What is a Yagi-Uda antenna?

A Yagi-Uda antenna is a directional antenna array consisting of a driven element (dipole), one reflector behind it, and one or more directors in front. The parasitic elements (reflector and directors) focus the radiation into a beam, increasing gain in the forward direction.

How accurate are these calculations?

They are wavelength-scaled starting dimensions, not a published optimized Yagi design. Element diameter, conductive boom effects, feed method and environment can change resonance, impedance, gain and front-to-back ratio. Model and measure before final cutting.

What material should I use for the elements?

Aluminum tubing or rod is the most common choice for its low weight and good conductivity. The diameter of the element affects the optimal length slightly; thinner elements (smaller diameter-to-wavelength ratio) need to be trimmed slightly longer. This calculator uses standard thin-element assumptions.

Can element count determine Yagi gain?

No. Element count alone does not determine gain. Boom length, spacing, element diameter, tuning and losses matter, so this calculator does not claim a gain value without electromagnetic modeling.

What is the driven element and how do I feed it?

The driven element is the active dipole connected to your feedline. It is typically a folded dipole or a split dipole with a balun. The calculator gives its total length; for a split dipole, cut it in half at the center feed point.

Can I use this calculator for Wi-Fi Yagis?

Yes. Enter 2400 MHz for 2.4 GHz Wi-Fi or 5800 MHz for 5.8 GHz. The resulting elements will be very short (a few centimeters), so precision cutting is important at these frequencies.

Yagi Antenna Calculator

Create a Yagi-Uda starting layout from frequency and element count, then control reflector spacing, director spacing, shortening factor or total boom length.

Antenna Parameters

Frequency (MHz)

Common: 144 MHz (2m), 432 MHz (70cm), 2400 MHz (Wi-Fi)

Number of Elements

2 = reflector + driven; 3+ adds directors

Element Length Scale

Rule-of-thumb shortening multiplier; tune the built antenna.

R–DE spacing (λ)

Director spacing (λ)

Target Boom Length (optional, mm)

For 3+ elements, overrides director spacing and distributes directors evenly.

Band Quick-Select

Set frequency and element count, then click Calculate.

Results include element lengths and boom spacing.

Frequency

Wavelength

Boom Length

RF Validation

Model + measure

Element Dimensions

Element	Type	Length (mm)	Length (cm)	Length (in)	Spacing from Previous (mm)	Pos. from Refl. (mm)

Antenna Diagram (top view, not to scale)

Design Notes

Method and engineering limits

This quick calculator scales a heuristic geometry; it does not reproduce an optimized DL6WU, NBS/NIST or other named design. Practical implementations must account for physical-build limitations including element diameter, boom/mounting corrections, impedance matching, and tuning, as outlined in NBS Technical Note 688.

References: NIST/NBS Technical Note 688 and NIST CODATA c. Use NEC modeling and an antenna analyzer before transmitting. Numeric inputs are calculated locally in your browser.

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Summary

This calculator scales a transparent rule-of-thumb Yagi-Uda starting layout from the free-space wavelength. You can adjust the element shortening factor, reflector-to-driven spacing, director spacing, or set a target boom length. Dimensions are construction starting points—not an electromagnetic optimization—because element diameter, boom interaction, feed system and surroundings affect resonance, impedance, gain and pattern. Verify the design with NEC modeling and an antenna analyzer before use.

How it works

Enter the target center frequency in MHz.
Select the number of antenna elements (2 to 12).
The calculator derives the free-space wavelength from the frequency.
Element lengths are computed from the displayed heuristic wavelength ratios and length scale.
Set spacing ratios directly or enter a target boom length to distribute directors evenly.
Results are displayed as a table with lengths in mm, cm, and inches plus total boom length.

Use cases

Designing a ham radio Yagi beam antenna for VHF or UHF bands.
Building a high-gain TV receiving antenna for a specific channel frequency.
Planning a point-to-point Wi-Fi link antenna for 2.4 GHz or 5.8 GHz.
Academic study of antenna design and electromagnetic wave propagation.
Verifying dimensions of a commercial Yagi against published specifications.
Cutting elements to length before assembling a homebrew antenna project.
Producing a geometry draft to transfer into NEC antenna-modeling software.
Scaling an existing design to a different operating frequency.

Frequently Asked Questions

Last updated: 2026-09-30 · Reviewed by Nham Vu