Moxon antenna
A rugged two-element parasitic array with high front-to-back ratio.
The Moxon antenna, or Moxon rectangle, is a rugged two-element parasitic array built for a single frequency. It was named after Les Moxon (G6XN), an amateur radio operator and antenna handbook author. The design uses a rectangular shape where slightly less than half serves as the driven element and slightly more than half as the reflector. It functions as a two-element Yagi-Uda antenna with folded dipole elements and no directors. Because the ends are folded, each element is about 70% of the length of a standard dipole. This setup provides modest directivity of roughly 2.0 dB, with a null to the rear that can produce a front-to-back ratio as high as 9.7 dBi at 28 MHz. Since the reflector’s size and placement depend heavily on wavelength, the antenna only works properly on the band it was designed for. Portable Moxon rectangles are popular among amateur radio operators for field day and emergency communications due to their light weight and strong build. In construction, the driven element is slightly shorter than a half-wavelength, and the reflector is slightly longer. Their ends connect through an insulator. The layout resembles the VK2ABQ-square. For shortwave bands, spreaders are often bamboo or fiberglass, carrying wire elements, which keeps wind load and weight low. At VHF and UHF, the antenna is small enough to be made from 3/8 to 3/4 inch aluminum tubing, which offers broader resonant bandwidth without excessive wind load. L.B. Cebik (W4RNL) performed detailed comparisons and calculations of various Moxon versions, and Maguire (AC6LA) provides a calculator based on Cebik’s empirical formulas.
- Type
- Two-element parasitic array
- Elements
- Driven element (radiator) and reflector
- Directivity
- About 2.0 dB
- Front-to-back ratio
- Up to 9.7 dBi at 28 MHz
- Element length
- Approximately 70% of equivalent dipole length
- Designer
- Les Moxon (G6XN)
Lore & Background
The Moxon antenna takes its name from amateur radio operator and antenna handbook author Les Moxon (call sign G6XN). Its design is rectangular, with slightly less than half of the rectangle being the driven element and the other part (slightly more than half) being the reflector. It is a two-element Yagi-Uda antenna with folded dipole elements and no director. Because the placement and size of the parasitic reflector depend highly on wavelength, each Moxon antenna functions properly only on the frequency band for which it is designed. Portable Moxon rectangles are favored by radio amateurs for field day and emergency communications use due to their light weight and robust construction.
Reader's Guide
The Moxon antenna is popular among amateur radio enthusiasts for its simplicity of construction. The driven element is slightly shorter than a half-wavelength, and the parasitic reflector is slightly longer than a half-wavelength, with their ends mechanically connected by an insulator. The layout is similar to the well-known VK2ABQ-square. For shortwave bands, spreaders are commonly made of bamboo or glass-fiber reinforced plastics, carrying a wire radiator and reflector, resulting in low wind load and minimal weight. For VHF and UHF, Moxon antennas are small enough to be made from aluminum tubing (about 3/8 to 3/4 inch diameter) to take advantage of broader resonant bandwidth without excessive wind load. L.B. Cebik (W4RNL) made detailed comparisons and calculations of several versions, and Maguire (AC6LA) provides a calculator based on empirical formulas developed by Cebik.
Did You Know?
- The Moxon antenna is named after amateur radio operator Les Moxon (G6XN).
- Its element lengths are approximately 70% of the equivalent dipole length.
- The antenna achieves a front-to-back ratio up to 9.7 dBi at 28 MHz.
- Portable versions are favored for field day and emergency communications due to light weight and robust construction.
More in Antenna Types, Part 2 1-24
Spotted an error? Know more?
Reader corrections go straight into our review queue. Suggest an edit · How this site is sourced