That says that narrow bandwidth contributes to higher efficiency
which is how I always understood it.(Though many do not accept that)
But as you say it is a shorthand type statement.
My antenna on 160 is very narrow banded at any particular setting or
frequency
( two loops and a short dipole coupled in tight cluster form),when
modelled ,shows part of the current curve breaking out into a sino
soidal oscillation (no phase change) for portions of the antenna.
Such modelling, ofcourse, requires a large amount of points per unit
length for high accuracy and the occillation would probably not show
up visually if calculation points were reduced.
It does not seem to affect things in practice on the air but I have
often wondered what the consequences would be if the bandwidth was
narrowed even more and the current oscillation possibly propagate over
all the of the antenna !
With the current taking on an occillation it would suggest changes in
radiation

Art



Richard Clark wrote in message . ..
On 4 Jun 2004 10:44:01 -0700, (Art Unwin KB9MZ)
wrote:
"According to current
theory, you have to give up one of the three-size, efficiency, or
bandwidth-to achieve any one of the other two."

snip
Is the above statement correct ?

Hi Art,

In a crude and shorthand way, yes. This is why your small 160M
vertical dipole is up to 15 to 17dB below performance in comparison to
a full size one. All common legacy for CFAs, EHs, fractals, and the
rest of this ilk that come down the pike.

73's
Richard Clark, KB7QHC