Hi Art

You know, I am really a slow learner. I still dont understand how
efficiency is defined. Can you try again to teach me how efficiency is
defined??

Thanks
Jerry



"art" wrote in message
ups.com...
Hi Jerry perhaps I am wrong that there ARE people who want to talk
antennas
We went thru this some time ago and I was referring to efficiency of
the yagi antenna
with respect to the radiation field where much is reflected to areas of
no concern.
Others did not like this and said efficiency referred to is one of the
radiation facets of a radiating array and the yagi is efficient and
then the sniping statrted and the newsgroup went down hill as others
joined to emulate and perpetuate abrasive non antenna related
subjects. I just popped back to see if the group wanted to change back
to antenna talk
and posted the term efficiency of the yagi in terms of radiation which
everybody was
auguing about. Well things haven't changed they still just want to
throw stones and more will join in as the thread goes on., Ill stick it
out for an hour or so and then move on again.
Cant wait for somebody to compare with free space stuff to add to the
confusion, I know it will come




Jerry Martes wrote:
"art" wrote in message
ups.com...
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.
At that time people said the antenna was efficient though
they wanted to talk about
actual radiation efficiency and the sniping began
.Nobody but nobody came back with the radiation
efficiency of a Yagi as they saw the question, they
just wanted to throw stones.Imagine that antennas
was not what the experts wanted to talk about and
the newsgroup took a turn for the worst
So I join in with the thoughts of radiation efficiency
of a yagi unless you prefere to give up this antenna
newsgroup. But before you scream out and throw
stones again I will referr to efficiency as most of the
members of this group what's left of them think of the term.
So let's look at that if that is what you preferr..

The basic small yagi has three elements one driven,
one a reflector and one a director yet only one
element has a truly resistive impedance whereas
the other two do not. Since two elements out of the
three are producing reactive impedances and wherein
the reactive portions of impedance is pure waste
pray tell me how one can consider a yagi as efficient?
And please, please don't waste time on "I don't understand"
otherwise everything drops down to the subject of spark noise
which was really decided by hams a long while ago.
On the other side of the coin, if the reactive portion of an
impedance is not waste then why is LCR
type mesh circuitry only revolve around lumped circuitry?
HINT add up the power emminating from each element
P =I sq times real resistance for those who are just followers.

There again maybe it is best that you be honest and say
you don't understand! Better that than join those who have
nothing to say about antennas!


Hi Art

OK, I dont understand. Perhaps I could begin to understand if I was
given the definition of efficiency we are using in this discussion. How
do
you define efficiency?

Jerry

Jerry Martes wrote:
...
How do you define efficiency?

Jerry



Jerry:

You make that sound like such a simple question.

Antenna efficiency is a complicated and often misused figure.

All antennas suffer from losses. A simple horn antenna for example will
not be as efficient as a perfect aperture of the same size because of
phase offset. The real efficiency of an antenna combines impedance match
with other factors such as aperture and radiation efficiency to give the
overall radiated signal for a given input. The best and mostwidely used
expression of this efficiency is to combine overall efficiency with
directivity (of the antenna) and express the efficiency times
directivity as gain.


The above is NOT mine, but taken from the web...
http://www.tmcdesign.com/antenna%20c...nformation.htm

So, we need to know if we are discussing antenna efficiency, or
radiation efficiency, or the skin effect as related to the ether
efficiency, etc. grin

Good that you are asking him!

Regards,
JS

"John Smith" wrote in message
...
Jerry Martes wrote:
...
How do you define efficiency?

Jerry



Jerry:

You make that sound like such a simple question.

Antenna efficiency is a complicated and often misused figure.

All antennas suffer from losses. A simple horn antenna for example will
not be as efficient as a perfect aperture of the same size because of
phase offset. The real efficiency of an antenna combines impedance match
with other factors such as aperture and radiation efficiency to give the
overall radiated signal for a given input. The best and mostwidely used
expression of this efficiency is to combine overall efficiency with
directivity (of the antenna) and express the efficiency times directivity
as gain.


