The two most popular configurations are the Diamond and Square. From a performance perspective there is no difference, in fact the element configuration may have many different shapes such as circular, triangle (Delta Loop), or rectangular. The key criteria is that the loop length must be nominally one wave length and the elements have to be symmetrical about a line through the feed point and bisecting the structure. Polarity is determined by were the feed point is located. On the bottom for horizontal and on the side (rotated 90deg) for vertical.

At Cubex Quads we use both configurations depending mostly on the desired band and other physical or mechanical considerations. Our large HF arrays are typically configured in the square or box and our smaller VHF (2m / 6m) and the EXPO series are Diamond configuration. The ARRL Antenna Book states that the diamond design is a superior mechanical design because the sloping element wires will shed water, thus reducing potential ice loading. We take issue with that premise, in fact we think it can be shown that the square is stronger and no more susceptible to ice loading then the diamond configuration and more importantly, it will support ice loads better.

Allow me to elaborate on our premise – first consider that the damaging stress for most spreader arms is not compression (the force down the axis of the arm) but the bending moment. I think it can be argued that when it is cold enough to freeze rain, an exposed element wire is colder and promotes freezing and therefore there is no run-off regardless of the angle. Considering this worst case that all element wires, regardless of orientation, will collect equal amounts of ice load; the Square configuration with it two supporting arms will be stronger.

Looking at the two figures below, visualize that the element wires above the boom are ice coated. If we assume that the 45 deg. sloping lines of the diamond collects less ice than horizontal lines, it follows that the two vertical parts of the square configuration will collect even less ice. Assuming that the ice load factor for the diamond sloping elements are each 0.5, (a total of 1). So in the diamond configuration this ice load of 1.0 is supported by only one arm or a 1:1 support ratio.

In the square case assume the horizontal wire element load is 1.0 and the two verticals are each 0.25 for a total of load of 1.5. Therefore with the square we have an Ice Load of 1.5 but with TWO arms resisting the fore and aft motion for a support factor of 2 to 1.5 or 33% stronger! This analysis can be refined, but I think it makes the point why we at Cubex Quads believe the square or box configuration is superior for large HF arrays. As an added benefit, the turning radius is smaller!

-We welcome alternative analyses-