Re: Physics of Wireless Transmission

["Tesla list" <tesla@xxxxxxxxxx>]

Original poster: "Bob (R.A.) Jones" <a1accounting@xxxxxxxxxxxxx>

Hi,

We are getting a bit off topic perhaps our esteemed  and tireless Moderator
(blatant attempt to curry favor with Terry) will indulge us.

Yes I believe your right. The laws of electromagnetic are invariant in any
constant motion frame.
Perhaps this is not so surprising given this was one of the clues Einstein
used to derive his theory.

In an article or letter in Wireless World it described the forces between
two moving electrons in both a stationary frame and in the moving frame of
the electrons. Which ever frame was chosen the laws of physics remained the
same.  I did not understand at the time that is precisely what Special
Relativity predicts or perhaps more accurately Special Relativity is derived
or confirmed by the invariance of physics in any constant motion frame.

I think it was also in Wireless World that I read how magnetic fields where
just relativistic effects of electrostatic fields. It derived the magnetic
force between parallel wires carrying a current using only electrostatics
and relativistic effects. So (according the article) a magnetic field is
just the effects of motion in a electrostatic field i.e. pick the right
frame of reference and the magnetic field disappears. Again this may not be
surprising as presumable Special Relativity would not be true if it was any
other way.

Accelerating charges emit electromagnetic waves not charges in constant
motion or perceived to be in a particular frame..
So as perceived in the accelerating frame no radiation ???  Presumable
that's  resolved special Relativity.

Robert (R. A.) Jones
A1 Accounting, Inc., Fl
407 649 6400
----- Original Message -----
From: "Tesla list" <tesla@xxxxxxxxxx>
To: <tesla@xxxxxxxxxx>
Sent: Friday, April 21, 2006 6:48 PM
Subject: RE: Physics of Wireless Transmission


> Original poster: "Godfrey Loudner" <ggreen@xxxxxxxx>
>
> Hello Gerry
>
> Maybe I'm not sure what your asking, but I'll take a shot. Fix a charge
> Q and an observer A at the origin of a rectangular coordinate system.
> Observer A sees E as a static field that varies inversely as the square
> of the distance from the origin (varies with position). Now fix an
> observer B in a rectangular coordinate system that is moving relative to
> the other. Observer B will see a non-static field with nonzero H. If
> observer B is moving uniformly along a straight line, then the Es and Hs
> of the two systems can be exchanged by the Lorentz transformations. If
> Observer B with accelerating relative to observer A, then I would have
> to dust off a relativity book and study to see what are the exchange
> transformations (that's general relativity).
>
> Godfrey Loudner
>
>   > I believe, there can be a static e field that varies with
>   > position and be a "pure electric field".  However, any E
>   > field that varies with time (aka electric wave) involves
>   > movement of charge that in turn creates an H field. Time
>   > varying E fields are always accompanied by a time varying H field.  >
>  > Even a static E field in one frame of reference will be a  > time
> varying E field in another moving frame of reference.
>
> Gerry
>
>