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 12 to 6m 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 100W FT8 and 250W SSB, while a higher-power version is available, rated for 800W FT8 and 1.5kW 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 1.5kW SSB / 600W 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 and 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 100W-class transceivers; high-power version supports 600W FT8 or 1.5kW SSB
- Dual-Pattern Operation: Supports both high-angle and low-angle propagation depending on band
Conclusion
The TermiLoop aims to provide a more balanced approach to broadband operation. While all terminated designs make compromises, careful attention to geometry, impedance, and installation height can significantly improve practical performance.
Choosing the right antenna still depends on operating goals, location, and power level. Terminated antennas aren’t always the most efficient, but for multiband coverage without external tuning, the TermiLoop offers a viable option with measured trade-offs.
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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.