The discussion(s) of ground planes, ground radials, etc, reminds me of an
antenna design that I saw about 20 years ago, when I was helping to
establish a Navy shore facility in San Diego. We needed some HF antennas
and researched existing building-mounted HF antennas in the area.. The
research led us to a local entrepreneur who built a few antennas and sold
them to the Navy. They worked well.

The radiator was a Slinky-like coil that was raised inside a fiber tube,
which I believe is the way the SteppIR tunes. To the point, the ground
plane for this antenna was described to us as Log Spiral, a shape found in
Nature from the curls of a conch shell up to the arms of a spiral galaxy.

At a price of $14,000 per copy, our program could not afford his antenna
and we made do with a base tuned whip. It worked.

Because we never bought and installed the antenna, I've forgotten all the
pertinent details of how many ground wires were involved, how long the wires
were, how they were spaced, etc. I'm pretty much a blank slate. :-(

What, if anything, do we know about the concept of a log spiral ground
plane? Genius or snake oil or something in-between???

Google is no help. The closest I got was a log spiral HF antenna for NVIS
operation described by L.B. Cebik, W4RNL, cited often here.

But then, that's the _antenna_, not the counterpoise. It's tempting to
imagine that the dimensions of that antenna might be the dimensions for a
corresponding counterpoise.

73,
"Sal"
(KD6VKW)

Sal M. Onella wrote:
What, if anything, do we know about the concept of a log spiral ground
plane? Genius or snake oil or something in-between???

I believe it's called the "Golden Ratio" based on
Fibonacci numbers and works as well as any other
ground plane including fractal ground planes. It,
like a fractal, is based on packing the most stuff
in the least amount of space. One sees the pattern
in pinecones, pineapples and sunflower seed heads.

http://www.psc.cornell.edu/gssop/cou...dex.php?page=4
--
73, Cecil http://www.w5dxp.com

In my (shudder) early days on the Dark Side (11 meters) I once shaped a half
wave length of house wiring into a conical spiral (roughly 30 inches high),
hung it from a ceiling using a refigerator top as groundplane. I
communicated well with folk in the White Rock Lake area from my Carrollton
home (approx 20 miles) with a legal unaltered 4 watt transceiver. Fiddling
about with antennas has always been an interest of mine.

Harold
KD5SAK

"Cecil Moore" wrote in message
. net...
Sal M. Onella wrote:
What, if anything, do we know about the concept of a log spiral ground
plane? Genius or snake oil or something in-between???

I believe it's called the "Golden Ratio" based on
Fibonacci numbers and works as well as any other
ground plane including fractal ground planes. It,
like a fractal, is based on packing the most stuff
in the least amount of space.