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What Exactly is a Radio Wave?
This may at first sound like a stupid question. But after some years
as a radio enthusiast, I don't know what a radio wave is - what it really is. Supposedly, modern physics does not believe there is such a thing as "action at a distance". In other words, if you launch a radio wave and I intercept it, there must be a transfer of "stuff" between you and me. You can't just say that if I wiggle an electron at point A, I can cause a wiggle at the same wiggle rate at point B. I mean you can say it, but it doesn't explain anything. OK, so the latest science says that electromagnetic energy is really particle-waves. I guess this means that when I transmit, my antenna is firing particles in the form of low-energy photons (energy packets), and that these photons do not really exist anywhere but exist only as probability waves - until, of course, someone intercepts the wave. Then, magically, the photons appear at the receiving antenna, in which they manage to produce oscillating electrons. So, the best I can ascertain is that radio waves are really probability waves. I'm not sure that really helps with an intuitive understanding. Does anyone have a good description for what a radio wave really is? - JJ |
JJ wrote,
So, the best I can ascertain is that radio waves are really probability waves. I'm not sure that really helps with an intuitive understanding. Does anyone have a good description for what a radio wave really is? - JJ Yes, go ask your question on sci.physics.electromag and you'll get some answers, although I can't guarantee they'll be of any use to you. 73, Tom Donaly, KA6RUH |
A radio wave is an electromagnetic field. On my first day of fields
class, I asked the professor what an electromagnetic field was. His reply: "An electromagnetic field is a mathematical model that enables us to explain certain phenomena which we can measure." The professor was Carl T. A. Johnk. I have in front of me his text, _Engineering Electromagnetic Fields and Waves_. On page 1, it says, "A field is taken to mean a mathematical function of space and time." "Stuff" isn't transferred from one place to another by electromagnetic fields, but energy most definitely is. Force can be applied through space from one place to another by means of an electromagnetic field, and energy can be transferred by means of a field. Since the energy contained in a field can be calculated, I'll go out on a limb and say that a radio wave can be regarded as a form of energy, like heat or falling water. Perhaps a purist or physicist can find grounds to argue with that statement, it's certainly a valid concept for engineering purposes. As far as photons and waves go, be really, really careful in extending your everyday experience to quantum mechanical objects. Feynman very nicely illustrates in "Quantum Behavior" in his book _Six Easy Pieces_ that neither particles nor waves is adequate to describe such things: "Things on a very small scale behave like nothing that you have any direct experience about. They do not behave like waves, they do not behave like particles, they do not behave like clouds, or billiard balls, or weights on springs, or like anything that you have ever seen. .. . Historically, the electron, for example, was thought to behave like a particle, and then it was found that in many resepects it behaved like a wave. So it really behaves like neither. Now we have given up. We say: 'It is like *neither*'" I highly recommend this book, and other of his writings, if you're interested in understanding these phenomena on a more basic level. Roy Lewallen, W7EL jj wrote: This may at first sound like a stupid question. But after some years as a radio enthusiast, I don't know what a radio wave is - what it really is. Supposedly, modern physics does not believe there is such a thing as "action at a distance". In other words, if you launch a radio wave and I intercept it, there must be a transfer of "stuff" between you and me. You can't just say that if I wiggle an electron at point A, I can cause a wiggle at the same wiggle rate at point B. I mean you can say it, but it doesn't explain anything. OK, so the latest science says that electromagnetic energy is really particle-waves. I guess this means that when I transmit, my antenna is firing particles in the form of low-energy photons (energy packets), and that these photons do not really exist anywhere but exist only as probability waves - until, of course, someone intercepts the wave. Then, magically, the photons appear at the receiving antenna, in which they manage to produce oscillating electrons. So, the best I can ascertain is that radio waves are really probability waves. I'm not sure that really helps with an intuitive understanding. Does anyone have a good description for what a radio wave really is? - JJ |