The above is NOT mine, but taken from the web...
http://www.tmcdesign.com/antenna%20c...nformation.htm

So, we need to know if we are discussing antenna efficiency, or radiation
efficiency, or the skin effect as related to the ether efficiency, etc.
grin

Good that you are asking him!

Regards,
JS

Hi John

It really *is* a simple question. Again, how is Efficienct being defined
for this investigation?? As you have written, that question has to be
answered by Art, the original poster, ?doesnt it?

I was a little embarrassed because that "definition" of gain in the
referenced site was really difficult for me to understand. I really admire
you guys who understand phrases like "phase offset" as related to
efficiency.

Jerry

Very good points John, the subject first started out some time ago when
I stated that thge yagi array was really an in efficient way of
providing communication point to poit because it can be seen that the
radiation field points all over the place. The comments first came back
that little energy was exposed outside the main lobe which then people
stated it wasn't a measure of yagiefficiency bringing gain and a lot of
miscellaneous stuff until they got to the point that the yagi was
efficient and the real efficiency revolves around radiation itself.
Then sniping started and I took off for a while.
When I came back I modified the question
to what people thought the question should be because that was what
they had an answer for but again they got screwed up because the
subject still remaines the yagi with respect to radiation fields
knowing full well that radiation cancellation enters heavily when
determining final radiation fields which is why one should not bring in
gain to the picture. So cutting out the clutter of environment and
dielectrics used etc the question is phrased around the transfer
arrangement that the Yagi uses to translate a electrical power input
for the production of a time varying field which is the most simple
basic aproach since we are dealing only with the eIR equation in
obtaining the energy change over efficiency with respect to the Yagi
antenna alone.No nead to show off your perceived knowelenge about
antennas or to change the subject so that one doesn't have to show
their ignorance of factors outside of Ohms law which is all one needs
to know. But sadly in this newsgroup people get upset if one doesn't
know the answer to the question prefer to divert things to a question
that they do know the answer to and do this by questioning the
intelligence of the poster first before their own intelligence becomes
the question. From the very beginning I gave the hint where it can be
reasoned out without a lot of uninportant clutter but unfortunately all
ignored it as possible drivel. Is it any wonder that antenna talk and
aspiring amateurs shy away from this newsgroup and where it attracts a
different sort of clientele in line with present day activities? My
goodness a dipole is a basic element in any antenna array with respect
to effiency but an arrays efficiency is based on the additions to the
driven dipole of other elements used to produce the near field to
produce perceived benefits which is outside of this question. I realise
that all hams do not have to be electrical engineers but it does seem
the purpose of some is to complicate things beyond the comprehension of
those who we wish to have in the fraternity in an attempt to elevate
them selves in fraternity fashion. Oh well I can't change the world!
The yagi has held its own since the 1920 so it must be sacrelidge to
examine it furthur to expose more efficient means of producing near
fields. For myself I have written around a new form to be published by
the PTO and was intending to discuss its merits with this group first
but I now realise that information iand knoweledge is not what is sort
after, only targets to throw stones at.



John Smith wrote:
Jerry Martes wrote:
...
How do you define efficiency?

Jerry



Jerry:

You make that sound like such a simple question.

Antenna efficiency is a complicated and often misused figure.

All antennas suffer from losses. A simple horn antenna for example will
not be as efficient as a perfect aperture of the same size because of
phase offset. The real efficiency of an antenna combines impedance match
with other factors such as aperture and radiation efficiency to give the
overall radiated signal for a given input. The best and mostwidely used
expression of this efficiency is to combine overall efficiency with
directivity (of the antenna) and express the efficiency times
directivity as gain.


The above is NOT mine, but taken from the web...
http://www.tmcdesign.com/antenna%20c...nformation.htm

So, we need to know if we are discussing antenna efficiency, or
radiation efficiency, or the skin effect as related to the ether
efficiency, etc. grin

Good that you are asking him!

Regards,
JS

Jerry Martes wrote:
Can you try again to teach me how efficiency is defined??

What kind of efficiency? antenna? beam? aperture?
overall? conduction-dielectric?

