Standing waves
 

"Art Unwin" wrote in message
...
On Sep 22, 6:28 pm, "christofire" wrote:
"Art Unwin" wrote in message

...
On Sep 22, 6:51 am, "christofire" wrote:

"Art Unwin" wrote in message

- - snip - -

* As I say, you should present your theory to sci.physics and
sci.physics.research if you have any interest in checking whether it is
correct, and not limit its exposure to this group. Do let us know when
you
have posted there.

No, that is not the choice I have made. I decided to merge a paper
aproach with that of a patent request . You have read one patent
request and you have to wait for the PTO to print out the concluding
application. I am sharing it with industry and not the boneheads
who bunch themselves into secret rooms away from those outside who
cannot possibly provide anything of interest. They have the common
interest that if it doesn't come from them..........!!!!!! Pretty much
the same as this group. We shall see
Art

* OK, at an appropriate juncture I'll invite some of them to come over and
take a look at what you write here (crossposting would probably be frowned
upon). It might be enlightening to receive the views of some physicists.

Chris

If you know of any I would welcome their views. There are many retired
educated people in this world today that turn to that which they had
an interest with when young. Now it is difficult to get up to speed in
different sciences because various journals get the rights of various
papers from Universities e.t.c which are then denied to libraries and
the public.
This is a resource the country should assist because its costs are low
and where all have
large experience obtained thru their working years. Imagine
professionals who when retired
have twenty or more years of experience be allowed to follow and
contribute in areas where an interest has laid dormant for so long.
Today's efforts are applied to computers where data comes out in
bundles which have to be sorted to determine if anything good is being
offered by using a mish mash of arithmetic formulae that are merged
with similar formulae from different functions. Sad, sad, sad.


* It's true that a lot of effort is put into the areas that yield the
greatest profit, and computing in one form or another does seem to have a
grip at the moment. However, it is enlightening to take a look from time to
time at news groups like the two I named to see the sorts of things they are
discussing, and the _unbounded_ nature of the universe (which is what I
wrote) is one of them. They too appear to have input from ex-professionals.

Have you ever tried to obtain access to a technical library in a university
or one of the engineering institutions? You might be surprised how easy or
inexpensive it turns out to be. As a member of the general public I have
access to the IET library in London to read as much as I wish, and to
photocopy.

Chris

Standing waves
 

On Sep 22, 5:30*pm, Registered User wrote:
On Tue, 22 Sep 2009 13:24:17 -0700 (PDT), Art Unwin

wrote:

Well look at how salvage yards sort out metals into different
enclosures.
They apply a displacement current *to a conveyor where each piece of
metal is elevated with spin such that it lands in the appropriate
enclosure which is dependent on the resistivity of the metal elevated.

This isn't exactly how such systems work. Abstractly the system is a
metal detector and a sorting table hanging off a CAN. A controller at
the other end of the CAN 'reads' the discriminator and 'writes' to the
sorter. The writes open and close ejector nozzles. These are the magic
devices that cause the material to 'elevate with spin'.

This method of elevating scrap for recovery has been used for years
and it is the same action that is applied to particles for radiation.
Why would you need a citation for a practice that is well known and in
use?

Because you might be wishing your agenda into how you propose things
work. Who'da thunk that!

Interesting. Can you point to an article or something on the web that
describes what you
say. For myself I have only run into articles by special purpose
machine manufacturers
who deal with sorting machines for scrap yards which deals with many
materials including plastics , glass etc as well as different metallic
materials. This sorting aproach that you mention sounds rather
interesting if they are relying on magic or voodoo!

Standing waves
 

On Sep 22, 6:48*pm, Art Unwin wrote
after major clippage:
Today's efforts are applied to computers where data comes out in
bundles which have to be sorted to determine if anything good is being
offered by using a mish mash of arithmetic formulae that are merged
with similar formulae from different functions. *Sad, sad, sad.

However as far as NEC is concerned, your sad-sad-sadness applies only
to those (possibly even yourself) using computer software without
sufficient understanding of how it should be used, and applied.

Note that the U.S. FCC has endorsed the use of NEC in the licensing
process of many types of directional MW broadcast arrays -- given that
such NEC analysis was performed by someone with provable and
acceptable competence.

RF

Standing waves
 

On Sep 22, 6:58*pm, "christofire" wrote:
"Art Unwin" wrote in message

...
On Sep 22, 6:28 pm, "christofire" wrote:



"Art Unwin" wrote in message

....
On Sep 22, 6:51 am, "christofire" wrote:

"Art Unwin" wrote in message

- - snip - -

* As I say, you should present your theory to sci.physics and
sci.physics.research if you have any interest in checking whether it is
correct, and not limit its exposure to this group. Do let us know when
you
have posted there.

No, that is not the choice I have made. I decided to merge a paper
aproach with that of a patent request . You have read one patent
request and you have to wait for the PTO to print out the concluding
application. I am sharing it with industry and not the boneheads
who bunch themselves into secret rooms away from those outside who
cannot possibly provide anything of interest. They have the common
interest that if it doesn't come from them..........!!!!!! Pretty much
the same as this group. We shall see
Art

* OK, at an appropriate juncture I'll invite some of them to come over and
take a look at what you write here (crossposting would probably be frowned
upon). It might be enlightening to receive the views of some physicists..

Chris

If you know of any I would welcome their views. There are many retired
educated people in this world today that turn to that which they had
an interest with when young. Now it is difficult to get up to speed in
different sciences because various journals get the rights of various
papers from Universities e.t.c which are then denied to libraries and
the public.
This is a resource the country should assist because its costs are low
and where all have
large experience obtained thru their working years. Imagine
professionals who when retired
have twenty or more years of experience be allowed to follow and
contribute in areas where an interest has laid dormant for so long.
Today's efforts are applied to computers where data comes out in
bundles which have to be sorted to determine if anything good is being
offered by using a mish mash of arithmetic formulae that are merged
with similar formulae from different functions. *Sad, sad, sad.

