, the graphic only contains information about TravWave.EZ Looking at TravWave.EZ with the current phase turned off, the current displayed is indeed the amplitude of the current up and down the wire which is essentially a constant RMS magnitude. But with the current phase turned on, the display does not display the same phase reported by "Load Dat". It displays a cosine function when the actual phase function is a straight sloping line varying from 0 degrees at the feedpoint to -90 degrees at the load resistor. What EZNEC is actually displaying associated with phase is unclear, confusing, and misleading. StndWave.EZ ... Please ignore what I said about StndWave.EZ To answer your question, EZNEC does not display phase when the current phase box is selected. To be more clear. EZNEC does not display the same phase as reported by the "Loads" feature. Cecil, I presume that this is a silly question, but "Did you read the manual"? EZNEC is displays the current phase exactly as described in the manual. Hint: Current is shown as distance from the axis. Current PHASE is shown by a rotation around the axis, not by the distance from the axis. 73, Gene W4SZ |
Standing-Wave Current vs Traveling-Wave Current
Gene Fuller wrote:
Hint: Current is shown as distance from the axis. Current PHASE is shown by a rotation around the axis, not by the distance from the axis. So I cannot display current phase vs length? No wonder Roy is so confused about the nature of current phase. Seems I have to paste the current phase into EXCEL just to get a decent graph of it. -- 73, Cecil http://www.w5dxp.com |
Standing-Wave Current vs Traveling-Wave Current
Humph, all this hot air just addles my aged brain...
I do know a FEW things however... I know that standing waves exist because I can slide my fluorescent bulb along the line and show precisely where they are I can measure the distance between peak voltage points with a metric wooden ruler and demonstrate/prove that 3X10^6meters / Fcycles = the length of the measured 2 radians of travel.... But most importantly I KNOW that the standing waves are real and have energy because my fluorescent tube lights up as it passes the peaks... That requires energy/watts/joules to flow through the gas of the tube... You can use all the damned words in the world to talk around and obscure the subject, but when I slide along my line the bulb lights to maximum brilliance every half wave length of the standing waves... Res Ipsa Loquiter denny / k8do |
Standing-Wave Current vs Traveling-Wave Current
On Dec 21, 8:01*am, Denny wrote:
Humph, all this hot air just addles my aged brain... I do know a FEW things however... I know that standing waves exist because I can slide my fluorescent bulb along the line and show precisely where they are I can measure the distance between peak voltage points with a metric wooden ruler and demonstrate/prove that 3X10^6meters / Fcycles = the length of the measured 2 radians of travel.... But most importantly I KNOW that the standing waves are real and have energy because my fluorescent tube lights up as it passes the peaks... That requires energy/watts/joules to flow through the gas of the tube... You can use all the damned words in the world to talk around and obscure the subject, but when I slide along my line the bulb lights to maximum brilliance every half wave length of the standing waves... But what does it mean at the other places along the line where the bulb does not light? Does it mean that there is no energy at these points on the line? ...Keith |
Standing-Wave Current vs Traveling-Wave Current
Denny wrote:
You can use all the damned words in the world to talk around and obscure the subject, but when I slide along my line the bulb lights to maximum brilliance every half wave length of the standing waves... Here's why: http://www.chemmybear.com/standing.html -- 73, Cecil http://www.w5dxp.com |
Standing-Wave Current vs Traveling-Wave Current
Gene Fuller wrote:
Hint: Current is shown as distance from the axis. Current PHASE is shown by a rotation around the axis, not by the distance from the axis. If it was a conscious design, I apologize for saying it is a bug. So how can I display a 2D graph of phase vs segments? -- 73, Cecil http://www.w5dxp.com |
Standing-Wave Current vs Traveling-Wave Current
On 21 Dec, 05:47, Keith Dysart wrote:
