On Wed, 05 Apr 2006 12:56:07 GMT, Cecil Moore
wrote:

Sorry, a typo. Should be 0.9969

Let's see, you responded to Roy twice, then responded to yourself, and
then responded to yourself again - DAMN, you are really trying hard to
convince yourself.

In your pursuit of a solitary pleasure, I can't tell which perspective
has the worst prospect: the teacher's, or the student's.

"Richard Clark" wrote

Hi Yuri,

I can also see that any metrics are entirely missing as to ACTUAL
efficiency. You already admit you don't know and don't really care to
go there when you dismiss this discussion:

But graphic representation gives rough idea to realize that it is not
unimportant or worthy ignoring.
If you wanna get precise metrics, stick the two versions of coil definition
in the EZNEC, generate the curves and compare areas under the curve from the
top of the coil to the tip. Then tell us that is negligible and was not
worth of this exercise.
I will get to it soon too.

Yuri, K3BU

"Richard Clark"
3. this does not explain how a 118.60° tall antenna comes to be
resonant through
On Tue, 4 Apr 2006 12:11:20 -0500, "Richard Fry" wrote:
The effective electrical length of a MW monople radiator determines its
resonant frequencies, and that must include the velocity of propagation
along the structure -- which is a function of the height AND width of the
radiator (mainly), and the operating frequency.
______________

I have not stated that an unloaded broadcast monopole of any physical height
should be made self-resonant, or even needs to be, for efficient radiation.
Very few broadcast monopoles are. The ones that aren't are matched to
resonance and the transmission line Zo by a network at the antenna
feedpoint, as I also stated.

What I wrote is that a radiator of "90 electrical degrees" when shown in the
FCC database is NOT self-resonant, and referred to the experimental data
from George Brown, and the work of Johnson & Jasik to confirm what I wrote.
Kraus, 3rd edition, Ch 14 has the mathematical analysis to support this,
also. NEC shows this effect, as well.

The rest of the examples in your post are based on your invalid assumption,
for which my response is given above.

RF

Cecil Moore wrote:
Ian White GM3SEK wrote:
Cecil Moore wrote:
Everybody seems to understand how a coil works.
Crucially, you don't. The main property of a "coil" is inductance,
and at the most fundamental level you do not understand what
inductance does.

Please stop the mind fornication, Ian.

I am simply telling you straight. If you find the implications
disturbing beyond the import of my actual words, that is beyond my
control.

I understand how a coil works
and I agree with you how a coil works in a lumped circuit or a traveling
wave environment. It's obvious that our basic disagreement is NOT about
coils but is, instead, about standing waves.

Our basic disagreements are about coils *and* current *and* their
behaviour when standing waves are present. There's no point in switching
the discussion to cover only part of those topics.


--
73 from Ian GM3SEK 'In Practice' columnist for RadCom (RSGB)
http://www.ifwtech.co.uk/g3sek

Ian White GM3SEK wrote:
I am simply telling you straight. If you find the implications
disturbing beyond the import of my actual words, that is beyond my control.

You are trying to tell me what I think when you have no clue
as to what I am thinking. Excuse my French, but that is called
mind-****ing, Ian. Please cease and desist from that practice.
The only ethical and honest thing you can say about my postings
is, "it seems to me that you are saying or thinking such and such ..."

Our basic disagreements are about coils *and* current *and* their
behaviour when standing waves are present. There's no point in switching
the discussion to cover only part of those topics.

Not switching the discussion to the only salient point of disagreement
will obfuscate the discussion. If that's what you want to do, then
your reasons for doing so are quite obvious, and readers are likely
to assume that you are not interested in technical facts at all but
more interested in preserving your omniscient guru status through
obfuscation.

So the real question is: Why have you avoided responding to my
tabular current posting based on EZNEC's take on traveling wave
current Vs standing wave current? Some may assume from that lack
of response that you are afraid to address the technical facts
as are W8JI and W7EL.

If you guys are so right, why are you afraid of discussint the
technical issues that I have posted?
--
73, Cecil http://www.qsl.net/w5dxp

Cecil Moore wrote:
Ian White GM3SEK wrote:
I am simply telling you straight. If you find the implications
disturbing beyond the import of my actual words, that is beyond my
control.

You are trying to tell me what I think when you have no clue
as to what I am thinking. Excuse my French, but that is called
mind-****ing, Ian. Please cease and desist from that practice.
The only ethical and honest thing you can say about my postings
is, "it seems to me that you are saying or thinking such and such ..."


I have no interest whatever in the workings of your mind. My only
interest is in what you say to the outside world.

Based entirely on what you yourself have written, I have told you that
you don't understand something. If you cannot handle that, and regard it
as an attempt to invade your mind, then this whole thing has gone way
too far.


--
73 from Ian GM3SEK 'In Practice' columnist for RadCom (RSGB)
http://www.ifwtech.co.uk/g3sek

On Wed, 5 Apr 2006 13:51:11 -0400, "Yuri Blanarovich"
wrote:

But graphic representation gives rough idea to realize that it is not
unimportant or worthy ignoring.

Hi Yuri,

But it gives nothing of that impression at all. If it were important,
then you could give me solid numbers instead of an art review.

