When installing a wire antenna, avoid over tightening the wire. It’s best to leave a slight bend or sag in the wire. This helps prevent excessive tension, which can damage the wire, insulators, or support structures, and allows for flexibility during temperature changes or wind. A little slack ensures better longevity and performance of the antenna.

For longer wire antennas, it can be beneficial to use a pulley system with a counterweight. This setup allows the wire to adjust naturally to changes in tension caused by wind, temperature variations, or movement in the support structures. The counterweight helps maintain consistent tension without overstressing the wire or its attachment points, reducing the risk of damage and ensuring better long-term stability and performance of the antenna.

Mounting Advice for EFLW Antennas (EFLW51, EFLW37, EFLW22)

EFLW antennas (End-Fed Long Wire antennas) differ from EFHW antennas in that they are non-resonant designs and typically require lower feedpoint heights for effective operation. Below are the recommendations for deploying the EFLW51 (160–30m), EFLW37 (80–15m), and EFLW22 (80–10m):

EFLW51 (160–30m) As a Sloper

For DX on Higher Bands (40m–30m):

• Use a slope angle of 30–45° to favor low-angle radiation for DX.
• A feedpoint height of 7–10m is recommended for optimal performance on 40m and 30m.
• Raising the feedpoint helps reduce ground losses and enhance low-angle radiation.

For Regional NVIS Communication (160m, 80m):

• A steeper slope (60–75°) enhances NVIS radiation by directing energy upward.
• A feedpoint height of 3–5m works well for NVIS operation, especially on 160m and 80m.

For Multi-Band Use (160–30m):

• A 45° slope serves as a balanced compromise for NVIS and DX.
• A feedpoint height of 5–7m provides adequate performance across all supported bands.

Directivity:

The primary radiation is toward the lower end of the slope.
For steep slopes, significant upward energy is radiated, supporting NVIS communication.

EFLW37 (80–15m) As a Sloper

For DX on Higher Bands (20m, 17m, 15m):

• Use a slope angle of 30–45° for low-angle radiation to maximize DX capabilities.
• A feedpoint height of 5–7m is sufficient to achieve good performance on the higher bands.

For Regional NVIS Communication (80m, 40m):

• A steeper slope (60–75°) improves NVIS performance by enhancing upward radiation.
• A feedpoint height of 3–5m works well for NVIS on 80m and 40m.

For Multi-Band Use (80–15m):

• A 45° slope offers a good compromise for DX and NVIS applications.
• A feedpoint height of 5m provides balanced performance across the supported bands.

Directivity:

• Similar to the EFLW51, the dominant radiation is toward the lower endpoint of the slope.
• NVIS energy is directed upward with steeper slope angles.

EFLW22 (80–10m) As a Sloper

For DX on Higher Bands (20m, 17m, 15m, 10m):

• Use a slope angle of 30–45° to favor low-angle radiation for DX.
• A feedpoint height of 3–5m is sufficient due to the shorter wavelengths and the antenna’s design.

For Regional Communication (20m, 40m):

• A steeper slope (45–60°) directs more energy upward for local or regional coverage.
• A feedpoint height of 3–4m works well for NVIS on 40m and 20m.

For Limited-Space Installations:

• The compact size of the EFLW22 makes it suitable for small spaces like gardens or urban environments.
• A 30–45° slope with a feedpoint height of 3–5m delivers effective performance for DX and local communications.

Directivity:

• The shorter length of the EFLW22 results in sharper directivity toward the lower endpoint of the slope.
• Steeper slopes introduce additional upward energy, making it versatile for local and regional communication.

General Alternatives

Inverted V:

• Best For: Balanced NVIS and DX performance on lower bands (EFLW51 and EFLW37).
• Feedpoint Height: A minimum of 3m is sufficient for operation, but raising it to 5–7m improves overall efficiency and pattern.
• Radiation Pattern: Equal radiation in both directions perpendicular to the plane of the V.

Inverted U:

• Best For: Compact spaces and DX performance on higher bands ( EFLW51 and EFLW37).
• Feedpoint Height: 3–5m works effectively due to the shorter wavelengths and design.
• Radiation Pattern: Strongest radiation broadside to the open ends of the U.

Technical Considerations

• EFLW antennas are non-resonant, reducing the dependency on precise feedpoint heights for tuning and operation.
• Feedpoint height primarily affects radiation pattern and efficiency, especially on lower bands like 160m and 80m.
• For NVIS applications, feedpoint heights as low as 3m are effective, particularly for 160m and 80m with the EFLW51 and EFLW37.
• For higher frequencies (20m–10m), the shorter wavelengths allow the EFLW22 to perform efficiently even at modest heights like 3–5m.

Summary

EFLW51 (160–30m): Ideal for low-band NVIS and DX on higher bands like 40m and 30m with a recommended height of 5–10m.

EFLW37 (80–15m): Offers a versatile mix of NVIS and DX performance, with a minimum feedpoint height of 5m.

EFLW22 (80–10m): Optimized for higher frequencies, achieving excellent performance at modest heights of 3–5m.

This guidance ensures optimal performance for DX and regional communication based on your available space and desired operating bands.

 

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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.