I wonder if Rich now agrees with me that the power gain of a system of two half-wave dipoles is the same as the power gain of a system of two quarter-wave monopoles above ground. If he agrees with that, he agrees that there is a reciprocity failure of the receiving monopole when receiving a groundwave. There simply is no way around that. If Rich still does not agree with that, I suggest now, as I did in previous posts, that he get his NEC program working, and prove this for himself. In Rich's previous posts, he cited NEC among the authorities he used against my assertions. It now looks like NEC is on my side. I submit NEC as the "authoritative reference" that Rich is looking for.
Edit:
(I was composing my reply to Rich offline when the previous comment was posted, so I missed it. I am glad that this discussion has a readership. I see that the read count for this thread is respectable. This subject is relevant to Part 15 AM because it applies to AM radio reception. It surprises me how much consternation this subject causes, not only between Rich and myself, but also between other RF engineers.)
The reciprocity failure of a monopole above ground receiving a groundwave is mathematically proved by comparing the system power gain of two parallel half-wave dipoles at the same height in free space to that of two parallel quarter-wave monopoles over a ground plane. If the power gains of these two antenna systems are the same, then what I am saying has been proved. QED.
Since the reciprocity failure with two monopoles has been proved, the same reciprocity failure applies to a single receiving monopole above ground. Also, since the reciprocity failure has been proved, quotes from authors who did not mention this exception to the principle of reciprocity, for whatever reason, are not relevant.
As for Rich's question about the elevation of the incident radiation at which the reciprocity failure applies, as I said in previous posts, it applies only to the surface wave traveling along the ground plane (groundwaves). It does not apply to waves that are reflected from the ground plane (sky waves). For that reason, plots of the receiver gain and the transmitter gain appear identical, because the reciprocity failure applies only to one ray, which can be missed on the plot. This one ray is the groundwave, which is a very important component of the signals transmitted in medium-wave radio communications.
I wonder if Rich now agrees with me that the power gain of a system of two half-wave dipoles is the same as the power gain of a system of two quarter-wave monopoles above ground. If he agrees with that, he agrees that there is a reciprocity failure of the receiving monopole when receiving a groundwave. There simply is no way around that. If Rich still does not agree with that, I suggest now, as I did in previous posts, that he get his NEC program working, and prove this for himself. In Rich's previous posts, he cited NEC among the authorities he used against my assertions. It now looks like NEC is on my side. I submit NEC as the "authoritative reference" that Rich is looking for.
Edit:
(I was composing my reply to Rich offline when the previous comment was posted, so I missed it. I am glad that this discussion has a readership. I see that the read count for this thread is respectable. This subject is relevant to Part 15 AM because it applies to AM radio reception. It surprises me how much consternation this subject causes, not only between Rich and myself, but also between other RF engineers.)
The reciprocity failure of a monopole above ground receiving a groundwave is mathematically proved by comparing the system power gain of two parallel half-wave dipoles at the same height in free space to that of two parallel quarter-wave monopoles over a ground plane. If the power gains of these two antenna systems are the same, then what I am saying has been proved. QED.
Since the reciprocity failure with two monopoles has been proved, the same reciprocity failure applies to a single receiving monopole above ground. Also, since the reciprocity failure has been proved, quotes from authors who did not mention this exception to the principle of reciprocity, for whatever reason, are not relevant.
As for Rich's question about the elevation of the incident radiation at which the reciprocity failure applies, as I said in previous posts, it applies only to the surface wave traveling along the ground plane (groundwaves). It does not apply to waves that are reflected from the ground plane (sky waves). For that reason, plots of the receiver gain and the transmitter gain appear identical, because the reciprocity failure applies only to one ray, which can be missed on the plot. This one ray is the groundwave, which is a very important component of the signals transmitted in medium-wave radio communications.
Ermi wrote: The reciprocity failure of a monopole above ground receiving a groundwave is mathematically proved by comparing the system power gain of two parallel half-wave dipoles at the same height in free space to that of two parallel quarter-wave monopoles over a ground plane. If the power gains of these two antenna systems are the same, then what I am saying has been proved. QED.
Not so. This is a comparison of apples with oranges. Ermi has stated that the zero-degree elevation angle (groundwave) gain of a receive monopole is 6 dB less than that of a transmit monopole. But that cannot be true, because as I pointed out, and Ermi already has acknowledged -- 3 dB of this 6 dB difference (if it exists) would be the result of the ground reflection from the transmit monopole.
