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A Physically Short 160 Meter Antenna Design of The Off-Center Loaded Dipole Antenna Southern New England NAVMARCORMARS NNNOIAD A Physically Short 160 Meter Antenna Design of The Off-Center Loaded Dipole Antenna • Step 1: Determine the overall physical length based on where you plan to install the antenna. • Step 2: Determine the physical length between the center insulator of the dipole and the loading coils. Ten to fifteen feet is recommended so that the center support will provide support for the weight of the coils, otherwise the dipole will sag. • Step 3: Calculate the coil reactance ( XL ) with the provided formula. • Step 4: Use the reactance to calculate the coil inductance (L). • Step 5. Use the inductance to calculate the number of turns required to build the coil. Southern New England NAVMARCORMARS NNNOIAD A Physically Short 160 Meter Antenna Review of The Reactance-Impedance Curves • Resonant Frequency formula derived from reactance calculations: • Tuned circuits operated below the resonant frequency “look” capacitive relative to the source energy. • Tuned circuits operated above the resonant frequency “look” inductive relative to the source energy. Southern New England NAVMARCORMARS NNNOIAD A Physically Short 160 Meter Antenna The Off-Center Loaded Dipole Antenna where: ln = natural log f = frequency A = overall antenna length B = distance from center to each loading coil, ft. D = diameter of radiator, inches Steps 1 & 2: Step 3: Coil Reactance Southern New England NAVMARCORMARS NNNOIAD A Physically Short 160 Meter Antenna The Off-Center Loaded Dipole Antenna Step 4: Step 5: Southern New England NAVMARCORMARS NNNOIAD