* It's true that a lot of effort is put into the areas that yield the
greatest profit, and computing in one form or another does seem to have a
grip at the moment. *However, it is enlightening to take a look from time to
time at news groups like the two I named to see the sorts of things they are
discussing, and the _unbounded_ nature of the universe (which is what I
wrote) is one of them. *They too appear to have input from ex-professionals.

Have you ever tried to obtain access to a technical library in a university
or one of the engineering institutions? *You might be surprised how easy or
inexpensive it turns out to be. *As a member of the general public I have
access to the IET library in London to read as much as I wish, and to
photocopy.

Chris

Yes, some university libraries allow access to the public but not for
copies. These must
come from journals at quite high prices. Here you can be a member of a
professional society say IEEE but to get the journals of say antennas
and propagation then you must pay a couple of $100 to have access to
them. This is on top of the fees for the institution and the group
that you are personally a member of which also requires fees. But the
U.S. is not like being in London where you can take the tube to any
where such as the patent office library or visit the one on Birdcage
Walk ( Royal Institution of Mechanical Engineers in the old days)
I am not aware of this IET that you mentioned. Here in Illinois which
is the size of the UK plus has a population that London sees every
day of the week! One library I would like to get into is on
Whitechapel road in Stepney ( Queen Mary college) where extensive work
is done on antennas. Anyway what I do is to start right at the
beginning ie first principles
and with antennas stuck in a rut for so long it was a good one for me
as a retired person
to fiddle with as it was nice to talk to my buddies at BAC St Albans
and nearby towns when radio itself was a hobby for me but most have
now passed away. Now I have finished my personal antenna studies and I
will have to turn to the honey doos that have piled up over the last
few years even tho I have had a handy man come in regularly even so I
go thru periods where every thing that I own is broken and I must turn
away from my hobbies.

Standing waves
 

"Art Unwin" wrote in message
...
On Sep 21, 7:33 pm, "christofire" wrote:

snip crap
No it does not appear in Kraus book. He never followed Maxwells laws
with respect to equilibrium.
snip more crap

and he had a good reason not to... because its all made up by you art, and
its totally WRONG!

Standing waves
 

"Szczepan Bialek" wrote in message
...

"Dave"
...

"Szczepan Bialek" wrote in message
...

In the Gas Analogy the monopole antena is exactly like the Kundt's
tube.

Heaviside did the Hydraulic Analogy. All is exactly the same like in
the fluids mechanics.
Next the electrons were discovered. Automatically Heaviside is a
history and the Gas Analogy is in power.

But you, radio people, are very close to waves and should be easy for
you to work out the answer for the Question:
Which Analogy is right?

neither analogy is 'right'. they are useful in limited circumstances
to demonstrate some basic pressure wave physics to young students. but
neither one properly reproduces electromagnetic waves.

"electromagnetic waves" are paper waves. Radio waves are real waves. Now
we must not know what the waves are like. Now we should estabilish from
which part of the radiator radiate the radio waves.
Do you agree with Richard Harisson:
"At the open circuited ends of a resonant antenna there is almost double
the forward voltage but zero total current due to cancellation of the
dorward and reflected currents at the open circuit. At the open circuit
in the wire, all the energy in the wave is transferred to the electric
field."
S*


we know what they are like, you just have to understand the mathematics.

I understand. Without that it was be impossible to know that Maxwell
proposed the displacement current to save the incompressible electric
fluid. In Maxwell times AC current was known. To pass the incompressible
fluid through a capacitor the displacement current is necessary. I prefere
the compressible electrons. They compress in the plates and nothing flow
between them. The polarization is not the macro flow.

and yes, richard's statements are true, but a bit too restrictive, it
doesn't HAVE to be resonant. Voltage doubles and current=0 at the end of
any wire fed with a time varying current, it doesn't even have to be a
sine wave... note the effect of sending square waves from a time domain
reflectometer down an open circuited wire.

Yes. But antennas are in resonance.
S*

antennas don't have to be 'in resonance'.... a very short dipole radiates
almost as well as one 1/2 wavelength long... its all in the fields.

Standing waves
 

On Sep 22, 8:13*pm, "Dave" wrote:
"Art Unwin" wrote in message

...
On Sep 21, 7:33 pm, "christofire" wrote:

snip crapNo it does not appear in Kraus book. He never followed Maxwells laws
with respect to equilibrium.

snip more crap

and he had a good reason not to... because its all made up by you art, and
its totally WRONG!

So you are back David ! have you built that four poster antenna yet,
of steel I presume,
for the top band? Hopefully the system of yours is in a state of
equilibrium so you can tell us good things about it. Did you have to
make a ground plane system? They are not needed for a system in
equilibrium so you may have displaced a lot of moles from their
habitat for no good reason. Haven't heard you mention anymore about
that book you were writing on antennas. I assume you do not have a
chapter about equilibrium as yet. And that problem you had about the
legality of turning a static field into a dynamic field, have you made
any progress on that yet ( just pulling your tail)

Standing waves
 

Dave wrote:
Yes. But antennas are in resonance.
S*

antennas don't have to be 'in resonance'.... a very short dipole
radiates almost as well as one 1/2 wavelength long... its all in the
fields.

As I tried to make Art understand with respect to yagis, it's not
necessarily resonant (or even usually), it's matched. By the matching
network.

It was like releasing excess nitrogen containing waste into the wind,
like all things are with Art.

