I found it interesting to read on a particular
antenna page that the antenna future will revolve
around what the person was presenting.
He may well be correct if we are all lemmings but
people who piddle with antennas are a different breed.
Personaly I see antennas gyrating towards smaller
antennas where radiation per unit length will finish
at the top of the heap
Antenna engineers have become so focussed on the half
wave patterns that they have completely ignored the
low efficiency portions at the ends of a half wave
antenna. Future antennas most surely will remove these
low efficient radiator parts together with the addition
of coupling techniques that will help to move away
from the Yagi syndrome, together with resolving the
of a "lossless" coupling direct to the transmitter
that will obsolete the need of matching interface.
Ofcourse this is where my intersts lie, but does this
vision of the future match yours or am I thinking
of the impossible? One noted Russion scientist stated
that theoretically radiation can come from a single point,
is this part of our future or just an impossible dream ?
Best regards, and please put your pea shooters aside
and try to get along rather than looking for
ten seconds of cheap glory.

Art Unwin KB9MZ......XG

He may well be correct if we are all lemmings.

Are they the rats that jump off the cliff into the sea? If they are, I am not
one of them.

people who piddle with antennas are a different breed.

I experiment with antennas, but piddle? I thought in Olde English that meant
something else.

The rest of you post was interesting, could you provide more detail? What is
"Yagi syndrome" and lossless coupling to the transmitter?


73 Gary N4AST

Hi Gary, seems like your the only one that is interesred in antennas on this
Jerry Springer group, so an answer there is.
Piddle means to mess around with things, since I am from
East London it could well be Olde English
With regard to efficiency per unit length. It is well known that the ends of
a 1/2 wave dipole can be lopped off without any noticable difference which
can be seen by the area lost under the normal current flow diagrams, so
efficiency can immediatly improved. When shortening the dipole even more we
get a transition to a straight line current flowline inplace of the sino
soidal curve which again shows a further inefficient portion at the ends
that can be lopped of. What this then shows that we can have a higher
current distribution per unit length with the mainly efficient portion in
the center of the dipole. Now one is in position to introduce a phase change
where one can have two dipoles in the same space taken up in the beginning,
collinier in form and containing only the mainly high efficient portions of
the center of a normal dipole. I see no reason why this transition can be
followed over and over again until the radiator contains an area under the
current curve that is uniform. Transformation to spot radiation
is totaly another matter which I believe should be left to our descendents.
Since you are an experimentor I would be happy to discuss my thoughts
privately rather than take up valuable space that is required for auguments
and pea shooters
Best regards
Art Unwin


"JGBOYLES" wrote in message
...
He may well be correct if we are all lemmings.

Are they the rats that jump off the cliff into the sea? If they are, I am
not
one of them.

people who piddle with antennas are a different breed.

I experiment with antennas, but piddle? I thought in Olde English that
meant
something else.

The rest of you post was interesting, could you provide more detail?
What is
"Yagi syndrome" and lossless coupling to the transmitter?


73 Gary N4AST

Art Unwin KB9MZ wrote:
Piddle means to mess around with things, ...

My unabridged dictionary says it has a second meaning.
There are many piddling contests on r.r.a.a :-)
--
73, Cecil, W5DXP

Cecil, are you discussing 'pea soup'?

Cecil Moore wrote:

Art Unwin KB9MZ wrote:

Piddle means to mess around with things, ...


My unabridged dictionary says it has a second meaning.
There are many piddling contests on r.r.a.a :-)
--
73, Cecil, W5DXP

Art wrote,
With regard to efficiency per unit length. It is well known that the ends of
a 1/2 wave dipole can be lopped off without any noticable difference which
can be seen by the area lost under the normal current flow diagrams, so
efficiency can immediatly improved. When shortening the dipole even more we
get a transition to a straight line current flowline inplace of the sino
soidal curve which again shows a further inefficient portion at the ends
that can be lopped of.


Hi, Art,
The above is untrue. Efficiency only has to do with the ratio of radiation
resistance
to total resistance. Also, the idea that the only part of an antenna that
contributes
to radiation is the center part because it carries most of the current is also
untrue.
The claim probably originates from the fact that most antenna parameters can be

calculated given a knowledge of current distribution. It's a false leap of
logic
to conclude that there are portions of a half wave dipole that don't radiate,
though. Since
those areas have high changing charge densities which are associated with
changing electrical fields which..., and so on, they radiate quite well.
I don't think most amateurs want to diddle around with infinitesimal
dipoles, anyway,
Art, which is what they'd end up with if they implemented your ideas. An array
of
infinitesimal dipoles such as you're suggesting would be fun to make, but I
doubt
the wisdom of expecting increased efficiency from it.
73,
Tom Donaly, KA6RUH

(P.S. Art, I hope you don't equate disagreement with ridicule. I reserve all my

ridicule for Cecil since he can take it.)

Tdonaly wrote:
(P.S. Art, I hope you don't equate disagreement with ridicule. I reserve all my
ridicule for Cecil since he can take it.)

.... .. .... ..

Tom, I notice you have not posted your calculations for
the phase angles of those superposed phasors I presented
yesterday. Did you come up with any phase angle other
than zero and 180 degrees? Do you understand why Kraus'
phase graph for standing wave current contains only two
possible values of phase?
--
73, Cecil, W5DXP

Cecil,

I am not Tom, but I will respond anyhow.

