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Old November 10th 14, 08:34 PM posted to rec.radio.amateur.antenna
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Default 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
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Old November 10th 14, 11:20 PM posted to rec.radio.amateur.antenna
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Default A short 160M antenna

wrote in :

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


Nevrr mind the context, you could sell that! Imagine the T-shirt trade
alone...


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Old November 11th 14, 01:08 AM posted to rec.radio.amateur.antenna
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Default 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
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