Why the EFOC17 is the Better Choice for 40M to 10M Operation
Why the EFOC17 is the Better Choice for 40 m to 10 m Operation
When selecting a wire antenna for 40 m through 10 m, two common choices emerge: the EFOC17 and the EFHW4010. While both cover similar ranges, the EFOC17 offers broader coverage, improved efficiency, and better current balance. Here’s why.
1. Impedance Matching: 4:1 vs 49:1
- EFOC17: Uses a 4:1 transformer, working with lower impedance → lower losses, more efficient power transfer.
- EFHW4010: Uses a 49:1 transformer to tame a 2.5–5 kΩ feedpoint → higher core losses, especially at higher power.
2. Counterpoise & Current Balance
- EFOC17: Uses a short counterpoise (via coax shield, ~3.7 m), making it an offset-fed design. Balanced current flow reduces feedline radiation.
- EFHW4010: Pure EFHW; works without explicit counterpoise but often carries more common-mode → higher RFI potential.
3. Band Coverage
- EFOC17: 40 m, 30 m, 20 m, 17 m, 15 m, 12 m, 10 m.
- EFHW4010: Only 40 m, 20 m, 15 m, 10 m.
Why it matters: The EFOC17 adds 30 m and 17 m — critical for CW/digital operators and mid-band DX.
4. Power Handling & Efficiency
The EFOC17’s lower transformation ratio means lower voltage stress and higher efficiency. It can handle more power with less heating, ensuring reliable contest and high-duty service.
5. Practical Installation
- EFOC17: Benefits from a simple coax choke; otherwise efficient and versatile.
- EFHW4010: Easier “plug-and-play,” but often less stable on all bands, and may require retuning at edges.
Final Verdict: EFOC17 Wins
- ✅ More bands, including 30 m and 17 m.
- ✅ Lower loss (4:1 vs 49:1 transformation).
- ✅ Higher power handling and efficiency.
- ✅ Balanced design → less RFI risk.
While the EFHW4010 is simple, the EFOC17 delivers better efficiency, more bands, and cleaner performance across 40–10 m. For serious multiband work, it’s the clear winner.
Mini-FAQ
- Why is 4:1 better than 49:1? — Lower ratio = less core stress, lower heat, and better efficiency.
- Which covers more bands? — EFOC17 adds 30 m and 17 m; EFHW4010 omits them.
- Do I need a choke? — Yes, both benefit. EFOC17 especially stable with a coax choke.
- Which is better for high power? — EFOC17. Lower ratio reduces core heating and improves voltage handling.
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