Szczepan Bia³ek wrote:

For practical engineers the math theory is useless.

But for real engineers math is everything. If you can't back it up with
figures, you're only guessing.

tom
K0TAR

Dave wrote:

predicting the properties of something that is impossible to make is
impossible.

Egad, not at all.

The elements we use in circuit analysis, for example -- pure
resistances, capacitances, inductances, sources, and so forth -- are all
impossible to make. Yet we know their properties in exacting detail. One
cannot cut a stick to a length of exactly pi meters, yet the properties
of pi are precisely known. For that matter, we can't even make a stick
that's exactly one meter long, but the meter is very well defined.

Those are just a very few of the vast number of things which are
impossible to make yet whose properties are known. Math, science and
engineering wouldn't be possible without them.

Roy Lewallen, W7EL

On Mon, 07 Sep 2009 16:27:40 -0400, Mike Coslo wrote:

What is old is new again - the alchemists were right!

Hi Mike,

Of late, I have been reading Herman Melville's "The Confidence Man." I
won't go into the plot (it strained the conventions of the day -
1850s) but mention one vignette where a kid was hustling two gentlemen
on a river boat on the Mississippi. When the kid struck a deal, he
sweetened it with a pamphlet on how to recognize counterfeit paper
money.

It seems that pamphlets like this wete very necessary back when any
bank could print their own bills (something like the great hornswaggle
of Wall Street). The banks then had to print pamphlets on how to
recognize the exquisite detail work of engraving on their bills so you
would recognize the 'real stuff.'

What is interesting is that the counterfeiters wrote their own
pamphlets too, describing the exquisite details in their engraving....

73's
Richard Clark, KB7QHC

"christofire" wrote
...

"Szczepan Bia³ek" wrote in message
...

"christofire" wrote
...

"Dave" wrote in message
news
"Szczepan Bialek" wrote in message
...
Take a rest in reading and look at the oryginal Hertz apparatus as the
two sources of longitudinal waves (radiated from ends). You should see
the Luxembourg effect (frequency doubling) and directional pattern.
S*

but you don't because that is not how it works. the waves are radiated
by the whole length of the connecting wire and are transverse... there
is no frequency doubling as you explain it.

... and the so-called 'Luxembourg effect' is not frequency doubling but
cross modulation; that is, generation in the ionosphere of
intermodulation products that carry the modulation of both sources.

So you should be able to repeat the phenomena. Richard did not: " I
worked four years in a European shortwave
broadcast station and I don`t remember any frequency doubling but we
aspired to hit the ionosphere with enough power to drive it into extreme
nonlinearity end impose our signal en all the others in the area ala
Luxembourg."

Help him.
S*


Huh?

What Richard wrote means he didn't encounter frequency doubling but he did
try to cause cross modulation, as in the 'Luxembourg effect'.

In the 'Luxembourg effect' was the frequency doubling. The LW were receiwed
as the MW.


What I wrote doesn't conflict with that.

Perhaps it's a language difficulty on your part.

"the waves are radiated by the whole length of the connecting wire and are
transverse... there is no frequency doubling as you explain it."
You prefer the cross modulation - I prefer the two sources.
S*

"tom" wrote
. net...
Szczepan Bia³ek wrote:

For practical engineers the math theory is useless.

But for real engineers math is everything. If you can't back it up with
figures, you're only guessing.

The figures are also in empiric equations. Engineers use only such.
S*

"christofire" wrote
...

"Szczepan Bia³ek" wrote in message
...

-- snip --

Do you know somebody who has more proven reputation in acoustic and
electrodynamics than Helmholtz?


* Yes: the late John D Kraus. He was a practical engineer as well as a
theoretician and his native language was English. He managed to put
into practice a lot of the theory that others had written about and he
recorded his work lucidly. I've already named two of Kraus's books -
can you cite something written by any of your favourites that provides
clear explanations that you understand? Answers.com doesn't explain
anything technical.

For practical engineers the math theory is useless.

