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The Dual Monoband Vertical Antenna Layout
The two full size quarter-wave monoband vertical antennas
making up the dual vertical array system must be properly
positioned. The example on the right shows a typical set up
where antenna 1 is toward the NE and antenna 2 is toward
the SW. You must adhere to the dimensions shown on the
next page for optimum performance. The placement of the
two vertical antennas in relation to each other is somewhat
critical. If the dimensions are more than five percent out of
specification, system performance can suffer.
The formula for determining the distance between each
antenna (1/4-wavelength) is:
246
L in Feet = ▬▬▬
MHz
Use 246 divided by the Frequency in MHz = Length in feet
Other spacing close to this value may work, but the characteristics of the main lobe will change. For
optimal gain, directivity and front-to-back, time spent in laying out a symmetrical installation will
pay solid dividends. The system is forgiving, but the best front-to-back is obtained when symmetry
is maintained and with each element resonant on the same frequency and with each antenna base at
the same elevation on flat land. Sloped land installations should not use one elevated and one
ground-mounted antenna.
The plots shown to the right are for a typical 40 meter
DXE-DVA
Dual Vertical Phased Array
pointing toward Europe (Northeast) is position number one on the DVA Control Console.
