Maker & Reference
Antenna Length Calculator
Antenna length = (speed of light × velocity factor) / frequency. Cut your CB whip, ham dipole, or WiFi antenna to the right length.
Quarter-wave (in)
—
- Half-wave (in)
- —
- Full wavelength (in)
- —
- Dipole each leg
- —
FAQ
Why velocity factor? +
Antenna wire is slower than light in air. Bare wire VF ~0.95-0.98. Insulated wire 0.85-0.95. PVC-coated 0.80-0.85.
Common antenna frequencies? +
CB: 27 MHz. 2m ham: 144 MHz. 70cm ham: 440 MHz. FM broadcast: 88-108 MHz. WiFi 2.4 GHz. WiFi 5 GHz.