"Things on a very small scale behave like nothing that you have any direct experience about. They do not behave like waves, they do not behave like particles, they do not behave like clouds, or billiard balls, or weights on springs, or like anything that you have ever seen. I love that part, and I always picture Ed Norton of the Honeymooners.. :) I picture it more or less, as sort of a tide in the wheeler foam, changing the probabilities. Works for me.. |
jj wrote:
So, the best I can ascertain is that radio waves are really probability waves. I'm not sure that really helps with an intuitive understanding. Photons behave strangely when you are dealing with one at a time. When you are dealing with billions of photons, quantum probability predicts their collective behavior very well. Quoting _QED_, by Feynman: "So now I present to you the three basic actions, from which all phenomena of light (including radio waves) and electrons arise: -Action #1: A photon goes from place to place. -Action #2: An electron goes from place to place. -Action #3: An electron emits or absorbs a photon. -- 73, Cecil http://www.qsl.net/w5dxp -----= Posted via Newsfeeds.Com, Uncensored Usenet News =----- http://www.newsfeeds.com - The #1 Newsgroup Service in the World! -----== Over 100,000 Newsgroups - 19 Different Servers! =----- |
Roy Lewallen wrote:
"Things on a very small scale behave like nothing that you have any direct experience about. They do not behave like waves, they do not behave like particles, they do not behave like clouds, or billiard balls, or weights on springs, or like anything that you have ever seen. . . Historically, the electron, for example, was thought to behave like a particle, and then it was found that in many resepects it behaved like a wave. So it really behaves like neither. Now we have given up. We say: 'It is like *neither*'" OTOH, quantum physics predicts the outcomes perfectly and has never been proven wrong so it doesn't matter what we call photons. If you really want to understand this stuff, you need to read a good book on string theory. May I suggest _The_Tenth_Dimension_, by Jeremy Bernstein or catch the two NOVAs that were on tonight. -- 73, Cecil http://www.qsl.net/w5dxp -----= Posted via Newsfeeds.Com, Uncensored Usenet News =----- http://www.newsfeeds.com - The #1 Newsgroup Service in the World! -----== Over 100,000 Newsgroups - 19 Different Servers! =----- |
Cecil Moore wrote:
Roy Lewallen wrote: "Things on a very small scale behave like nothing that you have any direct experience about. They do not behave like waves, they do not behave like particles, they do not behave like clouds, or billiard balls, or weights on springs, or like anything that you have ever seen. . . Historically, the electron, for example, was thought to behave like a particle, and then it was found that in many resepects it behaved like a wave. So it really behaves like neither. Now we have given up. We say: 'It is like *neither*'" OTOH, quantum physics predicts the outcomes perfectly and has never been proven wrong so it doesn't matter what we call photons. If you really want to understand this stuff, you need to read a good book on string theory. May I suggest _The_Tenth_Dimension_, by Jeremy Bernstein or catch the two NOVAs that were on tonight. Is that where we'll learn all about virtual photons, the fourth dimension, and their application to measuring voltage? Roy Lewallen, W7EL |
jj:
A round about way of defining a "radio wave" is that it is just any field function that satisfies a wave equation. Period, end of story. No one really knows any more than that! A wave equation is a partial differential equation of theoretical physics which describes the dynamics of electrical and magnetic fields. i.e. a wave equation is a simple derivation from Maxwell's celebrated equations of electrodynamics. In the beginning of electrodynamics there were only circuit-theoretic concepts [Kirchoff, Ohm] which sufficed to explain many electromagnetic phenomena. Then later wave-theoretic concepts or wave electrodynamics [Maxwell, Heaviside] were required to explain phenomena that circuit theory could not explain satisfactorily [radiation, skin effect, proximity effect, etc.]