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Old March 10th 10, 05:56 PM 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 9, 7:58*pm, tom wrote:
Art Unwin wrote:
Very, very quiet antenna, but it has been up less than 24 hours.
Feed is on one side only with the ground connection about 2 inches
away on the same side with the connections at the bottom some what
towards the center of the curtain length ways.


So he is center feeding a large curtain with a "_2 inch_" wide feed.

Yup, that WILL very definitely be quiet. *I hope the tuner has a lot of
loss in the way before the "antenna" (chortle) to dissipate the 99.999%
of the power fed to the short at the end.

Basically it is a long one wall
Faraday shield but without a drain ground on the front side.


It's not a Faraday shield if it's not completely surrounding something.
* I'd suggest a smaller one. *Of tinfoil. *Around your head. *It won't
help, but it would be amusing.

tom
K0TAR


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