As for Rich's question about the elevation of the incident radiation at which the reciprocity failure applies, as I said in previous posts, it applies only to the surface wave traveling along the ground plane (groundwaves). It does not apply to waves that are reflected from the ground plane (sky waves).
Note that a transmit monopole produces skywaves even with NO reflection from a ground plane.
For that reason, plots of the receiver gain and the transmitter gain appear identical, because the reciprocity failure applies only to one ray, which can be missed on the plot. This one ray is the groundwave, which is a very important component of the signals transmitted in medium-wave radio communications.
Apparently Ermi posits that the elevation gain of a receiving monopole instantaneously acquires its reciprocal (transmit) value once the elevation angle exceeds zero degrees by any amount.
But the slope of such a gain step would be infinite, which is "unlikely."
I'm not sure if this topic warrants more debate. Probably enough has been posted so that readers can reach their own conclusions, or research the subject more, should they wish to.
//
PS to Daniel: Thanks for your post in this thread. Glad to learn that there are more readers of it than just Ermi and me.
Ermi wrote: The reciprocity failure of a monopole above ground receiving a groundwave is mathematically proved by comparing the system power gain of two parallel half-wave dipoles at the same height in free space to that of two parallel quarter-wave monopoles over a ground plane. If the power gains of these two antenna systems are the same, then what I am saying has been proved. QED.
Not so. This is a comparison of apples with oranges. Ermi has stated that the zero-degree elevation angle (groundwave) gain of a receive monopole is 6 dB less than that of a transmit monopole. But that cannot be true, because as I pointed out, and Ermi already has acknowledged -- 3 dB of this 6 dB difference (if it exists) would be the result of the ground reflection from the transmit monopole.
As for Rich's question about the elevation of the incident radiation at which the reciprocity failure applies, as I said in previous posts, it applies only to the surface wave traveling along the ground plane (groundwaves). It does not apply to waves that are reflected from the ground plane (sky waves).
Note that a transmit monopole produces skywaves even with NO reflection from a ground plane.
For that reason, plots of the receiver gain and the transmitter gain appear identical, because the reciprocity failure applies only to one ray, which can be missed on the plot. This one ray is the groundwave, which is a very important component of the signals transmitted in medium-wave radio communications.
Apparently Ermi posits that the elevation gain of a receiving monopole instantaneously acquires its reciprocal (transmit) value once the elevation angle exceeds zero degrees by any amount.
But the slope of such a gain step would be infinite, which is "unlikely."
I'm not sure if this topic warrants more debate. Probably enough has been posted so that readers can reach their own conclusions, or research the subject more, should they wish to.
//
PS to Daniel: Thanks for your post in this thread. Glad to learn that there are more readers of it than just Ermi and me.
Rich seems to concede the truth of the theorem that the system gain of two half-wave dipoles in free space is the same as the system gain of two quarter-wave monopoles over a ground plane, but from his previous post, he seems not to understand why it must then follow that there is a reciprocity failure of a receiving monopole when receiving ground waves. So, I will once again attempt to explain why reciprocity failure for a monopole over ground must follow from this theorem.
I will begin by asking the reader to imagine two parallel dipoles in free space. At a great distance from each other, the transmitting dipole applies a single ray to the receiving dipole, and the receiving dipole intercepts a wavefront that originated at the transmitting dipole that is parallel to said receiving dipole.
Now, I ask the reader to imagine two parallel monopoles over a ground plane. Just like for the dipole system, at a great distance from each other, the transmitting monopole applies a single ray to the receiving monopole, and the receiving monopole intercepts a wavefront that originated from transmitting monopole that is parallel to said receiving monopole.
It would actually be better to draw the two antenna systems on a piece of paper to help in the visualization. In the dipole system, the single ray goes along a straight line between the centers of the two dipoles. In the monopole system, the single ray goes along the ground plane, and it represents the groundwave. There are obvious similarities in appearance between the monopole system and the dipole system, so it is natural to try to compare the two systems.
For the dipole system, the power gain between the transmitting dipole and the receiving dipole is proportional to Gdt X Gdr, where Gdt is the gain of the transmitting dipole, and Gdr is the gain of the receiving dipole. Since the reciprocity of the dipole system is unquestioned, the gain of the the transmitting dipole and the gain of the receiving dipole are the same. So, Gdt = Gdr. To simplify the notation slightly, we can call the gain of either the transmitting or receiving dipole Gd. Thus, the system gain of the dipole system is proportional to Gd^2.
