K4SAV:
>The only time I have verified EZNEC being different from my real world
measurements is usually because of some error I put into the model or
something I left out of the model. However I can't do comparisons of
high dipoles and verticals on 160 at my station because I don't have
them. I can look at data generated by others (who are likely to not be
in error) and check that with EZNEC. In the case of 160 (and only 160)
I can't get their results to agree with EZNEC. So I'm wondering if
there is some magic on 160 that says a vertical get a special advantage,
and what the heck is it?
>EZNEC says a 300 ft high dipole on 160 beats a quarter wave vertical at
all elevation angles under 54 degrees even if I assume zero near field
ground loss for the vertical. Real world data disagrees.
>By the way, this disagreement doesn't exist on 80 meters.
This problem has to do with something called magnetic coupling
(or polarization) loss. This primarily affects 160m which is closest to
the gyro-electron frequency which varies from about 0.7-1.7 MHz worldwide
depending on the intensity of the magnetic field). If you want to read
more, search the terms " magnetic polarization polarisation coupling
loss " in various combinations on the following Topband list archive page
(enter the above search terms into the box at the top):
http://lists.contesting.com/archives//html/Topband/2009-04/index.html
I agree with all of Jerry's comments above. EZNEC does not take
this effect into account. Here's a post with some modeling results for
a vertical and dipole, both with and without the coupling loss effect:
http://lists.contesting.com/archives//html/Topband/2002-05/msg00098.html
The results including coupling loss agree with my experience on 160.
73, Bill W4ZV
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