> The results show that it is a BETTER VERTICAL than horizontal by 3dbi
> at a elevation angle of 20 degrees to the horizon. This is off the
> ends. Horizontal is broadside.
Hi Don and all,
I may not have expressed it as well as possible, but this is worth
going over if you really want to know what polarization an antenna
has.
All horizontal dipole style antennas gradually tilt the radiation
towards vertical off the ends. As a matter of fact, radiation off the
ends is almost exclusively vertical. That's true for perfectly
horizontal dipoles as well as Inverted Vee dipoles.
This is so contrary to logic most of us would place a dipole's ends
towards a vertical to null the vertical, when the very opposite is
true! If I want to null a vertical's radiation from a dipole at the
same location the deepest null in coupling occurs when the dipole is
broadside to the vertical! Maximum coupling occurs off the ends of
the dipole.
Which begs the question, how many people with dipoles, especially
those near other structures, really have horizontal polarization in
the directions they think? Probably very few of us do.
The actual radiation at any given point in this example is always a
single polarization, but Eznec and other simple programs can not
display "tilt" in the electric field. The simple display in the
programs only expresses the field at two reference angles, vertical
and horizontal.
When we see equal vertical and horizontal components it actually
represents a wave that is tilted 45-degrees, the wave is neither
vertical or horizontal. Unfortunately without phase we can't tell if
the wave polarization, when viewed looking towards the antenna, is in
a line between lower left and upper right or upper left to lower
right. Rest assured whatever tilt angle the electric field has in any
given direction and angle, rotating 90 degrees from it is a perfect
null, so it is a single polarization and not a mix. (Which was my
point.)
Now imagine the great difficulty in predicting how antennas interact
with other things based on what we intuitively "feel", or what we see
when we look at the antenna, or at the pattern when expressed as a
ratio between two fixed reference of purely vertical and purely
horizontal electric field alignment.73, Tom W8JI
W8JI@contesting.com
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