Dave wrote:
If a simple dipole is fed with 100 watts and radiates 95 watts, it is 95% efficient.

David if you had a dipole that had inherrent directional capabilities
would you consider
that as a possible choice for better efficiency ? Where does the 95%
number come from and where did the 5% go so. Did turners post influence
your guess at that number? is he worth copying? Others can get an idea
what you are talking about ie. parameters of use for which you are
applying the 95% figure to. It is possible that we can at least one
negative from the discusion in search of the kernel of info. Does the
dipole become more or less efficient as it moves away from its design
frequency as it becomes "detuned" Give me some meat





snip/s/ DD

art wrote:

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!