. This is when the concept of radio waves as the solutions to partial differential wave equations arose. Then later quantum-theoretic concepts known as quantum electrodynamics, or QED [Einstein, Dirac, Pauli, Feynman] were required to explain phenomena that wave-theory could not explain satisfactorily [photoelectric effect]. This is when the concept of radio waves as a flow of particles [photons] arose. QED is completely without intuitive analogic interperation by anything closely related to regular human experience, like say waves. One just has to "crank" the formulas [Feynman] and see what comes out. Regardless, today in the first decade of the 21st century it seems that the QED theory which is now approximately 60 years old and which casts the "true" meaning of "radio waves" as a floww of discrete photons, remains as the only theory that can quantitatively explain exactly all of electromagnetic phenomena and the interaction of energy with matter. An interesting high school level introduction and explanation of all of this is available in the popular book on QED by one of the world's great teaching physicists. The guy from CalTech who dipped a piece of the Challenger rocket booster's O-ring in the glass of ice water at the Challenger space shuttle disaster hearings. cfr: Richard Phillips Feynman, QED - The Strange Theory of Light and Matter, Princeton University Press, Princeton, NJ 1985. ISBN:0-691-02417-0 [QC793.5P422F48] From the page 9 of the Introduction to "QED" Feynman says, "You're not going to be able to understand it... You see my Physics students don't understand it either. That is because I don't understand it. Nobody does!" Good luck with analogies to things we seem to "understand". -- Peter K1PO Indialantic By-the-Sea, FL. "jj" wrote in message om... This may at first sound like a stupid question. But after some years as a radio enthusiast, I don't know what a radio wave is - what it really is. Supposedly, modern physics does not believe there is such a thing as "action at a distance". In other words, if you launch a radio wave and I intercept it, there must be a transfer of "stuff" between you and me. You can't just say that if I wiggle an electron at point A, I can cause a wiggle at the same wiggle rate at point B. I mean you can say it, but it doesn't explain anything. OK, so the latest science says that electromagnetic energy is really particle-waves. I guess this means that when I transmit, my antenna is firing particles in the form of low-energy photons (energy packets), and that these photons do not really exist anywhere but exist only as probability waves - until, of course, someone intercepts the wave. Then, magically, the photons appear at the receiving antenna, in which they manage to produce oscillating electrons. So, the best I can ascertain is that radio waves are really probability waves. I'm not sure that really helps with an intuitive understanding. Does anyone have a good description for what a radio wave really is? - JJ |
Roy Lewallen wrote in message ...
.... (writing about Richard Feynman's books) I highly recommend this book, and other of his writings, if you're interested in understanding these phenomena on a more basic level. I strongly agree. You'll also find some interesting words about it in the opening pages of the "Antennas" chapter of King, Mimno and Wing's "Transmission Lines, Antennas and Waveguides." I would go so far as to say that everything we've summarized about "radio waves" in all our writings is all just models to explain our observations. On some level, we don't really know what anything is; we just have ways to communicate about those things. We have models. Some of them seem pretty darned good, but perhaps we're just looking at the actions in one tiny corner of our multi-dimensional universe and we may find that all our models are woefully inadequate to cover the big picture. So what? They work for what we're doing right now. We can deal with the inadequacies when they arise. We can stay constantly on the lookout for them, and accept them and learn from them. A couple hundred years ago, Newtonian physics seemed adequate, and for the time, for what people were observing and designing, it was. But we've learned more, and refined our models. You should expect it will continue to happen, as long as curious humans are around to ponder the problems. In fact, just because our models are somehow "better" now than they were five years ago, or fifty, or five hundred, that doesn't necessarily mean that the earlier models are now worthless. You just need to know their limitations, and apply them only where the limitations are practically unimportant. We still use Newtonian physics for a lot of engineering work because it's not worth the effort to add relativistic terms when we know that they won't be observable, and other errors will dominate. Cheers, Tom |
"Tom Bruhns" wrote in message ... On some level, we don't really know what anything is; we just have ways to communicate about those things. We have models. Cheers, Tom I like that definition, Tom. Instead of struggling with what every tiny thing is, just model it, apply it to your needs, and life (and radio waves) goes on. Al KA5JGV |
But that's NOT a definition.
