On Sat, 20 Aug 2005 20:00:16 -0400, "Tam/WB2TT"
wrote:

I have trouble visualizing what that means.

Hi Tam,

What do you mean by that? You have a source pushing current into an
element against a counterpoise, an active one albeit, but all
counterpoises support current too (hence the symmetry of resistance).
Just another condition of the ENTIRE structure radiating energy (where
some would have energy cancelled rather than the power product into a
remote load).

Yes, the three leaf trifoil is not very pronounced, and only below an
elevation or 45 degrees or so. However, Reg introduced this with the
strong suggestion of perfection. Perhaps his usual indirection. ;-)

A 4-phase antenna shows a similar lobing to a smaller degree, and a
5-phase antenna is for all practical purposes circular.

I had to solve a problem like this a couple of years ago with a design
for the Army to test their Helicopter pilots for mental alertness.
This involved building a uniform field of even illumination over a
visual angle of 180 degrees horizontal and 90 degrees vertical
(roughly the entire field of view). I was tasked to present no more
variation than a couple of percent ripple. It took about 100 light
sources 1 cM from the eyes.

73's
Richard Clark, KB7QHC