* No, that's quite wrong. Practical engineers use mathematics a great
deal.

They make calculations using empirical equations.

Amateurs may not, but they're not all engineers. To make a statement like
that it would appear you have never worked successfully as a practical
engineer using the conventional definition of 'engineer': a person trained
in any branch of engineering.

It si very funny to read this. Todays engineers use the Ampere,Gauss, Weber
Electrodynamisc but are sure that they use the Maxwell's.


* Heaviside's documentation is appaling! I remember going through a
catalogue of his work in an effort to get to the truth about the origin
of the 'Heaviside condition' - a lot of it was written in obfuscation
babble, a bit like some of the contributors to this group.

He is the father of the hydraulic analogy where the electricity is the
incompressble masless flud.
Electrons in antenns are compressible and have mass. What is electricity
in J. D. Kraus?

* It's the passage of charge through conductors, the same as it is
everywhere else, of course. Compressibilty of electrons doesn't feateure
in any of Kraus's books that I've read, which must mean it is not a
necessary concept for normal, physical, antennas and propagation.

He use (probably) the term voltage. Voltage is the same as pressure or the
electron density. Is the voltage the necessary concept or no?
And what about the mass of electrons in the books?

* What 'two loudspeaker'? If you're drawing comparison between a
direct-radiator loudspeaker and a dipole and using that as a basis for
saying that EM waves are longitudinal, as I suspect you are, then you
should also consider a horn loudspeaker. Sound is radiated from the
mouth of a horn 'speaker and the other side of the compression driver
diaphragm can be totally enclosed. There is no simple comparison with
a dipole antenna in this case.

The horn is a monopole. See:
http://paws.kettering.edu/~drussell/Demos/rad2/mdq.html
The unboxed loudspeaker is a dipole.

* Why don't you look into horn louspeakers and then report back. You
may find them fascinating and very unlike dipoles.

Like fascinating is the two monopoles antennas (your dipoles).
S*

* You claimed that EM waves are longitudinal,
Not me. It is Helmholtz and many others.

like sound waves, and you used some comparison between a loudspeaker and a
dipole as justification. So now you understand that not all loudspeakers
behave that way ... so what? Do you still believe EM waves are
longitudinal or have you changed your mind? If you believe Dan Russell
then where on his site does he state that EM waves are longitudinal? Of
course, he doesn't.

Dan Russel do not state enything about EM. EM waves will be always
transversal because such we assumed before writting the math. Real electric
waves radiated by one monopole end two monopoles you can see on this
animation.

On second thought, don't bother replying - this dialogue is going nowhere
and is a waste of our time.

Dave is right: "only if you take it seriously... i consider it great
entertainment"

It is very funny that radio enginners do not know that they do not use the
Maxwell's model of the eather.
S*

On Sep 7, 6:00*pm, wrote:
Nope, the energy in both the tube of marbles and the walking stick
travels at the speed of sound in the medium.

What happens when the walking stick is traveling faster than
the speed of sound?

....Keith

christofire wrote:
Extrapolating, if an incompressible/inextensible rod or
string could be made, wouldn't that permit communication faster than the
speed of light?

Faster than light communications has already happened.
Entangled particles communicate with each other
instantaneously over any distance. Some say it
proves that reality is non-local but is being
projected from somewhere else. Question is: Who is
running the projector? :-)
--
73, Cecil, IEEE, OOTC, http://www.w5dxp.com

christofire wrote:
Agreed, but c is finite so is there a degree of compressibility or
expansibility below which faster-than-c communication would be possible? ...
or would the whole principle be scuppered by Lorentz contraction?

Years ago, quantum tunneling was reported to have passed
information at faster than the speed of light. I haven't
heard anything about that lately.
--
73, Cecil, IEEE, OOTC, http://www.w5dxp.com

Keith Dysart wrote:
What happens when the walking stick is traveling faster than
the speed of sound?

Exactly how much faster?
--
73, Cecil, IEEE, OOTC, http://www.w5dxp.com