See wall, hit with head, repeat.

tom
K0TAR

Standing waves
 

Art Unwin wrote:
So you are back David ! have you built that four poster antenna yet,
of steel I presume,
for the top band? Hopefully the system of yours is in a state of
equilibrium so you can tell us good things about it. Did you have to
make a ground plane system? They are not needed for a system in
equilibrium

Wow! No ground system needed for top band. The AM broadcasters are
going to be all over this. Art, you are about to become very very rich.
This overturns every measurement ever made on AM broadcast antenna
arrays. You should be very proud that hundreds of engineers and their
measurements were wrong.

Again, congratulations.

tom
K0TAR

Standing waves
 

On Sep 22, 8:32*pm, tom wrote:
Dave wrote:
Yes. But antennas are in resonance.
S*

antennas don't have to be 'in resonance'.... a very short dipole
radiates almost as well as one 1/2 wavelength long... its all in the
fields.

As I tried to make Art understand with respect to yagis, it's not
necessarily resonant (or even usually), it's matched. *By the matching
network.

It was like releasing excess nitrogen containing waste into the wind,
like all things are with Art.

See wall, hit with head, repeat.

tom
K0TAR

And you think I didn't know that like it was a personal secret of
yours?
I don't even remember discussing yagis with you. I moved away from
those years ago when I was building antennas with 80 foot booms and a
dozen or more elements all made of fishing poles with aluminum foil
surfaces. Now I am interested in antennas the size that Chip works
with but not with the same aproach. In fact I am committed to having
antennas made that are small enough for those with small gardens to
use, where how much money or land that you have allow you to run over
others is not a measure of ones skills. As for you you just sit on the
side lines with nothing to offer but insults since you appear to live
alone berift of friends. Try smiling instead of just growling and get
a life.

Standing waves
 

On Sep 22, 8:47*pm, tom wrote:
Art Unwin wrote:
So you are back David ! have you built that four poster antenna yet,
of steel I presume,
for the top band? Hopefully the system of yours is in a state of
equilibrium so you can tell us good things about it. Did you have to
make a ground plane system? They are not needed for a system in
equilibrium

Wow! *No ground system needed for top band. *The AM broadcasters are
going to be all over this. *Art, you are about to become very very rich..
* This overturns every measurement ever made on AM broadcast antenna
arrays. *You should be very proud that hundreds of engineers and their
measurements were wrong.

Again, congratulations.

tom
K0TAR

No congratulations necessary. The methods will be available to all
amateurs when the PTO print out comes about. All of this represents a
different aproach than that taken before me. If it is 90 % in error
where only 10% is useful that's fine by me as it represents an advance
supplied by an amateur who wasn't detered from experimenting by
others.
If I feel that something that is taken for granted is in error just
because an author had it printed in a book I will always step forward
if I feel the emperer does not wear any clothes.
Which of you have the courage to stand along side me knowing full well
your character will be dismantled before the true facts become known?

Standing waves
 

On Tue, 22 Sep 2009 18:12:09 -0700 (PDT), Art Unwin
wrote:

Yes, some university libraries allow access to the public but not for
copies. These must
come from journals at quite high prices. Here you can be a member of a
professional society say IEEE but to get the journals of say antennas
and propagation then you must pay a couple of $100 to have access to
them. This is on top of the fees for the institution and the group
that you are personally a member of which also requires fees.

Ummm... IEEE full membership is now $175/year. Membership in the
Antennas and Progagation group is $24/year.
http://www.ieee.org/web/membership/Cost/dues.html
That's about 4000 pages for the extra $24.

If you are a retired former IEEE member, currently unemployed,
disabled, or are working for only peanuts or stock options, you can
get up to a 50% discount on dues.
http://www.ieee.org/web/membership/Cost/special_circumstances.html

You can see the articles in each past issue at:
http://ieeexplore.ieee.org/xpl/RecentIssue.jsp?puNumber=8

If you're a cheap tightwad non-member, like me, you can buy individual
articles ala carte for $29 each:
http://ieeexplore.ieee.org/guide/g_tools_apo.jsp

If you don't mind just older papers, a member can buy the DVD with
everything from AP-S from 1952-2000:
http://www.ict.csiro.au/aps/cdrom.htm
for $100.

If you're a non-member, you really pay hansomly for the printed
publications.
http://www.ieee.org/portal/cms_docs_iportals/iportals/publications/subscriptions/info/IEEE_Sub_Price_List_2010.pdf
For example, the Antenna and Propagation IEEE Transactions for a year
(12 issues) costs $1,200.



--
Jeff Liebermann
150 Felker St #D http://www.LearnByDestroying.com
Santa Cruz CA 95060 http://802.11junk.com
Skype: JeffLiebermann AE6KS 831-336-2558

Standing waves
 

"Richard Clark" wrote
...

I'm glad to see you shed that nonsense about hydraulics. As you
understood that topic far less than RF (which is in itself on very
shaky ground), it wouldn't have done to poison the well.

This poor understanding is quite obvious by your last comment above.

I was absent. You wrote:
"All is exactly the same like in the fluids mechanics.

"Exactly" makes it very, very easy to show how an analogy fails:
Describe the laminar flow in terms of
the Reynolds number for
the interface between RF and a Biconical Antenna
and
the interface between RF and a thin wire Antenna."

Maxwell's math is the same as for fluid:

"Maxwell's equations are simply a re-arrangement of relationships worked
out by Faraday in respect of charge and only verified at low speed.
Maxwell discovered that the relationships could be arranged in a form
which mirrored the mathematical description of a fluid"

In fluid are whirls. The magnetic field is like whirl. But not for all
scientists.
"Maxwell's equations" were wrote by Heaviside.
S*

Standing waves
 

"Dave" wrote
...

"Szczepan Bialek" wrote in message
...

In the Gas Analogy the monopole antena is exactly like the Kundt's
tube.


antennas don't have to be 'in resonance'.... a very short dipole radiates
almost as well as one 1/2 wavelength long... its all in the fields.

