EFHW 160/80 Inverted L for F4VUX: Performance on Challenging Ground

This case study covers a deployment of the RF.Guru EFHW16080 4 kW High Power Inverted L Endfed Halfwave antenna, as installed by Marc, F4VUX, in the French Ardennes. The site features acidic, sandy loam soils over weathered schist or granite — far from ideal RF ground. Yet the antenna performs strongly on both 160 m and 80 m, with particularly good NVIS results on 80 m.

Installation Configuration

• Callsign: F4VUX (Marc)
• Location: French Ardennes
• Antenna: RF.Guru EFHW16080 4 kW High Power Inverted L (68:1)
• Feedpoint Height: ~25 cm above ground, near house wall
• Vertical Section: 8 m up
• Horizontal Section: ~69.5 m horizontal
• Counterpoise: 1 m wire to RVS ground stake
• Line Isolator: 9 kW Wide Band HF +30 dB CMR isolator at 5–10 m from feedpoint

Ground Conditions

Soil is acidic, sandy/loamy, with poor conductivity. Despite this, SWR remained manageable with a tuner:

SWR Measurements

• 80 m:
  • Dip: 1.1:1 @ 3515 kHz
  • 3.6:1 @ 3800 kHz
• 160 m:
  • Dip: 2.8:1 @ 1800 kHz
  • 6.6:1 @ 2000 kHz

The long horizontal wire improves NVIS coverage on 80 m. On 160 m, performance is reduced by lossy ground, but still tuner-serviceable.

Installation Notes

• Feedpoint proximity to the wall caused no significant imbalance thanks to proper choke placement.
• Poor soil conductivity unexpectedly smoothed 80 m SWR due to extra capacitive loading and decoupling.

Conclusion

This F4VUX deployment shows that even with poor soil and minimal vertical height, the EFHW16080 can provide strong results on 80 m (NVIS and mid-DX) and usable 160 m performance with a tuner. Correct isolator placement is key to maintaining balance and avoiding feedline radiation.

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