Balanis defines overall antenna efficiency as the
product of:

1. reflection (mismatch) efficiency
2. conduction efficiency
3. dielectric efficiency

He gives the conduction-dielectric efficiency as:

Rr/(RL + Rr)

where Rr is the radiation resistance and
RL is the (conduction + dielectric) losses

He gives beam efficiency as:

(Beam cone power)/(Total radiated power)

He also says for a 1-dimensional aperture as a
function of taper: "The aperture efficiency is
a maximum with no taper, while the beam efficiency
is a maximum with full taper."
--
73, Cecil http://www.w5dxp.com

Cecil Moore wrote:
He also says for a 1-dimensional aperture as a
function of taper: "The aperture efficiency is
a maximum with no taper, while the beam efficiency
is a maximum with full taper."

Oops, Kraus said that, not Balanis.
--
73, Cecil http://www.w5dxp.com

"Cecil Moore" wrote in message
. ..
Jerry Martes wrote:
Can you try again to teach me how efficiency is defined??

What kind of efficiency? antenna? beam? aperture?
overall? conduction-dielectric?

Balanis defines overall antenna efficiency as the
product of:

1. reflection (mismatch) efficiency
2. conduction efficiency
3. dielectric efficiency

He gives the conduction-dielectric efficiency as:

Rr/(RL + Rr)

where Rr is the radiation resistance and
RL is the (conduction + dielectric) losses

He gives beam efficiency as:

(Beam cone power)/(Total radiated power)

He also says for a 1-dimensional aperture as a
function of taper: "The aperture efficiency is
a maximum with no taper, while the beam efficiency
is a maximum with full taper."
--
73, Cecil http://www.w5dxp.com

Hi Cecil

How does Art define Efficiency for evaluating Yagi antennas?

Jerry

Hi Jerry sorry that I didn't respond to you earlier but here goes
untuned elements which haveWhen you decide to get something going you
need a means to get there.
When you decide on the means you need to know if you are expending the
minimum energy to get there
In this particular case we have decided on generating a time varying
field around some reradiatiung elements to obtain a radiating field of
some sort Since we are applying energy
to elements we want to know if the elements are doing a good job or are
they losing out on energy translation by generating heat e.t.c instead
of it all going where I want it to. So what we do is find out what
energy we put in to obtain our objective and measure what we got out
towards our objective to see how effective we were which is a measure
of efficiency... Ideally we dont want to produce heat and all that
other stuff but the anteena array that we have chosen to do this is a
yagi array of elements which starts of with a resonant dipole which has
a purely resistive impedance. But the yagi then goes on to upset things
by adding which have a reactive impedance which detracts from the purly
resistive value of the impedance which means losses when we should have
added extra resonant elements to the set up as a means of adding to the
structure to maintain zero losses BUT the yagi does go a long way
towards our objectives so it has hung around for a long while. As a
side issue
we should also consider the environment that our array is working in
and also the type of element material we are using as well as the means
taken to input power but that gets more complicated so the question is
really revolving around the energy input versus a magnetic near field
generation that goes on to form a far field radiation field.
SOOOOOOOooooo
efficiency in this case compares the electrical power applied to the
yagi to generate a magnetic and electric fieldaround the yagi and to
check how much energy was lost on the way to our objective. Sorry for
the delay but fortunately I did check back in before I moved on to
other things
Regards
Art





Jerry Martes wrote:
Hi Art

You know, I am really a slow learner. I still dont understand how
efficiency is defined. Can you try again to teach me how efficiency is
defined??