In my antenna radiate the end where the voltage is doubled. In your
something alse. What?
S*

Standing waves
 

"Richard Fry" wrote
...
On Sep 22, 3:34 am, Szczepan Bia³ek wrote:

Up to now the acoustic analogy is fully applicable.

Not if one understands the physics of radiation.

Physics of radiation is unknown. Antennas are the nice apparatus to analyse
it.

But it is experimentally proved. Stationary charge - electric field,
Moving charge - magnetic field.

Untrue, and I challenge you to cite any credible experimental data
that you think proves your belief.

Far-field EM radiation is produced only by the current flow on the
antenna, and that radiation contains BOTH the electric and the
magnetic fields.

For me the magnetic field is the illusion.

You may have missed the accurate description posted by Chris, and
pasted below.

"The acceleration of charge in an antenna results almost entirely from
the
applied potential difference at its terminals. The radiated fields
result
from the alternating current effectively passing through the radiation
resistance, and all the other, reactive, fields have no direct effect
on the
radiation resistance, or the component of the current that passes
through it
in phase with the voltage that is developed across it, which together,
of
course, represent the radiated power. The reactive fields affect the
terminal impedance and a large imaginary part can upset the device
trying to
send power into the antenna, but that is more of a system issue. The
alternating current that passes through the radiation resistance is
composed
of charge that moves in time with each RF cycle, accelerating and
decelerating accordingly. The electrostatic field developed between
the
ends of a half-wave dipole reaches its maximum value a quarter of a
cycle
later than the voltage at the drive point so any effect it has on the
charge
in the antenna elements during each cycle must be reactive, and it
doesn't
affect the radiation resistance or the radiated wave."

My description is shorter:
The supply unit sends the voltage pulses (in opposite phase) in the
transmissing line. If such pulses collide the voltage is doubled and the
strong radiation take place. In straight radiator the forward pulse collides
with the reflected. In folded dipoles with that from the other wire.
S*

Standing waves
 

"Cecil Moore" wrote
...
Szczepan Bia³ek wrote:
Each dipole antenna radiate two times the applied frequency, ...

Sorry, 2*sin(2wt) sin(wt)

Here's the question: Is the radiated RF wave in phase
with the standing wave current or in phase with the
standing wave voltage? The radiated RF wave cannot be
in phase with both since they are 90 degrees out of
phase on the standing wave antenna.

In the Gas analogy radiate only the doubled voltage. The doubling take place
in the ends of the two radiators. The two spherical waves are radiated. So
some receiver antennas can work on doubled frequency (Luxembourg effect).
S*

Standing waves
 

"Richard Fry" wrote
...
On Sep 22, 1:44 pm, Szczepan Bia³ek wrote:
If what you are saying were really happening,
an antenna would radiate two times the applied frequency,
but it obviously doesn't.

We do not have the both. But we have the Luxembourg effect. Each dipole
antena radiate two times the applied frequency, The pulses from the ends
are 180 degrees apart.

So then, Szczepan, should transmissions using such antennas, and
expecting to be received on frequency "X" transmit on frequency "X" /
2 ? Note that such is not the reality.

It happened in 1930. The Luxembourg LW were received on MW radio sets.

Some low-level radiation from the transmit antenna may exist at twice
the carrier frequency, but in almost all cases it arises from
insufficient suppression of the 2nd harmonic of, and in the
transmitter.

The Luxembourg effect is only possible if the both ends of the dipole are
"visible". The mast was on the tip top.

And in NO case is it produced as you describe above.

It is easy to check. Now no vertical LW masts. But everybody has a
horizontal dipole.
S*

Standing waves
 

"Richard Fry" wrote
...
On Sep 22, Szczepan Bia³ek wrote:

But what radiate in 0.05WL dipole? There the
"maximum radiation" is in the transmission line (1/4WL from the end).
The feed point is also in the transmissing line.

Then later the same day he wrote:

The feed point is the part of the transmissing line and not radiate.

Pick one of the above comments, only, Szczepan.

The feed points are terminals of the antenna. On center-fed dipoles
that are 1/2WL or less in length, antenna current is highest at those
terminals.

Highest antenna current do not means high enough to radiate. The high
current is in transmissing line of the short antennas.
In 0.05 no currents at all at the feed point.

How long are the folded dipoles and the
loop antennas? Are there the short version?

They can be any length, but some lengths have better input
characteristics and/or more useful radiation patterns than others.

Are a loop antennas 0.05WL?
S*

Standing waves
 

tom wrote:
Note that none of these are particularly close to resonance at the
design frequency.

Yagis do have a resonant frequency but that frequency
is not at the design frequency. At the resonant frequency,
the forward gain and F/B ratio are not optimum. At the
optimum forward gain frequency and/or F/B ratio frequency,
the Yagi, sans matching network, is not resonant.
--
73, Cecil, IEEE, OOTC, http://www.w5dxp.com

Standing waves
 

Art Unwin wrote:
On top of that, all the antennas that you point to could all be made
resonant in the right type of environment.

Point is, the Yagi radiation pattern sucks at the resonant
frequency, f(r). When one meets the designed-for radiation
pattern, i.e. gain, F/B ratio, beamwidth, etc., the Yagi is
NOT resonant at the design frequency.
--
73, Cecil, IEEE, OOTC, http://www.w5dxp.com

Standing waves
 

On Sep 23, 6:05*am, Szczepan Bia³ek wrote:

The Luxembourg effect is only possible if the both ends of the dipole are
"visible". The mast was on the tip top.

The Luxemburg effect is not produced by a dipole.

It has been ascribed to be produced in the ionosphere when two very
strong EM waves cross-modulate. More likely it occurs when co-
located, high power transmitters cross-modulate in their output stages
due to coupling between their antennas.

Now no vertical LW masts. But everybody has a
horizontal dipole.

A horizontal dipole produces horizontally polarized EM radiation,
which has very high propagation loss for the ground wave.

