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Old September 15th 09, 12:06 PM posted to rec.radio.amateur.antenna
christofire christofire is offline
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First recorded activity by RadioBanter: Oct 2008
Posts: 173
Default Spherical radiation pattern


"Szczepan Białek" wrote in message
...

"Richard Clark" wrote
...

As I stand on the corner waving goodbye to that bus, I fondly recall
how the logic stood that no current could be found on the tips of
radiators, thus trim them off to no loss of radiation. It took very
few decades before Art had then recognized that his new antenna's tips
had no more current than the full-length one, and he trimmed that one
once again! New and improved (as the saying goes). Another decade
passed into the new millennium and he observed that he could extend
this logic once again to the point where his last design encompassed a
160M full sized antenna in the space of two shoe boxes. The TRIUMPH
OF TITANIC PROPORTIONS.


Is any simillarity between Art and Tesla?
Bill Miller wrote: "*But* Tesla's "antennas" were similar physically to
the well-known "Tesla
Coil." These antennas, in spite of their enormous size, were electrically
"small" when compared with a wavelength. They were essentially a metallic
ball that was fed from the secondary of a resonant transformer. But they
appear to have had fairly large effective bandwidths in spite of their
electrically small size,"
S*



Tesla created HF transformers. He didn't design them as antennas but,
because of their significant length at the operating wavelength, they did
act that way to some extent. The metallic ball (often a torus nowadays) is
a means of terminating the secondary in a way that reduces spurious
discharges - its radius of curvature is large. His ideas to distribute
electrical power using Tesla coils were crazy and dangerous, but some argue
he was the inspiration for AC distribution at much lower voltages, which is
a good thing.

There is very little apparent similarity between Nicola Tesla and that 'Art
Unwin' character. Tesla was an inventor who realised amazing feats of
hardware construction, some of which worked as intended. 'Professor Unwin'
doesn't appear to create anything in hardware - he just talks about his own,
paraphysical theories and expects others to believe what he says.

Again, don't believe what I write - go to a technical library and read the
stuff that made it into books. You can't rely on what people write on the
internet; there are too many 'Unwins' out there.

Chris