CUBE Impedance Transformers (<1:1, 1:1, >1:1)
CUBE™ Impedance Transformers
Match your antenna with precision — wide-range baluns & ununs from Palomar Engineers®
Overview
The CUBE™ series impedance transformers from Palomar Engineers® provide reliable broadband matching between 50 Ω feed lines and a variety of antenna loads. Ratios from 1:1 to 16:1 cover dipoles, loops, ladder-line systems, off center fed, end-fed, BBTD and TTFD antennas.
Each transformer features stainless-steel hardware, weather-resistant NEMA enclosures, and heavy-duty windings for continuous HF operation (up to 5 kW PEP, model-dependent). Built and tested in the USA — continuing Palomar’s 65-year tradition of RF excellence.
Why Matching Matters
- Reduces SWR and maximizes RF transfer efficiency.
- Prevents unwanted common-mode currents and RFI on feed lines.
- Improves tuner performance and overall station reliability.
Quick-Selection Guide
Choose the right transformer ratio based on your antenna type or impedance range.
| Antenna Type / Scenario | Typical Load (Ω) | Matching Ratio (Output:Input) | Suggested CUBE™ Model | Notes |
|---|---|---|---|---|
| Standard 50 Ω Dipole | ≈ 50-75 | 1:1 | CUBE™ 1:1 Balun | Ideal for balanced antennas — basic isolation. |
| Multi-Band Full Wave Loop or Off Center Fed Dipole (200 Ω) | ≈ 200 | 4:1+1:1 | CUBE™ 4:1 Balun + 1:1 Choke Hybrid | Use for 200 Ω balanced feed to 50 Ω coax and suppress common mode current on coax |
| Ladder-Line Fed Windom (450 Ω) | ≈ 450 | 9:1 | CUBE™ 9:1 Balun | For higher-Z ladder-line loads. |
| End-Fed Non-Resonant Long Wire Antenna | ≈ 400-500 | 9:1 | CUBE™ 9:1 Unun | Classic end-fed matching — wideband HF coverage. |
| End Fed Resonant Antenna (~200 Ω) | ≈ 200 | 4:1 | CUBE™ 4:1 Unun | Raises low impedance to match 50 Ω feed line. |
| BBTD, T2FD (450 or 1000 Ω) Balanced | 100–112 | 9:1+1:1 or 16:1+1:1 Hybrid | CUBE™ 9:1+1:1 or 16:1+1"1 Balun | For custom feed systems and high SWR margins. |
Installation Tips
- Choose a transformer rated for your maximum PEP output.
- Mount with the enclosure drain-hole down for outdoor use.
- For extra RFI suppression, add a feed-line choke near the station.

















