EFHW8010

Flat Top @ 10M height

• 80m: Efficiency is moderate (78%) due to higher ground losses and transformer losses.
• Higher Bands (40m–10m): Efficiency improves significantly (88–96%) due to reduced ground losses and higher radiation resistance.

Band	Height Relative to λ	Low-Angle Radiation (<15°)	DX Suitability	NVIS Capabilities
80m	0.125 λ	Weak	Poor*	Excellent
40m	0.25 λ	Moderate	Moderate*	Strong
30m	0.34 λ	Moderate	Moderate*	Weak
20m	0.5 λ	Strong	Excellent	N/A
17m	0.67 λ	Strong	Excellent	N/A
15m	0.89 λ	Very Strong	Excellent	N/A
12m	1.11 λ	Compromised	Poor	N/A
10m	1.3 λ	Compromised	Poor	N/A

* If your goal is to improve DX performance on 80m, 40m, or 30m, raise the antenna to a height of at least 18M above the ground.

EFHW4010

Flat Top @ 10M height

• 40m: Efficiency is slightly reduced (86%) due to moderate ground losses and transformer losses.
• 20m–10m: Efficiency improves significantly (93–97%) due to reduced ground losses and higher radiation resistance.

Band	Height Relative to λ	Low-Angle Radiation (<15°)	DX Suitability	NVIS Capabilities
40m	0.25 λ	Weak	Poor	Strong
20m	0.5 λ	Strong	Excellent	N/A
15m	0.67 λ	Very Strong	Excellent	N/A
10m	1.0 λ	Outstanding	Outstanding	N/A

* If your goal is to improve DX performance on 40m, raise the antenna to a height of at least 15M above the ground.

EFHW16080

Inverted L ... 18M SpiderBeam pole

• 160m: Efficiency is slightly reduced (56%) due to ground losses and transformer losses.
• 80m: Efficiency improves significantly (93–97%) due to reduced ground losses and higher radiation resistance.

 

Band	Height Relative to λ	Low-Angle Radiation (<15°)	DX Suitability	NVIS Capabilities
160m	0.093 λ (Vertical Portion)	Weak	Poor	Strong
80m	0.187 λ (Vertical Portion)	Moderate	Moderate	Excellent

 

Inverted L ... 26M SpiderBeam pole

• 160m: Efficiency is moderate (65%) due to ground losses and transformer losses.
• 80m: Extremely high efficiency (~99.88%) because of high radiation resistance and low ground losses. 

Band	Height Relative to λ	Low-Angle Radiation (<15°)	DX Suitability	NVIS Capabilities
160m	0.16 λ (Vertical Portion)	Moderate	Moderate	Good
80m	0.33 λ (Vertical Portion)	Strong	Good	Moderate

 

EFHW8040

Inverted L ... 18M SpiderBeam pole

• 80m: Efficiency is moderate (78%) due to higher ground losses and transformer losses.
• 40m: Efficiency improves significantly (88–96%) due to reduced ground losses and higher radiation resistance.

Band	Height Relative to λ	Low-Angle Radiation (<15°)	DX Suitability	NVIS Capabilities
80m	0.187 λ (Vertical Portion)	Moderate	Moderate	Strong
40m	0.375 λ (Vertical Portion)	Strong	Good	Moderate

 

 

Inverted L ... 26M SpiderBeam pole

• 80m: Good efficiency (89%) with reasonable radiation resistance. 
• 40m: Very high efficiency (~94%) due to excellent radiation resistance and minimal ground losses.

Band	Height Relative to λ	Low-Angle Radiation (<15°)	DX Suitability	NVIS Capabilities
80m	0.33 λ (Vertical Portion)	Strong	Good	Moderate
40m	0.66 λ (Vertical Portion)	Very Strong	Excellent	Weak

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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.