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



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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



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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