We have a similar situation with the monopole system. The system power gain is proportional to Gmt X Gmr, where Gmt is is the gain of the transmitting monopole, and Gmr is the gain of the receiving monopole. We know that the transmitting monopole has twice the power gain of a dipole, so we can replace Gmt with 2Gd. So, the system gain of the monopose system is proportional to 2Gd X Gmr. The theorem that states that the system gain of two monopoles is the same as the system gain of two dipoles gives the result that Gd^2 = 2Gd X Gmr. The unknown in this equation is the monopole receiver gain, Gmr. Gmr = (Gd^2)/ 2Gd = Gd/2. So, we see that the gain of the receiving monopole is half of that of the dipole. Since the transmitting monopole has the gain 2Gd, and the gain of the receiving monopole is Gd/2, the ratio of the gain of the receiving monopole to the gain of the transmitting monopole is (Gd/2)/2Gd = 1/4 = - 6dB.
I hope that this extensive derivation is convincing to Rich. But, if not, I hope that he will wake up one morning and "get it."
Rich seems to concede the truth of the theorem that the system gain of two half-wave dipoles in free space is the same as the system gain of two quarter-wave monopoles over a ground plane, but from his previous post, he seems not to understand why it must then follow that there is a reciprocity failure of a receiving monopole when receiving ground waves. So, I will once again attempt to explain why reciprocity failure for a monopole over ground must follow from this theorem.
I will begin by asking the reader to imagine two parallel dipoles in free space. At a great distance from each other, the transmitting dipole applies a single ray to the receiving dipole, and the receiving dipole intercepts a wavefront that originated at the transmitting dipole that is parallel to said receiving dipole.
Now, I ask the reader to imagine two parallel monopoles over a ground plane. Just like for the dipole system, at a great distance from each other, the transmitting monopole applies a single ray to the receiving monopole, and the receiving monopole intercepts a wavefront that originated from transmitting monopole that is parallel to said receiving monopole.
It would actually be better to draw the two antenna systems on a piece of paper to help in the visualization. In the dipole system, the single ray goes along a straight line between the centers of the two dipoles. In the monopole system, the single ray goes along the ground plane, and it represents the groundwave. There are obvious similarities in appearance between the monopole system and the dipole system, so it is natural to try to compare the two systems.
For the dipole system, the power gain between the transmitting dipole and the receiving dipole is proportional to Gdt X Gdr, where Gdt is the gain of the transmitting dipole, and Gdr is the gain of the receiving dipole. Since the reciprocity of the dipole system is unquestioned, the gain of the the transmitting dipole and the gain of the receiving dipole are the same. So, Gdt = Gdr. To simplify the notation slightly, we can call the gain of either the transmitting or receiving dipole Gd. Thus, the system gain of the dipole system is proportional to Gd^2.
We have a similar situation with the monopole system. The system power gain is proportional to Gmt X Gmr, where Gmt is is the gain of the transmitting monopole, and Gmr is the gain of the receiving monopole. We know that the transmitting monopole has twice the power gain of a dipole, so we can replace Gmt with 2Gd. So, the system gain of the monopose system is proportional to 2Gd X Gmr. The theorem that states that the system gain of two monopoles is the same as the system gain of two dipoles gives the result that Gd^2 = 2Gd X Gmr. The unknown in this equation is the monopole receiver gain, Gmr. Gmr = (Gd^2)/ 2Gd = Gd/2. So, we see that the gain of the receiving monopole is half of that of the dipole. Since the transmitting monopole has the gain 2Gd, and the gain of the receiving monopole is Gd/2, the ratio of the gain of the receiving monopole to the gain of the transmitting monopole is (Gd/2)/2Gd = 1/4 = - 6dB.
I hope that this extensive derivation is convincing to Rich. But, if not, I hope that he will wake up one morning and "get it."
I have used a 1959 paper by Kenneth A. Norton as a reference for some of what I said in this thread. I thought I would post about who Norton is.
Norton was a pioneer in the theory of radio propagation in the 1930s and 1940s. Terman uses Norton's ground wave attenuation curves for various frequencies and ground conductivities in "Radio Engineering." Norton originally published these curves in 1932. His 1959 paper, which I referenced in this thread, must have been written near the end of his career.
