art wrote:
You also have circulating current because of inherrant
inductance and capacitance since we are dealing with a series
circuit.

Every real world network contains both inductance
and capacitance. The circulating currents between
them are maximum at resonance, i.e. when the
reactances appear to disappear but they don't.
--
73, Cecil http://www.w5dxp.com

art wrote:

IIf you can design a bandpass filter in a RLC or complex circuitry
method then you can design an antenna array that does the same thing.
That is not out of the box thinking.Just remove coupling from the
overall function


Designing an RLC circuit is trivial. The equations are simple and well known
to any 2nd year EE student.

However, you need field theory and materials knowledge (among other
things)to design an antenna.

If you design an antenna only looking at ohm's law, you will never be
successful.

art wrote:


Cecil Moore wrote:
Remember only R is of consideration for the addition of power from each
element which provides flux unless you can quantasize reaction for me
as producing the emmision of flux other than a indication of the
direction it takes .

I agree there are other losses but to prevent including losses that are
outside the E and H process change over such as ground reflections etc
is it not better to just accept The pure resistance only so there is no
need to characterize individual losses Once you go beyond the near
field it gets complicated as losses are created outside the EH
generation process.
Ii am not sure how the EZNEC thing functions but if you design the
array where all elements are driven you can then use the individual
element impedances to determine overall efficiency.i.e. power in versus
power out
Fortunately thats the way my program can operate
Art



Does this mean you are ignoring any interaction between elements?

Re "it does not agree...".When you look at the main characteristic of a
yagi antenna which is the gain of the main lobe and then compare it
with the rest of the radiation field then I would say it is
inefficient. I sure wish I had a picture of all the radiation vectors
that go into the shaping of the field. I did a circular pattern array
the other day where a circular cone was radiated vertically and I
thought that was as close to a beam that I ever had seen but why it
formed that way is a mystery. Frankly I feel the major need nowadays is
a broard beam as possible for line of site use for wireless devices
where the gain is constant for excess of 90 degrees coverage plus
large bandwidth rather than a emphasis on gain itself
Art

Richard Fry wrote:
"art" wrote in message
Some time ago I mentioned how inefficient Yagi design
antennas were thinking more in the way of how little of
the radiation used got to its required direction. etc
_________________

The above statement does not agree with the measured patterns and
performance results of Yagi antennas.

A well-designed, 6-element Yagi has a peak gain of at least 10 dBi, which
means that it radiates about 6.3 times more power in that direction than if
the same input power was radiated by a reference 1/2-wave dipole, and
measured in its direction of maximum gain.

RF

Ofcourse they are.They are both resonant and have the same "Q" which is
equivalent to half power. Isnt that why we talk of a half power width
of a main beam because of the assertion I just made. This is a
excellent candidate for a complex circuit analysis since the Q is the
same regardles of movement away from the resonant frequency and
coupling is not a factor!
Art
Art

Cecil Moore wrote:
art wrote:
Cecil Moore wrote:
Actually Art, adding reactance reduces the current in
the element thus *decreasing* losses below what a resonant
passive element would have. Pure reactance is lossless.

This current that you are referring to, I used P =I squared R
which leads to lower power. Where did I go wrong

Lower power results in lowering the loss due to heat.
That leaves more power available to be radiated by
the antenna system but not necessarily radiated by
this single element that we are discussing. I suspect
two driven elements are theoretically capable of
better performance than a two element Yagi given
equal total power input into the elements.
--
73, Cecil http://www.w5dxp.com

Ofcourse they are.They are both resonant and have the same "Q" which is
equivalent to half power. Isnt that why we talk of a half power width
of a main beam because of the assertion I just made. This is a
excellent candidate for a complex circuit analysis since the Q is the
same regardles of movement away from the resonant frequency and
coupling is not a factor!
Art
Art

Cecil Moore wrote:
art wrote:
Cecil Moore wrote:
Actually Art, adding reactance reduces the current in
the element thus *decreasing* losses below what a resonant
passive element would have. Pure reactance is lossless.

This current that you are referring to, I used P =I squared R
which leads to lower power. Where did I go wrong

Lower power results in lowering the loss due to heat.
That leaves more power available to be radiated by
the antenna system but not necessarily radiated by
this single element that we are discussing. I suspect
two driven elements are theoretically capable of
better performance than a two element Yagi given
equal total power input into the elements.
--
73, Cecil http://www.w5dxp.com

Cecil Moore wrote:
The feedpoint impedance is 20 ohms and the current
induced in the passive element is 0.84 amps.


Cecil:

Does Roy's program allow you to insert a reflector made of
nickel-chromium wire. Stick one of those turkeys in there and see if
that doesn't cut that 0.84 amps down a bit! grin

Chuckling,
JS

art wrote:
Tom Ring wrote:
art wrote:
They are of a group that everything is known about antennas and is
written in books. If you refer to something that is not in the books


Art:

If you refer to something that is "not in the books" one should take
great care. Why I do think evidence can be brought out and can be
demonstrated that some of the ways we "think" antennas are working is
not real, however, great men have developed thinking models and formulas
which are able to let us design and use WORKING antennas which are
PRACTICAL. I site that mysterious 377 ohms as an example, or for
another, incorporating the spin rate of the earth into antenna formulas
(time), ridiculous (but useful!) But, those "old books" contain methods
and means to develop antennas which do work and which do work well, we
owe much to those who have gone before us ...

