Gene Fuller wrote:
. . .
What I found was interesting, but not surprising.

When the wires were treated as lossless, there was virtually no
difference in bandwidth or any other parameter. The parasitic winding
had essentially no impact.

When I changed the wires to copper, the bandwidth increased in both
cases. However, in the case with the parasitic winding the new bandwidth
was 2.5 times as large as the case without the extra winding. The
resonant input impedance was also about 2.5 times larger.

There is only one plausible explanation for this observation. The
parasitic winding adds loss to the antenna system. I won't claim this is
"bad". Depends on the characteristics desired.

You can easily verify this by noting the change in gain as the extra
winding is added and deleted. You should also see a corresponding change
in feedpoint resistance, assuming that the extra winding doesn't change
the current distribution. A couple of additional interesting experiments
would be:

1. Increase the loss of the coil in a model without the extra winding
until the gain is the same as the model with copper loss and no extra
winding. Then see how the bandwidth compares to the original model with
extra winding.

2. Instead of increasing the loss of the coil, add a resistor to the
base of the copper loss non-extra winding antenna and adjust it so the
gain is the same as for the model with copper loss and extra winding.
How does the bandwidth compare to the original model with the extra winding?

The bottom line is that there is no wondrous invention here. Either
Vincent knew about this effect and chose to ignore it, or he did not
understand what was happening. The capacitance explanation is just baloney.

I'm afraid that's probably true. With antennas, you can choose any two
of efficient, and broadband, and electrically small. This antenna claims
all three, so I'm very skeptical.

Roy Lewallen, W7EL