Swiss Quad Antenna

| August 7, 2026 | Amateur Radio (Ham Radio) | No Comments

The Swiss Quad is a highly efficient directional loop antenna, developed in 1960 by Swiss amateur radio operator HB9CV. It is a unique variation of the traditional cubical quad that solves some of the mechanical fragility of the original design while also altering its electrical properties to improve performance.

How It Differs from a Standard Quad

A conventional two-element cubical quad uses one driven element and one parasitic element (a reflector or director), supported by an X-shaped frame of fiberglass or bamboo spreaders attached to a horizontal boom. The Swiss Quad throws out both the boom and the spreaders.

1. Phased Array (Electrical Design)

Unlike a standard quad, both elements in a Swiss Quad are driven. It is effectively a folded-loop version of the famous HB9CV phased array. The two loops are fed with a phase difference of approximately 180 degrees (usually via a double gamma match or T-match).This phased feeding creates a highly directional pattern with a very deep null off the back of the antenna.

2. Self-Supporting Structure (Mechanical Design)

Instead of using non-conductive spreaders, the horizontal top and bottom sections of the loops are made of rigid metal tubing (usually aluminium or copper).

  • The centers of these horizontal tubes are bent inward at a 45-degree angle until they meet at the central vertical support mast.
  • Because the exact center of a driven quad loop sits at zero RF potential, these metal arms can be bolted directly to the grounded mast without requiring insulators.
  • For HF bands, the vertical sides of the loops are simply made of wire strung between the rigid top and bottom tubes. For VHF/UHF bands, the entire structure is often made of tubing.

Advantages of the Swiss Quad

  • Superior Sturdiness:By eliminating the boom and the large, flexible X-spreaders, the Swiss Quad is mechanically much stronger and handles wind loads far better than a traditional quad.
  • Better Gain: The dual-driven phased elements provide slightly more forward gain than a standard parasitic two-element quad, performing closer to a three-element Yagi.
  • High Front-to-Back Ratio: The phasing creates excellent rejection of signals coming from the rear, making it highly effective for rejecting QRM (interference).
  • DC Grounded: Because the elements are physically clamped to the grounded mast, the entire antenna sits at DC ground. This bleeds off precipitation static, resulting in a significantly lower noise floor on reception, and offers better lightning protection.

Because of the physical size of the horizontal metal tubing required, Swiss Quads are most popular on VHF (2m and 6m) and the higher HF bands (10m, 12m, and 15m).