Norton's most famous accomplishment was finding, in 1935, a blunder in the mathematical derivation in Sommerfeld's 1909 article about ground wave propagation. Sommerfeld's article was known for several years to not give very accurate results. Norton published new formulas for Sommerfeld's theory, which have been found to give accurate results.
Norton investigated the Heaviside Layer (1932), the nightime range of AM broadcast stations (1935), the physical nature of surface waves and sky waves (1937), the propagation of waves along the ground and the upper atmosphere (1936), the theory of tropospheric wave propagation (1940), and many other subjects.
Norton is not particularly well known to radio engineers, but he made very significant contributions to radio.
I have used a 1959 paper by Kenneth A. Norton as a reference for some of what I said in this thread. I thought I would post about who Norton is.
Norton was a pioneer in the theory of radio propagation in the 1930s and 1940s. Terman uses Norton's ground wave attenuation curves for various frequencies and ground conductivities in "Radio Engineering." Norton originally published these curves in 1932. His 1959 paper, which I referenced in this thread, must have been written near the end of his career.
Norton's most famous accomplishment was finding, in 1935, a blunder in the mathematical derivation in Sommerfeld's 1909 article about ground wave propagation. Sommerfeld's article was known for several years to not give very accurate results. Norton published new formulas for Sommerfeld's theory, which have been found to give accurate results.
Norton investigated the Heaviside Layer (1932), the nightime range of AM broadcast stations (1935), the physical nature of surface waves and sky waves (1937), the propagation of waves along the ground and the upper atmosphere (1936), the theory of tropospheric wave propagation (1940), and many other subjects.
Norton is not particularly well known to radio engineers, but he made very significant contributions to radio.
Those who do not know about Sommerfeld may not appreciate how remakable it was for Norton to discover an error in one of Sommerfeld's scientific papers. Sommerfeld was one of the greatest mathematical physicists of the Twentieth Century. Norton himself apparently knew how significant his discovery of this error was, so he did not publish his correction in an engineering journal, but in the British scientific journal, "Nature."
Sommerfeld's first important accomplishment was made in 1896, when he derived the first exact solution ever to a diffraction problem using electromagnetic theory. Other scientists, like Fresnel, Fraunhofer, Huygens, and Arago had obtained approximate solutions, but Sommerfeld's solution was a rigorous application of Maxwell's laws. He determined the diffraction of a plane wave by a thin, perfectly conducting, semi-infinite, plate.
Sommerfeld was one of the few great scientists to be known as a great teacher. Several Nobel Prize winners were among his students.
He wrote a textbook about the use of partial differential equations in physics.
Sommerfeld made numerous contributions to several subjects in physics, including relativity, orbits of electrons, and quantum theory. The so-called "fine-structure constant" (at one time thought to be exactly 137, but now known to be about 137.036), is due to Sommerfeld.
So, Norton's discovery of a significant error by a great man like Sommerfeld was quite an accomplishment. This discovery did not hurt Sommerfeld's reputation, either, because Norton had proved that Sommerfeld's theory, which had previously given the wrong results, was essentially correct.
Like Norton, Sommerfeld is not as well-known as he should be. A really remarkable situation is that he was never awarded the Nobel Prize. Considerably lesser people than Sommerfeld have received the Nobel Prize. Richard Zsigmondy comes to mind. He invented the "ultramicroscope," which is of no significance today. Lenard is an extreme example. His theories are now known to be completely wrong.
Those who do not know about Sommerfeld may not appreciate how remakable it was for Norton to discover an error in one of Sommerfeld's scientific papers. Sommerfeld was one of the greatest mathematical physicists of the Twentieth Century. Norton himself apparently knew how significant his discovery of this error was, so he did not publish his correction in an engineering journal, but in the British scientific journal, "Nature."
Sommerfeld's first important accomplishment was made in 1896, when he derived the first exact solution ever to a diffraction problem using electromagnetic theory. Other scientists, like Fresnel, Fraunhofer, Huygens, and Arago had obtained approximate solutions, but Sommerfeld's solution was a rigorous application of Maxwell's laws. He determined the diffraction of a plane wave by a thin, perfectly conducting, semi-infinite, plate.
Sommerfeld was one of the few great scientists to be known as a great teacher. Several Nobel Prize winners were among his students.
He wrote a textbook about the use of partial differential equations in physics.
