On Sun, 25 Dec 2005 06:25:08 -0500, Scott in Baltimore
wrote:

+James, you need to learn the power transfer theorum and how
+little is actually lost by a 1.5:1 or less SWR. You gain
+more with a resonant antenna, then a bit of impedance mismatch.


Scott.

A 1.5:1 SWR means that about 4% of the source power is reflected back
from the load. This is entirely different from antenna efficiency and
how much delivered power is actually radiated. Again your
understanding of antenna efficeincy and radiated power density is
quite lacking.

A resonant antenna is just that, a resonant antenna. It will often
give the widest possible bandwidth for SWR and radiation efficiency.
That is all. Physically short or exceptionaly long antenna can be made
to operate over a small frequency bandwidth with equal or better
radiation efficiency. For example consider electrically short loop
antenna can be as efficient as 98% in radiation. Due to their low
radiation resistance the antenna is quite high in Q. Thus a relatively
small bandwidth for efficient radiation.

SWR is the measure of power delivered to the load and what is
reflected back from the load to the source. Nothing more, nothing
less. It is a measure of what is happening inside the transmission
line. Not necessarily the performance of the antenna. Just because you
have a 1:1 SWR does not mean that all the power is being radiated. In
fact in some installations as little a 10% is actually being radiated.
The rest is heat.

james