Enter your target frequency and get exact cut lengths for the most common ham radio antenna builds — dipole, vertical, and J-pole.
Use 0.95 for bare wire, 0.66–0.80 for coax, 0.97 for aluminum tubing.
The classic dipole — two equal legs fed at the center. The 468 constant accounts for the velocity factor of bare wire (vs. the theoretical 492 for speed of light). Each leg is half the total length. Most forgiving antenna to build and tune.
A vertical radiator of one quarter wavelength, requiring a ground plane of 2–4 radials at roughly 90° to the element. Simple and compact. The standard for mobile and base VHF/UHF installations.
Slightly longer than a quarter wave, the 5/8 wave vertical has lower radiation angle and modest gain (~3 dBi) over a quarter wave. Popular for 2m and 70cm mobile antennas where low-angle radiation is an advantage.
A half-wave radiator fed with a quarter-wave matching stub (the "J" shape). Requires no ground plane, making it ideal for portable and rooftop installations. The long element is ½λ, the stub is ¼λ, with a 2" gap at the feed point.