HF antenna calculator
Pick an antenna type, move the controls and watch the drawing, the radiation pattern and the efficiency change. Everything is calculated in your browser: nothing is sent anywhere.
Half-wave dipole
The classic: two equal legs fed in the middle.
Results
SWR from 1.5 to 30 MHz and on 6 m
- Up to 2:1: straight into the rig
- 2:1 to 3:1: use the rig's built-in tuner
- Above 3:1: needs an external tuner
Hover or drag a finger across it, or use the arrow keys, to read the SWR and impedance at any frequency.