On Mar 23, 1:10*pm, JIMMIE wrote:
On Mar 23, 1:56*pm, Art Unwin wrote:
On Mar 23, 12:13*pm, Tim Shoppa wrote:
On Mar 22, 9:24*pm, "Joel Koltner"
wrote:
I know that many people think G3LHZ is a little bit off his rocker, but out of
curiosity... what he suggests on slide 15 hehttp://frrl.files.wordpress.com/2009...ts-of-small-an...
- is that a valid approach to measuring antenna efficiency? -- Use a thermal
camera to note how much an antenna heats up with a given input power, find out
how much DC power it required to heat it to the same temperature (the
antenna's loss), and -- poof! -- antenna efficiency = (input power-loss)/input
power?
What are the significant loss mechanisms that he's not accounting for? *(He
claims his matching network isn't getting at all hot.)
With some feedlines and frequencies, feedline radiation can become an
issue. For example, using 4" ladder line at UHF.
I think his method, especially for physically compact antennas and
feed systems which tend to have very low radiation resistance at HF
frequencies, is a great check on theoretical calculations. There has
to be a meeting point between mathematical models/NEC and reality and
he is working at one such point. There are of course other points too
(e.g. near field and far field measurements).
Tim.
I can't see how the external fields come into it! * That would
automatically be within the two vectors that supply acceleration, this
would be measure by the skin depth created by the displacement
current. The accelleration of charge is a constant dependent on the
conductor used. Where the particle goes when acceleration stops i.e.
after leaving the boundary is of no consequence.This would be seen in
the oscillation losses of the radiator
in the same way as with a pendulum
If you dont understand external fields then you dont understand
Maxwell's equations at all. Maxwell is all about fields. This pretty
much means you havent had a clue about anything you have ever said
about antennas.
Jimmie
Jimmy
I am referring to the boundary laws which is energy in versus energy
out.
Maxwells laws finish with the completion of acceleration of charge.
The boundary laws are covered by this action and reaction per Newton.
The particle that is accellerated is the smallest known with respect
to mass and we know that it is accellerated to the speed of light
which is known for any particular medium.
Thus knowing the energy supplied we must equate it to the ejection
vector applied to the particles and the reaction force applied to the
radiating member.
NEC computer programs do just this and for such equations produce
arrays where each
element is resonant and tipped to oppose the two vectors of gravity
and the rotation of the Earth by supplying the array only where it is
in a state of equilibrium and all elements are resonant as a result of
the initial two vectors. The NEC computer programs do just this when
applying Newton's laws which are not mismanaged to reflect planar
forms.
Again I state that Newtons equations account for all vectors involved
in radiation and does not in any way reflect the fields that are
generated beyond acceleration and how the particles are dispersed
beyond this point. This way it represents all types of radiation that
the radiator is capable of and likewise makes it sensitive to all that
is thrown at the receiving end ie H,V, cw, ccw signals e.t.c. and all
the rest that is thrown at it which it converts to a useable current
signal for the radio.Now if you are still in a state of flux as to the
use of equilibrium in all the laws of the Universe then you are still
spitting into the wind.
Art Unwin KB9MZ....xg