Part two I finished up talking about eddy currents that form a
magnetic field in opposition
to the primrary magnetic field. It is this eddy current that is
considered a loss in the building of transformers
and forms as a circulating current which can penetrate quite deeply in
a transformer. To cut down this loss a transformer is made of
laminated steel parts bound together so the depth of the eddy current
is confined to a single laminate to control its penetration or skin
depth. Eddy currents formed on an antenna are also circulartory such
that the current flow is at right angles to the applied current flow.
So the conception of skin depth of a radiator as being some sort of
high resistance or corrosion skin is not quite correct. What we
actually have is a force or current running into the side of another
current flow so that the summation of such is deflected sideways and
upwards in three dimensional terms.
As I mentioned earlier this eddy field or magnetic field comes into
contact with the magnetic field of the particle and where the particle
is ejected together with a spin applied to it so it can maintain a
straight trajectory. Remember, the particle is extremely small so it
takes only a small amount of energy to send it on its way. For those
who are aware of the magnetic elevation experiments the elevation
force is a fraction more than the gravity force in the opposite
direction and as many know to keep an article stable while elevated it
is difficult to preventing the elevated article from turning over
which is particle spin. So when the particle is ejected from the
antenna surface it has spin so that it can maintain a straight line
trajectory as well as the ability to negotiate thru areas affected by
gravitational pull which is nullified by the upthrust of the elevation
force created by the magnetic field of the eddy currents. However
these ejected particles passing from one antenna to another does not
explain the transmission of intelligence so something else has to
occur otherwise we are stymied. Well remember that Newtons laws of
action and reaction means there is a reactionary force on the
radiator from the ejection of the particles is similar to what you
see at the swimming pool with a spring board. A diver jumps on the
spring board which is a downward force and the reactionary force is
that applied by the spring board to the diver so in the case of an
antenna it must move in a reaction to the downwards motion and you
then see a repartition of what you saw with the spring board where
after the diver has left it continues to oscillate for a short time.
But in the case of antenna another particle quickly takes the place of
the ejected particle for a place to rest such that the antenna
oscillation continually takes place over a short length of time. To
fully understand this repartition of ejection and replacement with
respect to the natural frequency and time factors we must now
investigate further the electrical circuit that simulates such
action .This is called a Tank circuit where the energy supplied
sloshes back and forth between a capacitor and a inductor and where
the capacitor itself cannot radiate and the inductor can cause
radiation in two different ways ie. when the field is being generated
and when it is dissapating for each full cycle or period of the tank
circuit operation. This represents the full sinosoidal of the applied
alternating current when applied not to a fractional WL antenna but a
full WL antenna because a period represents the repetitive function of
BOTH phases of the applied current.
More on the Tank circuit operation in the next Part four. If you can
get ahead of the game and study the operation of a tanks circuit you
will see it is not as simple as it appears because it involves time
constants,
voltage multiplication as well as phase change each of which is
important in terms of sequence to provide
for the ejection of particles . I may have to Google to get the
sequence correct ie copy the description or refer to a URL for
simplicity
Art Unwin
unwinantennas.com/