Build a Lazy H Stacked Array
The Lazy H stacks two collinear pairs of in-phase half-wave elements one above the other, combining two separate sources of gain — the collinear pair's own broadside gain, and the extra gain from stacking two rows vertically. Each row forms a wire shaped roughly like the letter H, and two H's stacked give the design its name. It's a large antenna needing real estate and two supports, but it rewards that investment with meaningful bidirectional gain and a genuinely low radiation angle, historically a favorite for serious 20m and 15m DX work. This guide covers the complete build from element and phasing dimensions through feedpoint assembly and tuning.
The Collinear Row (Each "H")
Each horizontal row of the Lazy H is two half-wave elements placed end to end and fed in phase through a phasing section between them. Two in-phase collinear half-wave elements produce modest broadside gain over a single dipole — the current in each element flows the same direction at the same time, reinforcing the far-field pattern broadside to the wire run.
The Stacking Gain (Two Rows Combined)
Placing a second identical collinear row above or below the first, fed in phase with equal-length feedlines, adds stacking gain on top of the collinear row's own gain — the same principle used in stacked Yagi arrays for VHF/UHF contest stations, just applied here to a wire antenna. The combined effect of collinear gain plus stacking gain is what gives the Lazy H its reputation as a serious low-angle DX performer.
Feeding Both Rows in Phase
Both H rows must be fed with the same phase for the stacking gain to add constructively rather than cancel. The most common practical approach is to feed each row's own center-fed phasing point with an equal, electrically identical length of open-wire line, then combine both feedlines at a single junction point partway down to the shack (or feed each with its own line to a switchable phasing harness, if you want to explore feeding out of phase for a different pattern).
- Equal-length feeders: the simplest reliable way to keep both rows in phase — cut both feeder runs to the same electrical length.
- Support requirements: this design needs two support points at different heights (or one tall support with two crossarms) — plan your site accordingly before committing to this build.
Feedpoint Impedance and Matching
As with most collinear and stacked wire arrays, the feedpoint impedance doesn't land near a clean 50Ω and varies with exact geometry — feed with open-wire or ladder line into a balanced antenna tuner rather than expecting a direct coax match.
| Band | Element length (ft) | Collinear row span, 2 elements + phasing (ft) | Stack spacing at 0.5λ (ft) |
|---|---|---|---|
| 40m (7.15 MHz) | 65.5 ft | ~131 ft | 68.8 ft |
| 20m (14.15 MHz) | 33.1 ft | ~66.2 ft | 34.8 ft |
| 17m (18.1 MHz) | 25.9 ft | ~51.8 ft | 27.2 ft |
| 15m (21.2 MHz) | 22.1 ft | ~44.2 ft | 23.2 ft |
| 10m (28.4 MHz) | 16.5 ft | ~33.0 ft | 17.3 ft |
Lazy H Array Calculator
Materials for a complete Lazy H array
Building the Lazy H Stacked Array
This is one of the larger wire antennas on this site — plan your two support points before cutting any wire.
Plan Your Two Support Points
Confirm you have two supports at heights separated by the stack spacing from the calculator, or one tall mast with crossarms at both heights. This design's footprint is set by the collinear row span, not just a single dimension.
Cut All Four Elements
Cut four identical half-wave elements to the length from the dimensions table, each about 3% long for final trimming.
Build Each Collinear Row
For each row, connect two elements end to end through a half-wave phasing section, keeping both elements in the same straight line. Attach end insulators and support rope at the outer ends of each row.
Establish Each Row's Feedpoint
At the center of each row's phasing section, install a spreader block as the feedpoint tap for that row.
Run Equal-Length Feedlines from Both Rows
Cut two feeder runs of open-wire or ladder line, electrically identical in length, from each row's feedpoint down to a common combining point.
Raise Both Rows
Raise the lower row first, then the upper row, maintaining accurate stack spacing between them. Keep both rows level and parallel to each other.
Combine Feedlines and Route to the Shack
Join the two equal-length feeders at the combining point and run a single feedline from there to your balanced tuner.
Tune and Verify
Find a low-SWR tuner setting at your target frequency. If you have access to a field-strength meter or a distant station for comparison, confirm the expected low-angle, bidirectional pattern before considering the build finished.
| Symptom | Most likely cause | Diagnosis | Fix |
|---|---|---|---|
| No noticeable improvement over a single dipole | Feeders to the two rows not equal length, breaking the in-phase relationship | Measure both feeder runs from row to combining point | Re-cut whichever feeder is off to match the other exactly |
| Collinear row phasing section accidentally crossed | Confusing this build with a W8JK-style transposed feed | Check the phasing section wiring at each row's center | Re-wire straight through, no transposition, for in-phase collinear feed |
| Tuner can't find a low SWR | Feedline or phasing-section connection fault | Check continuity through all phasing sections and feeders | Re-solder connections; verify no shorts at spreader blocks |
| Rows sag unevenly or aren't parallel | Uneven support tension or mismatched support heights | Sight along both rows for level and parallel alignment | Adjust support rope tension; re-check support point heights |
| Gain seems underwhelming despite correct wiring | Stack spacing too tight, or installed height too low overall | Compare actual stack spacing and height to the calculator | Increase stack spacing toward 0.75-1.0λ if support height allows |
Why is it called a "Lazy H"?
Each row of two collinear elements with a center feedpoint tap, viewed from above, looks roughly like the letter H lying on its side ("lazy") — two vertical strokes (the phasing/feed points) connected by a horizontal crossbar (though in practice it's simply a straight run of wire, the shape is descriptive of the electrical layout).
Do I really need two separate support points?
Yes — the stacking gain that gives this design its performance specifically requires two rows at different heights. A single-row version is really just a 2-element collinear antenna with less gain and a different (still useful, just smaller) design.
How much real estate does this need?
Quite a lot — the collinear row span alone is roughly a full wavelength per row (two half-wave elements plus a phasing section), and you need two supports at the calculated stack spacing. This is a serious commitment antenna for operators with the space for it.
Can I feed the two rows out of phase instead?
Some experimenters do, to get a different radiation pattern, but the classic Lazy H design and its documented gain figures assume in-phase feed with equal-length feeders. Treat out-of-phase feeding as a separate experiment, not the standard build.
How does this compare to the W8JK array?
The W8JK uses close-spaced, out-of-phase elements to get gain from a compact footprint. The Lazy H uses in-phase collinear elements plus vertical stacking to get more total gain from a much larger footprint. They solve a similar problem (more gain than a dipole) with very different space/gain tradeoffs.
What height should the lower row be at minimum?
Aim for at least 0.5λ for the lower row so the whole array sits at a reasonable height above ground — much lower and both the collinear and stacking gain benefits are undermined by poor ground interaction.