TermiLoop vs Other Terminated Antennas: A Practical Comparison
Terminated antennas offer simplicity: broad frequency coverage, reduced sensitivity to height, and less need for external tuners. But not all designs perform equally well. In this article, we compare the TermiLoop™ to commonly used terminated antennas like the BBTD, T2FD, and commercial broadband systems such as the B&W BWD-90.
What is the TermiLoop?
The TermiLoop is a terminated, folded off-center-fed wire antenna with a matched 4:1 UNUN at the feedpoint and a non-inductive terminating resistor near the far end. It is designed to operate from 160 to 10 meters, and becomes effectively tunable with most internal tuners when installed at heights over 5 meters above ground and only 14 to 6 m wide.
- On 160, 80, and 60 meters, it supports NVIS-type coverage
- On 40 to 10 meters, it performs similarly to an off-center-fed antenna with a low-angle DX pattern
The basic version is rated for 100 W FT8 and 250 W SSB, while a higher-power version is available, rated for 800 W FT8 and 1.5 kW SSB.
Comparison Table
| Antenna Type | Folded Geometry | Feedpoint Type | Terminated | Multiband | QRO Capable | Efficiency (80m) | Pattern Use |
|---|---|---|---|---|---|---|---|
| TermiLoop | Yes | Off-center + 4:1 UNUN | Yes | Yes | Yes (up to 1.5 kW SSB / 600 W FT8) | Moderate to good | NVIS + DX hybrid |
| T2FD | Yes | Symmetric + 4:1 | Yes | Yes | Sometimes | Low to moderate | NVIS only |
| BBTD | No | Symmetric + 9:1 | Yes | Yes | No | Low | NVIS only |
| B&W BWD-90 (BBTA) | No | Symmetric + 4:1 | Yes | Yes | Limited | Low | Broad NVIS |
Notes on Other Designs
T2FD (Tilted Terminated Folded Dipole)
- Developed for shortwave NVIS applications
- Efficiency generally remains low, especially on lower bands
- Choking is often required to suppress common-mode currents
- Not typically intended for digital modes or long-duty-cycle use
BBTD (Broadband Terminated Dipole)
- Designed for coverage without tuning, but with high resistive losses
- Uses a 9:1 UNUN and a terminating resistor typically between 450–600 Ω
- Easy to match, but substantial power is lost as heat, especially on lower bands
B&W BWD-90
- Commercial solution aiming at broad HF coverage
- Known for consistent impedance but limited in radiated efficiency
- Suited for shortwave listening or NVIS voice operation rather than efficient transmission
Why the TermiLoop Differs
- Broad Compatibility: Tunable with internal tuner from 160 to 10 meters when installed properly
- Matched UNUN: Uses a 4:1 ratio tailored to expected line impedance
- Folded Geometry: Improves current distribution and reduces loss resistance
- Configurable Power Levels: Basic version supports typical 100 W-class transceivers; high-power version supports 600 W FT8 or 1.5 kW SSB
- Dual-Pattern Operation: Supports both high-angle and low-angle propagation depending on band
Conclusion
The TermiLoop provides a more balanced approach to broadband operation. While all terminated designs involve trade-offs, careful attention to geometry, impedance, and installation height significantly improves real-world performance compared to older terminated dipole concepts.
Mini-FAQ
- Is the TermiLoop efficient? — More efficient than classic BBTD and BWD-90 designs, but still lower than a resonant dipole.
- Does it need a tuner? — Most radios’ internal tuners handle it fine across 160–10 m.
- Can I run digital modes? — Yes, up to 100 W on the standard model or 800 W FT8 on the high-power model.
- What about NVIS vs DX? — Lower bands support NVIS; higher bands favor low-angle DX propagation.
Interested in more technical content? Subscribe to our updates for deep-dive RF articles and lab notes.
Questions or experiences to share? Feel free to contact RF.Guru.