For this reason vertical polarization is universally used for LW and
MW signals.

RF

Standing waves
 

Cecil Moore wrote:
tom wrote:
Note that none of these are particularly close to resonance at the
design frequency.

Yagis do have a resonant frequency but that frequency
is not at the design frequency. At the resonant frequency,
the forward gain and F/B ratio are not optimum. At the
optimum forward gain frequency and/or F/B ratio frequency,
the Yagi, sans matching network, is not resonant.

Agreed, although it has become popular to make designs with about 50+j0
driven elements lately. I think it's to make them simpler and lighter
because, as you say, the other characteristics are not optimum if you do.

tom
K0TAR

Standing waves
 

Szczepan Bia³ek wrote:
In my antenna radiate the end where the voltage is doubled. In your
something alse. What?

Unfortunately, the voltage doubling is accompanied by
transmission line currents at the ends of the antenna
which are known not to radiate. The reason is obvious.

When two currents are equal in magnitude and opposite
in phase, they do not radiate (much) because their fields
engage in destructive interference. These currents
are commonly known as transmission line currents but
also exist at the ends of a dipole as forward and
reflected currents.

When the phases of two currents are equal they engage
in constructive interference and radiate. These currents
are commonly known as antenna currents and exist at
the middle of a dipole that is equal to or less than
0.5WL long.

Unfortunately for your theory, since the standing wave
voltage is ~90 degrees out of phase with the standing
wave current (in standing wave antennas), the higher
the standing wave voltage the greater the destructive
interference between the forward and reverse currents,
i.e. the higher the voltage, the lower the radiation.

Sorry, but that is a simple fact of physics. If you
want the ends of a dipole to radiate, you need to
terminate those ends in the characteristic impedance
of the antenna in order to prevent transmission line
currents on the antenna.

If one models a 1/2WL dipole with the center 1/4WL part
horizontal and the 1/8WL ends vertical, one will get
a magnitude more horizontal radiation from the center
half of the antenna than vertical radiation from the
vertical half of the antenna. That's easy proof that the
center of a 1/2WL dipole radiates more than the ends.
The vertical radiation is 10 dB down from the horizontal
radiation even though equal lengths of horizontal and
vertical wire exists. Is EZNEC wrong?

Running the above dipole at double the frequency
results in equal currents in each 1/8WL of antenna and
indeed, the vertical radiation equals the horizontal
radiation.
--
73, Cecil, IEEE, OOTC, http://www.w5dxp.com

Standing waves
 

On Sep 23, 6:14*am, Szczepan Bia³ek wrote:

Highest antenna current do not means high enough to radiate. The high
current is in transmissing line of the short antennas.
In 0.05 no currents at all at the feed point.

If there is no current at the feedpoint terminals of a 0.05WL dipole
then there is no current anywhere else in it, and there would be no
radiation. Obviously that is not the reality.

The current distribution in such short dipoles is triangular in form:
highest at the center, and zero at the ends of the dipole arms.

RF

Standing waves
 

On Tue, 22 Sep 2009 16:59:19 -0700 (PDT), Art Unwin
wrote:

On Sep 22, 5:30*pm, Registered User wrote:
On Tue, 22 Sep 2009 13:24:17 -0700 (PDT), Art Unwin

wrote:

Well look at how salvage yards sort out metals into different
enclosures.
They apply a displacement current *to a conveyor where each piece of
metal is elevated with spin such that it lands in the appropriate
enclosure which is dependent on the resistivity of the metal elevated.

This isn't exactly how such systems work. Abstractly the system is a
metal detector and a sorting table hanging off a CAN. A controller at
the other end of the CAN 'reads' the discriminator and 'writes' to the
sorter. The writes open and close ejector nozzles. These are the magic
devices that cause the material to 'elevate with spin'.

This method of elevating scrap for recovery has been used for years
and it is the same action that is applied to particles for radiation.
Why would you need a citation for a practice that is well known and in
use?

Because you might be wishing your agenda into how you propose things
work. Who'da thunk that!

Interesting. Can you point to an article or something on the web that
describes what you
say. For myself I have only run into articles by special purpose
machine manufacturers
who deal with sorting machines for scrap yards which deals with many
materials including plastics , glass etc as well as different metallic
materials. This sorting aproach that you mention sounds rather
interesting if they are relying on magic or voodoo!

There is no magic or voodoo involved with a controller area network.

There are all manners of industrial separators and practically all are
custom purposed for the user and the particular type of refuse
stream(s) they will be dealing with. It's certainly not a
one-size-fits-all industry. Most use a combination of methodologies.
Magnetic eddy currents are one means and their use in the industry
only goes back a couple of decades.

In a nutshell here is how eddy currents are primarily used in
materials sorting.

As the eddy current roller spins it creates alternating polar fields.
When inert (non-metallic) material enters a field a field of the same
charge is generated around the object. As the roller spins the next
field is of opposite charge to the field of the object and the object
is repulsed. The momentum provided by the conveyor belt added to the
repulsive force changes the trajectory of the object as it leaves the
end of the conveyor belt. As a consequence inert objects travel
further off the end of the belt.

Non-ferrous metals do not benefit from a charged field and fall
straight down due to good old gravity. Ferrous metals are attracted to
the roller and remain on the conveyor belt until they move past the
roller on the underside of the table. Then those materials also fall
straight down but at a different location from the non-ferrous metals.

http://tinyurl.com/meo9py

Standing waves
 

On Wed, 23 Sep 2009 12:13:33 +0200, Szczepan Bia?ek
wrote:

"Exactly" makes it very, very easy to show how an analogy fails:
Describe the laminar flow in terms of
the Reynolds number for
the interface between RF and a Biconical Antenna
and
the interface between RF and a thin wire Antenna."

We've already determined you don't know how to do this, and that you
don't have the vaguest idea.

