Vertical Dipole Array Calculator

Instructions

This calculator determines the approximate dimensions of a vertical dipole array. A vertical dipole array consists of multiple dipole antennas arranged vertically to increase gain in a particular direction.

Input:

• Enter the desired operating frequency in Megahertz (MHz).
• Enter the number of dipoles in the array (minimum 2).
• Enter the spacing between the dipoles in wavelengths (e.g., 0.5 for half-wavelength spacing).

Calculation: Click the "Calculate" button. The calculator will determine the length of each dipole, the spacing between dipoles (in chosen units), and the total height of the array.

Units: Use the buttons to toggle between imperial (feet and inches) and metric (meters and centimeters) units for the results.

Formula (Approximation):

Metric:
Dipole Length (meters) = 142.5 / Frequency (MHz)
Spacing (meters) = Spacing (wavelengths) * (300 / Frequency (MHz)) / 2
Array Height (meters) = (Number of Dipoles * Dipole Length) + ((Number of Dipoles - 1) * Spacing)
Harness Length (meters) = Spacing / 2 (This is an approximation)

Imperial:
Dipole Length (feet) = 468 / Frequency (MHz)
Spacing (feet) = Spacing (wavelengths) * (984 / Frequency (MHz)) / 2
Array Height (feet) = (Number of Dipoles * Dipole Length) + ((Number of Dipoles - 1) * Spacing)
Harness Length (feet) = Spacing / 2 (This is an approximation)

Important Considerations:

• These calculations provide a starting point. The actual performance of the array can be affected by many factors, including the height above ground, the diameter of the wire or tubing used, the type of feed system, and nearby objects.
• The harness lengths given are approximations. The actual harness lengths may need to be adjusted based on the specific design and impedance matching method used.
• For more precise design and tuning, especially for transmitting arrays, it is highly recommended to use antenna modeling software and an antenna analyzer to measure the SWR and make necessary adjustments.
• Always observe safe practices when working with antennas, especially regarding power levels and heights.