Tom,I agree with much of what you say but the problem goes much deeper
than that, and much of the blame rests with academics taught.
Let us look at what is called by some as a 'simple dipole'.
The dipole is very inefficient radiator.
The only claim that you can place on it is that it is has a low
impedance
at resonance...Period. There is no calculation available in any of the
touted books that maximum gain per unit length is design related to a
dipole! The dipole is only a reference that other antennas can be
related to even tho it is a very inefficient radiator per unit length.
Over time academics have made the dipole as something very efficient
about which every advance must be related .
That Tom is very incorrect and it is that which is what prevents the
emergence of new ideas that push the envelope. If one just spouts what
is in present day books then they are just followers that suck up the
dipole aproach which thus prevents them from contributing anything
that pushes out the envelope. Education
can only take you so far and it is dependent on those who have
received an education to push the envelope further. If one doesn't do
this then they are just quoting things that were told to them or they
read in some book and thus are not equiped to pushing the envelope.
Until the simple dipole is shead of its illusionary powers by the
academics who write the books newcomers can only copy, and not
progress. Ofcourse, academics who just memorise can still attack
people, those who do not agree with them, in a personal way in the
hope that a raucous crowd of peasants will echo the academics trash
around the Gillotine.

Regards
Art






(Tdonaly) wrote in message ...
Steve's info will get you a beginners understanding of circuit
theory which is based on a low-frequency, quasi-static simplification
of electromagnetic theory. Unfortunately, anything that has any
appreciable length, such as a transmission line or an antenna, or
a long coil of wire as Yuri and Cecil are arguing about,
can't be adequately explained by simple circuit theory; you have to
study wave mechanics to get any real idea of what is happening
in these situations. That isn't the end of it, though, since in order
to understand what is happening when an object radiates, you
have to understand Maxwell's equations. In order to understand
Maxwell's equations, you'd better know vector calculus. That isn't the
end, either, but it's as close as any *normal* human wants to go.
Whenever someone who was taught circuit theory tries to
apply its vocabulary and concepts to explain all electromagnetic
phenomena, that someone is going to run into trouble and
come up with a multitude of idiocies for which which he'll find no end of
people ready to criticize him.
This is the problem: Cecil and Yuri want to explain the current taper
through a long solenoidal coil using the vocabulary and concepts of
circuit theory rather than the difficult but more precise
language of electromagnetic theory. So far they've failed
miserably, not least because they don't even seem to have
a coherent idea of what they mean by "current flow." I
wish them luck, but I hope no one takes any of their
ideas seriously.
73,
Tom Donaly, KA6RUH






Steve wrote,

Unable to resist at least trying to provide the basis for some
understanding, Steve proceeds.

Snip

Art, KB9MZ wrote:
"The dipole is a very inefficient radiator."

Kraus, unfortunately, wasn`t one of my books until recently. I don`t
have the words memorized or know where they appear as I do with some of
Terman.

I seem to remember Kraus saying 95% efficiency was not unusual as a
dipole efficiency. As there are so many variations, it`s like a baseball
statistic, there must be a statistic that fits somewhere.

In any case, "efficient" is only as compared with similar devices.
Recall that dBd is the norm as an isotropic antenna is only a
theoretical creature. Catalogs are filled with antenna characteristics
as compared with a 1/2-wave dipole in free space. It is the standard of
comparison. It could hardly be correctly called inefficient.

Best regards, Richard Harrison, KB5WZI

On Fri, 20 Feb 2004 14:34:46 -0600 (CST),
(Richard Harrison) wrote:
Art, KB9MZ wrote:
"The dipole is a very inefficient radiator."

.... It could hardly be correctly called inefficient.

Hi Richard,

We are back into this stale wheeze about efficiency "per unit length"
which is the same siren song of the cfa.

Put one out in the field, measure it against one of those "inefficient
radiators" and we find it roughly -30dB more "efficient" than the
standard BCB antenna.

The cfa may well be more efficient "per unit length" because it costs
less in steel and is smaller, its coverage follows that downward
spiral too. On those terms, hoisting a dummy load 30 feet into the
air would be far more efficient "per unit length" with roughly -60dB
more "efficiency."

Properly speaking, this new usage of "efficiency" should have been
confined to the thread Semantic Nonsense where we could properly
appreciate the ratio:

Semantic Nonsense + Nonsense
--------------------------------------
Nonsense

As any adept calculator puncher can appreciate, almost anything said
shows more than 100% efficiency. :-)

The acid test of the capitalist broadcast marketplace has shown not
one cfa sold. Now, in the socialist world, like Egypt, they had one
(1) provisional sale? If there were still an Iron Curtain, they would
have bought this nonsense up like Pravda at the red square newsstands.
Even at that, the Iron Curtain would probably be a necessary
resonating structure to make it work.

73's
Richard Clark, KB7QHC

Richard Harrison wrote:

Art, KB9MZ wrote:
"The dipole is a very inefficient radiator."

I seem to remember Kraus saying 95% efficiency was not unusual as a
dipole efficiency.

I don't think that's the efficiency that Art is talking about. Art's
efficiency seems to be defined as the power delivered to the receiver
divided by the power sourced by the transmitter.
--
73, Cecil http://www.qsl.net/w5dxp



-----= Posted via Newsfeeds.Com, Uncensored Usenet News =-----
http://www.newsfeeds.com - The #1 Newsgroup Service in the World!
-----== Over 100,000 Newsgroups - 19 Different Servers! =-----

Good for you Cecil. Brevity and to the point is so much better than a
personal monologue about unrelated subjects that one would expect from a
drunk .
Regards
Art.


"Cecil Moore" wrote in message
...
Richard Harrison wrote:

Art, KB9MZ wrote:
"The dipole is a very inefficient radiator."