My guess is that you don't even understand the few simple terms in the
quote above. Can you tell us what laminar means? How about
interface? Your response is wholly devoid of their discussion, so I
suppose you cannot except to quote someone else - unfortunately that
does not reveal knowledge.

If you cannot give us a Reynolds number (something like any mechanical
engineer like Art can do - well, yes, I admit that is an unwarranted
presumption on my part), then you may as well let your boat drift on.

73's
Richard Clark, KB7QHC

Standing waves
 

On Wed, 23 Sep 2009 07:16:49 -0500, tom wrote:

Cecil Moore wrote:
tom wrote:
Note that none of these are particularly close to resonance at the
design frequency.

Yagis do have a resonant frequency but that frequency
is not at the design frequency. At the resonant frequency,
the forward gain and F/B ratio are not optimum. At the
optimum forward gain frequency and/or F/B ratio frequency,
the Yagi, sans matching network, is not resonant.

That's about as useful as saying you do not obtain the maximum miles
per gallon in your car when the ashtray is half full or when the
carpets are at their optimal brushed out nap.

73's
Richard Clark, KB7QHC

Standing waves
 

On Tue, 22 Sep 2009 23:59:59 -0700, Jeff Liebermann
wrote:

For example, the Antenna and Propagation IEEE Transactions for a year
(12 issues) costs $1,200.

Or you can go to the library and read (and copy) them for free.

Oh, and yes, If you have access to an engineering library on campus.

Oh, and yes, if they let you back on campus..... Sorry, some (Art)
have spit on too many professors.

73's
Richard Clark, KB7QHC

Standing waves
 

On Sep 23, 9:38*am, Registered User wrote:
On Tue, 22 Sep 2009 16:59:19 -0700 (PDT), Art Unwin



wrote:
On Sep 22, 5:30*pm, Registered User wrote:
On Tue, 22 Sep 2009 13:24:17 -0700 (PDT), Art Unwin

wrote:

Well look at how salvage yards sort out metals into different
enclosures.
They apply a displacement current *to a conveyor where each piece of
metal is elevated with spin such that it lands in the appropriate
enclosure which is dependent on the resistivity of the metal elevated..

This isn't exactly how such systems work. Abstractly the system is a
metal detector and a sorting table hanging off a CAN. A controller at
the other end of the CAN 'reads' the discriminator and 'writes' to the
sorter. The writes open and close ejector nozzles. These are the magic
devices that cause the material to 'elevate with spin'.

This method of elevating scrap for recovery has been used for years
and it is the same action that is applied to particles for radiation.
Why would you need a citation for a practice that is well known and in
use?

Because you might be wishing your agenda into how you propose things
work. Who'da thunk that!

Interesting. Can you point to an article or something on the web that
describes what you
say. For myself I have only run into articles by special purpose
machine manufacturers
who deal with sorting machines for scrap yards which deals with many
materials including plastics , glass etc as well as different metallic
materials. This sorting aproach that you mention sounds rather
interesting if they are relying on magic or voodoo!

There is no magic or voodoo involved with a controller area network.

There are all manners of industrial separators and practically all are
custom purposed for the user and the particular type of refuse
stream(s) they will be dealing with. It's certainly not a
one-size-fits-all industry. Most use a combination of methodologies.
Magnetic eddy currents are one means and their use in the industry
only goes back a couple of decades.

In a nutshell here is how eddy currents are primarily used in
materials sorting.

As the eddy current roller spins it creates alternating polar fields.
When inert (non-metallic) material enters a field a field of the same
charge is generated around the object. As the roller spins the next
field is of opposite charge to the field of the object and the object
is repulsed. The momentum provided by the conveyor belt added to the
repulsive force changes the trajectory of the object as it leaves the
end of the conveyor belt. As a consequence inert objects travel
further off the end of the belt.

Non-ferrous metals do not benefit from a charged field and fall
straight down due to good old gravity. Ferrous metals are attracted to
the roller and remain on the conveyor belt until they move past the
roller on the underside of the table. Then those materials also fall
straight down but at a different location from the non-ferrous metals.

http://tinyurl.com/meo9py

Thank you for confirming the use of eddy currents in the elevation and
projection of scrap materials. My understanding is that the special
purpose machinery industry has now advanced to the ability of sorting
plastic and the like.

Standing waves
 

"Richard Clark" wrote
...
On Wed, 23 Sep 2009 12:13:33 +0200, Szczepan Bia?ek
wrote:

"Exactly" makes it very, very easy to show how an analogy fails:
Describe the laminar flow in terms of
the Reynolds number for
the interface between RF and a Biconical Antenna
and
the interface between RF and a thin wire Antenna."

We've already determined you don't know how to do this, and that you
don't have the vaguest idea.

My guess is that you don't even understand the few simple terms in the
quote above. Can you tell us what laminar means? How about
interface? Your response is wholly devoid of their discussion, so I
suppose you cannot except to quote someone else - unfortunately that
does not reveal knowledge.

If you cannot give us a Reynolds number (something like any mechanical
engineer like Art can do - well, yes, I admit that is an unwarranted
presumption on my part), then you may as well let your boat drift on.

I have onmy shelf the Fluid dynamics by Dr Ludwig Prandtl. Prandtl is a big
name.
S*

Standing waves
 

On Wed, 23 Sep 2009 19:17:19 +0200, Szczepan Bia?ek
wrote:

If you cannot give us a Reynolds number (something like any mechanical
engineer like Art can do - well, yes, I admit that is an unwarranted
presumption on my part), then you may as well let your boat drift on.

I have onmy shelf the Fluid dynamics by Dr Ludwig Prandtl. Prandtl is a big
name.

Too big to comprehend?

