The quad-versus-Yagi debate has been running since the 1960s. It'll never end because both sides have legitimate points and nobody can agree on the measurements. I've built and used both. Here's my take without the tribal loyalty.

What a Quad Is

A cubical quad uses full-wavelength loop elements instead of half-wave linear elements. Each element is a square (or diamond) loop with a perimeter of one wavelength at the design frequency.

  • Driven element: one-wavelength loop, fed at the bottom center
  • Reflector: slightly larger loop (about 5% longer perimeter) behind the driven element
  • Director(s): slightly smaller loops in front

The loops can be square, diamond-shaped (rotated 45°), or triangular (delta loop). Square and diamond are most common. The shape affects mechanical construction but the electrical performance is nearly identical.

A two-element quad (driven + reflector) is the most common homebrew configuration. Three elements (add a director) offers more gain but much more construction complexity.

Gain Comparison: The Honest Numbers

This is where the flame wars happen. Quad proponents claim 1-2 dB advantage over equivalent Yagis. Yagi proponents say they're the same or the quad is worse.

What NEC modeling consistently shows (and what careful measurements confirm):

  • 2-element quad vs 2-element Yagi: The quad wins by about 1.5-2 dB. This is real. The full-wave loop captures more aperture than a half-wave element.
  • 2-element quad vs 3-element Yagi: About equal. The third Yagi element compensates for the aperture advantage.
  • 3-element quad vs 3-element Yagi: The quad wins by about 0.5-1 dB — but the mechanical complexity is enormous.

So the quad has a genuine gain advantage element-for-element. But adding elements to a Yagi is mechanically trivial (bolt on more aluminum tubing) while adding elements to a quad is a major structural project.

The Real Advantage: Low-Angle Radiation

Here's what I actually notice using quads on the air — not the gain difference but the pattern difference.

A quad's first sidelobe is further depressed compared to a Yagi's. For DX work, this means less wasted energy going upward and more energy at the low angles that actually reach distant stations.

The practical difference on 20m: my 2-element quad seemed to work DX about as well as a buddy's 3-element Yagi on the same band. Similar S-meter reports from DX stations. That tracks with the models showing roughly equal forward gain between those configurations.

Construction: Where the Quad Loses

A Yagi is metal tubes on a metal boom. Strong, proven, commercially available, relatively straightforward to build.

A quad is wire loops stretched between fiberglass or bamboo spreader arms on a central hub, mounted on a boom between elements. Every part of this sentence represents an engineering challenge:

Spreaders: Must be non-conductive (fiberglass, bamboo, G10 tubing), light enough not to overload the hub, stiff enough not to droop, and strong enough to survive wind. They break. I've replaced fiberglass spreaders on my 20m quad three times in four years.

Wire management: The loop wire is under tension from the spreaders. Temperature changes cause expansion/contraction. The wire can creep off the spreader tips over time. UV degrades insulation.

Hub design: Where the spreaders meet the boom — this is the point of maximum stress and the most common failure point. Commercial quad hubs (Spider beam, Lightning Bolt) work well but cost $50-100 per element.

Wind loading: A quad presents a large flat surface to wind. A 2-element 20m quad has roughly twice the wind load of a 3-element 20m Yagi with equivalent gain. Towers, rotators, and mast hardware must be rated accordingly.

Ice loading: When ice forms on wire elements, the weight increases dramatically. Spreaders that were fine dry suddenly have pounds of additional load. This is how quads die in winter climates. Ask the operators in Minnesota and Maine.

When a Quad Makes Sense

Limited element count situations. If you can only support two elements mechanically (light-duty rotator, small tower), a 2-element quad gives you 3-element Yagi performance. That's a legitimate advantage.

Wire antennas on a budget. A 2-element quad for 20m costs maybe $60 in wire, fiberglass poles, and hardware. A 3-element Yagi for 20m costs $300-500 for commercial aluminum elements and hardware, or $150+ for homebrew aluminum.

Multiband without traps. Nesting multiple quads on the same frame (20m loop inside, 15m inside that, 10m smallest) gives you a multiband beam without lossy traps. The loops don't interact much if properly designed. Spiderbeam builds their commercial product on this principle.

Where you already have bamboo. Seriously. If you live somewhere with access to strong bamboo (Pacific islands, Southeast Asia, tropical climates), bamboo spreaders are free and replaceable. Several DXpeditions have built quads from local bamboo.

When a Yagi Makes Sense

Reliability in weather. Aluminum survives what destroys quad wire and fiberglass. In areas with ice, heavy wind, or severe storms — Yagis outlast quads by years.

Multiple elements. Going from 3 to 5 to 7 elements on a Yagi is just a longer boom and more tubing. Going from 2 to 3 elements on a quad doubles the mechanical complexity. For maximum gain: Yagi.

Commercial availability. You can buy a high-quality Yagi from Cushcraft, Mosley, OptiBeam, or Force 12 ready to install. Commercial quads exist (Lightning Bolt, Cubex) but the selection is limited.

Maintenance. A Yagi on a tower can be ignored for a decade. A quad needs periodic inspection of wire connections, spreader tips, and hub integrity. I check mine twice a year.

My Experience: 2-Element 20m Quad

Built mine from two fiberglass spreader kits (DX Engineering bamboo-style poles, about $40 each), wire loops of 14 AWG stranded THHN, and aluminum boom with homebrew hubs.

Total materials cost: about $120. Construction time: a full weekend.

Performance: about 5.5-6 dBd forward gain with good front-to-back (20+ dB). Matches well to 50 ohms with a gamma match. Bandwidth is moderate — covers 14.000-14.350 MHz under 2:1 SWR.

Survived three years with two spreader replacements and one rewiring of the reflector loop (UV damage to the insulation caused a short at a spreader tip). Overall happy with it but the maintenance is real.

Would I build it again? Honestly — probably not. I'd buy a used 3-element tribander Yagi (Cushcraft A3S, $200-300 used) and have equivalent performance with less maintenance and more bands. The quad was a fun project and a learning experience. But for permanent installation, the Yagi's reliability wins for me.

The Delta Loop Alternative

A delta loop is a triangular full-wave loop — same electrical principle as the quad but with three sides instead of four. Advantage: only needs one upper support per element instead of four spreaders. Much simpler mechanically.

Two-element delta loop on 20m: wire from a single high point (tree or mast) down to two low points. Reflector behind it. Simple, cheap, effective. Performance matches the quad because it's the same antenna electrically — just a different shape.

If the quad concept appeals to you but the construction scares you: build a delta loop instead. Same gain, 75% less hardware.

Bottom Line

The quad has a real but modest gain advantage over element-equivalent Yagis. The Yagi has massive advantages in mechanical simplicity, weather survival, and scalability. For permanent installations, Yagis win on practicality. For homebrew experimenters and budget builders, quads offer more performance per dollar invested. Choose based on your situation, not tribal loyalty.