Sommerfeld made numerous contributions to several subjects in physics, including relativity, orbits of electrons, and quantum theory. The so-called "fine-structure constant" (at one time thought to be exactly 137, but now known to be about 137.036), is due to Sommerfeld.
So, Norton's discovery of a significant error by a great man like Sommerfeld was quite an accomplishment. This discovery did not hurt Sommerfeld's reputation, either, because Norton had proved that Sommerfeld's theory, which had previously given the wrong results, was essentially correct.
Like Norton, Sommerfeld is not as well-known as he should be. A really remarkable situation is that he was never awarded the Nobel Prize. Considerably lesser people than Sommerfeld have received the Nobel Prize. Richard Zsigmondy comes to mind. He invented the "ultramicroscope," which is of no significance today. Lenard is an extreme example. His theories are now known to be completely wrong.
At the risk of derailing the thread on a nitpicking point, while you may not feel Zsigmondy's slit ultramicroscope is of any significance today, it was considered a significant development back in the 1920s when it won him the Nobel prize. A purely optical device that allowed observing particles of less than a millionth of a millimeter in diameter?
Ok, maybe no *obvious* direct applications to RF or part15, perhaps. But it was used for studying colloids, and some of the semiconductors we use use colloidal processes for their manufacture. Not to mention some of the plastics we use and photographic processes.
Maybe *now* we have something better, but it was a breakthrough in it's day that advanced colloidal chemistry to the point where it's a useful part of the manufacture of the substrates of large scale integrated circuits. His ultramicroscope allowed direct observation of the tiny particles in a colloidal suspension or a mist and as such the first definitive way of measuring the actual density in terms of the ratio of particles to fluids.
Aside from that, I know the ultramicroscope at least *used* to be what they used for studying Brownian motion in gases, very small cloud chamber ionization tracks, and (perhaps the most interesting for electronics) for observing the oil droplets in some of the Millikan oil drop experiments. The oil drop experiments allowed measurement of the actual charge on a single electron.
I'm not real up to date on what they use currently for such observation/analysis, but the ultramicroscope would at least have been a stepping stone to it, and to many things we got from the advances in colloidal chemistry over the last century.
I may be overly picky on this point, but I wouldn't agree to that invention being "of no signifigance today". One also has to bear in mind that things like the Nobel prize is awarded by people that are not omniscient as to what will be of greatest importance in 80 years from the time they award it. LOL
Daniel
At the risk of derailing the thread on a nitpicking point, while you may not feel Zsigmondy's slit ultramicroscope is of any significance today, it was considered a significant development back in the 1920s when it won him the Nobel prize. A purely optical device that allowed observing particles of less than a millionth of a millimeter in diameter?
Ok, maybe no *obvious* direct applications to RF or part15, perhaps. But it was used for studying colloids, and some of the semiconductors we use use colloidal processes for their manufacture. Not to mention some of the plastics we use and photographic processes.
Maybe *now* we have something better, but it was a breakthrough in it's day that advanced colloidal chemistry to the point where it's a useful part of the manufacture of the substrates of large scale integrated circuits. His ultramicroscope allowed direct observation of the tiny particles in a colloidal suspension or a mist and as such the first definitive way of measuring the actual density in terms of the ratio of particles to fluids.
Aside from that, I know the ultramicroscope at least *used* to be what they used for studying Brownian motion in gases, very small cloud chamber ionization tracks, and (perhaps the most interesting for electronics) for observing the oil droplets in some of the Millikan oil drop experiments. The oil drop experiments allowed measurement of the actual charge on a single electron.
I'm not real up to date on what they use currently for such observation/analysis, but the ultramicroscope would at least have been a stepping stone to it, and to many things we got from the advances in colloidal chemistry over the last century.
I may be overly picky on this point, but I wouldn't agree to that invention being "of no signifigance today". One also has to bear in mind that things like the Nobel prize is awarded by people that are not omniscient as to what will be of greatest importance in 80 years from the time they award it. LOL
Daniel
Rattan,
I appreciate your comments about Richard Zsigmondy and his contributions to the study of colloidal suspensions. As far as I could tell, the facts you stated are completely correct.
There is nothing wrong with Zsigmondy's work, but I think that it is not impressive enough for the Royal Swedish Academy to make the hyperbolic declaration that their decision was "the unanimous verdict of the entire scientific world."
