On Jul 6, 5:23*am, Keith Dysart wrote:
On Jul 5, 9:57*pm, Cecil Moore wrote:

On Jul 5, 7:44*pm, Keith Dysart wrote:

When, exactly, does the EM wave cease to exist?

I don't know exactly but it will be when DC steady-state has been
achieved, i.e. when electrons are no longer being accelerated or
decelerated.

More evasion. So are now saying there may indeed be an EM wave
present with DC? Even with DC, the electrons are not moving with
constant velocity but hop from atom to atom. Seems like
acceleration and deceleration to me.

...Keith

DC does not an EM wave make... nor does one year make DC, the
summation is infinite, you must wait FOREVER for DC to be achieved and
by then you just won't care any more.

On Jul 6, 6:07*pm, K1TTT wrote:
On Jul 6, 5:23*am, Keith Dysart wrote:





On Jul 5, 9:57*pm, Cecil Moore wrote:

On Jul 5, 7:44*pm, Keith Dysart wrote:

When, exactly, does the EM wave cease to exist?

I don't know exactly but it will be when DC steady-state has been
achieved, i.e. when electrons are no longer being accelerated or
decelerated.

More evasion. So are now saying there may indeed be an EM wave
present with DC? Even with DC, the electrons are not moving with
constant velocity but hop from atom to atom. Seems like
acceleration and deceleration to me.

...Keith

DC does not an EM wave make... nor does one year make DC, the
summation is infinite, you must wait FOREVER for DC to be achieved and
by then you just won't care any more

But previously you said the line would settle after one round trip if
the source was matched. How is this consistent with having to wait
forever?

....Keith

On 6 jul, 19:07, K1TTT wrote:
On Jul 6, 5:23*am, Keith Dysart wrote:





On Jul 5, 9:57*pm, Cecil Moore wrote:

On Jul 5, 7:44*pm, Keith Dysart wrote:

When, exactly, does the EM wave cease to exist?

I don't know exactly but it will be when DC steady-state has been
achieved, i.e. when electrons are no longer being accelerated or
decelerated.

More evasion. So are now saying there may indeed be an EM wave
present with DC? Even with DC, the electrons are not moving with
constant velocity but hop from atom to atom. Seems like
acceleration and deceleration to me.

...Keith

DC does not an EM wave make... nor does one year make DC, the
summation is infinite, you must wait FOREVER for DC to be achieved and
by then you just won't care any more.- Ocultar texto de la cita -

- Mostrar texto de la cita -

Hello friends:

A few years ago I posted in this newsgroup a doubt from a friend of me
about DC current (such a batery connected to a lamp) radiating EM
waves... It was in topic "Antenna gain question" (2005-10-31). My
answer wold be that classic physics postulate EM radiation from
accelerated charges in closed circuit because charges are under
centripetal acceleration (I though of ciclotron radiation analogy, of
course). My friend Richard Clarke disagreed with my hypothesis and I
archived the issue for a couple of years, (he give me some analogies
with moving cars, I remember...)

Time later I was casually reading some pages from Kraus and I found
the answer! :D: Kraus says: "a charge moving at uniform velocity
along a curved or bent wire it is accelerated and radiates".
The clue was in words "straight wire" , he says: "Electric charge
moving with uniform velocity along a straight wire does not radiate".
then, a DC also must be rectlinear (perhaps it must move on a
geodesic, but I do not know general relativity enough to say it) (*)

(*) "Antennas" John D. Krauss - Second Edition -1997 Page 50.

73 - Miguel Ghezzi - LU6ETJ

"lu6etj" wrote
...

D: Kraus says: "a charge moving at uniform velocity
along a curved or bent wire it is accelerated and radiates".
The clue was in words "straight wire" , he says: "Electric charge
moving with uniform velocity along a straight wire does not radiate".

This principle is used today to produce the light in the free electron
laser: http://en.wikipedia.org/wiki/File:FEL_principle.png
S*

On 7 jul, 16:55, "Szczepan Bialek" wrote:
*"lu6etj" ...

D: Kraus says: "a charge moving at uniform velocity

along a curved or bent wire it is accelerated and radiates".
The clue was in words "straight wire" , he says: "Electric charge
moving with uniform velocity along a straight wire does not radiate".

This principle is used today to produce the light in the free electron
laser:http://en.wikipedia.org/wiki/File:FEL_principle.png
S*

Yes, very interesting example (and device),

Cecil it is right respect a photon/noise power ratio, even one photon
of 80 m per second it is very below of noise at 1 K, 80 m-quantum/
Noise dB ratio @1 Hz BW = -38 dB.

