9-Circle vs 4-Square on 160, 80 and 40 Meters

A compact YCCC-style 9-circle is often assumed to be a major step above a good 4-square receive array. In practice, that is usually not what happens. On 160, 80, and 40 meters, both antennas live in the same compact high-directivity family, and both are being asked to cover a very wide frequency span from roughly 0.11 wavelength up to nearly 0.43 wavelength when the physical footprint stays around the 18 m class.

Pattern shape, RDF, and null quality always depend on symmetry, soil, feedline choking, phasing accuracy, and nearby reradiating structures. A clean installation matters as much as the headline geometry.

Start with the geometry, not the mythology

In the published YCCC 9-circle geometry, the center-to-outer spacing is 60 ft, or about 18.3 m, which makes the full array about 120 ft in diameter. A receive 4-square is usually described by side length rather than center spacing, and its electrical behavior shifts strongly with that choice. Around the 18 m class, the same physical spacing is only about 0.11 wavelength on 160 meters, about 0.22 wavelength on 80 meters, and about 0.43 wavelength on 40 meters. That means any compact array of this size is not operating in one clean regime. It is being stretched across three very different electrical worlds.

That alone explains why neither a compact 9-circle nor a compact 4-square is a universal winner from 160 through 40. Each is a compromise, and each compromise shows up differently as frequency rises.

The 9-circle is not a 9-element beam in one direction

This is the first big misunderstanding. A 9-circle does not behave like a classic 9-element beam pointed at one azimuth. In the YCCC concept, the basic beam-forming block is a 3-element inline array. The 3-inline, the 5-square, and the 9-circle all use that same core idea for each selected heading. What changes is the number of headings available, not a huge leap in single-heading aperture.

That is why the 9-circle feels better described as a steering convenience array than as a major raw-performance jump. You get more positions to listen in, but not a completely different class of directivity every time you rotate the heading selector.

Crossfire, end-fire, and what the 4-square really is

The 9-circle is fundamentally an end-fire system because each selected direction is generated by a 3-element inline arrangement. The common diagonal-mode receive 4-square is also not well described as a simple broadside array. In practical receive terms, it behaves more like a phased square or a crossed end-fire system than like a classic monoband broadside TX array.

Part of the confusion comes from transmit-array language. Broadside and side-mode thinking makes sense in many monoband TX discussions, but on a compact multioctave receive array the more useful question is much simpler: how does the phasing create useful nulls and forward directivity over a very wide frequency span? Once you frame it that way, the apparent difference between a 9-circle and a good 4-square becomes much smaller.

Why a good 4-square often lands in the same performance class

Published numbers put both designs in roughly the same directivity neighborhood when they are built as compact low-band receive arrays. In other words, these are not different leagues of antenna. They are different implementations inside the same small-lot, high-RDF category.

That is why a well-executed 4-square can sound every bit as convincing as a 9-circle in day-to-day use. Once two arrays are within about a couple of dB of each other in RDF, real-world variables such as arrival angle, polarization, local noise geometry, soil, and installation tolerances can easily flip which one sounds better on a given signal.

Where the 9-circle really does help

The 9-circle’s real advantage is not mystery gain. It is steering granularity. With eight headings every 45 degrees, it can point closer to the wanted azimuth or the dominant QRM source than a standard four-direction receive square. That matters most when the wanted DX or the strongest interference falls between the coarse headings of a 4-square.

In practical terms, the gain is often not “more signal” so much as “less compromise.” The beam crossover between adjacent headings is smoother, and that can be useful when the best listening angle is awkwardly placed between two standard 4-square directions.

Why the inactive elements matter, but not in the way people often think

Your instinct that the inactive elements are not irrelevant is correct. They are nearby conductors in the near field and they do couple. But it is better to think of them as parasitically coupled surrounding elements, not as simple lumped objects. They are part of the geometry, and the geometry has already been baked into the published 9-circle behavior.

So the presence of the six unused perimeter elements is not, by itself, the reason a 9-circle fails to pull away from a good 4-square. The bigger issue is that compact high-RDF arrays are brutally sensitive to installation quality. Missing chokes, asymmetrical feed routing, wires through the array interior, nearby metal, resonant verticals, support structures, or local reradiators can do more damage than the theoretical array choice ever fixes.

Band coverage makes the comparison even less dramatic

The published 9-circle concept was optimized primarily for 160 meters and then 80 meters, with 40 meters still usable but less directive. A compact 4-square shows a similar tradeoff in a different way: the larger you make it, the more it favors 160; the smaller you make it, the more the sweet spot shifts upward toward 80 and 40.

So when people compare a 9-circle and a compact 4-square across 160 through 40, they are often not comparing a superior and an inferior design. They are comparing two different compromises with different steering behavior, different sensitivity to errors, and different frequency priorities.

What the real-world result usually sounds like

On air, a clean 4-square often feels “just as good” because the big battle is usually not raw signal voltage. It is directivity versus local noise. Some 4-square phasing choices also trade a little RDF for cleaner sidelobe behavior, which can be exactly what matters when a specific off-angle QRM source is the real problem.

That is also why the 9-circle’s extra headings can be genuinely useful without turning it into a night-and-day winner. It may place the null or forward lobe closer to where you need it, but the underlying directivity class is still compact-array territory, not large-aperture territory.

When the 9-circle makes sense

A 9-circle is attractive when you want a compact footprint, strong rear rejection, and more heading choices without going to a much bigger site. It is especially appealing when your QRM environment is strongly directional and the useful listening azimuth often falls between the standard headings of a four-direction array.

When a 4-square is the smarter choice

A good 4-square remains the smarter choice when you want simpler mechanics, cleaner installation, less switching complexity, and performance that is already in the same compact-RDF class. If the 4-square is installed with excellent symmetry, proper choking, sensible spacing for the target band, and minimal nearby reradiators, it will often get surprisingly close to what a compact 9-circle delivers.

The real step beyond a very good compact 4-square usually comes from more aperture, not merely more headings. That means moving into larger receive-array families rather than expecting a compact 9-circle to behave like a completely different performance class.

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