On Dec 1, 6:53*pm, Richard Clark wrote:
On Tue, 01 Dec 2009 18:37:51 -0600, tom wrote:
Nice explanation Richard. *And I had never put together the
squared-squared relationship. *That's a powerful thing to know.

I suppose this is why it ends up that a 1/10 lambda opening is
considered the rule of thumb cutoff frequency on a dish.

tom
K0TAR

Hi Tom,

Radiation resistance certainly plummets quickly. *Look at all the
tunable loops for HF that are 1 M in size AND made on an herculean
scale. *I don't think any are rated at 80M (Rr ~ 5 milliOhms), and
even less so for 160M (Rr ~ 29 microOhms). *This is the principle
reason why Art's inventions are doomed to abysmal transmit performance
in that band (the shoe-box sized 160M loop).

73's
Richard Clark, KB7QHC

I have two Faraday shield antennas at the moment. One of which is a
large one sitting on the ground tho sometimes I raise it a foot or so
off the ground. This is an all band antenna
which the tuner in my solid state radio handles quite well., It is
made of mesh on a aluminum frame and at the moment I have not been
able to discern any noise difference and the like say on top band. I
compare it with a smaller Faraday shield which sits in the roter atop
of my tower. The antenna on the ground is square but the one on the
tower is a hexigon aluminum frame which is approx from memory about
four or five foot long and the hex is approx 3 foot across. This
antenna I use for comparison purposes where both antennas are end fed.
The smallest radiator that I have made for top band was a 1 inch
plastic pipe by about 4 foot tall. The radiator mesh was folded over
several times and then wound in helix form on the plastic tube. This
was also end fed. I could have folded it over upon itself to make it
even smaller but I declined to pursue matters. Now one can accuse me
of making up physics, but it was the understanding of physics which
the books state is not fully understood that I followed in every step
while maintaining equilibrium of the radiator.
At the moment I am not inclined to throw away either of these antennas
as they are easily confirmed for gain using a NEC with optimizer
where, at the same time, the physics that I mention is not in
agreement with this group or apparently the many plagerised books on
the market today. The bottom line with the pursuit of antennas is to
make them small but not electrically small. It is also desirable to
make them rotatable and directive with gain.
Maximum efficiency of a radiator is determined by how its size fits
within a sphere and with the Faraday apparatus the radiator is the
inside of the Faraday shield which makes it very efficient. I am
continuing with my findings and the antennas and will not be
discarding them as a child might say when lacking the knoweledge that
is achieved by growing into an adult
they attain a modicom of logic that they can some meaning to their
outburst
The antenna info is all on my page unwin antennas so that amateurs can
join me in the joys of antenna design. As for the couch potatoes they
can wave their arms as long as they want. I have also discussed it in
full on qrz antennas if one wants to delve more into the physics.
Nobody over the years I have explained my findings has ever applied
existing classical physics to disprove my findings providing only the
crying of a child with no physics
substantiation applied.