73's
Richard Clark, KB7QHC

Standing waves
 

"Cecil Moore" wrote
...
Szczepan Bia³ek wrote:
In my antenna radiate the end where the voltage is doubled. In your
something alse. What?

Unfortunately, the voltage doubling is accompanied by
transmission line currents at the ends of the antenna
which are known not to radiate. The reason is obvious.

When two currents are equal in magnitude and opposite
in phase, they do not radiate (much) because their fields
engage in destructive interference. These currents
are commonly known as transmission line currents but
also exist at the ends of a dipole as forward and
reflected currents.

When the phases of two currents are equal they engage
in constructive interference and radiate. These currents
are commonly known as antenna currents and exist at
the middle of a dipole

In the middle of todays dipole is the air. Current was in the Hertz'
apparatus.

that is equal to or less than
0.5WL long.

Unfortunately for your theory, since the standing wave
voltage is ~90 degrees out of phase with the standing
wave current (in standing wave antennas), the higher
the standing wave voltage the greater the destructive
interference between the forward and reverse currents,
i.e. the higher the voltage, the lower the radiation.

In one antenna can be only one mechanism.
In my antenna the current radiation is very weak.

Sorry, but that is a simple fact of physics. If you
want the ends of a dipole to radiate, you need to
terminate those ends in the characteristic impedance
of the antenna in order to prevent transmission line
currents on the antenna.

Doubled voltage do the work. Current not.

If one models a 1/2WL dipole with the center 1/4WL part
horizontal and the 1/8WL ends vertical, one will get
a magnitude more horizontal radiation from the center
half of the antenna than vertical radiation from the
vertical half of the antenna. That's easy proof that the
center of a 1/2WL dipole radiates more than the ends.
The vertical radiation is 10 dB down from the horizontal
radiation even though equal lengths of horizontal and
vertical wire exists. Is EZNEC wrong?

Radiation depends on the shape of the ends. Thin vertical wire radiate in
horizontal plane. Tipped (big ball) vertical wire omnidirectional.

Running the above dipole at double the frequency
results in equal currents in each 1/8WL of antenna and
indeed, the vertical radiation equals the horizontal
radiation.

Look at the Kundt's tube. At doubled frequency in the horizontal parts the
new sources (doubled voltage) appear.
The sources on the horizontal wires radiate in all direstion perpendicular
to the wires.

S*

Standing waves
 

On Wed, 23 Sep 2009 08:25:12 -0700, Richard Clark
wrote:

On Tue, 22 Sep 2009 23:59:59 -0700, Jeff Liebermann
wrote:

For example, the Antenna and Propagation IEEE Transactions for a year
(12 issues) costs $1,200.

Or you can go to the library and read (and copy) them for free.

The local Santa Cruz libraries are in serious financial trouble. The
main library has severely limited hours, while the satellite branches
are only open two to five days per week.
http://www.santacruzpl.org/news/2009/jun/09/new-hours-all-branches-effective-july-1-2009/
None of the local libraries stock IEEE AP-S Transactions.

Oh, and yes, If you have access to an engineering library on campus.

I joined the UCSC "Friends of the Library" association in order to
obtain an account. $35 to $60/year.
http://giving.ucsc.edu/giving_detail.php?web_id=631
Most IEEE Transactions are available online from off campus.
http://library.ucsc.edu/gateways/gateways-for-visitors-and-neighbors
Most colleges have similar arrangements. I would also join my alumni
association (Cal Poly, Pomona), which offers similar privileges, but
find the local college more convenient. However, there's a catch.
Most of the online IEEE AP-S Transactions are about a year or more
behind. The various libraries seem to prefer annual subscriptions,
which means most recent issues are often unavailable. If that
happens, I either pay the price of the download (only if desperate),
or borrow an issue from a friend with a subscription.

Oh, and yes, if they let you back on campus..... Sorry, some (Art)
have spit on too many professors.

Most of the stuff is available online. No need to visit the campus.
However, when I do, the real problem is parking. There isn't much
available. Going to the UCSC library is a major expedition for me.

I suspect that Art will be ok at a library, as long as he doesn't
bring his soap box and attract attention by loudly denouncing the
content of the physics, antenna design, or grammar books.



--
Jeff Liebermann
150 Felker St #D http://www.LearnByDestroying.com
Santa Cruz CA 95060 http://802.11junk.com
Skype: JeffLiebermann AE6KS 831-336-2558

Standing waves
 

On Wed, 23 Sep 2009 10:41:38 -0700, Jeff Liebermann
wrote:

I joined the UCSC "Friends of the Library" association in order to
obtain an account. $35 to $60/year.
http://giving.ucsc.edu/giving_detail.php?web_id=631

I went to re-join. Now it's $75/year.
http://library.ucsc.edu/giving/friends/friends-of-the-library-membership-benefits
Sigh...



--
Jeff Liebermann
150 Felker St #D http://www.LearnByDestroying.com
Santa Cruz CA 95060 http://802.11junk.com
Skype: JeffLiebermann AE6KS 831-336-2558

Standing waves
 

"Richard Fry" wrote
...
On Sep 23, 6:05 am, Szczepan Bia³ek wrote:

The Luxembourg effect is only possible if the both ends of the dipole are
"visible". The mast was on the tip top.

The Luxemburg effect is not produced by a dipole.

It was the vertical 1/2WL dipole. The doubled frequency was received in
England (I am not sure).
The same was in Warsaw (but collapsed - now is the monopole mast 1/4WL). The
doubled frequency was received in Austria.


It has been ascribed to be produced in the ionosphere when two very
strong EM waves cross-modulate. More likely it occurs when co-
located, high power transmitters cross-modulate in their output stages
due to coupling between their antennas.

Now you have my description. Which one do you prefer?

Now no vertical LW masts. But everybody has a
horizontal dipole.

A horizontal dipole produces horizontally polarized EM radiation,
which has very high propagation loss for the ground wave.