If you wanna get precise metrics, stick the two versions of coil definition
in the EZNEC, generate the curves and compare areas under the curve from the
top of the coil to the tip. Then tell us that is negligible and was not
worth of this exercise.

Yuri, I did that two years ago. You have yet to disagree with the
pitiful difference and the best chance of you doing it yourself is:

I will get to it soon too.

I heard that two years ago too.

You don't give any impression that the topic at hand is nearly as
important to you as duking it out with Tom. But if after two years of
swinging and you still haven't connected a solid KO, don't expect us
to hand you a TKO (because your Technical part is a marshmallow
punch).

73's
Richard Clark, KB7QHC

On Wed, 5 Apr 2006 15:07:53 -0500, "Richard Fry"
wrote:

The rest of the examples in your post are based on your invalid assumption,
for which my response is given above.

Sounds like you have a problem following context. The Xerox school of
churning out references and loose associations is already chaired by
Cecil.

73's
Richard Clark, KB7QHC

"Richard Clark"wrote
Sounds like you have a problem following context.
___________

No, from your posts IMO it is YOU who has a problem with your reading
comprehension, and/or possibly your professional integrity.

I posted "The effective electrical length of a MW monopole radiator
determines its resonant frequencies, and that must include the velocity of
propagation along the structure -- which is a function of the height AND
width of the radiator (mainly), and the operating frequency." I have also
posted several references in the literature which support this in technical
detail.

You then posted "3. this does not explain how a 118.60° tall antenna comes
to be resonant ," and several ridiculous examples of broadcast tower widths
of 364 feet and more that you falsely attribute as flowing from my
statements.

Contrary to your recent post, I have never written anything that remotely
implied that your 118.60 degree radiator, or a broadcast radiator of any
other length can/should be made self-resonant by the use of an impractical
ratio of width to length. I have posted several times that (conventional)
broadcast radiators that are not self-resonant are brought to resonance at
the feedpoint by the use of a matching network there.

If you can find ANYTHING in my posts on this subject to support your
statements, please quote them to the NG. Otherwise I suggest you let this
thread close, and (hopefully), learn from it.

RF

I'm not at all sure what all the hoop-lah following Richard Fry's
posting reproduced below is all about. What Richard wrote is accurate,
as he says confirmed by NEC simulation, and also from the
King-Middleton second-order theory of linear antennas. From the date,
it sounds like Brown's paper was a confirmation of the theory,
actually. An antenna resonant at 95% of a freespace quarter wave,
above perfect ground, would be about 150 times as long as its
diameter--a 75 meter tower about half a meter effective diameter. NEC
gives slightly different numbers, but perhaps more interesting is that
even for VERY thin wires, the resonant length is noticably shorter than
a freespace quarter wave. A wire a millionth as thick as it is long
still shows resonance more than a percent shorter than the freespace
wavelength.

It's an interesting observation, but I thought everyone (with a serious
interest in antennas) would know about it.

The effect at full-wave dipole resonance/half-wave above a ground plane
is considerably more pronounced, over ten percent for a moderately
thick antenna.

Cheers,
Tom


Richard Fry wrote in Message-ID: :

"Richard Harrison" wrote:
It is the convention to describe AM broadcast towers in electrical
degrees. Harold Ennes reprints an RCA resistance chart for heights
between 50 and 200 degrees in "AM-FM Broadcast Maintenance".

Formula given is:
Height in electrical degrees = Height in feet X frequency in kc X
1.016 X 10 to the minus 6 power.

_______________

If electrical length is defined as the physical condition where
feedpoint
reactance is zero (e.g., resonance), then the true electrical length of
an
AM broadcast radiator on a given frequency is a function of the
physical
length AND physical width of that radiator. This was proven
experimentally,
and documented by George Brown of RCA Labs in his paper "Experimentally
Determined Impedance Characteristics of Cylindrical Antennas" published
in
the Proceedings of the I.R.E. in April, 1945. It also has been proven
in
thousands of independent measurements of AM broadcast radiators ever
since.

The curves in Figure 3 of Brown's paper show the feedpoint reactance
terms
of the base impedance of an unloaded monopole of various lengths and
widths,
working against a nearly perfect ground plane. Those values cross the
zero
reactance axis at physical heights ranging from about 80 degrees (for
the
widest radiator) to about 86 degrees for the most narrow.

Brown calculated height in degrees as (Physical Height in feet x
Frequency
in kHz ) / 2725 . Brown's equation, the one in the Harold Ennes quote
above, and the one that the FCC uses in their published data all define
only
the relationship of the physical length of the radiator to its
free-space
wavelength in degrees at that frequency.

But clearly these lengths in degrees do not define the self-resonant
length
of that radiator. The self-resonant length, invariably, will be
shorter by
several percent. This fact is easily confirmed by simple NEC models,
for
those who want to probe into George Brown's data.

Tables relating a single value of base impedance as typical for towers
of
various electrical heights (only) must be read with an understanding of
the
above realities. For example, Ennes' list shows a tower of 90
electrical
degrees to have zero reactance. But Brown's 1945 paper and a great
amount
of later field experience shows that this is incorrect, for the
conventional
use of this term.

RF