EFOC17 Antenna Installation Guide

Thank you for your order! You have received 18 meters of high-quality antenna wire, 14 meters of coaxial cable (EXTRAFLEX-BURY-7), and a big ferrite choke, which can be used for various configurations. Below are approximate wire lengths required for different antenna setups.

1. Flat-Top (Horizontal) Configuration

• Recommended Antenna Wire Length: ±16-18 meters
• A classic setup where the wire is fully extended in a straight line, ideal for low-angle radiation and general HF coverage.
• Recommended Feed Point height is 5-8M

2. Inverted-L Configuration

• Recommended Length: ±15-17 meters (Horizontal: 9-12m, Vertical: 5-8m)
• The wire runs vertically for a section and then horizontally, often supported by a mast and a tree or pole.
• Good for both NVIS and DX operation, depending on height.
• Recommended Feed Point height is 5-8M
• The lowest section (bottom of the vertical part) needs to be 2-4M above ground

3. Inverted-U Configuration

• Recommended Length: ±14-16 meters (Vertical sections: 4-7m, Horizontal top: 6-10m)
• The wire is supported at two high points with a sagging section in between.
• Useful where space is limited, balancing horizontal and vertical radiation.
• Recommended Feed Point height is 4-6M

4. Sloper Configuration

• Recommended Length: ±16-17 meters
• One end is elevated, and the other slopes downward toward a lower anchor point.
• Provides directional properties and lower noise in some setups.
• Recommended Feed Point height is 5-8M
• The end of the sloper needs to be 3-4M above ground !

5. Choke Placement

The first 3.7 meters of coax braid acts as the counterpoise for the antenna. This section can be laid horizontally, or placed flat on the ground, but for optimal performance, slight elevation above ground is recommended to minimize losses. At 3.7 meters, you need to install the included choke (6 turns around the coax) to isolate the counterpoise from the rest of the feedline. 

6. Optimizing SWR Measurements

To achieve the best performance from your End-Fed Antenna, follow these key SWR optimization practices:

• Measure SWR Away from Nearby Objects: Keep your SWR meter and feedline away from large metal objects and structures that can distort readings.
• Check Multiple Frequencies: Take SWR measurements across different bands to ensure a broad resonance range.
• Avoid Coax Interference: Ensure your coaxial cable is properly routed and decoupled to prevent unwanted common mode currents from affecting SWR readings.

For more details on Optimizing SWR Measurements for End-Fed Antennas, visit: https://shop.rf.guru/pages/optimizing-swr-measurements-for-end-fed-antennas

7. Folding Back vs. Cutting Wire for Tuning

If your antenna needs tuning, consider folding back the excess wire instead of cutting it. This allows for easy adjustments without permanently altering the wire length. Folding back also helps maintain structural integrity and enables future modifications. If cutting is necessary, do so gradually and test the resonance after each adjustment.

For more details on folding back vs. cutting wire antennas, visit: https://shop.rf.guru/pages/folding-back-vs-cutting-wire-antennas-essential-tips-for-optimal-performance

7. Tuning

Start by focusing on the 40M band, ensuring that the SWR dip appears just before the band (near resonance). 

For 20M and 15M, the SWR dip should fall within the band, while on 10M, it will typically be slightly beyond the band.

Keep in mind that antenna height plays a major role in SWR behavior. To achieve a more consistent SWR across all bands, aim to mount the antenna above 8 meters.

These measurements were taken using 30 meters of coaxial cable.

Installation Tips:

• Insulation & Tension: Always use proper insulators and avoid excessive tension to prevent breakage.
• Height Considerations: Higher installations improve performance, but NVIS operation benefits from lower heights.
• Tuning: Lengths may need fine-tuning depending on local conditions and resonance.

For further assistance, feel free to contact us!