On Dec 21, 8:01*am, Denny wrote: Humph, all this hot air just addles my aged brain... I do know a FEW things however... I know that standing waves exist because I can slide my fluorescent bulb along the line and show precisely where they are I can measure the distance between peak voltage points with a metric wooden ruler and demonstrate/prove that 3X10^6meters / Fcycles = the length of the measured 2 radians of travel.... But most importantly I KNOW that the standing waves are real and have energy because my fluorescent tube lights up as it passes the peaks... That requires energy/watts/joules to flow through the gas of the tube... You can use all the damned words in the world to talk around and obscure the subject, but when I slide along my line the bulb lights to maximum brilliance every half wave length of the standing waves... But what does it mean at the other places along the line where the bulb does not light? Does it mean that there is no energy at these points on the line? ...Keith- Hide quoted text - - Show quoted text - Ofcourse not!. The energy is directed else where, it usually changes to heat. As I have stated before, in a tank circuit the resistance in the circuit also is cyclic with respect to energy distribution. Where there is resonance the resistance factor is quite small. As one moves to the "near stable" position the resistance factor becomes larger with respect to energy distribution. If you wish to pursue what is happening in such a circuit then break up the application of voltage in consequitive steps to see the rotational effects of capacitor and inductance energy discharge together with the energy distribution when the voltage drop over the energy storage units are equal. Art |
Standing-Wave Current vs Traveling-Wave Current
You can use all the damned words in the world to talk around and
obscure the subject, but when I slide along my line the bulb lights to maximum brilliance every half wave length of the standing waves... But what does it mean at the other places along the line where the bulb does not light? Does it mean that there is no energy at these points on the line? ....Keith Fluorescent bulb or neon bulb respond, are fired, by voltage being higher. Where the voltage is high, the current is low and vice versa (standing waves). Energy is the same along the antenna, just standing waves exhibit max and min according to distribution of current or voltage along the radiator. If W8JI, W7EL and their followers moved neon bulb along the loading coil, they would see the change in brightness along the coil (getting brighter closer to the top) indicating diminishing current along the same length. Ergo (standing wave) current is not constant along the loading coil as they tried to convince their followers to the contrary. 73 and Merry Christmas to all Yuri, www.K3BU.us |
Standing-Wave Current vs Traveling-Wave Current
Yuri Blanarovich wrote:
If W8JI, W7EL and their followers moved neon bulb along the loading coil, they would see the change in brightness along the coil (getting brighter closer to the top) indicating diminishing current along the same length. Ergo (standing wave) current is not constant along the loading coil as they tried to convince their followers to the contrary. One can just look at the standing wave current equation and tell it is not constant. The standing wave current varies with location on the antenna. -- 73, Cecil http://www.w5dxp.com |
Standing-Wave Current vs Traveling-Wave Current
Nice graphic, Cecil.. But the thread has drifted beyond recognition..
Part of the original dispute across a couple of threads as I remember it, was the contention that there is no energy contained within the reflected wave and therefore no energy contained within the standing wave, i.e. a mere artifact... I simply wanted to point out that the standing wave on a line does contain energy and it is a childishly simple exercise to prove it, therefore the reflected wave must contain energy... As far as the questioner, where does the energy go between the standing wave peaks - oy vey.... If it is a real question - as opposed to a rhetorical device which I hope was the intent - then the profound ignorance of basic physics is vastly beyond the limited space I have to go over it... See ANY introductory level, physics textbook for details... cheers ... denny |
Standing-Wave Current vs Traveling-Wave Current
"Denny" wrote in message
... Nice graphic, Cecil.. But the thread has drifted beyond recognition.. Part of the original dispute across a couple of threads as I remember it, was the contention that there is no energy contained within the reflected wave and therefore no energy contained within the standing wave, i.e. a mere artifact... I simply wanted to point out that the standing wave on a line does contain energy and it is a childishly simple exercise to prove it, therefore the reflected wave must contain energy... As far as the questioner, where does the energy go between the standing wave peaks - oy vey.... If it is a real question - as opposed to a rhetorical device which I hope was the intent - then the profound ignorance of basic physics is vastly beyond the limited space I have to go over it... See ANY introductory level, physics textbook for details... cheers ... denny the REAL answer is that the 'standing' wave is a creation of experimenters 100 years ago who didn't have the impedance, current, and voltage measurement tools we have today, and didn't know of or understand superposition. 'standing' waves are nothing but a result of superposition of the forward and reflected waves, they have no physical significance beyond that. it is worthless to talk about power or energy in them since they can always be broken down into the component waves which make more sense to work with. |
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