It is so hard to keep up with you. This entire thread started a few days ago
with a debate between you and Roy. You chastised Roy for considering the net
current instead of the individual components. Now you have switched back to
talking about net currents resulting from the addition of individual phasor
currents.

Which one do you want to talk about?

It is unlikely that anyone reading this newsgroup is confused regarding the back
and forth nature of the current on a thin wire. To insinuate such is merely a
cheap shot that appears intended to intimidate. (Go ahead, take your best shot.)
8-)

The concept of phasors is a common and useful tool for visualization and some
elementary numerical solutions. The simple standing wave analysis currently
under discussion and debate is certainly an appropriate subject for phasor
treatment. However, once outside of the realm of ideal one-dimensional systems
the use of phasors gets much more complicated. The use of conventional
mathematics for such problems is pretty standard.

The typical equation describing a standing wave is:

I = A * sin (kx) sin (wt)

The spatial phase of this equation is "kx", while the temporal phase is "wt". At
no time do these phases suddenly reverse direction. The resulting value for I
ranges through positive and negative values, and again it is unlikely that
anyone is confused.

If you choose to call the switch from current flow in the positive direction to
the negative direction a 180 degree phase shift, so be it. I prefer to keep the
phase in its place and let the sine function do its thing to reverse the value
of the equation.

73,
Gene
W4SZ


Cecil Moore wrote:

Tdonaly wrote:

(P.S. Art, I hope you don't equate disagreement with ridicule. I
reserve all my
ridicule for Cecil since he can take it.)


.... .. .... ..

Tom, I notice you have not posted your calculations for
the phase angles of those superposed phasors I presented
yesterday. Did you come up with any phase angle other
than zero and 180 degrees? Do you understand why Kraus'
phase graph for standing wave current contains only two
possible values of phase?
--
73, Cecil, W5DXP

Cecil wrote,

Tdonaly wrote:
(P.S. Art, I hope you don't equate disagreement with ridicule. I reserve
all my
ridicule for Cecil since he can take it.)

.... .. .... ..

Tom, I notice you have not posted your calculations for
the phase angles of those superposed phasors I presented
yesterday. Did you come up with any phase angle other
than zero and 180 degrees? Do you understand why Kraus'
phase graph for standing wave current contains only two
possible values of phase?
--
73, Cecil, W5DXP




What! And get into a 500 post exchange with you? You must think I'm
mad.
73,
Tom Donaly, KA6RUH

"Tdonaly" wrote in message
...
Art wrote,
With regard to efficiency per unit length. It is well known that the ends
of
a 1/2 wave dipole can be lopped off without any noticable difference
which
can be seen by the area lost under the normal current flow diagrams, so
efficiency can immediatly improved. When shortening the dipole even more
we
get a transition to a straight line current flowline inplace of the sino
soidal curve which again shows a further inefficient portion at the ends
that can be lopped of.


Hi, Art,
The above is untrue. Efficiency only has to do with the ratio of
radiation
resistance
to total resistance. Also, the idea that the only part of an antenna that
contributes
to radiation is the center part because it carries most of the current is
also
untrue.
The claim probably originates from the fact that most antenna parameters
can be

calculated given a knowledge of current distribution. It's a false leap
of
logic
to conclude that there are portions of a half wave dipole that don't
radiate,
though.
Don't make up a false augument, nowhere do I say that parts of a dipole
does not radiate, soon you will have half the neibourhood up in arms
regarding something I didn't say. As for your parlying the term 'false' so
liberaly it is clear that you were sleeping during class, but then even
those who know little of radiation can have an oponion.
So what is your vision of the future with respect to antenna and are you
doing anything to make that vision come true i.e. walking the walk.or are
your jollies gained by shooting at those such as Cecil that does have the
required knoweledge? On top of all that read carefully regarding'
efficiency' since I have qualified it as ' per unit length'
Best regards
Art Unwin




Since
those areas have high changing charge densities which are associated with
changing electrical fields which..., and so on, they radiate quite well.
I don't think most amateurs want to diddle around with infinitesimal
dipoles, anyway,
Art, which is what they'd end up with if they implemented your ideas.
Lots of words but all meaningless, I never said that I was persueing the
ultimate point radiation suggestion. I
experiment to the point that all antennas regardles of frequency can be made
such that they are rotatable in the horisontal mode which means for 160
meters inovation has to be involved to reduced such a monster such that it
can be rotated around its center point. I HVE REACHED THAT POINT AT THE
PRESENT TIME and am now looking at ways to reduce it further, but maybe the
next generation will achieve that jump.! I fully expect that somebody will
say I have violated a law of old but until then I will continue to use it on
the bands




An array
of
infinitesimal dipoles such as you're suggesting would be fun to make, but
I
doubt
the wisdom of expecting increased efficiency from it.
73,
Tom Donaly, KA6RUH

(P.S. Art, I hope you don't equate disagreement with ridicule. I reserve
all my

ridicule for Cecil since he can take it.)

I don't see why he should take it! We have lost so many talented people from
this group Tom,Gary Roy and so on
but we are still not at the point where Richard and his followers ( not
Richard Harrison ) pseudo Doktors and what ever have the forum completely to
themselves.
Regards
Art Unwin KB9MZ.....XG