Moxon Antenna: The Compact Two-Element Beam for HF
Many operators would like a directional antenna but cannot fit or afford a full-size Yagi. The Moxon antenna, often called the Moxon rectangle, is one of the best answers. It is a two-element beam whose element ends are folded back towards each other, so it occupies a much smaller turning radius than a comparable Yagi. In return for that compact shape, it offers useful forward gain, an excellent front-to-back ratio and a feed point that can usually be connected to 50-ohm coax without a matching network.
This guide explains how the Moxon works, why its front-to-back ratio is so good, how it compares with other small beams, and how to build and tune one. It does not quote dimensions for particular bands. Moxon dimensions depend on frequency, wire or tubing diameter and construction, so use a dedicated Moxon dimension calculator or a modelling program to generate them for your materials.
What a Moxon Antenna Is
A Moxon antenna is a two-element parasitic beam: one driven element connected to the feed line, and one reflector that is not connected to anything. Both elements are bent into a U shape, and the open ends of the two Us face each other across a small gap. Seen from above, the whole antenna is a rectangle, about three-quarters as wide as a straight half-wave element.
The design is associated with Les Moxon, G6XN, who described bent-element beams, and it was later refined into the rectangular form that most builders use today. Its popularity comes from a combination of features that are hard to find together in a small antenna: a clean pattern, a strong rejection of signals from the rear, and a feed point impedance close to 50 ohms.
Driven element and reflector
The driven element is fed at its centre. The reflector is slightly longer, so it is tuned below the operating frequency, and it is placed behind the driven element. Current induced in the reflector re-radiates with a phase relationship that reinforces radiation in the forward direction and reduces it to the rear. This is the same principle as in a two-element Yagi-Uda antenna.
Why the folded tips matter
In a straight two-element Yagi, the elements interact mainly through their spacing. In a Moxon, the folded tips come close to each other, and the coupling across that tip gap adds to the coupling between the main element sections. Careful choice of tip length and gap lets the designer adjust that coupling to achieve a particularly deep null to the rear, while keeping the feed point impedance near 50 ohms. The gap is therefore one of the most important dimensions in the antenna.
Gain and Front-to-Back Ratio
A two-element beam cannot match the forward gain of a long Yagi with many elements. What the Moxon does unusually well is the front-to-back ratio, meaning how strongly it rejects signals arriving from behind. A well-built Moxon has a broad, deep rear null, which makes it valuable for reducing interference, for focusing on one direction in a pileup and for hearing weak stations under strong signals from the opposite direction.
Its forward gain is modest but real, and it is achieved with a wide forward beamwidth. That suits general DX operation, because you do not need to point it with great precision. The pattern also tends to remain reasonably clean across the band, rather than changing drastically between the bottom and top edges.
As with any horizontal antenna, height above ground strongly influences the elevation pattern and therefore the practical results. Our guide to antenna height and takeoff angle explains why a Moxon at a good height in wavelengths will outperform the same antenna mounted low.
Moxon vs Other Small Beams
The Moxon competes with several other compact directional antennas. The table below gives a general comparison. Real performance depends on construction, height and the specific design.
| Antenna | Turning radius | Front-to-back | Feed | Bands per antenna |
|---|---|---|---|---|
| Moxon rectangle | Smaller than a 2-element Yagi | Excellent | Usually direct 50-ohm coax | Usually one |
| Two-element Yagi | Full half-wave elements | Moderate | Often needs a matching network | One, or several with traps |
| Hexagonal beam | Compact, wire on a spreader frame | Good | Single feed for several bands | Several |
| Two-element quad | Compact, but tall | Good | Needs matching to 50 ohms | One or several |
| Rotatable dipole | Full half-wave | None, bidirectional | Direct coax with choke | One |
If you are deciding between a Yagi and a hexagonal beam, our comparison of Yagi and hex beam antennas covers the multiband options in more depth. The Moxon is usually the choice when you want the best possible pattern on one band in a small space.
Where the Moxon Shines
The Moxon is not the right answer for every station, but it fits several situations particularly well.
- Small lots and roofs: the reduced width and modest weight allow a beam where a full-size Yagi would not fit or would be too heavy for a light rotator.
- Single-band DX on the higher bands: on 10, 12, 15 and 17 metres, a Moxon is small enough to build from wire on a fibreglass spreader frame or from aluminium tubing.
- Six metres: a Moxon is a popular choice for 6 metre DX and sporadic E work, where a small, clean pattern and a direct coax feed are welcome.
- Portable and field operation: a lightweight wire Moxon on a telescopic mast can be turned by hand and gives a clear advantage over a dipole on field day or a DXpedition.
- Fixed-direction antennas: on the lower HF bands, a wire Moxon can be hung between supports and aimed permanently at a target area such as Japan or North America.
Building a Moxon
Construction methods vary widely, from wire on a light frame to all-aluminium designs. The general steps are similar whichever method you choose.
Calculate the dimensions
Use a Moxon dimension calculator or an antenna modelling program, and enter your design frequency and the actual diameter of the wire or tubing you will use. Conductor diameter has a noticeable effect on the correct dimensions. Our antenna modelling walkthrough shows how to check a design and see its pattern before you cut anything.
Choose a frame
Wire Moxons are commonly built on an X-shaped frame of fibreglass spreaders, with the wire forming the rectangle around the ends. The frame must be rigid enough to hold the tip gap steady, because small changes in the gap shift the tuning. Aluminium tubing versions use a boom with insulated element mounts and are more durable but heavier.
