On 21 Sep 2006 17:05:44 -0700, "art" wrote:

Hi Art,

To close this out, we have discovered through the various
correspondents that:

When one looks at a.radiating array pattern one can see that the yagi
is very inefficient.

Is false. That much is clear through evidence, no theory necessary.

Does anybody know of the relative volume
contained in the main radiation lobe versus the total volume of the
entire pattern?

Yes, someone does. It was pointed out quite clearly that ALL the gain
from sidelobe or back lobe could not be assembled into very much
constructive gain. Economists call this the law of diminishing
return.

A casual look at a yagi radiation pattern would suggest
that it is less than 50% efficient at best

Is false. One can certainly contrive for abysmal efficiency (you use
mylar and bamboo in place of tubing don't you?); but that does not
make the range of yagis fall into disrepute through aberrations of one
designer.

especially when considering

Is false - there are no externalities, except local ground loss, to an
antenna (and that exception is because ground is part of the radiating
system).

DX work
where even the main lobe is less than 50% efficient when looking at
available
signal paths beyond 4000 miles which are somewhat below 12 degrees and
where the main lobe itself is centered between 13 and 14 degrees with
an
average amateur antennah

You don't have any choice in the matter. No element pair is ever
going to offer better. No single yagi is going to draw the peak
launch angle down to the elevations I've already identified. A stack
of yagis is hardly likely either.

The long and short of it is that you are facing 0.001% "efficiency"
without any probable method to even budge it up to 0.0015%.

Creationist scienze might help tho'.

73's
Richard Clark, KB7QHC