Ham Radio Antenna Calculators
Fourteen antenna calculators covering every common HF and VHF antenna type — dipoles, Yagis, Moxon rectangles, cubical quads, delta loops, J-poles, end-fed half-waves, loading coils, traps, and bandwidth. All calculations run in your browser with no data sent anywhere.
Half-Wave Dipole Length Calculator
Calculates each arm length and total span for a horizontal or inverted-V half-wave dipole. Applies the standard end-effect velocity factor for wire or tube elements.
Yagi Antenna Element Length Calculator
Generates a complete element length and spacing table for 2–11 element Yagis using DL6WU-based scaling, with boom correction for aluminium booms.
Moxon Rectangle Dimension Calculator (Cebik Equations)
All five Cebik dimensions (A–E) for any frequency. Includes wire cut lengths, frame size, and installation notes. Works for any HF or VHF band.
Cubical Quad Element Calculator
Full-wave loop dimensions for 1, 2, or 3-element quad antennas. Outputs side length, circumference, spreader arm length, and total wire required.
Full-Wave Delta Loop Calculator
Equilateral triangle loop dimensions — total wire, side length, apex height, base width, and phasing line for a two-element beam.
J-Pole Antenna Dimension Calculator
Radiating element length, matching stub length, and approximate feed tap position for any frequency. Works for 2m, 70cm, 1.25m, and HF J-poles.
EFHW Wire Length and UNUN Calculator
Half-wave wire length for any band, plus 49:1 UNUN winding specification for FT-140-43 or FT-240-43 toroid. Includes multi-band harmonic coverage.
Quarter-Wave Vertical and Radial Calculator
Vertical element length, radial lengths for angled or flat radials, and estimated feed point impedance for various radial configurations.
Base Loading Coil Calculator
Required inductance to resonate a short vertical or mobile whip, plus Wheeler formula coil winding specification.
Antenna Trap LC Calculator
Calculates inductance and capacitance for a parallel LC trap resonant at a specified frequency, with coil winding details.
Antenna Gain dBd ↔ dBi Converter
Convert between dBd (referenced to dipole) and dBi (referenced to isotropic). Also converts to ERP and EIRP given transmitter power.
Inverted-V Dipole Height and Span Calculator
Given apex height and desired arm angle, calculates horizontal span, tip height above ground, and effective arm length.
Antenna SWR Bandwidth and Q Calculator
Estimates SWR 2:1 bandwidth from element diameter and resonant frequency. Also converts between Q, bandwidth, and resonant frequency.
Yagi Stacking Distance and Gain Calculator
Optimum vertical and horizontal stacking distance for two identical Yagis, combined gain estimate, and power splitter notes.