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Old May 1st 10, 12:45 AM posted to rec.radio.amateur.antenna
Art Unwin Art Unwin is offline
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First recorded activity by RadioBanter: Mar 2008
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Default What exactly is radio

On Apr 30, 5:05*pm, Owen Duffy wrote:
Roy Lewallen wrote om:

The time phase angle between E and H is determined by the medium the
wave is propagating through. The (complex) ratio of E to H is called
the intrinsic impedance of the medium, and for lossless media, it's
always a purely real number (about 377 ohms for air or free space),
meaning that E and H are in phase. Only when propagating through a
lossy medium are E and H not in time phase, and then the maximum phase
difference is always less than 45 degrees.


If I understand this correctly, a field arrangement with E and H in time
and space quadrature is not propagating energy, but rather energy
exchange.

In very close to an antenna, the time phase relationship of E and H may
be close to quadrature due to the inductive or reactive field close to
the conductors, but that changes eventually to 'in-phase' in the far
radiation field in free space (as the induction field components decay
more quickly with distance than the radiation field components).

If that is the case, the complex value of E/H varies from very close to
the far field. I have seen plots of E/H vs distance that treated E/H as a
real number, but I suspect that it is more complex when all of the
components of E and H are included.

Thoughts?

Owen


Owen
By observation the E and H fields can be seen as a tank circuit where
all vectors are accounted for so that
one follows the notion that energy cannot be created or destroyed plus
the other laws of Newton.
When we stray from that scenario we get into new theories or
imaginations The moment we stray from boundary laws one is coersed
into thinking like somebody of a lesser nature than past masters who
determine phenomina from observation that is matched by known
principles. How on earth can we relate to near fields and far fields
if we haven't decided what the media concists of. My approach was to
stick with the laws of Maxwell which dictates static and dynamic
fields where all forces are accounted for, which shows that gravity
can only be negated by the use of Newton's laws. Thus my foundations
were not built on a layer of sand but what is accepted via Maxwell's
laws. In other words, the laws of Maxwell points to the presence of
particles when dealing with fields and displacements by virtue of the
units used. There are lots of things that exhibit properties of other
materials and thus by observation can be compared to other things in
action, but they should never be considered as one and the same unless
they are matched in their entirety. Particles and waves
have lurched beyond science by considering them to be one and the same
purely by action and not by substance.
If one is going to discuss energy exchange as with inductance and
capacitance to determine relative phase angles , fields etc one cannot
stray from the tank circuit
observations.
Regards
Art