Hold the tip gap accurately
The gap between the tips of the driven element and the reflector is small and critical. Use insulating spacers or a non-conductive cord to fix it. If the gap changes in the wind, the pattern and feed point impedance change too.
Feed it properly
Connect the coax at the centre of the driven element and fit a common mode choke at the feed point. Without a choke, current on the outside of the coax can spoil the front-to-back ratio, which is the antenna’s main strength. Our guide to common mode chokes explains how to build or choose one.
Tuning and Checking a Moxon
A carefully built Moxon often needs little adjustment, but checking it properly is still worthwhile.
- Measure the feed point with an antenna analyser at a reasonable height, away from conductive objects. Measuring a beam close to the ground gives misleading results.
- Adjust the driven element to move the resonant frequency. Small changes in the length of the driven element tips usually do this.
- Check the front-to-back ratio on the air. Listen to a steady signal, such as a beacon or a cooperative station, and rotate the antenna. A deep null to the rear is the sign that the reflector and gap are right.
- Adjust the reflector only if needed. The reflector mainly sets the pattern; changing it shifts the frequency of best front-to-back and has some effect on the match.
Many builders mark their element tips with tape before adjustment, so that they can return to a known setting if a change makes things worse. Write down each step.
Rotating a Moxon
On the higher HF bands and on 6 metres, a Moxon is light enough for a modest rotator. Even so, consider wind load, ice and the strength of the mast. A small, lightweight antenna still applies leverage at the top of a mast. Our antenna rotator guide covers sizing a rotator and running control cables.
Because the Moxon’s forward lobe is broad, you do not need precise azimuth control. A rotator with coarse indication is often sufficient, which can make this a budget-friendly beam project.
Wire or Tubing?
The two main construction styles each have a place, and the right choice depends on the band, the weather at your location and how permanent the installation will be.
A wire Moxon on fibreglass spreaders is light, inexpensive and easy to transport. It is the natural choice for portable work, for the lower HF bands where tubing would be heavy, and for operators who want to experiment before committing to a permanent antenna. Its weaknesses are mechanical: wire can stretch, spreaders can flex in the wind, and the critical tip gap can move unless it is firmly secured. Ice loading on a wire frame can also distort the shape.
A tubing Moxon is rigid and holds its dimensions well, which keeps the tuning stable year after year. It handles wind better and looks tidier on a roof. It is heavier and more expensive, needs proper insulated mounts at the element centres and a mechanically sound way of supporting the folded tips. On 10 metres and 6 metres a tubing version is very manageable; on lower bands it becomes a serious mechanical project.
Some builders combine the two: tubing for the main element sections and wire for the folded tails, held in place by a non-conductive cord across the gap. This hybrid approach keeps weight down while giving better stability than a pure wire frame.
Common Moxon Mistakes
Most disappointing Moxons suffer from one of a handful of avoidable problems.
- Using dimensions for the wrong conductor size: a design calculated for thin wire will be off when built from thicker tubing, and vice versa.
- Testing too close to the ground: a beam measured at head height over the lawn shows a different resonance and match from the same beam on a mast.
- Letting the tip gap drift: a few centimetres of movement can noticeably reduce the front-to-back ratio.
- Skipping the choke: feed line current spoils the pattern and can make the rear null disappear.
- Nearby metal: a Moxon mounted close to other antennas, gutters or guy wires can be detuned and its pattern distorted. Keep it clear, or model the interaction.
The Bottom Line
The Moxon antenna is a compact two-element beam with folded element tips that make it smaller than a comparable Yagi. It offers modest forward gain, a broad forward lobe and an excellent front-to-back ratio, and it can usually be fed directly with 50-ohm coax. Calculate the dimensions for your actual materials, hold the tip gap accurately, choke the feed line and check the rear null on the air. For a single band in a small space, especially on the higher HF bands or 6 metres, few antennas offer as much performance for so little size and complexity.
Frequently Asked Questions
What is a Moxon antenna?
A Moxon antenna is a two-element parasitic beam made of a driven element and a reflector, both bent into a U shape with their tips facing each other. The result is a compact rectangle with a strong front-to-back ratio.
Is a Moxon better than a two-element Yagi?
For many builders, yes. A Moxon typically gives similar forward gain, a better front-to-back ratio and a feed point close to 50 ohms in a smaller turning radius. A Yagi can be easier to extend with more elements.
Can a Moxon antenna be fed directly with coax?
Usually, yes. A correctly dimensioned Moxon has a feed point impedance close to 50 ohms, so it can be fed directly with coax. A common mode choke at the feed point is still recommended.
How critical is the gap between the Moxon element tips?
Very critical. The tip gap sets the coupling between driven element and reflector, which affects both the front-to-back ratio and the match. Hold it steady with insulating spacers or a non-conductive cord.
Can a Moxon cover several bands?
A Moxon is usually a single-band antenna. Multiband versions exist with nested elements, but they are harder to tune. Many operators use separate Moxons or choose a hexagonal beam for multiband coverage.
Where do I get Moxon dimensions?
Use a dedicated Moxon dimension calculator or an antenna modelling program, entering your design frequency and the actual diameter of your wire or tubing. Published dimensions for other materials can be noticeably wrong for yours.