I am only hoping that by refusing to allow "magic numbers" to be
embedded into equations without any suitable explanation of what those
numbers are "REALLY ABOUT" will one day awake the man who can form the
vision and see what the others have all been unable to, Tesla seemed to
have had an excellent ability which I hold as example of the type of
"vision seer" I mean.

I have an open mind, I guess you are as likely as the next guy to "be
the one!" Never hurts to try anyway ...

However, thank God practical antennas work and we have the tools to
design and build them.

Regards,
JS

I figure that if it works ok on my program AO PRO and it is then
checked out OK on NEC4
independently,and I can produce the electrical laws that backs it up it
will get into the books tho for the present time it is not there now.
For a very long time I have tried to introduce this and others to those
who are experienced in that sort of thing but I could never get it off
the ground because the thread kept on being changed to suit somebodies
whim or it developed into a name calling setup that it was impossible
to procede. Actually I let one patent application drop during the
examination process because of the badmouthing that I got but my back
is now stiffer and this one is going all the way. I do it not for money
reasons but because antennas is my hobby despite my so called lack of
knoweledge I have had patents during my working years at G.E. and other
places so the idea of patents doesn't carry much with me any more. For
all the experts we have had over the years on this newsgroup I have
never been able to thrash out one of my ideas to fruition because of
various nebulous reasons. If I brought one up involving SWR, coupling,
baluns e.t.c. the thread will grow by leaps and bounds in minuits
because everybody has something to say about it. If a subject is
brought up that one cannot provide insight then that person feels
denied that he cant post so he will resort to firing bullets and
stones.
Art

John Smith wrote:
art wrote:
Tom Ring wrote:
art wrote:
They are of a group that everything is known about antennas and is
written in books. If you refer to something that is not in the books


Art:

If you refer to something that is "not in the books" one should take
great care. Why I do think evidence can be brought out and can be
demonstrated that some of the ways we "think" antennas are working is
not real, however, great men have developed thinking models and formulas
which are able to let us design and use WORKING antennas which are
PRACTICAL. I site that mysterious 377 ohms as an example, or for
another, incorporating the spin rate of the earth into antenna formulas
(time), ridiculous (but useful!) But, those "old books" contain methods
and means to develop antennas which do work and which do work well, we
owe much to those who have gone before us ...

I am only hoping that by refusing to allow "magic numbers" to be
embedded into equations without any suitable explanation of what those
numbers are "REALLY ABOUT" will one day awake the man who can form the
vision and see what the others have all been unable to, Tesla seemed to
have had an excellent ability which I hold as example of the type of
"vision seer" I mean.

I have an open mind, I guess you are as likely as the next guy to "be
the one!" Never hurts to try anyway ...

However, thank God practical antennas work and we have the tools to
design and build them.

Regards,
JS

"art" wrote in message
ups.com...
Interesting Jimmy
Could you show me how me how a vector directed at a socalled reflector
behaves with respect to a constant plane without the implication of a
neutralising effect.
Now the reflector "works" only as a part of a particular plane so
please go on from there.
I often read of additive and subtractive radiation in books written by
the masters and I have seemed to have got the wrong idea about these
matters
Art

Then give a reference to what you are talking about if you are so familar
with the "masters".


Jimmie D wrote:
"art" wrote in message
oups.com...
From a theoretical way of getting at the answer it seems
a logical way of proceding. So now to the rest of the task.1 how do we
determine volumes that you talk about that are a result of deflection 2
How do we determine
radiation that was cancelled or neutralised and 3 How do you determine
the radiation volume created by ground reflection so we can work back
to search for ground losses. That last one really bothers me as I have
never got a good handle on the contribution of ground reflection to any
particular part of the radiation envelope.

Art



Denny wrote:
For those who wish to actually learn and not just insult each other,
get a calculator, learn how to calculate Cosine Theta a trivial math
problem that any 9th grader can be taught in 5 minutes flat, get a
BIG
piece of paper reason to come, and actually calculate the shape and
vector length of the lobes of a two element Yagi-Uda antenna... Do
the
calculation in both the horizonal and vertical planes... From that you
can calculate the volume of each lobe, which is proportional to the
percentage of power in each lobe... From that number you can very
simply calculate what percentage went into the lobes you prefer and
what went in the lobes you don't prefer...

Now, the reason for the BIG piece of paper... The antenna patterns you
see on the screen with EZNEC, or in the antenna handbooks, are
logarithmic, not linear and there are flavors to them, ARRL, linear
logarithmic, modified logarithmic... So, the patterns are
distorted... Why is that? Because if they were linear and the front
lobe and the rear lobe are to the same scale the front lobe will take
up the entire length of the screen/paper and the rear lobe will need a
magnifying glass to be seen... A rear lobe that is 20dB down from the
front lobe is down by the power ratio of 100... So, if your forward
lobe calculates out to be 10 inches long, the rear lobe will be be
1/10
of an inch.... I'll let you figure out the size of a lobe that is
30dB
down (get out your microscope)

For those who want to review do a search on Joseph Reisert, who has
published numerous writings on antennas and patterns... There many
are
others also, but Joe is published on the web, and very readable...

cheers ... denny / k8do

The radiation IS NOT cancelled or Neutralized. You need to learn more
about
what is going on with an antenna. I suggest you do some serious reading,
actually reading with an open mind and not reading trying to find little
phrases that seem to you to prove your beliefs. It should be fairly
obvious
that if an antenna worked by neutralization or cancelation that it would
take more energy to cancel out radiation in the undesired direction of a
yagi than is available in the desired direction. Therefore a Yagi or any
other antenna does not work by cancellation.

I gues I could express this a lot better but its late and whats the use.