[antennaware] 4-SQUARE Model: 8dbi ?!?!?!
L. B. Cebik
Fri, 17 Sep 1999 10:10:51 -0400 (EDT)
There may be nothing wrong with the model. However, it appears to be set
up over perfect ground. The gain of the system in these conditions can be
estimated by comparing it with a model over the same perfect ground of a
standard 1/4 wl vertical, which should show 5.1-5.2 dBi gain--for a
difference of about 3 dB.
If my guess about perfect ground under the model is correct, even though
the relative gain values will be roughly correct to reality, the actual
gain of each system will be reduced by the losses incurred by erecting
them over the particular ground with which you have to work. Developing a
model of the ground plane system and getting accurate numbers relative to
these horizontal wires close to ground would require use of a version of
NEC (rather than MININEC) and the Sommerfeld-Norton ground calculation
system. Expect as well adjustments to the phase line system to maximize
either gain or front-to-back to account for slight changes in the
feedpoint impedances occasioned by going to a real ground system. As
well, it is also useful not to assume (as many hypothetical studies do)
that you have "average" ground. Instead, try to determine within reason
more precise values for conductivity and dielectric constant that reflect
your actual ground conditions. The ARRL Antenna Book has a map that can
start the process.
I hope I have not misread your note and led you astray.
L. B. Cebik, W4RNL /\ /\ * / / / Tel: (423) 938-6335
1434 High Mesa Drive / \/ \/\ ----/\---
Knoxville, Tennessee /\ \ \ \ / / || / http://www.cebik.com
37938-4443 USA / \ \ \ \ || e-mail: firstname.lastname@example.org
FAQ on WWW: http://www.contesting.com/antennaware-faq.html
Administrative requests: antennaware-REQUEST@contesting.com