- 10 -
When the upper element sections are assembled together install the black vinyl cap in place at the
top of the smallest element section. Carefully mount the element sections into the 2" base section
(don't forget to install and tighten the bottom element clamp).
CAUTION: Attempting final assembly without proper precaution can be dangerous.
You should have someone help you steady the vertical antenna sections during
mating with the base section.
An ideal option would be the
DXE-TB-4P
Tilt Base to make raising and
lowering the vertical antenna a safer, one person task.
Connect your coaxial cable feedline center conductor to the bottom section of the vertical antenna
as shown in
Figure 7
. Connect your coaxial cable shield to the radial system ground. Refer to
Appendix A if you are using the
DXE-RADP-3
Radial Plate, or to Appendix C if you are using the
optional
DXE-VFCC-H05-A
Vertical Feedline Current Choke.
Figure 7
Tuning the Vertical Antenna System
The vertical operates over the entire 40 meter band with an SWR of under 1.5:1 using the indicated
section lengths. Local conditions, including proximity to structures, other antennas, the number of
radials, or personal preference may require a slight re-adjustment of the top element section length
to achieve resonance in the center of the band. Adjust the top element section slightly longer or
shorter as needed. Adjust all sections to a shorter length to achieve resonance on higher frequencies,
including monoband operation on higher frequency bands.
The use of an antenna analyzer such as the MFJ-259B can make adjustments easier. Use a short
piece of coax between the vertical and the analyzer when making measurements. If you don’t have
an analyzer, you can use the SWR indicator of your radio or tuner.
If you are having trouble achieving resonance, make sure the tube section lengths are correct and
they have been properly assembled. The radial system affects the tuning as well. Make sure you
have at a minimum, 16 radials, 30 feet long, symmetrically placed around the vertical. In-fact, a
very low SWR might indicate a poor ground radial system. The top section may be adjusted to vary
the overall length from 33 to 36 feet for fine tuning adjustment if necessary.