The "ultramicroscope" is a dark-field microscope, an instrument that was invented in the 1700s. The dark-field feature is a part of most ordinary laboratory microscopes made today. A typical dark-field microscope can detect particles as small as about 30 nm in diameter. This is pretty good, considering that the wavelength of light is about 500 nm, and the limit of resolution of an optical microscope is about 250 nm. Zsigmondy, by applying very intense illumination from such sources as sunlight and arc lamps, was able to detect particles as small as 4 nm in diameter. By using nucleation techniques, he was able to detect particles as small as 1.5 nm in diameter. This is quite an achievement, and it cannot be done even with a scanning electron microscope today. It would be necessary to use a transmission electron microscope to get this kind of performance.
To be sure, the apparatus gave impressive results, although it was based on an old idea. Since I am an engineer myself, it slightly annoys me that the Zeiss engineer who designed and built the remakable equipment, Siedentopf, did not share this Nobel Prize. Of course, it is not unusual for engineers to fail to get the recognition they deserve.
The Academy apparently considered Siedentopf to be just a lab assistant.
As I said, I don't find any fault with Zsigmondy's work. His investigations were very thorough and laborious. The major scientific significance of his work is that it proved that colloids were pariculate in nature. It had already been observed at the time that coarser colloids were paricles, but Zsigmondy proved that colloids were particulate in nature to very small dimensions.
I would call Zsigmondy's accomplishments "very good work," but not "best in the world."
I did not mention Zsigmondy in isolation, but in comparison to Sommerfeld. If Zsigmondy had not been awarded the Nobel Prize, it would not have caused great astonishment. But it is truly amazing that Sommerfeld was never awarded the Nobel Prize.
Rattan,
I appreciate your comments about Richard Zsigmondy and his contributions to the study of colloidal suspensions. As far as I could tell, the facts you stated are completely correct.
There is nothing wrong with Zsigmondy's work, but I think that it is not impressive enough for the Royal Swedish Academy to make the hyperbolic declaration that their decision was "the unanimous verdict of the entire scientific world."
The "ultramicroscope" is a dark-field microscope, an instrument that was invented in the 1700s. The dark-field feature is a part of most ordinary laboratory microscopes made today. A typical dark-field microscope can detect particles as small as about 30 nm in diameter. This is pretty good, considering that the wavelength of light is about 500 nm, and the limit of resolution of an optical microscope is about 250 nm. Zsigmondy, by applying very intense illumination from such sources as sunlight and arc lamps, was able to detect particles as small as 4 nm in diameter. By using nucleation techniques, he was able to detect particles as small as 1.5 nm in diameter. This is quite an achievement, and it cannot be done even with a scanning electron microscope today. It would be necessary to use a transmission electron microscope to get this kind of performance.
To be sure, the apparatus gave impressive results, although it was based on an old idea. Since I am an engineer myself, it slightly annoys me that the Zeiss engineer who designed and built the remakable equipment, Siedentopf, did not share this Nobel Prize. Of course, it is not unusual for engineers to fail to get the recognition they deserve.
The Academy apparently considered Siedentopf to be just a lab assistant.
As I said, I don't find any fault with Zsigmondy's work. His investigations were very thorough and laborious. The major scientific significance of his work is that it proved that colloids were pariculate in nature. It had already been observed at the time that coarser colloids were paricles, but Zsigmondy proved that colloids were particulate in nature to very small dimensions.
I would call Zsigmondy's accomplishments "very good work," but not "best in the world."
I did not mention Zsigmondy in isolation, but in comparison to Sommerfeld. If Zsigmondy had not been awarded the Nobel Prize, it would not have caused great astonishment. But it is truly amazing that Sommerfeld was never awarded the Nobel Prize.
I think that sadly a lot of it is "politics" all too many times. Some of the people get awarded it because of who was aware of their work and not always because of it being the absolute best work.
My only exception to your statements was that it was of "no" significance today. I do not argue, however, that they might have made better choices or that very deserving individuals have sometimes gone unsung.
I concur that it is annoying that engineers and other parties critical to some inventions are never credited for the very significant parts they play in the process of developing the idea into a practical device or procedure. Consider how many "Edison" devices were actually invented by others and purchased by Edison or developed at his laboratories but where he was not directly involved. But there it was a matter of marketing, his name was well known at the time. Sure, he invented a lot. But not everything that ended up with his name on it.
Daniel