Alan WN4HOG -- Windsurfing Club: http://www.ibscc.org "Al - KA5JGV" wrote in I like that definition, Tom. Instead of struggling with what every tiny thing is, just model it, apply it to your needs, and life (and radio waves) goes on. Al KA5JGV |
Roy Lewallen wrote:
Cecil Moore wrote: Roy Lewallen wrote: "Things on a very small scale behave like nothing that you have any direct experience about. They do not behave like waves, they do not behave like particles, they do not behave like clouds, or billiard balls, or weights on springs, or like anything that you have ever seen. . . Historically, the electron, for example, was thought to behave like a particle, and then it was found that in many resepects it behaved like a wave. So it really behaves like neither. Now we have given up. We say: 'It is like *neither*'" OTOH, quantum physics predicts the outcomes perfectly and has never been proven wrong so it doesn't matter what we call photons. If you really want to understand this stuff, you need to read a good book on string theory. May I suggest _The_Tenth_Dimension_, by Jeremy Bernstein or catch the two NOVAs that were on tonight. Is that where we'll learn all about virtual photons, the fourth dimension, and their application to measuring voltage? Yes, six of the dimensions are thought to support the fabric of space, the æther, if you will. String theory has yielded a unified field theory including massless gravitons. The point is that just because photons do not behave like pure waves or pure particles, doesn't mean they are useless. It just means that we don't yet have a one word handle to describe their true nature. -- 73, Cecil http://www.qsl.net/w5dxp -----= Posted via Newsfeeds.Com, Uncensored Usenet News =----- http://www.newsfeeds.com - The #1 Newsgroup Service in the World! -----== Over 100,000 Newsgroups - 19 Different Servers! =----- |
Alan wrote:
But that's NOT a definition. From the IEEE Dictionary: "radio wave - An electromagnetic wave of radio frequency." -- 73, Cecil http://www.qsl.net/w5dxp -----= Posted via Newsfeeds.Com, Uncensored Usenet News =----- http://www.newsfeeds.com - The #1 Newsgroup Service in the World! -----== Over 100,000 Newsgroups - 19 Different Servers! =----- |
I've been expecting one of the gurus in the ng would be saying Real Radio
Hams build their own theories. Lionel Carter "W7TI" wrote in message ... On 28 Oct 2003 16:18:17 -0800, (jj) wrote: Does anyone have a good description for what a radio wave really is? __________________________________________________ _______ The short answer is "no". Many people confuse the measurement of things with having an understanding of them. Scientists are very good at measuring things; less good at understanding what they measure. For example, gravity is measurable down to a gnat's eyelash, but nobody knows what it really "is". -- Bill, W7TI |
Sounds good to me. Thanks!
Alan WN4HOG -- Windsurfing Club: http://www.ibscc.org "Cecil Moore" wrote in message ... Alan wrote: But that's NOT a definition. From the IEEE Dictionary: "radio wave - An electromagnetic wave of radio frequency." -- 73, Cecil http://www.qsl.net/w5dxp -----= Posted via Newsfeeds.Com, Uncensored Usenet News =----- http://www.newsfeeds.com - The #1 Newsgroup Service in the World! -----== Over 100,000 Newsgroups - 19 Different Servers! =----- |
On Wed, 29 Oct 2003 17:18:39 -0000, "Lionel Carter"
wrote: I've been expecting one of the gurus in the ng would be saying Real Radio Hams build their own theories. Lionel Carter Hi Lionel, Some of the "explanations" couched in Quantum nonsense have accomplished that end none the less. 73's Richard Clark, KB7QHC |
From the page 9 of the Introduction to "QED" Feynman says, "You're not going to be able to understand it... You see my Physics students don't understand it either. That is because I don't understand it. Nobody does!" Good luck with analogies to things we seem to "understand". -- Peter K1PO Indialantic By-the-Sea, FL. Makes me feel better :-) but.... I just picked up "Advanced Electromagnetism and Vacuum Physics" by Patrick Cornille (Advanced Electromagnetic Systems, France) published by World Scientific Publishing Co. 2003 while browsing Strand Book Store in NYC (sale $32) and the following Preface introduction caught my interest: "The electromagnetic theory is the most important theory in physics, first because the electromagnetic force is the only force that can be easily manipulated by man with wellknown applications, secondly an extension of this theory in the future may explain all the fundamental forces known to day in nature. A large volume of literature has appeared since the latter days of World war II, written by researchers expanding the basic principles of electromagnetic theory and applying Maxwell's equations to many important practical problems. However, it is my opinion that the electromagnetic theory