I seem to remember Kraus saying 95% efficiency was not unusual as a
dipole efficiency.

I don't think that's the efficiency that Art is talking about. Art's
efficiency seems to be defined as the power delivered to the receiver
divided by the power sourced by the transmitter.
--
73, Cecil http://www.qsl.net/w5dxp



-----= Posted via Newsfeeds.Com, Uncensored Usenet News =-----
http://www.newsfeeds.com - The #1 Newsgroup Service in the World!
-----== Over 100,000 Newsgroups - 19 Different Servers! =-----

Cecil, defining efficiency as from transmitter to receiver. Isn't
the proper term 'Path Loss' and it's a variable due to propagation
variations. So are we comparing my wet noodle to your wet noodle and we
wiggle it in the middle.

Conclusion: It is not valid to define efficiency based on unknowable and
uncontrollable variables..

Deacon Dave

Cecil Moore wrote:

Richard Harrison wrote:

Art, KB9MZ wrote:
"The dipole is a very inefficient radiator."

I seem to remember Kraus saying 95% efficiency was not unusual as a
dipole efficiency.


I don't think that's the efficiency that Art is talking about. Art's
efficiency seems to be defined as the power delivered to the receiver
divided by the power sourced by the transmitter.

Guys, you're off on a tangent!

I believe Efficiency is the ratio of power radiated to power input.

If a dipole is 95% efficient it radiates 95 out of 100 watts.

If a Yagi is 95% efficient it radiates 95 out of 100 watts.

If a Quad is 95% efficient it radiates 95 out of 100 watts.

If a vertical is 95% efficient it radiates 95 out of 100 watts.

If a Log Periodic is 95% efficient it radiates 95 out of 100 watts.

If a 1/10 wavelength antenna made of unobtainium is 95% efficient it
radiates 95 out of 100 watts.

Don't confuse Gain, Directivity and Efficiency in the discussion.

Deacon Dave

Richard Harrison wrote:
Art, KB9MZ wrote:


SNIP

In any case, "efficient" is only as compared with similar devices.

SNIP: Wrong!! See above

Recall that dBd is the norm as an isotropic antenna is only a
theoretical creature. Catalogs are filled with antenna characteristics
as compared with a 1/2-wave dipole in free space.

SNIP: The comparison is generally Gain as dBd, dBi, or dBu
[unobtainium]. Not Efficiency!!!

It is the standard of
comparison. It could hardly be correctly called inefficient.

Best regards, Richard Harrison, KB5WZI

David
I think you can help me out on this efficiency malarkey. A dipole receives
all signals within the dipoles range so its receive capabilities are well
beyond
the frequency span of choice
I would venture to say that when discussing efficiency we should place
bandwidth of choice received divided by the total bandwidth that the dipole
actually receives and then multiply by 100. To say a dipole is 90 %
efficient when some parts of a dipole supply radiation that is many times
its other parts of equal lengths supply demands further explanation. Maximum
radiation can only come about when the current flow is a maximum regardless
of current input and is a constant per unit length and that description does
not match a dipole which always require added insertion losses for equipment
to overcome its inefficiences. If the dipole exceeds 90% efficiency then why
waste effort and energy on interface devices between the antenna and the
transformation to say.... audio?
Efficiency should always be aimed at the energy needs required over the
total energy
that has to be supplied to meet required needs. If a truck carries a grain
of desired gold buried in a ton of junk would you call the mining operation
100% efficient by ignoring search costs of finding the grain of gold and the
removal costs for the junk? I believe the above verifies my initial
statement that a dipole can be seen as inefficient. As an engineer I cannot
agree
with power in versus power out ( radiation) type statements as energy
cannot be created or destroyed. Energy supplied by a lump of coal does not
lose any energy in its change of state but as far as efficiency is concerned
I do not count the energy that escaped in smoke as beneficial
and thus quantified as a positive with respect to efficiency
Regards
Art



"Dave Shrader" wrote in message
news:_ozZb.356634$I06.3765208@attbi_s01...
Guys, you're off on a tangent!

I believe Efficiency is the ratio of power radiated to power input.

If a dipole is 95% efficient it radiates 95 out of 100 watts.

If a Yagi is 95% efficient it radiates 95 out of 100 watts.

If a Quad is 95% efficient it radiates 95 out of 100 watts.

If a vertical is 95% efficient it radiates 95 out of 100 watts.

If a Log Periodic is 95% efficient it radiates 95 out of 100 watts.

If a 1/10 wavelength antenna made of unobtainium is 95% efficient it
radiates 95 out of 100 watts.

Don't confuse Gain, Directivity and Efficiency in the discussion.

Deacon Dave

Richard Harrison wrote:
Art, KB9MZ wrote:


SNIP

In any case, "efficient" is only as compared with similar devices.

SNIP: Wrong!! See above

Recall that dBd is the norm as an isotropic antenna is only a
theoretical creature. Catalogs are filled with antenna characteristics
as compared with a 1/2-wave dipole in free space.

SNIP: The comparison is generally Gain as dBd, dBi, or dBu
[unobtainium]. Not Efficiency!!!

It is the standard of
comparison. It could hardly be correctly called inefficient.

Best regards, Richard Harrison, KB5WZI

Typical 'Art Unwin'. Good word count. Zero meaning.
'Doc

Ofcourse it is meaningless to you as you are lacking in independent thought.
Because you are mentally disabled
you should not condemn independant thoughts of others"'Doc"
I am still amazed that you think that by referring to yourself as a Doctor
your statements then carry an aura of authenticity
when in actual fact it shows your lack of knowledge

wrote in message ...
Typical 'Art Unwin'. Good word count. Zero meaning.
'Doc