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5kW ICAS High Power Dual Core 1:1 Current Balun For Spiderbeam®
5kW ICAS High Power Dual Core 1:1 Current Balun For Spiderbeam®
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Purpose-built for SpiderBeam 5-Band Yagis and similar multiband beam antennas, this 30–10 m dual-core current choke provides wideband isolation across all upper-HF bands. It eliminates feedline-induced RF that can distort beam patterns, increase SWR drift, or raise the shack noise floor. Housed in a polycarbonate HV-coated enclosure with custom gaskets and a decompression valve, it’s made to endure long-term outdoor installation on tower booms or feedline drops. All listed performance data are conservative, measured under real-world load conditions.
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Optimized for SpiderBeam Systems
Installed at the feedpoint or boom-mounted balun junction, this choke ensures proper current balance across all five SpiderBeam bands (20 / 17 / 15 / 12 / 10 m). It suppresses unwanted common-mode currents that otherwise flow on the coax shield, improving SWR stability, pattern symmetry, and receive quietness. Available with PL-259 or N-type connectors for seamless integration into your SpiderBeam feed harness or switch box.
30–10 m Dual-Core Current Choke (9 kW ICAS)
Broad upper-HF design delivering consistent isolation from 30 through 10 m — ideal for SpiderBeam, OptiBeam, or any five-band HF Yagi. All impedance and CMR values are conservative, measured using calibrated current-injection techniques.
| 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 |
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 ferrite stack for superior magnetic and thermal margin
- HV internal coating prevents corona or arcing at high voltage
- UV-resistant polycarbonate housing with precision silicone gaskets
- Integrated decompression valve for pressure equalization
- Connector options: PL-259 or N-type (field-serviceable)
- All values are conservative, verified under power
All RF.Guru chokes are tested using dual-probe EMC common-mode measurement. One probe injects controlled current into the choke, while another measures the residual output current — directly calculating common-mode rejection (CMR) in dB. This is the same principle used in professional EMC compliance labs.
Differential VNA sweeps, commonly seen online, show only impedance between inner and outer conductors — not real-world common-mode suppression. Our method quantifies true shield current reduction, giving you data that reflect on-air performance, not simulation artifacts.
Mini-FAQ
-
Q: Is this choke made specifically for SpiderBeam antennas?
— Yes. It covers all five SpiderBeam bands (20–10 m) with broad, flat CMR response and beam-friendly mounting geometry. -
Q: Where should I install it?
— Directly at the SpiderBeam feedpoint or balun junction to suppress shield currents before they enter the boom or mast. -
Q: What connectors are available?
— PL-259 or N-type (choose to match your feedline). Both rated for QRO service. -
Q: Is it weatherproof?
— Yes. Fully gasket-sealed, HV-coated, and equipped with a decompression valve for long-term outdoor use. -
Q: Can it handle full legal limit power?
— Absolutely — 9 kW ICAS rating ensures headroom for high-duty cycles and amplifier operation.
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