Thread: New antenna
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Old October 13th 07, 06:23 PM posted to rec.radio.amateur.antenna
Dave Dave is offline
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First recorded activity by RadioBanter: Jul 2006
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Default New antenna


"art" wrote in message
ups.com...
On 13 Oct, 06:28, "Richard Fry" wrote:
"Dave" wrote and ONE MORE TIME.... define 'equilibrium'. write the
equations.
just what is in 'equilibrium' with what??


__________

Art posted his definition in this thread on Oct 11. But no math
to support it.

\\ If he understood Gaussian law then he could have made the Gaussian
antenna which requires an element in equilibrium which means a
FULLWAVELENGTH. I know you dislike the meaning of the term equilibrium
but
here it is indispesable. //

What I get from his comments is that Art believes fractional wavelength
radiators are inefficient because they are not in equilibrium, ie, they
are
not a full wave length and therefore don't act like a tank circuit (he
says) -- which he believes is necessary for efficient radiation.

I've sent Art several emails with NEC results and math-based discussion
showing that a 1/4-wave monopole working against a 2-ohm r-f ground plane
radiates about 95% of the power applied by a matched source between it
base
feedpoint and r-f ground. This is the configuration used by virtually
all
commercial AM broadcast stations, and its very high system radiation
efficiency has been proven thousands of times since the earliest days of
broadcasting. Of course that is at odds with the beliefs Art continues
to
post here and elsewhere.

In a response to my emails Art seemed to understand, and even thanked me
for
"sticking with it." But I guess he was not convinced, because he started
this thread _after_ our email exchange.

Since my discussions with Art I put together a chart showing the
groundwave
field generated at 1 km by several, fractional wavelength monopoles at
applied powers from 1-10 kW (see link below). I used a perfect ground
plane
in preparing the chart, but the values would be only slightly less with a
2-ohm r-f ground.

ART: Note that the 1 kW field for the 1/4-wave monopole is exactly the
peak
field of a 1/2-wave dipole in free space (about 313 mV/m). Taller
monopoles generate more groundwave field, given the same applied power
and
r-f ground, because their radiation patterns have more gain in the
horizontal plane and less gain in other directions -- not because they
are
more "efficient." All of the monopoles in this chart radiate all of the
power applied to them (100% efficient).

Also note, Art, that a 1/2-wave monopole and its ground image comprise a
full-wave antenna (eg, having your "equilibrium"), yet the 195-degree and
225-degree monopoles produce higher groundwave fields, even though they
are
NOT by your definition "in equilibrium."

http://i62.photobucket.com/albums/h8...veFieldvsPower...

RF


When you said if the Gaussian antenna was real it would have been
invented long ago
or something like that and yet they are still giving out patents and
Nobel
prizes out for things that are newly discovered I lost interest in
your musings.
When you added things like an image is real I have to walk away
because you are
just not on my wavelength. I fed the half wave image and also hooked
it
up to a receiver and I heard nothing, let me know when you make a
contact
or maybe I should dig a little bit deeper!
Art
Art


the basic problem is art that you forget we had a long conversation about
what a 'gaussian' antenna in your dream was. and you specifically said a
single halfwave dipole was a 'gaussian' antenna. you can go back and search
if you like, but i doubt that you will since you have now changed your
imaginary antenna. please art, go take a long walk... a very long walk, the
fresh air may do you good.