RSGB RadCom December 2007 Issue
 

art wrote:

...
And Richard, when you have finished reading from Terman
to get us to sleep, would you consider for your next book
to read to us, like Lady Chatterlies Lover by D.H. Lawrence?
That book may well prevent you going to sleep as well while
reading on the net Most of us have read all the volumes by
Terman so a different reading book may well be of more interest.
Art

Art;

This text wastes time/space/patience.

You fault others for such petty "stick poking" as the above. Are you
sure you wouldn't rather keep this to a minimum?

Regards,
JS

RSGB RadCom December 2007 Issue
 

Cecil, W5DXP wrote:
"Does this cause and effect chain of events result in aphase lag between
electric and magnetic fields?"

Never saw a phase lag suggested. As radiation impedance is a resistance
even in free space, I expect rise and fall in electric and magnetic
fields is simultaneous even as they speed away at the velocity of light.
Which came first, the electric or the magnetic?

Best regards, Richard Harrison, KB5WZI

RSGB RadCom December 2007 Issue
 

Cecil Moore wrote:

Jim Kelley wrote:

Richard Feynman said there is a probability that reflection will occur
at any point within a partially reflecting media.


Of course, there are always 2nd, 3rd, ... Nth order effects.
On this newsgroup, we are usually talking about first order
effects.

And so was Dr. Feynman. You really ought to freshen up on your QED. ;-)

73, ac6xg

RSGB RadCom December 2007 Issue
 

Richard Harrison wrote:
Never saw a phase lag suggested. As radiation impedance is a resistance
even in free space, I expect rise and fall in electric and magnetic
fields is simultaneous even as they speed away at the velocity of light.
Which came first, the electric or the magnetic?

Does "simultaneous" imply faster than light? :-)
(Photons don't have the phase lag problem).
--
73, Cecil http://www.w5dxp.com

RSGB RadCom December 2007 Issue
 

Jim Kelley wrote:

Cecil Moore wrote:
Of course, there are always 2nd, 3rd, ... Nth order effects.
On this newsgroup, we are usually talking about first order
effects.

And so was Dr. Feynman.

I seriously doubt that Dr. Feynman ever said that the
majority of reflections occur somewhere else besides
the junction of two mediums.
--
73, Cecil http://www.w5dxp.com

RSGB RadCom December 2007 Issue
 

Richard Harrison wrote:
Cecil, W5DXP wrote:
"Does this cause and effect chain of events result in aphase lag between
electric and magnetic fields?"

Never saw a phase lag suggested. As radiation impedance is a resistance
even in free space, I expect rise and fall in electric and magnetic
fields is simultaneous even as they speed away at the velocity of light.
Which came first, the electric or the magnetic?

The ratio of E to H fields of a wave is known as the wave impedance. It
has both a magnitude and a phase angle (or real and imaginary
components). The impedance of a plane wave propagating through a medium
is the intrinsic impedance of the medium. For example, the ratio of E to
H of a plane wave propagating through space equals the intrinsic
impedance of space. The intrinsic impedance of space is purely real
(~377 + j0 ohms), which tells you that the ratio of E to H of a plane
wave propagating through it is purely real. This means there is no phase
difference between the two - E and H are in phase.

But the intrinsic impedance of many materials (e.g., dirt) isn't purely
real, so there is a non-zero phase angle between E and H fields of plane
waves propagating through them.

The ratio of E to H is also often complex in the near field around an
antenna, and usually with a magnitude other than 377 ohms. So in that
region, there's also a phase difference between E and H.

Roy Lewallen, W7EL

RSGB RadCom December 2007 Issue
 

Roy Lewallen wrote:
For example, the ratio of E to
H of a plane wave propagating through space equals the intrinsic
impedance of space. The intrinsic impedance of space is purely real
(~377 + j0 ohms), which tells you that the ratio of E to H of a plane
wave propagating through it is purely real. This means there is no phase
difference between the two - E and H are in phase.

But if the E-field causes the H-field which in turn causes
the E-field, how is a delay avoided? Isn't that faster than
light generation of fields?
--
73, Cecil http://www.w5dxp.com