Respect to DC current EM radiation, In that time Richard bring an
interesting example of 20 kV electron rectilinear beam rendering a
frequency of 34.6 EHz, the calculus it was quite right, but that
frequency it is not EM waves radiated by electrons but a "matter wave'
frequency... (idem with car analogy = not charged and acelerated
cars :) do not radiates EM waves, but may have a matter wave
asociated to them).
For these reasons IMHO I think -as Cecil do-: basic (undergraduated?)
physics books are very useful to helping us to better understand and
enjoy our ham topics.

73 - Miguel

"lu6etj" wrote
...
On 7 jul, 16:55, "Szczepan Bialek" wrote:

This principle is used today to produce the light in the free electron
laser: http://en.wikipedia.org/wiki/File:FEL_principle.png

Yes, very interesting example (and device),

Respect to DC current EM radiation, In that time Richard bring an
interesting example of 20 kV electron rectilinear beam rendering a
frequency of 34.6 EHz, the calculus it was quite right, but that
frequency it is not EM waves radiated by electrons but a "matter wave'
frequency... (idem with car analogy = not charged and acelerated
cars :) do not radiates EM waves, but may have a matter wave
asociated to them).

Each waves are the matter waves. The speed is the particles mass dependent.
So in the wire the sound waves travel with the low speed (medium are ions),
and the electric waves (medium are the free electrons) with the extremally
high speed.

For these reasons IMHO I think -as Cecil do-: basic (undergraduated?)
physics books are very useful to helping us to better understand and
enjoy our ham topics.

For graduated is the field math only.
S*

73 - Miguel

On 8 jul, 04:44, "Szczepan Bialek" wrote:
*"lu6etj" ...
On 7 jul, 16:55, "Szczepan Bialek" wrote:



This principle is used today to produce the light in the free electron
laser:http://en.wikipedia.org/wiki/File:FEL_principle.png
Yes, very interesting example (and device),
Respect to DC current EM radiation, In that time Richard bring an

interesting example of 20 kV electron rectilinear beam rendering a
frequency of 34.6 EHz, the calculus it was quite right, but that
frequency it is not EM waves radiated by electrons but a "matter wave'
frequency... (idem with car analogy = not charged and acelerated
cars :) do not radiates EM waves, but may have a matter wave
asociated to them).

Each waves are the matter waves. The speed is the particles mass dependent.

"lu6etj" wrote
...
On 8 jul, 04:44, "Szczepan Bialek" wrote:

Each waves are the matter waves. The speed is the particles mass
dependent.
So in the wire the sound waves travel with the low speed (medium are
ions),
and the electric waves (medium are the free electrons) with the
extremally
high speed.

For these reasons IMHO I think -as Cecil do-: basic (undergraduated?)

physics books are very useful to helping us to better understand and
enjoy our ham topics.

For graduated is the field math only.

Hello Szczepan, good day:

I do not know if I undestood quit right your sentences (we are both
out of our native lenaguage) correct me if I am wrong.

Such as we have more troubles with writting than with understanding.

Today we do not conceive unverse as a material thing, then if you want
to say with "each waves are material waves" that all is mater you are
talking with century XIX words/concepts.

Some things were discovered before XIX century. Many more after.

However matter waves are not neither mater nor energy waves, they are
"probabilty waves", probability it is not a "thing", it is a
mathematical concept, surely you know that.

The new concepts are create every day. All must be verified by experiments.

All concepts on "inmaterial waves" was created by scientists who did not
know that in the space is matter.
Ludwig Lorenz know that because he had known what the sublimation is.
"surely you know that" also.

If you accept the matter in the space when you do not need the EM waves and
"probabilty waves".
S*

..

On 7/8/2010 2:44 AM, Szczepan Bialek wrote:
wrote
...
On 7 jul, 16:55, "Szczepan wrote:

This principle is used today to produce the light in the free electron
laser: http://en.wikipedia.org/wiki/File:FEL_principle.png

Yes, very interesting example (and device),

Respect to DC current EM radiation, In that time Richard bring an
interesting example of 20 kV electron rectilinear beam rendering a
frequency of 34.6 EHz, the calculus it was quite right, but that
frequency it is not EM waves radiated by electrons but a "matter wave'
frequency... (idem with car analogy = not charged and acelerated
cars :) do not radiates EM waves, but may have a matter wave
asociated to them).

Each waves are the matter waves. The speed is the particles mass dependent.
So in the wire the sound waves travel with the low speed (medium are ions),
and the electric waves (medium are the free electrons) with the extremally
high speed.

For these reasons IMHO I think -as Cecil do-: basic (undergraduated?)
physics books are very useful to helping us to better understand and
enjoy our ham topics.

For graduated is the field math only.
S*

73 - Miguel



You guys are better than Monty Python.

tom
K0TAR