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9kW ICAS Dual Core 1:1 Balun For Verticals, Beams and Rotary Dipoles
9kW ICAS Dual Core 1:1 Balun For Verticals, Beams and Rotary Dipoles
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Engineered for serious HF operators using rotary dipoles, verticals or beam antennas, these high-power current chokes are built on stacked dual-core architecture inside a rugged polycarbonate enclosure with HV coating, custom gaskets, and a decompression valve for outdoor QRO use. Each choke has a single PL-259 or N-type input connector and two stainless-steel M6 output terminals for direct feed to your balanced driven element. All performance values listed below are conservative real-world figures based on measured results.
Baluns in a Nutshell
Why “Common-Mode” Is the Most Abused Term in Ham Radio
How Much Choking Do You Really Need — for RX and TX?
Built for the Long Run
Each model is designed for high-power ICAS duty cycles, tested to withstand sustained legal-limit operation and beyond. The fully sealed build resists moisture, salt, and UV exposure, while the internal HV coating prevents corona discharge and maintains stable impedance under high voltage stress. Available with PL-259 or N-type input and dual stainless-steel M6 terminals for direct element connection.
Variants
160–40 m Rotary-Dipole / Low-Band Beam Choke (9 kW ICAS)
Optimized for the low bands, offering deep rejection of common-mode currents on 160, 80, and 40 meters. Ideal for full-size 40 m rotary dipoles or 2-element 40 m beams. Impedance and CMR values are conservative and verified under real QRO load conditions.
| Band | Choking Impedance (Ω) | Common-Mode Rejection (dB) |
|---|---|---|
| 160 m | 4.0 kΩ | 44.1 dB |
| 80 m | 8.0 kΩ | 50.1 dB |
| 40 m | 2.0 kΩ | 38.2 dB |
| Approx. 0.5 kΩ → 26.4 dB on 30 m. Add a 30-10M choke in series for ≈ 3.5 kΩ / 43 dB. | ||
30–10 m Beam Feed Choke (5 kW ICAS)
Broad upper-HF design providing consistent isolation from 30 through 10 meters. Ideal as a boom-mounted feed choke for monoband or triband Yagis. Supplied with PL-259 or N-type input and dual M6 outputs for balanced driven elements. All impedance and CMR numbers are conservative and based on practical test setups.
| Band | Choking Impedance (Ω) | Common‑Mode Rejection (dB) |
|---|---|---|
| 30 m | 1.90 kΩ | 37.6 dB |
| 20 m | 1.25 kΩ | 34.0 dB |
| 17 m | 1.30 kΩ | 34.3 dB |
| 15 m | 1.25 kΩ | 34.0 dB |
| 12 m | 1.10 kΩ | 32.9 dB |
| 10 m | 1.00 kΩ | 32.0 dB |
6 m VHF Beam Choke (3 kW ICAS)
Compact VHF choke engineered for 50–54 MHz operation. Provides high-frequency common-mode isolation for 6 m beams and rotatable dipoles. Equipped with PL-259 or N-type input and dual M6 terminals. All figures represent conservative, verified real-world performance data.
| Band | Choking Impedance (Ω) | Common-Mode Rejection (dB) |
|---|---|---|
| 6 m (50–54 MHz) | 1.0 kΩ | 32.3 dB |
Maximum ICAS/CCS Power Ratings
| Connector Type | 160–40 m Band | 30–10 m Band | 6–2 m Band | Limiting Factor |
|---|---|---|---|---|
| PL-259 / UHF | ≈ 2.7 kW ICAS | ≈ 1.3 kW ICAS | ≈ 0.6 kW ICAS | Connector |
| Type-N | ≈ 10 kW ICAS | ≈ 5 kW ICAS | ≈ 2 kW ICAS | Coax |
| 7/16 DIN | ≈ 10 kW ICAS | ≈ 5 kW ICAS | ≈ 2 kW ICAS | Coax |
Construction Highlights
- Dual-core architecture for extended thermal and magnetic headroom
- Single PL-259 or N-type input with dual M6 stainless-steel terminals for balanced outputs
- High-voltage internal coating to prevent corona and arcing
- Polycarbonate housing with precision-cut silicone gaskets for IP-rated sealing
- Integrated decompression valve for pressure equalization
- All impedance and CMR values stated are conservative, verified under load
At RF.Guru Lab, all choke measurements follow industry-standard EMC procedures. We use a calibrated setup that injects controlled common-mode current into the device under test and measures the residual output current using precision probes. This directly quantifies Common-Mode Rejection (CMR in dB) — the true metric of how well the choke suppresses RF on the feedline shield.
Most “choke tests” found online use a VNA in differential mode and measure the wrong path. Our method follows the same principles as professional EMC compliance testing, so every dB quoted represents real common-mode suppression.
Mini-FAQ
-
Q: Can I use the 160–40 m choke on a rotary dipole?
— Yes. It’s optimized for 40 m rotary dipoles and low-band beams. -
Q: Is the 30–10 m variant better for Yagis?
— Exactly. Use it for multiband beams covering 30 to 10 m. -
Q: What about 6 m beams?
— The 6 m version provides excellent VHF isolation and is ideal for rotatable 6 m arrays. -
Q: Are these waterproof for outdoor use?
— Yes. Each enclosure is gasket-sealed, HV-coated, and has a decompression valve. -
Q: What connectors are available?
— PL-259 or N-type input, dual M6 stainless outputs.
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