For this reason vertical polarization is universally used for LW and
MW signals.

Are now vertical dipole masts 1/2WL?

Frequency doubling is at all waves. To observe the frequency doubling the
both ends must have the same possibilities. The vertical dipoles have ends
on difeferent altitudes.
S*

Standing waves
 

Richard Clark wrote:
That's about as useful as saying you do not obtain the maximum miles
per gallon in your car when the ashtray is half full or when the
carpets are at their optimal brushed out nap.

Nope, it's as useful as saying one cannot get the
advertised miles per gallon when one is driving
the car uphill at 80 mph. Miles per gallon is
related to incline and speed. Frequency, gain,
and F/B ratio are related. I surprised you don't
know that.
--
73, Cecil, IEEE, OOTC, http://www.w5dxp.com

Standing waves
 

"Richard Fry" wrote
...
On Sep 23, 6:14 am, Szczepan Bia³ek wrote:

Highest antenna current do not means high enough to radiate. The high
current is in transmissing line of the short antennas.
. In 0.05 no currents at all at the feed point

If there is no current at the feedpoint terminals of a 0.05WL dipole
then there is no current anywhere else in it, and there would be no
radiation. Obviously that is not the reality.

The simplest dipole is a transmissing line (the two wires).The standing
waves are always 1/2WL apart. The max current is always 1/4WL from the
standing waves. " In 0.05 no currents at all at the feed point" means, of
course, that the current is very very small.

The current distribution in such short dipoles is triangular in form:
highest at the center, and zero at the ends of the dipole arms.

No such oddity in the reality.
S*

Standing waves
 

On Wed, 23 Sep 2009 10:41:38 -0700, Jeff Liebermann
wrote:

Oh, and yes, if they let you back on campus..... Sorry, some (Art)
have spit on too many professors.

Most of the stuff is available online. No need to visit the campus.
However, when I do, the real problem is parking. There isn't much
available. Going to the UCSC library is a major expedition for me.

Hi Jeff,

For me, its a short ride on one bus. I'm on campus twice a week. As
an Alumni, I get library privileges.

I suspect that Art will be ok at a library, as long as he doesn't
bring his soap box and attract attention by loudly denouncing the
content of the physics, antenna design, or grammar books.

He would be lost in the din of the LaRouche crowd (although he might
fit in with them their Coriolis politics).

73's
Richard Clark, KB7QHC

Standing waves
 

On Sep 23, 1:12*pm, Szczepan Bia³ek wrote:

" In 0.05 no currents at all at the *feed point" means, of
course, that the current is very very small.

However small it is, it is still the greatest current value that
exists on that dipole.

RF wrote:
The current distribution in such short dipoles is triangular in form:
highest at the center, and zero at the ends of the dipole arms.

S* answered:
No such oddity in the reality.

No matter how short a dipole antenna is in wavelengths, current is
always zero at the ends of each arm of that dipole.

The current distribution on a thin, wire dipole takes the form of a
sine wave. If the antenna is short, as in this case, then the only
part of the sine that can exist is nearly linear. Hence the
~triangular shape for the total current on the dipole.

Confirm this for yourself using Figure 2-2(b) on page 2-4 of the
following link.

http://books.google.com/books?id=xTS... tenna&f=false

RF

Standing waves
 

On Sep 23, 12:41*pm, Jeff Liebermann wrote:
On Wed, 23 Sep 2009 08:25:12 -0700, Richard Clark
wrote:

On Tue, 22 Sep 2009 23:59:59 -0700, Jeff Liebermann
wrote:

For example, the Antenna and Propagation IEEE Transactions for a year
(12 issues) costs $1,200.

Or you can go to the library and read (and copy) them for free. *

The local Santa Cruz libraries are in serious financial trouble. *The
main library has severely limited hours, while the satellite branches
are only open two to five days per week.
http://www.santacruzpl.org/news/2009/jun/09/new-hours-all-branches-ef...
None of the local libraries stock IEEE AP-S Transactions.

None of the public libraries in Illinois stock them either





Oh, and yes, If you have access to an engineering library on campus.

I joined the UCSC "Friends of the Library" association in order to
obtain an account. *$35 to $60/year. *

Now that is interesting!
Visitors can only get on line if the University have them on their
list as being invited
Time period 45 days. I understand that you can't get copies because of
copywrite laws and oversite by the societies so I assume they get
freebees.
There is some pressure on lab schools to place results on the web
since it is public money. The Governor signed a bill a little while
ago on transparency as to where the money goes
But then nobody actually follow all the laws in Chicago and down
state.


http://giving.ucsc.edu/giving_detail.php?web_id=631
Most IEEE Transactions are available online from off campus.
http://library.ucsc.edu/gateways/gateways-for-visitors-and-neighbors
Most colleges have similar arrangements. *I would also join my alumni
association (Cal Poly, Pomona), which offers similar privileges, but
find the local college more convenient. *However, there's a catch.
Most of the online IEEE AP-S Transactions are about a year or more
behind. *The various libraries seem to prefer annual subscriptions,
which means most recent issues are often unavailable. *If that
happens, I either pay the price of the download (only if desperate),
or borrow an issue from a friend with a subscription.

Oh, and yes, if they let you back on campus..... *Sorry, some (Art)
have spit on too many professors.

Most of the stuff is available online. *No need to visit the campus.
However, when I do, the real problem is parking. * There isn't much
available. *Going to the UCSC library is a major expedition for me.

I suspect that Art will be ok at a library, as long as he doesn't
bring his soap box and attract attention by loudly denouncing the
content of the physics, antenna design, or grammar books.

--
Jeff Liebermann * *
150 Felker St #D * *http://www.LearnByDestroying.com
Santa Cruz CA 95060http://802.11junk.com
Skype: JeffLiebermann * * AE6KS * *831-336-2558