End Fed Half Wave Antennas: Energy Efficiency and DX capabilities

End‑Fed Half‑Wave Antennas: Energy Efficiency and DX Capabilities

EFHW16080 — Inverted‑L

18 m Spiderbeam pole

• 160 m: Efficiency modest (~56%) from ground/transformer losses.
• 80 m: Higher efficiency (~93–97%) with greater radiation resistance.

Band	Height Rel. to λ (Vertical)	Low‑Angle (<15°)	DX	NVIS
160 m	≈0.093 λ	Weak	Poor	Strong
80 m	≈0.187 λ	Moderate	Moderate	Excellent

26 m Spiderbeam pole

• 160 m: Efficiency improves (~65%).
• 80 m: Very high efficiency (~99%+), low ground loss.

Band	Height Rel. to λ (Vertical)	Low‑Angle	DX	NVIS
160 m	≈0.16 λ	Moderate	Moderate	Good
80 m	≈0.33 λ	Strong	Good	Moderate

EFHW8040 — Inverted‑L

18 m Spiderbeam pole

• 80 m: Moderate efficiency (~78%).
• 40 m: Higher efficiency (~88–96%).

Band	Height Rel. to λ (Vertical)	Low‑Angle	DX	NVIS
80 m	≈0.187 λ	Moderate	Moderate	Strong
40 m	≈0.375 λ	Strong	Good	Moderate

26 m Spiderbeam pole

• 80 m: Good (~89%).
• 40 m: Very high (~94%).

Band	Height Rel. to λ (Vertical)	Low‑Angle	DX	NVIS
80 m	≈0.33 λ	Strong	Good	Moderate
40 m	≈0.66 λ	Very Strong	Excellent	Weak

EFHW4020 — Sloper / Flattop

Flattop @ 10 m

• 40 m: ~0.25 λ height — balanced NVIS/DX; low‑angle moderate, NVIS moderate–strong.
• 20 m: ~0.5 λ height — strong low‑angle DX; NVIS weak.

Band	Height Rel. to λ	Low‑Angle	DX	NVIS
40 m	≈0.25 λ	Moderate	Good	Moderate–Strong
20 m	≈0.50 λ	Strong	Excellent	Weak

Sloper @ 10–12 m feedpoint

• Slope 30–45° toward target area for best DX focus.
• Primary radiation is toward the low end of the slope; steeper slopes add upward energy for regional work on 40 m.

EFHW20 Monoband — Sloper / Flattop

Flattop

• @ 10 m (~0.5 λ): strong low‑angle radiation, excellent DX.
• @ 6–7 m (~0.3–0.35 λ): moderate low‑angle, good DX; some mid‑angle fill for regional QSOs.

Height	h/λ (20 m)	Low‑Angle	DX	Notes
≈10 m	≈0.50 λ	Strong	Excellent	Best for DX
≈6–7 m	≈0.30–0.35 λ	Moderate	Good	More mid‑angle energy

Sloper

• 30–45° slope toward desired DX azimuth; keep feedpoint as high as practical.
• Dominant lobe points toward the lower end of the wire; use to steer coverage.

Interested in more technical content like this? Subscribe to our updates.

Questions or experiences to share? Contact RF.Guru or join our feedback group.