Yagi Antenna

Calculate basic Yagi element lengths, boom spacing, and expected performance for amateur radio bands.

Yagi

A directional beam with reflector, driven element, and directors. More elements usually increase gain, but also increase boom length and construction complexity.

Band

Design Frequency (MHz)

Number of Elements

Element Diameter (inches)

Yagi Formula

These are the sizing relationships used by this calculator.

Base Wavelength

lambda (m) = 299.792458 / f(MHz)

Diameter Correction

Correction factor = 1 - (Element diameter in inches * 0.02)

Element Length Heuristics

Reflector = lambda * 0.51 * Correction; Driven = lambda * 0.475 * Correction; Directors = lambda * (0.44 - 0.01 * n) * Correction

FAQ

What does this Yagi calculator estimate?

It estimates reflector, driven element, and director lengths along with spacing, boom length, and rough performance figures.

Is this enough to build a final Yagi design?

No. It is a practical starting point. Final optimization still benefits from antenna modeling and measurement after construction.

Antenna Calculators

Use these as starting dimensions

Real antennas still depend on environment, conductor diameter, insulation, feed method, and nearby structures. Expect to trim and retune.

Good field workflow

Cut slightly long when possible.
Measure with the feed system you will actually use.
Make small tuning changes and record each one.

Velocity factor note

Bare wire is commonly near 95%, but different conductors and insulated wire can shift the practical length enough to matter.