Thanks
Jerry



"art" wrote in message
ups.com...
Hi Jerry perhaps I am wrong that there ARE people who want to talk
antennas
We went thru this some time ago and I was referring to efficiency of
the yagi antenna
with respect to the radiation field where much is reflected to areas of
no concern.
Others did not like this and said efficiency referred to is one of the
radiation facets of a radiating array and the yagi is efficient and
then the sniping statrted and the newsgroup went down hill as others
joined to emulate and perpetuate abrasive non antenna related
subjects. I just popped back to see if the group wanted to change back
to antenna talk
and posted the term efficiency of the yagi in terms of radiation which
everybody was
auguing about. Well things haven't changed they still just want to
throw stones and more will join in as the thread goes on., Ill stick it
out for an hour or so and then move on again.
Cant wait for somebody to compare with free space stuff to add to the
confusion, I know it will come




Jerry Martes wrote:
"art" wrote in message
ups.com...
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.
At that time people said the antenna was efficient though
they wanted to talk about
actual radiation efficiency and the sniping began
.Nobody but nobody came back with the radiation
efficiency of a Yagi as they saw the question, they
just wanted to throw stones.Imagine that antennas
was not what the experts wanted to talk about and
the newsgroup took a turn for the worst
So I join in with the thoughts of radiation efficiency
of a yagi unless you prefere to give up this antenna
newsgroup. But before you scream out and throw
stones again I will referr to efficiency as most of the
members of this group what's left of them think of the term.
So let's look at that if that is what you preferr..

The basic small yagi has three elements one driven,
one a reflector and one a director yet only one
element has a truly resistive impedance whereas
the other two do not. Since two elements out of the
three are producing reactive impedances and wherein
the reactive portions of impedance is pure waste
pray tell me how one can consider a yagi as efficient?
And please, please don't waste time on "I don't understand"
otherwise everything drops down to the subject of spark noise
which was really decided by hams a long while ago.
On the other side of the coin, if the reactive portion of an
impedance is not waste then why is LCR
type mesh circuitry only revolve around lumped circuitry?
HINT add up the power emminating from each element
P =I sq times real resistance for those who are just followers.

There again maybe it is best that you be honest and say
you don't understand! Better that than join those who have
nothing to say about antennas!


Hi Art

OK, I dont understand. Perhaps I could begin to understand if I was
given the definition of efficiency we are using in this discussion. How
do
you define efficiency?

Jerry

"art" wrote in message
ps.com...
Hi Jerry sorry that I didn't respond to you earlier but here goes
untuned elements which haveWhen you decide to get something going you
need a means to get there.
When you decide on the means you need to know if you are expending the
minimum energy to get there
In this particular case we have decided on generating a time varying
field around some reradiatiung elements to obtain a radiating field of
some sort Since we are applying energy
to elements we want to know if the elements are doing a good job or are
they losing out on energy translation by generating heat e.t.c instead
of it all going where I want it to. So what we do is find out what
energy we put in to obtain our objective and measure what we got out
towards our objective to see how effective we were which is a measure
of efficiency... Ideally we dont want to produce heat and all that
other stuff but the anteena array that we have chosen to do this is a
yagi array of elements which starts of with a resonant dipole which has
a purely resistive impedance. But the yagi then goes on to upset things
by adding which have a reactive impedance which detracts from the purly
resistive value of the impedance which means losses when we should have
added extra resonant elements to the set up as a means of adding to the
structure to maintain zero losses BUT the yagi does go a long way
towards our objectives so it has hung around for a long while. As a
side issue
we should also consider the environment that our array is working in
and also the type of element material we are using as well as the means
taken to input power but that gets more complicated so the question is
really revolving around the energy input versus a magnetic near field
generation that goes on to form a far field radiation field.
SOOOOOOOooooo
efficiency in this case compares the electrical power applied to the
yagi to generate a magnetic and electric fieldaround the yagi and to
check how much energy was lost on the way to our objective. Sorry for
the delay but fortunately I did check back in before I moved on to
other things
Regards
Art

Hi Art

As I read it, the efficiency (in percentage) we are using for this
discussion is Power Out divided by Power In, if the "objective" is to
radiate power. Or, correct me if I misread.

Jerry

art wrote:
But the yagi then goes on to upset things
by adding which have a reactive impedance which detracts from the purly
resistive value of the impedance which means losses ...

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.

Seems to me that the reactance in the passive elements
provides a phase shift that causes destructive interference
in the desired places and constructive interference in
the desired places.

I came in late and thus apologize if anyone else has stated
this earlier.
--
73, Cecil http://www.w5dxp.com