Front, Back, and 0°: Why Phasing Still Needs a Convention

A recent discussion between Joeri Van Dooren, ON6URE, and Hugo Cnudde, ON7FU, started with a deceptively simple question: in a crossfire-fed 4-square, what exactly do we mean by front, back, and 0°? The longer you stay around phased arrays, the more obvious it becomes that these words are not nearly as fixed as many diagrams make them look.

That matters, because real confusion often starts long before anyone has made a technical mistake. It starts when two competent people are looking at the same array through two different labeling systems.

Crossfire Is Not Just “Ordinary Phasing with Better Marketing”

Crossfire is not simply classic single-band phasing with a prettier schematic. Tom Rauch, W8JI, describes crossfire as a method that progressively transposes phase by 180°, causing the network to behave more like time delay than simple phase delay as frequency changes. That is exactly why crossfire remains attractive for wideband receive arrays: it holds its directional behavior over a wider frequency span than a narrow, single-frequency phase-only solution.

That same broad theme shows up in the ARRL material around John Devoldere, ON4UN’s Low-Band DXing, where receiving antennas and phased arrays were treated as a major area of development, not as a trivial re-labeling of older 4-square ideas.

But the discussion between ON6URE and ON7FU was not really about whether crossfire is real. It was about something more slippery: notation.

The Physics Stays Put... The Bookkeeping Moves

On his own four-square material, W8JI notes that he placed the phasing common point in the direction of maximum radiation. He also points out that the 240° lead he needed is electrically the same as a 120° lag. That exposes the heart of the problem in one clean sentence.

The array currents do not magically change because one author writes a phase relationship as a lead, another writes it as a lag, and a third moves the 0° reference to a different branch. The antenna does not care what the diagram calls “zero.” The lobes, nulls, and current relationships are the real thing. The labels are just accounting.

That is why two phase tables can look different and still describe the same physical array.

Where the Convention Starts to Slip

In well-known ON4UN receiving-array examples, the front element is often shown as the no-delay branch, with the two side or center elements taking the intermediate branch and the rear element taking the long-delay path. In that style of notation, the front element is the 0° element.

Yet other published ON4UN material, including the well-circulated Dayton 2005 slide deck for four-square feeding, explicitly uses the back element as the reference branch. In that presentation, the back element is the reference signal, the center elements are derived from the phasing network, and the front element is shown as the more lagging branch. Same family of array behavior... different reference choice.

That is the point many people miss. The apparent contradiction is often not in the antenna at all. It is in the choice of which branch gets called 0°, and in whether the author is writing phases as lag, lead, or modulo-360 equivalents.

So when one diagram says front = 0° and another says back = 0°, the first question should not be, “Which one is wrong?” The first question should be, “What is the reference?”

Why ON6URE and ON7FU Could Both Read It Differently

That is exactly why the discussion between ON6URE and ON7FU was so easy to start and so hard to finish. ON7FU was reading the no-delay front-element notation, which is a perfectly fair reading. ON6URE was looking at the same physical phasing through a different reference branch and a different way of writing the angles. Both were looking at the same real antenna array. They were just not using the same bookkeeping.

There is another layer to the confusion as well. Many of us instinctively picture a receiving array from the direction the signal arrives from, while others picture it from the direction the array points toward. Those are not the same viewing convention. Add that to moving 0° references, plus lead-versus-lag notation, and it becomes very easy for two experienced operators to sound far more opposed than they really are.

Without That, the Words Are Too Slippery

Without those labels, front, back, and 0° are too slippery to stand on. A diagram may be internally correct and still be externally confusing, simply because it does not tell the reader where its reference lives.

This is not a purely academic complaint. It affects how builders wire switching networks, how readers interpret arrows on diagrams, how people compare one author’s work to another’s, and even how they argue about whether a diagram is “backward.” In many cases, the antenna is not backward at all. The chosen reference convention is just unstated.

Maybe What Low-Banders Need Is a Convention

That, to me, is the real lesson from our discussion. Crossfire is real. Its wideband advantage is real. The network topology is real. But the language wrapped around it is often not standardized.

When one author says front = 0° and another says back = 0°, the real question is not who made the bigger mistake. The real question is: what is your reference, and what exactly are you plotting?

Maybe what low-banders need now is not another circular argument over arrows and labels.

Maybe we do need a convention?

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