On Jul 8, 7:55 am, Michael Coslo wrote:
Art Unwin wrote:
On posting part one I finished up with a reference to a full
wavelength antenna and we need to talk about this choice of a
wavelengrh. Equilibrium comes from Newtons laws where force equals
reaction force or upthrust equals down thrust where all forces around
a point equals zero. All the masters such as Faraday,Gauss and others
based all their discoveries around this notion.. In the last century a
frenchman saw this as a period in a occillation of a repetitive nature
as being the point where a cycle of events begin again. In other words
a full cycle was completed and another cycle started. This Frenchman
by the name of Foucault built a large, long pendulum in terms of a
hundred feet to deetermine the time of one sequence of events that
signifies equilibrium.
To his surprise the pendulum not only swung left to right and back it
also moved rotaed about the center a slight degree.

Minor quibble - the pendulum was a proof, not serendipity. His best
known pendulum, at the Pantheon, rotated 11 degrees per hour, making a
full circle in a bit less than 33 hours.

This meant that
there was another force, a rotational force must be at work over and
above the two dimensional swing and thus for true equilibrium a period
is many times a single to and fro movement.

The rotation of the earth was the force.

The angular speed could be calculated and proven as:

angular speed = 360 * sin (latitude)

Which is to say that at the poles, the rotation takes one sidereal day,
taking progressively longer as one heads to the equator, at which point
the oscillation plane stays fixed.

Thisw is analagous to our year system of time where every four years
we add a correction to the period of time
by summing all these slight incorrection of time as a full day in what
we term as a leap year.

More precisely, it is a way to correct our calendar system without major
disruption. As the ability to measure time became more precise, coupled
with the obvious shifting of seasons as the error in the calendar added
up, it was a way to correlate the calendar system with as little
disruption as possible. So it is a time measurement accuracy issue,
coupled with change in the rotation of the earth. The former is the most
significant error source.

This is the reason for the choice of a full wavelength radiatorl since
it represents a single oscillation of its harmonics PLUS this small
extra force required to meet equilibrium.

Now this is interesting. Does it follow that the radiator therefore
needs to change in relation to it's latitude?

- 73 de Mike N3LI -

Michael, you are the first to get to the cusp of this discussion by
coming from the other side
relatively speaking by invoking the time difference which when filled
by a force closes the vector circuit reqiered for equilibrium.
Perhaps you can now take over and explain the rest of the story where
instead of lengthening the pendulum the radiator
you instead shorten it to the other resonant point and thus deduce the
shape of the resulting oscillations i.e. less damening. It seams as if
hams are totally enamoured with fractional WL antennas . Such an
escursion is what they want to see first like looking at the last page
of a book to get some commonality to their every day thinking. Will
you do that for me?
Best regards
Art
unwinantennas.com/