What diametric ratio must a fractional wave length radiator be to
allow contrary current flow thru it's center. ?
Diameter / wavelength = 1.0, 0.5, 0.1. 0.001, 0.0001,
0.00001,...?
Regards
Art

"Art Unwin" wrote in message
...


What diametric ratio must a fractional wave length radiator be to
allow contrary current flow thru it's center. ?
Diameter / wavelength = 1.0, 0.5, 0.1. 0.001, 0.0001,
0.00001,...?
Regards
Art

infinite

"Art Unwin" wrote in message
...


What diametric ratio must a fractional wave length radiator be to
allow contrary current flow thru it's center. ?
Diameter / wavelength = 1.0, 0.5, 0.1. 0.001, 0.0001,
0.00001,...?
Regards
Art

Art, Did you look at my link below? What does "diametric" mean?

Ansoft's (www.ansoft.com) "Maxwell" is a "Finite Element Modeling"
(FEM) program which, among other things, can accurately produce
a graphical representation of the current distribution in a cylindrical
conductor. See examples at:
http://www3.telus.net/nighttrainexpr...in%20depth.htm
These graphs are reproduced from an article in the November/December
issue of QEX magazine, pp20 - 29, by Rudy Severns, N6LF.

73,

Frank

On Jan 13, 3:02*pm, "Frank" wrote:
"Art Unwin" wrote in message

...



What diametric ratio must a fractional wave length radiator be to
allow contrary current flow thru it's center. ?
Diameter / wavelength = 1.0, * *0.5, *0.1. * * 0.001, * * *0.0001,
0.00001,...?
Regards
Art

Art, Did you look at my link below? *What does "diametric" mean?

Ansoft's (www.ansoft.com) "Maxwell" is a "Finite Element Modeling"
(FEM) program which, among other things, can accurately produce
a graphical representation of the current distribution in a cylindrical
conductor. *See examples at:http://www3.telus.net/nighttrainexpr...in%20depth.htm
These graphs are reproduced from an article in the November/December
issue of QEX magazine, pp20 - 29, by Rudy Severns, N6LF.

73,

Frank

No, but I will now. First I will look up the word "finite" and
"finite"
Just now going out for dinner
Re diametrics, I was referring to the ratio of diameter with respect
to wavelength
( I am assuming that skin depthg is not limitless.)
Best regards
Art

"Art Unwin" wrote in message
...

( I am assuming that skin depthg is not limitless.)

of course it is limitless, it is an exponential function so it never goes to
zero. the so called 'skin depth' is only the point where the current has
dropped to 1/e or about 37% of the surface value, still a significant
current.

Dave wrote:

"Art Unwin" wrote in message
...

( I am assuming that skin depthg is not limitless.)

of course it is limitless, it is an exponential function so it never
goes to zero. the so called 'skin depth' is only the point where the
current has dropped to 1/e or about 37% of the surface value, still a
significant current.

The plots at the link Frank provided show current going rather abruptly
to zero - even negative ("contrary"?) in some cases. I wouldn't presume
to know whether it is modeled correctly.

ac6xg

On Jan 13, 5:00*pm, "Dave" wrote:
"Art Unwin" wrote in message

...

( I am assuming that skin depthg is not limitless.)

of course it is limitless, it is an exponential function so it never goes to
zero. *the so called 'skin depth' is only the point where the current has
dropped to 1/e or about 37% of the surface value, still a significant
current.

Yes, skin depth is measured or referred to as 1/e which incorporates
decay.
I am totally unaware how" decay" comes into the picture or what
happens with respect to density
Now I question the term "decay" in this instance as it is the
displacement field
that creats resistance ala eddy current which I allude to as the
levitating force
on a unbound electron. At the moment I cannot see how a unbound
electro within an empty shell
can be absorbed by a tight matrics consisting of bound electrons or
when reaching the inside of a tubular conductor fall off the inner
surface! The morer I get into the radiation subject the more I begin
to question things. The idea that a circulating current /field is
limitless in depth blows my mind.
Art

The plots at the link Frank provided show current going rather abruptly
to zero - even negative ("contrary"?) in some cases. I wouldn't presume
to know whether it is modeled correctly.

ac6xg

Having some expience of Ansoft's FEM modeling software I feel the
results are highly credible. Also Rudy Severns publishing list is pretty
impressive:
http://www.snubberdesign.com/Springt...terprises.html

73,

Frank (VE6CB)

On Jan 13, 10:19*pm, "Frank" wrote:
The plots at the link Frank provided show current going rather abruptly
to zero - even negative ("contrary"?) in some cases. *I wouldn't presume
to know whether it is modeled correctly.

ac6xg

Having some expience of Ansoft's FEM modeling software I feel the
results are highly credible. *Also Rudy Severns publishing list is pretty
impressive:http://www.snubberdesign.com/Springt...terprises.html

73,

Frank (VE6CB)

Frank, I am not saying he is not credible but he is part of the older
generation and there was not enough detail supplied to determine
whether I accept it on trust. When the antenna programs
throw out the yagi in favor of arrays or radiators in equilibrium form
should we throw it out in favor of conforming with the past? Yes,the
article is in line with what the older generation has lived with
but the new generation have more tools and information than the
present dying generation.
Problem with present day authors is up against the "publish or
perish" format regure references to prior papers in quantity to
provide legitamacy to any new papers, without which they will have a
hard time publishing. Greasing the wheels of fellow contributers or
white paper authors is much preferable to declaring those who judge
are in error. Frank, a lot of the theory of antennas is either based
on vanishingly thin radiators without regard to room required for eddy
field and in some cases with transmission lines where it is possible
to get three different current flows together with a closed circuit,
yet we are now protecting the idea of non closed circuits where the
current flow
is on top of each other. No wonder it is said over the last 100 years
that we don't fully understand radiation especially when it takes over
70 posts on how to make a cantenna from a panel of experts
Best regards
Art

Frank, I am not saying he is not credible but he is part of the older
generation and there was not enough detail supplied to determine
whether I accept it on trust. When the antenna programs
throw out the yagi in favor of arrays or radiators in equilibrium form
should we throw it out in favor of conforming with the past? Yes,the
article is in line with what the older generation has lived with
but the new generation have more tools and information than the
present dying generation.
Problem with present day authors is up against the "publish or
perish" format regure references to prior papers in quantity to
provide legitamacy to any new papers, without which they will have a
hard time publishing. Greasing the wheels of fellow contributers or
white paper authors is much preferable to declaring those who judge
are in error. Frank, a lot of the theory of antennas is either based
on vanishingly thin radiators without regard to room required for eddy
field and in some cases with transmission lines where it is possible
to get three different current flows together with a closed circuit,
yet we are now protecting the idea of non closed circuits where the
current flow
is on top of each other. No wonder it is said over the last 100 years
that we don't fully understand radiation especially when it takes over
70 posts on how to make a cantenna from a panel of experts
Best regards
Art

I would hardly call the tools used in this simulation "Older".
Ansoft produces some of the most sophisticated, and up to
date FEM software available. I have seen Ansoft's HFSS
accurately model current flow through PCB vias, around an end-
launch connector at 20 GHz. CST Microwave also
produces high end FEM software. All the models are
done in full 3 D, with actual physical dimensions. This
FEM software started to apear about 10 years ago and
costs in the range of $40,000 to $50,000, with a $10,000
per year maintenance fee.

"Publish or perish" is usually applied to university positions.
It is doubtfull that too many people are able to pubish in
the Proceedings of the IEEE, or one of the IEEE Society
Transactions.