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art wrote:
All those degrees in his possesion and all we get is a belching black
smoke column. It's going to be another long night Cecil!

Art, I'm still waiting for someone to prove that
an EM wave can stand still and continue to exist
in violation of Einstein's theory that light (and
RF waves) always travel at the speed of light.
--
73, Cecil http://www.w5dxp.com

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Owen Duffy wrote:
- that V/I=Zo for a travelling wave in a transmission line, and that
(Vf+Vr)/(If-Ir) at the load end of the line must equal Zload;

It seems that we can draw some conclusions from these
assumptions.

Vf*If*cos(0) = forward joules/sec

Vr*Ir*cos(0) = reflected joules/sec

The forward and reflected energy waves actually exist
and are the building blocks of the standing wave.

Vf and Vr are phasors and therefore subject to
superposition and interference.
--
73, Cecil http://www.w5dxp.com

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Dave wrote:
How do the physics type adjust their definition to include the Poynting
Vector?

The same way they handle the Power Flow Vector and
the "IEEE Dictionary", like a hot potato. :-)
--
73, Cecil http://www.w5dxp.com

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Cecil Moore wrote:
art wrote:
All those degrees in his possesion and all we get is a belching black
smoke column. It's going to be another long night Cecil!

Art, I'm still waiting for someone to prove that
an EM wave can stand still and continue to exist
in violation of Einstein's theory that light (and
RF waves) always travel at the speed of light.

Not everything about light (or EM waves) travels at the speed of light.

Standing waves are simply the RF equivalent of stationary optical
interference fringes.


--

73 from Ian GM3SEK 'In Practice' columnist for RadCom (RSGB)
http://www.ifwtech.co.uk/g3sek

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Cecil Moore wrote:


You apparently still cling to the mistaken notion that
standing waves can exist without their forward and
reflected wave building blocks. It is the standing
wave equation that is the math construct that only
exists in the human mind. EM waves cannot stand still.
They must necessarily move at the speed of light.
Anything else violates the principles of relativity.

Cecil,

You have fallen into the same trap as those who don't understand the
difference between phase velocity and group velocity. Relativity is a
physical concept, not a mere result of mathematical manipulation.

73,
Gene
W4SZ

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Ian White GM3SEK wrote:
Not everything about light (or EM waves) travels at the speed of light.

All EM waves (photons) travel at the speed of light.
Anything else would violate the principles of relativity.
Any detection of light results in the dissipation
(absorption) of the associated photons.

Standing waves are simply the RF equivalent of stationary optical
interference fringes.

That they appear to stand still is just an illusion.
Photons are continuously traveling at the speed of
light to get to your eyes where they are dissipated.
When you see an interference ring that appears to
stand still, you are actually receiving speed-of-
light photons into your eyes. (If the interference rings
were truly stationary, you wouldn't be able to see them.)

If the interference fringes are being absorbed, photons
are being dissipated. If the interference fringes are
being scattered, the photons are moving at the speed
of light. The photons either disappear or they travel
at the speed of light.

The photons in a transmission line cannot stand still.
Standing waves are caused by superposition and
interference between separate and distinct forward
and reflected energy waves. And the photons in the
standing wave are NOT standing still.

Consider two coherent nearly co-linear beams of light.
There are bright points of constructive interference
and dark points of destructive interference but the
interference has no effect on the two waves which
emerge from the superposition unaffected and continue
on their merry way. Those waves never slow down from
their speed-of-light velocity. The "stationary" bright
and dark points are an illusion.

At every point, photons are either being dissipated
or are traveling at the speed of light (including VF
of course). Nothing else is possible.
--
73, Cecil, http://www.qsl.net/w5dxp

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Dave wrote:
Cecil Moore wrote:

Dave wrote:

Cecil, as an engineer you should stick with standard vocabulary.


Just trying to appease the physicists, Dave. They are
arguing that it is not power until work is done.

A Poynting vector is watts/square angle [watts/degree^2]. It is not
being dissipated in free space. It is Diverging [vector relationship].
How do the physics type adjust their definition to include the Poynting
Vector?

I'll sit back and read the follow up posts for the next few weeks :-)



Dave,

Physicists are basically reasonable, but clever, folks. ;-) They define
power as the time rate at which work is done, OR, the time rate at which
energy is transferred. With some imagination applied to the context, the
definitions converge. In the case of the Poynting vector, convergence
(of the definitions) would require dealing with the ultimate destination
of the flowing energy. Might be troublesome in infinite space, but on
earth, all of the energy ultimately produces power.

The problem seems to be the careless use of "power flow" which, if not
meaningless, I find impossible to conceptualize. The flow of the flow of
energy? Sort of like common usage of "current flow", which is also the
flow of a flow.

73,

Chuck


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Gene Fuller wrote:
Relativity is a
physical concept, not a mere result of mathematical manipulation.

My point exactly! All your mathematical manipulation
is not going to get a photon to stand still.
--
73, Cecil, http://www.qsl.net/w5dxp

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Dave wrote:
Cecil Moore wrote:

Dave wrote:

Cecil, as an engineer you should stick with standard vocabulary.


Just trying to appease the physicists, Dave. They are
arguing that it is not power until work is done.

A Poynting vector is watts/square angle [watts/degree^2]. It is not
being dissipated in free space. It is Diverging [vector relationship].
How do the physics type adjust their definition to include the Poynting
Vector?

I'll sit back and read the follow up posts for the next few weeks :-)



And now one for the engineers!

How do you interpret a non-zero Poynting vector determined by static E-
and H- fields?

73,

Chuck

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On 2 Mar, 08:45, chuck wrote:
Dave wrote:
Cecil Moore wrote:

Dave wrote:

Cecil, as an engineer you should stick with standard vocabulary.

Just trying to appease the physicists, Dave. They are
arguing that it is not power until work is done.

A Poynting vector is watts/square angle [watts/degree^2]. It is not
being dissipated in free space. It is Diverging [vector relationship].
How do the physics type adjust their definition to include the Poynting
Vector?

I'll sit back and read the follow up posts for the next few weeks :-)

And now one for the engineers!

How do you interpret a non-zero Poynting vector determined by static E-
and H- fields?

73,

Chuck

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- Show quoted text -

That is a simple question for an engineer! You invest in a antenna
computor program that gives you the answer that you expect
and move on to the next problem. How would you solve it Chuck?
Art