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Old September 15th 09, 04:45 PM posted to rec.radio.amateur.antenna
Art Unwin Art Unwin is offline
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First recorded activity by RadioBanter: Mar 2008
Posts: 1,339
Default Spherical radiation pattern

On Sep 15, 10:24*am, "christofire" wrote:
"Art Unwin" wrote in message

...
On Sep 15, 8:15 am, "christofire" wrote:

"jaroslav lipka" wrote in message


....
On Sep 15, 7:06 pm, "christofire" wrote:


- - snip - -



I certainly haven't arrived here by sitting on anyone's shirt tails. If
you'd care to read some of the history of this NG you'd see where I come
from.


Your question is not put clearly, although I have seen garbled sentences
like this before in this Usenet group. My first question is: have you
bothered to read any of the respected books on the subject, such as
'Electromagnetics with applications' by Krauss and Fleisch. I suspect if
you had you wouldn't be asking me such a question - it makes no sense! Do
I
take it you are referring to Gauss's law for electric fields? Are you
aware
that there is a counterpart Gauss's law for magnetic fields? I don't
believe there is such a thing as a single 'Gaussian law of statics' -
someone has made that up!


Gauss's law for electric fields states: the integral of the electric flux
density over a closed surface equals the charge enclosed. This is an
important part of the basis of electrostatics, that is the study of
electrical phenomena caused by static charges, but it applicable at a
point
in time to any scenario that involves an enclosed charge - which means any
electrical conductor, whether it carries a non-moving charge, DC or AC.
Gauss's law for magnetic fields states: the integral of the magnetic flux
density over a closed surface is equal to zero, and this is an important
part of the basis of magnetics, again whether static or changing.


Both of Gauss's laws are embodied in Maxwell's equations and for the
normal
RF case of sinusoidally-alternating variables a number of different
notations can be used, a popular one being phasor notation. As you will
know, phasors are vectors that rotate at the same angular frequency but
have
arbitrary phase relationships and amplitudes - so phasor notation is a
compact way of expressing quite a lot. But, in this case, every one of the
phasors involved, D the displacement current density, rho the enclosed
charge, and B the magnetic flux density, is a variable that alternates
with
the passage of time. 'Dynamic' variables if you want to call them that.


Neither of Gauss's laws applies directly to strength of an electric or
magnetic field but the linkage is the other two of Maxwell's equations
based
on Ampere's law and Faraday's law, which are both applicable to
time-varying
fields - 'dynamic fields' if you must.


So ... would you like to put your question more clearly? What do you
actually mean by 'to change a static field into a dynamic field' in
respect
of antennas, where all the electrical and magnetic variables are changing
with time, especially the fields? Is this the result of a misunderstanding
of the meaning of the word 'electrostatic' - used to differentiate between
those phenomena caused by the presence of contained charge and those
caused
by its movement?


Chris


(written by Unwin)
Gauss's law of statics is enclosed *particles in equilibrium. Add a
time varying field *to same it becomes a dynamic field *in equilibrium
and thus equates with Maxwell's laws.

(written by Chris)
This appears to be paraphysical nonsense, once again.

(a) There are no 'Maxwell's laws' - there are the four Maxwell's equations
based on laws ascribed to the other three authors named above. *The term
'eqilibrium' does not feature in, and is not required in, Maxwell's
equations or the laws it is based upon. *Radio communication has been based
on Maxwell's equations for more than 100 years without need for
modification.

(b) There is no single 'Gauss's law of statics' as I explained above, and
both of Gauss's laws can be applied to time varying quantities but neither
contains a field.

(c) Both of Gauss's laws are included in Maxwell's equations without
modification - there is no need to 'Add a time varying field *to same' - it
is there already in each case.
* * * * Once again: Gauss's laws are already applicable to time varying
quantities.

(d) What Maxwell provided was unification of the presentation of the four
equations in differential, integral or phasor form, so the relationships and
linkage between them became clear and they could all be used together to
solve electromagnetic problems.

I think the group is aware by now what I think of the writings of people who
claim to know better than Kraus, Jordan & Balmain, Jasik, et al, on the
basis of no practical evidence.

Chris


You still did not put a stake in the ground, just walked around the
question and then walked away. One more chance before I place you in
"unsure". Where in Maxwell's equations does it refer to "particles" or
do they have no place in his views on radiation?
What is your call sign or do you prefer to remain as a unknown?