It is easy to model a low dipole on EZNEC, provided that you do need to
set "Display Options" to Horizontal AND Vertical. Then you will see a
nice figure 8 pattern broadside to the dipole for horizontally polarized
signals and a 90 degree rotated pattern (otherwise identical) for
vertical polarization where the dipole receives local vertically
polarized noise off the ends. Both polarizations have elevation
patterns of the cloud warmer type, for any practical ham radio height.
This explains why a low dipole RX antenna may by luck reject a local
noise source at a fortuitous broadside azimuth and therefore do great
things on receive, while other times the noise source is in an "unlucky"
direction off one of the ends, then the same low dipole does nothing
great.
All of this has nothing to do with any far field skewed propagation,
etc., that you might also have.
---
Rick Karlquist
N6RK
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