[Towertalk] 40M Dipoles (Was: Need EZNEC model 402CD..)
Tue, 9 Jul 2002 19:06:13 -0400
> Note that Bill's model shows a simple (full size) 40M Dipole
> at 1/2 WL (70 ft high) is 2.3 dB stronger than a 4 Square,
> providing further support to the notion that a 40M rotary
> dipole is a good, simple, and competitive antenna alternative.
In my experience models tend to fall in line more on 40 meters and up
with real-world results, while on 160 results vary the most. Using a
model to predict fractions of a dB, or even a couple dB, when system
are close might not be wise. There are multiple reasons for using
My main points are:
1.) Actual working results often vary from a model when the system is
heavily dependent on things that models drastically short-cut, like
2.) On lower bands vertical tend to not be as bad in real-world
performance as models might indicate.
3.) For receiving, gain is unimportant. The important parameter is
directivity, which you can find by factoring loss out of the results.
My web-page describes that.
Receiving performance should not be discounted when picking an
antenna, especially on a trashy sky-wave band like 40.73, Tom W8JI