"Art Unwin" wrote in message
...
On Sep 21, 4:19 pm, "christofire" wrote:
"Art Unwin" wrote in message

- - snip - -

Chris you are being stupid as well as acting as a fool.
Acceleration of the particle only occurs while within the
electrostatic field. When it exits it has the speed of light because
it has emmerged from the intersecting two fields.and thus from the
accellerating forces. I remind you of Newtons law of ut + 1/2 ft sqd
The first expression is for the speed attained on entering the
accelerating field and the other half is for the length of the
accelerating electrostatic field. On leaving the two fields it looses
the applied accelerating force where it has arrived at a particular
speed.Maybe you should look up the workings of a CRT using Newtons
laws instead of shooting from the hip.
It was at a different time that the speed of light was measured where
it was found to equal the sppeed emerging from two intersecting fields.


* Actually, I'm well aware of the principle involved in accelerating
electrons in an electron gun as used in CRTs, klystrons, TWTs, and so on, by
subjecting an electron cloud to a potential difference using an anode with a
hole in it (!), but that's different from what happens in an antenna.

The acceleration of charge in an antenna results almost entirely from the
applied potential difference at its terminals. The radiated fields result
from the alternating current effectively passing through the radiation
resistance, and all the other, reactive, fields have no direct effect on the
radiation resistance, or the component of the current that passes through it
in phase with the voltage that is developed across it, which together, of
course, represent the radiated power. The reactive fields affect the
terminal impedance and a large imaginary part can upset the device trying to
send power into the antenna, but that is more of a system issue. The
alternating current that passes through the radiation resistance is composed
of charge that moves in time with each RF cycle, accelerating and
decelerating accordingly. The electrostatic field developed between the
ends of a half-wave dipole reaches its maximum value a quarter of a cycle
later than the voltage at the drive point so any effect it has on the charge
in the antenna elements during each cycle must be reactive, and it doesn't
affect the radiation resistance or the radiated wave.

But all this can be looked up from any one of the respected books on
antennas. Kraus, and others, gives expressions for the different field
components and the theory all hangs together quite readily using Maxwell's
equations without modification.

I don't care if you think me stupid, and I'll continue to try to avoid name
calling of individuals, although I may criticise what they write especially
if it appears ignorant of proper science yet attempts to re-write
established theory, and therefore appears arrogant.

Chris