Precision Antenna Calculations. Instant & Accessible.
A modern, mobile-responsive alternative to clunky legacy tools. Large typography, zero layout shift, and 100% client-side physics executing right in your browser.
Antenna Engineering Suite
Select an antenna calculator below to access dedicated formulas, interactive wire schematics, and cut specs.
Half-Wave Dipole
Calculate exact cutting dimensions for quarter-wave legs and full dipole spans. Supports flat-top (468/f) and Inverted-Vee (455/f) configurations with dual imperial & metric display.
End-Fed Half-Wave (EFHW)
Design multi-band end-fed antennas with 49:1 and 64:1 UNUN impedance transformers. Includes bare vs insulated wire velocity factors and automatic harmonic resonance mapping across HF bands.
Moxon Rectangle Beam
Precision 2-element directional beam dimensions. Computes dimensions A, B, C, D, and E with millimeter accuracy based on wire gauge (AWG) or tubing diameter for a direct 50Ω coaxial feed.
Coax Cable Attenuation & SWR
Calculate actual RF decibel loss and power dissipated in coaxial transmission lines. Accurately factors in additional reflected wave losses caused by load SWR for 10 common coax types.
Engineering References & Standards
Frequently Asked Questions
Are online antenna calculators accurate for real-world building?
Yes, but they provide a mathematical starting point (free space). Local ground conductivity, nearby structures, and wire insulation will require you to physically trim or tune the antenna slightly after building.
What is the best ham radio antenna for a beginner?
A standard half-wave dipole or an End-Fed Half-Wave (EFHW) are the best starting points. They are inexpensive, easy to calculate, and perform excellently on HF bands.
Does an SWR meter or antenna analyzer replace the need for an antenna calculator?
No. A calculator gives you the exact dimensions to cut your wire before you put it in the air. An analyzer is used after the build to fine-tune those initial measurements.