is not complete and fully understood. A simple example proven these claims is given in this book when the Helmholtz theorem is analyzed. We proved from a mathematical point of view that Maxwell's equations are not complete since a scalar polarization must be taken into account in the equations. It is worth insisting that Maxwell, when he formulated out his theory, was mainly guided by the experimental work performed by the physicists of his time. He tried to give an hydrodynamics understanding of his theory, which is still favored by certain physicists. Even today, Maxwell's equations are given as granted, their validity being justified by experiments. Actually, there is no demonstration of Maxwell's equations from first principles since the mechanical approach used by Maxwell was rapidly abandoned in favor of a novel nonmechanical entity: the electromagnetic field. While the Maxwell's equations can obviously be obtained from a variational principle where they are derived from an action appropriately chosen in order to recover them. In spite of the success of the Maxwell theory in our present technology, we believe that the last word on Maxwell's equations has not been said yet. The reason is that Maxwell's equations raise a number of fundamental questions which have not been answered in a satisfactory manner to date: - One of these questions deals with the existence of a medium sustaining transverse electromagnetic waves. - Another question concerns the fact that Maxwell's equations are not Galilean invariant. - The question of covariance is also strongly related to the electromagnetic induction phenomena, which is difficult to understand within the framework of the special relativity theory. - The discrete nature of the electric charge, where no physical concept has been proposed to explain its quantization, remains one of the deepest mysteries of physics. - There is also the reason why the Lorentz force does not come from the Maxwell's equations, but is additional to them. The reader is reminded that classical electrodynamics demands a connection between the Maxwell's equations and the Lorentz force. In view of a prevalent trend towards a hydrodynamic description of matter and radiation, we propose in this book another hydrodynamic wave model for the existence and the propagation of matter and radiation in the vacuum where equations of electrodynamics can be derived from simple fundamental principles. We shall answer the above questions. " etc. Hoping to find answers to some of the puzzling questions relating to antennas and propagation, I am looking forward to time when I can immerse myself deeply into this new stuff (and get more confused?) Maybe this will intrigue some of youze guyz and help in sheding some light on our neandertal brains? 73 Yuri, K3BU |
I just picked up "Advanced Electromagnetism and Vacuum Physics" by Patrick
Cornille (Advanced Electromagnetic Systems, France) published by World Scientific Publishing Co. 2003 while browsing Strand Book Store in NYC (sale $32) and the following Preface introduction caught my interest: Good deal. Amazon wants $96 new, and $91 used. (VERY gently, I hope!) |
I just picked up "Advanced Electromagnetism and Vacuum Physics" by Patrick Cornille (Advanced Electromagnetic Systems, France) published by World Scientific Publishing Co. 2003 while browsing Strand Book Store in NYC (sale $32) and the following Preface introduction caught my interest: Good deal. Amazon wants $96 new, and $91 used. (VERY gently, I hope!) There was one more left on the shelf as I remember. If anyone wants, I might be able to check it out at this "World's Largest Used Bookstore". I giured it was worth for the third I wanted to read in the book :-) Yuri |
I guess for now I will accept that a radio wave is a force field (or
energy field, if you like), and leave it at that (still seems to imply action-at-a-distance). When I was in school, if this question were asked, the professor would right down Maxwell's Equations on the blackboard and state that they explain everything. I suppose that's about as good as anything. Thanks for the responses. JJ |
jj:
[snip] I guess for now I will accept that a radio wave is a force field (or energy field, if you like), and leave it at that (still seems to imply action-at-a-distance). : : Thanks for the responses. JJ [snip] There is a phenomena associated with Quantum ElectroDynamics or QED known as "entaglement" which really does involve instantaneous action at a distance. Entanglement was/is the most controversial part of quantum theory and it's predicted existence comprised the main "objection" that Einstein had to QED. In recent years "entanglement" has been experimentally verified in several ways at several different authoratative laboratories by leading Physics researchers around the world. Entanglement of quantum particles is a facinating part