The Rybakov Antenna

The Rybakov antenna has earned its place as one of the most practical and adaptable vertical wire antennas in amateur radio. Whether you operate portable, in the field, or from a small lot at home, this end-fed design delivers reliable multi-band performance with minimal effort and cost.

In this comprehensive guide, we’ll explore what makes the Rybakov antenna so effective, how it performs across the HF spectrum, and how to build one using common materials. It’s a design that combines simplicity with serious capability.

What Is a Rybakov Antenna?

The Rybakov antenna is a non-resonant, end-fed vertical wire antenna matched through an impedance transformer (usually a 4:1 or 9:1 unun) and typically used with an antenna tuner. It’s based on a simple concept: feed a long wire through an impedance transformer and let your tuner handle the rest. The result is a multi-band performer that’s surprisingly efficient for its size.

Most versions use around 7.6 to 8 meters (25 to 26 feet) of wire as the radiator, paired with a single counterpoise or several short radials. With an ATU, it can operate from 40 meters up through 10 meters—and sometimes even 6 meters. The length isn’t critical, but avoiding exact half-wave multiples helps maintain an easy match across bands.

The Science Behind Its Performance

As a vertical antenna, the Rybakov naturally produces low-angle radiation ideal for DX (long-distance) contacts. Unlike horizontal dipoles, which favor higher-angle radiation for regional work, the Rybakov focuses more of its energy toward the horizon.

Modeling shows that when properly installed over a modest radial or counterpoise system, the Rybakov delivers roughly 0 dBi gain at a 10° takeoff angle—typical for a short vertical but excellent for long-haul propagation.

The unun reduces the high feedpoint impedance of the end-fed wire (often between 200 and 600 ohms) down to a manageable range for your tuner and 50-ohm coax. This balance ensures low losses and effective power transfer across multiple HF bands.

Modeling and Theory Insights

NEC-based simulations and field measurements show that the Rybakov’s radiation efficiency depends heavily on ground losses and feedpoint height. Raising the feedpoint by just 1 meter can improve efficiency by 2–3 dB, and using a resonant or elevated counterpoise further sharpens the current distribution along the wire.

When modeled over average soil (conductivity 0.005 S/m, dielectric constant 13), the Rybakov demonstrates a broad current maximum near the lower third of the radiator, resulting in a useful compromise between bandwidth and stability. Adding even a few radial wires reduces ground loss by up to 30%, improving effective radiated power.

Building Your Own Rybakov

Constructing your own Rybakov is a straightforward weekend project. Here’s what you’ll need:

• Wire Element: 7.6–8m (25–26ft) of 14–18 AWG stranded copper wire
• Unun: 4:1 or 9:1 built on an FT-240-43 or FT-240-52 ferrite toroid (avoid powdered iron cores such as T200-2)
• Counterpoise: 4–5 meters (16 ft) of wire laid along the ground or slightly elevated
• Support: Fiberglass fishing pole, mast, or telescoping whip
• Feedline: 50-ohm coax such as RG-58 or RG-8X

To assemble: connect the radiator to the unun’s output terminal, attach your counterpoise to the ground lug, and feed your coax into the input. Adding ferrite beads or a choke balun (mix 31 or 43) near the feedpoint helps suppress common-mode currents and RF feedback.

4:1 vs 9:1 Unun — Which One Should You Use?

One of the most common questions about the Rybakov is whether to use a 4:1 or a 9:1 unun. Both can work effectively, but they behave differently depending on the wire length and frequency range you intend to cover.

4:1 Unun: Best suited for shorter radiators (around 7–9 meters) where feedpoint impedance typically falls between 150–300 Ω on most bands. It provides a closer match for a tuner and minimizes losses, especially on 20–10 meters. Many operators prefer this version for portable setups and when running moderate power levels.

9:1 Unun: Designed for higher impedances (400–800 Ω) and longer random-wire applications. It can improve matching on lower bands such as 40 m and 80 m when the radiator is longer than 8 meters or when the counterpoise system is minimal. However, on upper bands the impedance transformation can be excessive, increasing mismatch loss or tuner stress.

In practice, a 4:1 unun generally offers a better compromise for the standard Rybakov length (≈8 m), while a 9:1 may make sense if you extend the radiator for 80 m coverage or run it as a true “random wire” with no well-defined counterpoise.

Tip: If you’re unsure, start with a 4:1 unun — it will provide a smoother tuning curve across most of the HF spectrum for the classic 8 m Rybakov configuration.

Performance vs. Other HF Verticals

How does the Rybakov compare to other popular vertical designs? Here’s a look at how it stacks up against an EFHW and a quarter-wave vertical:

Common Mistakes and How to Fix Them

• Using the wrong core: Avoid powdered iron (e.g., T200-2); it saturates easily and causes loss. Use ferrite cores like FT-240-43 or 52.
• No choke balun: Always use ferrite beads or a choke to block RF on the feedline; otherwise, expect RFI and unstable tuning.
• Improper counterpoise length: Too short or missing counterpoises cause tuner difficulty. Try at least 4–5 meters and adjust if needed.
• Exact half-wave wire length: Avoid wire lengths that correspond to half-wave multiples; these create very high impedances that even tuners struggle with.
• Mounting too low: Keep the feedpoint and wire as high and clear as possible to reduce ground loss.

Testing Results and On-Air Performance

Using WSPR and FT8 digital modes, operators consistently report that the Rybakov punches above its weight. Even with QRP power (5 watts or less), signals often reach thousands of miles under average propagation conditions.

• Average WSPR reach: 6,000–9,000 miles on 20m and 15m (reported by operators)
• Steady DX contacts with 10–15 watts on FT8
• Good noise performance for a vertical antenna
• Stable SWR across HF when paired with a quality tuner

Deployment Tips and Variations

1. Vertical Mounting: The classic configuration for DX; elevate the radiator and keep it as vertical as possible.
2. Sloper Setup: Ideal for limited space—mount the feedpoint low and the wire at a 45° angle.
3. Inverted-L Variation: Combine vertical and horizontal elements for a blend of DX and NVIS coverage.
4. Counterpoise Placement: Lay out 1–3 wires radially to improve ground return and stability.

Even in small yards or portable setups, the Rybakov’s small footprint makes it easy to deploy quickly. Many operators use telescoping poles or push-up masts to keep it lightweight and field-ready.