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