of the whole field of quantum mechanics. There is a recent popular book on the subject of entanglement which outlines the delightful history of the controversy and the study of how quantum particles can become "entangled" and can then exert instantaneous [faster than light] force at a distance and helps to clarify the subject for lay folks. The book develops some basic "understanding" of QED but it needs a "little" bit of tolerance for maths. cfr: Amir D. Aczel, "Entanglement - The Greatest Mystery in Physics", Four Walls Eight Windows, New York, 2001. ISBN: 1-568-58-232-3 [QC174.12.A29] Aczel's book is not strictly a Science or Physics book but is more of a popular account of the subject. Aczel has personally known many of the famous protaganists of quantum theory on a personal basis and the book includes photos of him together with some of the world famous physicists at their homes, where he visited and got their views/contributions on the subject. Facinating stuff... -- Peter K1PO Indialantic By-the-Sea, FL |
Yuri:
[snip] Maybe this will intrigue some of youze guyz and help in sheding some light on our neandertal brains? 73 Yuri, K3BU [snip] Maxwell's Equations? No thanks... Maxwell is soooo pase. I prefer to use the equations of quantum electrodynamics when computing the lengths of the wire loops for my twenty meter quad antennas! I get better accuracy and more gain that way. :-) -- Peter K1PO Indialantic By-by-the-Sea, FL. |
Hi,
Here is an excellent website with explanations, full of animations: http://users.telenet.be/educypedia/e...ics/javarf.htm My webiste also contain an explanation but it is written in French in section devoted to quantum physics. 73's Thierry ON4SKY, LX3SKY http://www.astrosurf.com/lombry "jj" wrote in message om... This may at first sound like a stupid question. But after some years as a radio enthusiast, I don't know what a radio wave is - what it really is. Supposedly, modern physics does not believe there is such a thing as "action at a distance". In other words, if you launch a radio wave and I intercept it, there must be a transfer of "stuff" between you and me. You can't just say that if I wiggle an electron at point A, I can cause a wiggle at the same wiggle rate at point B. I mean you can say it, but it doesn't explain anything. OK, so the latest science says that electromagnetic energy is really particle-waves. I guess this means that when I transmit, my antenna is firing particles in the form of low-energy photons (energy packets), and that these photons do not really exist anywhere but exist only as probability waves - until, of course, someone intercepts the wave. Then, magically, the photons appear at the receiving antenna, in which they manage to produce oscillating electrons. So, the best I can ascertain is that radio waves are really probability waves. I'm not sure that really helps with an intuitive understanding. Does anyone have a good description for what a radio wave really is? - JJ |
"W7TI" wrote in message ... On 28 Oct 2003 16:18:17 -0800, (jj) wrote: Does anyone have a good description for what a radio wave really is? __________________________________________________ _______ The short answer is "no". Many people confuse the measurement of things with having an understanding of them. Scientists are very good at measuring things; less good at understanding what they measure. For example, gravity is measurable down to a gnat's eyelash, but nobody knows what it really "is". -- Bill, W7TI It would be more accurate to say that we can measure gravity's effect, not that we can measure gravity itself. Same for an electromagnetic field. We have great models for predicting the effects; some models are so good we call them Laws. Beyond that, before you know exactly what a field is, do you really know what ANYTHING really is? How about a copper wire? What really is copper? Will you find the answer if you can look smaller & smaller? Will you eventually disturb the observation just by observing? How do we know anything? Questions like this are best treated with beer. Ed wb6wsn |
Ed:
[snip] Questions like this are best treated with beer. Ed wb6wsn [snip] I prefer to treat those questions with Don Julio tequilla "on the rocks". After a couple of Don Julio's *I* understand everything! -- Peter K1PO Indialantic By-the-Sea, FL |
On Thu, 30 Oct 2003 15:48:01 +0100, "Thierry" Thierry, see
http://www.astrosurf.com/lombry/ wrote: Hi, Here is an excellent website with explanations, full of animations: http://users.telenet.be/educypedia/e...ics/javarf.htm My webiste also contain an explanation but it is written in French in section devoted to quantum physics. I thought all quantum physics was written in "Greek" Roger Halstead (K8RI EN73 & ARRL Life Member) www.rogerhalstead.com N833R World's oldest Debonair? (S# CD-2) |
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