Many antenna manufacturers and amateur radio operators seek a single-wire antenna that covers 160M to 10M or 80M to 10M efficiently. While some designs claim to offer multiband operation, the reality is that efficiency and performance degrade significantly on higher bands due to poor current distribution and undesirable radiation patterns.

Understanding the 2.5 Lambda Rule

One of the fundamental limitations of long-wire antennas is how current distribution changes as the antenna length increases beyond 2.5 wavelengths (λ) at a given frequency:

• Below 2.5λ, current distribution is still relatively stable, and the antenna maintains an efficient radiation pattern.
• Beyond 2.5λ, the current breaks into multiple lobes with poor gain, unpredictable takeoff angles, and increased losses. The energy no longer radiates effectively in useful directions for communication.

For example, an 80-10M EFHW (End-Fed Half-Wave) antenna designed for 40M resonance will work efficiently on harmonic multiples (e.g., 20M and 15M), but 12M and 10M become problematic due to:

• No strong resonance at those frequencies.
• Poor current distribution, leading to inefficient radiation.
• Lobe patterns becoming chaotic, reducing useful gain for DXing.

Are 160M-10M or 80M-10M End-Fed Long Wires Efficient?

Many commercial 160M-10M end-fed long-wire (EFLW) antennas use a 9:1 unun to match impedance. While these antennas appear to function across all bands, but their efficiency depends strongly on wire length, too long you loose higher frequencies, to short you loose lower frequencies.

Example: when the wire is about 50 meters (164 ft)

Efficiency acceptable up to the 30M band, but on 20M-10M it's suffering from poor radiation angles and gain and radiation lobes become highly irregular so the antenna pattern becomes suboptimal for DX.

Best Multiband Single-Wire End-Fed: The EFOC29

For those looking for the most efficient multiband single-wire end-fed antenna, the EFOC29 is the best tradeoff among end-fed designs. Unlike the standard EFHW, the EFOC29 offers better efficiency and covers more bands with usable gain:

• Operates effectively on 80M-10M.

• Less compromise compared to EFHW due to improved impedance behavior.

• 10M is still usable, although with some limitations.

• Better radiation efficiency than standard EFHW antennas.

For operators wanting a single-wire solution with the least compromise, the EFOC29 is the best choice.

The Doublet Fed with Ladder Line – A More Efficient Multiband Option but no a single wire one!

For those looking for a truly efficient multiband antenna, a center-fed doublet with ladder line is an excellent alternative. While it is not a single-wire antenna, it provides much better efficiency across multiple bands when paired with a good Z-match tuner.

An 80M-10M doublet works quite well across those bands, offering:

• A balanced radiation pattern
• Good impedance matching with ladder line.

A 160M-40M doublet, however, comes with trade-offs. The effectiveness depends largely on the length of the dipole wires:

• If optimized for lower bands (160M-40M), it becomes less effective on the higher bands.
• If optimized for higher bands (40M-10M), performance on the lower bands will suffer.

The doublet with ladder line remains one of the most efficient wire antenna solutions, but it still requires a compromise based on the bands of interest.

Conclusion: No “One Size Fits All”  Antennas

While some single-wire antennas claim to cover 160M to 10M or 80M to 10M, efficiency is often sacrificed on higher bands due to poor current distribution and chaotic lobes beyond 2.5λ. For serious DX or contesting, a single-wire antenna will always have limitations.

• The best tradeoff for a single-wire end-fed antenna is the EFOC29, which remains more efficient than a standard EFHW, covers more bands, and keeps 10M usable.
• The best multiband option overall remains a doublet fed with ladder line, which provides better efficiency across all bands, although it is not a single-wire antenna.

Read our article about using two antennas: Advice on Wire Antennas for Those with Limited Space

Article written by Joeri Van Dooren, ON6URE – RF engineer, antenna designer, and founder of RF.Guru. With extensive experience in active and passive antenna systems, high-power RF transformers, and custom RF solutions, Joeri shares insights into cutting-edge radio communication technologies.