BUDDIPOLE IN THE FIELD

6 Ground Mounted Verticals
As discussed earlier, ground
mounted horizontal dipoles on
Buddipole masts and tripods cannot
be raised to a sufficient height to
achieve a reasonable radiation
pattern for most HF bands. Only
10m dipoles when raised to a ½
wavelength in height (5 meters or
about 16 feet) deliver the power
to low angles that give us good
DX opportunities. So, if
horizontal dipoles are out, what
simple deployment designs
remain? Two options come to
mind immediately: vertical dipoles
and vertical monopoles with
elevated radials. We’ll examine
each in turn.
Vertical dipoles are just as they
sound: a dipole antenna deployed
such that the elements are
Ground mounted vertical
antenna for 17m on VP2M
perpendicular to the ground instead of parallel to it. The two general
problems deploying such antennas are managing its height (a full-sized
20m vertical dipole will be ½ wavelength high or 33 feet!), and to get the
feed line to the feedpoint.
A dipole is typically constructed such that both elements lie straight on
an imaginary line. In the case of a vertical dipole, both elements would
be perpendicular to the ground, one element directly above the other.
What about an antenna where the bottom element is not quite
perpendicular? What about one where the bottom element is at a 45
degree angle to the ground? The collection of far field plots in Figure 20
show how the radiation pattern of a 10m antenna with its feedpoint at 15
feet changes as the lower element is rotated from directly under the top
element (at 180 degrees from that top element) to perpendicular to it (at
90 degrees from that top element).
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