Why an EFHW Inverted-L for 80m/40m Outperforms a 10m or 13m long Quarter-Wave Vertical

Many hams consider using a 10m or 13m vertical with a tuner for multiple bands, but how does it compare to an End-Fed Half-Wave (EFHW) Inverted-L for 80m/40m? The differences in efficiency, radiation pattern, and matching losses make the EFHW Inverted-L a superior choice for practical operation.

1. Efficiency: Why the EFHW Wins

A 10m or 13m vertical is:

  • ¼-wave on 40m → Efficient with a good ground system.
  • ⅛-wave on 80m → High ground losses and poor efficiency.

On 80m, a 10m or 13m vertical is too short, leading to a very low radiation resistance (~1-5Ω) and high ground losses. While it works well on 40m, using it across both bands requires a matching network, introducing additional losses.

In contrast, an EFHW Inverted-L (such as those from RF.Guru) is:

  • Resonant, requiring no lossy matching networks.
  • Half-wave in length, ensuring higher radiation resistance (~2-5 kΩ).
  • Less ground-dependent, as the current is distributed along the antenna rather than concentrated at the base.

2. Radiation Pattern: The EFHW Offers More Usable Takeoff Angles

A 10m or 13m vertical has different radiation characteristics on each band:

  • On 40m, it radiates well at low angles for DX.
  • On 80m, it has high ground losses and less efficient NVIS performance.

An EFHW Inverted-L, when installed properly, provides:

  • A mix of low-angle radiation for DX and higher-angle radiation for NVIS (on 80m).
  • More consistent performance across both bands.

3. Matching & Losses

  • A 10m or 13m vertical requires a tuner, which adds insertion loss.
  • On 80m, the extreme mismatch leads to very poor efficiency in a tuner or matching network.
  • An EFHW Inverted-L uses a simple transformer (49:1 or 64:1), which is far more efficient than a reactive matching network.

4. Practical Considerations

  • A 10m or 13m vertical requires a ground radial system for best performance.
  • An EFHW Inverted-L can be installed more flexibly, requiring only one support.

Conclusion

While a 10m or 13m vertical works well on 40m, it performs poorly on 80m due to excessive losses. An EFHW Inverted-L is a better solution because:

  • Higher efficiency, especially on 80m.
  • A more balanced radiation pattern suited for both DX and NVIS.
  • Lower losses by avoiding inefficient matching networks.
  • Easier installation and tuning.

For high-performance multi-band operation, consider:

If you want to work 80m and 40m effectively, a properly installed EFHW Inverted-L is a far better investment than trying to force a 10m or 13m vertical to work inefficiently on lower bands.

Written by Joeri Van Dooren, ON6URE – RF, electronics and software engineer, complex platform and antenna designer. Founder of RF.Guru. An expert in active and passive antennas, high-power RF transformers, and custom RF solutions, he has also engineered telecom and broadcast hardware, including set-top boxes, transcoders, and E1/T1 switchboards. His expertise spans high-power RF, embedded systems, digital signal processing, and complex software platforms, driving innovation in both amateur and professional communications industries.