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

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

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.