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Old March 11th 10, 05:36 AM posted to rec.radio.amateur.antenna
Art Unwin Art Unwin is offline
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First recorded activity by RadioBanter: Mar 2008
Posts: 1,339
Default Mesh curtain antenna

On Mar 10, 8:07*pm, tom wrote:
Art Unwin wrote:

A Faraday shield allows for magnetic and elerctrical fields to
separate and cancell leaving a RF current thast radios are designed to
handle


No, that's absolutely incorrect. *Nothing is separated. *And what's left
over, if anything measurable is, is an electromagnetic wave.

The shield unlike what we view as radiators has two side that
are independent of each other where as a "normal" radiators surface is
not separated electrically. The Faraday shield operates at 90 degrees
to an oncomming signal by a blocking method and does not operate as a
recieving type surface
that is directly connected to a radio.


No it doesn't. *You are wrong.

* The Faraday shield as a single



wall still has a blocking action as fields can encircle the wall but
it cannot protect all. It does however protect the rear surface from
field impingement and the field usually will connefct to a alternate
surface leaving a void directly behind the shielding wall.
The Faraday shield on the other hand is an enclosure that shields the
inside from encroachment on the outside such thast fields do not
interfere with activities within. It does not perform the function of
field separation. In most radio circuits you will see examples of bot
enclosures and shields where the latter incorporates physically
unconnected surfaces for electricaly closed loops.
I don't mind your postings Tom as it provides those that are educated
some idea of your true standing in life.
With respect to a closely aligned feed which to your mind leaves an
imediate short;.
I suggest you look at a three band dipole all connected at the same
point. Each dipole provides a low resistance path for a particular
applied frequency in its seach for a closed circuit. The applied
current will not divert to a path of higher resistance or impedance in
this case because we have to consider the effect of phase differences.
With these sort of actions we can have several different paths for the
current to follow but I assure you that it will pick the same one
every time dependent on the frequency applied.
Now to the wire mesh curtain. It provides a separate low impedence
path for every frequency applied to it as well as a separate path for
the displacement current that encloses a separate field ( see my page)
which has the abilitity to accellerate mass as with an electric
gun.The maximum accelleration applied to mass is obviously determined
by its intrinsic mass where a minimum mass determines the speed of
light. Today the smallest particle found is that of a Neutrino thus
one can see the connection of the Sun to communication as we see it
today.
Regarding your description of the shield to a long wire or dipole,
gthe curtain or shield does not provide a electrical connection for
both sides of the shield as a dipole or long wire does.
See Tom, your past postings are completely devoid of technical content
and probably provide all readers with a silent chucklel
By the way, a curtain is able to supply a very large aperture which is
synonimous with the amount of gain it supplies. You might want to
ponder on that aspect before you disparage it.
The above is provided for you and your friends to salivate apon so you
may provide a few more chuckles to those on the side lines.
Note I have left some grammerr and spelling errors for you to comment
upon in the absence of any technical content.
Cheers and beers
Art Unwin KB9MZ.....xg


And I'll just summarize all the last part, since it would be a total
waste of time to comment individually on points -

YOU ARE WRONG. *Totally, completely, and terribly wrong.

And no, I'm not going into how or why, because you never ever listen or
understand.

tom
K0TAR


Oh My. I am wrong but you are unable to describe how I am wrong,how
convenient!
You need to brush up on attenuation versus skin depth, surface
conduction and a host of other things such as a sealed surface can be
considered as an aperture with respect to shielding. I would recommend
a book on shielding etc by Ralph Morrison 5 th edition that will bring
you up to date on the function of perforated shielding plates,
screening etc.Just saying that I am wrong without explanation or
explaining your record on the subject is nothing more than the voice
of a child exercising free speech.If you can provide technical data to
support your position we can discuss but just saying one is wrong
serves nobody.
One thing you really need to understand is the nature of a
accellerated and decellerated charge and its connection with a time
varient current, the latter being the only connection
that a xmitter or rcvr can handle to provide communication and its
connection with a parallel tank circuit.

Have a happy day
Art