The prrof of he pudding?
 

On 11/10/2014 2:21 PM, wrote:
gareth wrote:
wrote in message
...
All the proof so far having acutal numbers has been that "a short antenna
is a poor radiator" is arm waving nonsense, gas bag, and all you have
presented so far is arm waving and no numbers.

Grow up, child.

Show some numbers, gas bag.

Children, children! Return to your seats and stop this nonsense!

--

Rick

The prrof of he pudding?
 

In rec.radio.amateur.antenna gareth wrote:

snip

Why not contribute to the technical discussion?

You mean like showing some actual numbers, which you have so far failed
to do?



--
Jim Pennino

A short 160M antenna
 

El 10-11-14 19:39, escribió:
wrote:

snip

Jim, I would encourage you to dive into rotating magnetic dipole
radiation.

You mean like in a pulsar?
To be more precise, I mean the radiation with same frequency as pulsar
rotation, of course only present when there is a net magnetic dipole
moment. I am not pointing to the pulsed RF radiation.


For practical electromechanical systems (even in practial vacuo) it is
negligible as (c0)^5 is in the denominator and (2*pi*rev/s)^4 is in
the numerator, but that doesn't mean it isn't present from a
theoretical point of view.

Again, not talking about any "electromechanical system", just a permanet
magnet spining.

That just spinning magnet produces dB/dt, hence an E-field (not
conservative).

Superposition of two quadrature magnetic oscillating dipoles (small
loop antnenas) gives a rotating magnetic dipole field. Such a
quadrature setup can be exchanged by a rotating permanent magnet.


Also implied is the macro level, i.e. a magnet one can hold in one's
hand and velocities well below any relativisitc effects.

I considered non-relativistic velocities only.



--
Wim
PA3DJS
Please remove abc first in case of PM

A short 160M antenna
 

Wimpie wrote:
El 10-11-14 19:39, escribió:
wrote:

snip

Jim, I would encourage you to dive into rotating magnetic dipole
radiation.

You mean like in a pulsar?
To be more precise, I mean the radiation with same frequency as pulsar
rotation, of course only present when there is a net magnetic dipole
moment. I am not pointing to the pulsed RF radiation.


For practical electromechanical systems (even in practial vacuo) it is
negligible as (c0)^5 is in the denominator and (2*pi*rev/s)^4 is in
the numerator, but that doesn't mean it isn't present from a
theoretical point of view.

Again, not talking about any "electromechanical system", just a permanet
magnet spining.

That just spinning magnet produces dB/dt, hence an E-field (not
conservative).

Superposition of two quadrature magnetic oscillating dipoles (small
loop antnenas) gives a rotating magnetic dipole field. Such a
quadrature setup can be exchanged by a rotating permanent magnet.


Also implied is the macro level, i.e. a magnet one can hold in one's
hand and velocities well below any relativisitc effects.

I considered non-relativistic velocities only.

Did you concider it is difficult to hold a pulsar in one's hand?



--
Jim Pennino

A short 160M antenna
 

A short 160M antenna
 

"Wimpie" wrote in message
...
El 10-11-14 19:42, escribió:
wrote:
On an astronomical scale things are different.
Yep, and the discussion is not about pulsars or astronomical phenomena,
it is about magnets one can hold in their hand.




Someone said that a rotating magnet produces an EM radiation field. You
said it is nonsense without arguments, a link to a useful reference, or
query.

And, of course, with the complete lack of the numbers for which he is
issuing challenges.

A short 160M antenna
 

El 10-11-14 19:42, escribió:
wrote:

snip

On an astronomical scale things are different.

Yep, and the discussion is not about pulsars or astronomical phenomena,
it is about magnets one can hold in their hand.




Someone said that a rotating magnet produces an EM radiation field.
You said it is nonsense without arguments, a link to a useful
reference, or query.

There is nothing wrong with a jump to another branch of science (for
example astrophysics) to find out whether the statement is right or
wrong.


--
Wim
PA3DJS
Please remove abc first in case of PM

A short 160M antenna
 

Wimpie wrote:
El 10-11-14 19:42, escribió:
wrote:

snip

On an astronomical scale things are different.

Yep, and the discussion is not about pulsars or astronomical phenomena,
it is about magnets one can hold in their hand.




Someone said that a rotating magnet produces an EM radiation field.
You said it is nonsense without arguments, a link to a useful
reference, or query.

There is nothing wrong with a jump to another branch of science (for
example astrophysics) to find out whether the statement is right or
wrong.

You mean other than the fact that the context is immediately obvious?



--
Jim Pennino

A short 160M antenna
 

gareth wrote:
"Wimpie" wrote in message
...
El 10-11-14 19:42, escribi?:
wrote:
On an astronomical scale things are different.
Yep, and the discussion is not about pulsars or astronomical phenomena,
it is about magnets one can hold in their hand.




Someone said that a rotating magnet produces an EM radiation field. You
said it is nonsense without arguments, a link to a useful reference, or
query.

And, of course, with the complete lack of the numbers for which he is
issuing challenges.

How short is a "short antenna"?

What is the metric for "poor performance"?



--
Jim Pennino

A short 160M antenna
 

On 11/10/2014 6:00 PM, Wimpie wrote:
El 10-11-14 19:39, escribió:
wrote:

snip

Jim, I would encourage you to dive into rotating magnetic dipole
radiation.

You mean like in a pulsar?
To be more precise, I mean the radiation with same frequency as pulsar
rotation, of course only present when there is a net magnetic dipole
moment. I am not pointing to the pulsed RF radiation.

I want to be clear on this. You are saying that a rotating magnetic
dipole *does* create EM waves just the same as any antenna? The only
difference between a Pulsar and a handheld magnet is one of scale?


For practical electromechanical systems (even in practial vacuo) it is
negligible as (c0)^5 is in the denominator and (2*pi*rev/s)^4 is in
the numerator, but that doesn't mean it isn't present from a
theoretical point of view.

Again, not talking about any "electromechanical system", just a permanet
magnet spining.

That just spinning magnet produces dB/dt, hence an E-field (not
conservative).

Superposition of two quadrature magnetic oscillating dipoles (small loop
antnenas) gives a rotating magnetic dipole field. Such a quadrature
setup can be exchanged by a rotating permanent magnet.


Also implied is the macro level, i.e. a magnet one can hold in one's
hand and velocities well below any relativisitc effects.

I considered non-relativistic velocities only.

I'm not interested in Jim's hand waving. Either a magnet can or can't
generate EM waves. If a big one does it, then a little one does it too.

--

Rick