RadioM1DLG

¼-wave ground-plane calculator

v1.0.0

Quarter-wave vertical radiator with 3–8 equal radials • radial droop and footprint drawing

01 Frequency & radials
02 Construction
03 Geometry

Radiator and radial cut lengths start at one quarter wavelength × the length factor. Droop changes only the mechanical footprint in this calculator.

DIMENSIONED LAYOUT

Your ground-plane

Starting cut lengths only. Mounting hardware, radial angle, mast coupling and surroundings affect resonance and feed impedance.

Formula, assumptions & accuracy

Radiator and each radial start at 0.25 × λ × the entered length factor. Radial horizontal reach = radial length × cos(droop); vertical drop = radial length × sin(droop).

Radials are assumed evenly spaced around the feedpoint. No exact feed impedance, matching, SWR, gain or radiation pattern is predicted.