First antenna is a 1/4
wavelength Vertical Dipole Second antenna is a
1/2 wavelength Vertical Dipole (Collinear Array)
Notice the reflection in the "Ground Plane" creates
a Virtual Second Element
As
the second dipole is introduced, note the Flattening of the pattern, this
is effectively doubling the Antenna Gain, i.e., reducing the skywave and
groundwaves.
This page was created
with the intent to give general concepts.
Conveying:
1) a vertical
antenna is omni-directional;
2) the ground
plane (reflection) creates virtual elements;
3) and the
effect of adding more elements (Collinear Array) on
directional gain. --Less sky & ground
waves.