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RF Guru

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

€206,00 EUR
€206,00 EUR
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Frequency
Connector
Antenna Connector Placement
Complementary: Stainless Steel (RVS / INOX 316) Mounting Kit available — use the small version for this choke.
All our products are handmade, and fulfilment times may vary depending on order volume.
Please allow 2–3 weeks for your order to be completed and shipped.

Engineered for rotary dipoles, verticals, and beam antennas, these high-power current chokes suppress feedline-induced RF currents directly at the driven element. Built on a stacked dual-core ferrite structure inside a sealed polycarbonate HV-coated enclosure, they include a PL-259 or N-type input and dual INOX M6 terminals for antenna connection. All performance values below are conservative real-world figures.

Related reading:
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

Designed for ICAS duty cycles and high drive imbalance, these chokes provide stable suppression on high-power beams and rotary dipoles. The enclosure is HV coated, gasket sealed, and pressure equalized for long-term reliability.

Variants

160–40 m Rotary-Dipole / Low-Band Beam Choke (9 kW ICAS)

Optimized for 160, 80, and 40 m. All values conservative, verified under QRO load.

Band Choking Impedance (Ω) Impedance-Equivalent dB (from |Zc|)
160 m 3.5 kΩ 42.9 dB
80 m 7.0 kΩ 48.9 dB
40 m 8.0 kΩ 50.1 dB
Approx. 5 kΩ → 44.0 dB on 30 m alone.
In series with the 30–10 m choke (≈3 kΩ / 41.6 dB) gives ≈8 kΩ / 50.1 dB total.

*Impedance-Equivalent (dB) values are derived directly from |ZCM| using a 50 Ω common-mode source reference. Real antennas rarely present 50 Ω CM, so these values represent the choke’s intrinsic suppression capability — not loaded attenuation. See: Why dB Attenuation Specs on Ham Chokes Are a Mess.*

30–10 m Beam Feed Choke (5 kW ICAS)

Ideal as a boom-mounted feed choke for monoband and multiband HF Yagis (30–10 m). All values based on field + lab measurement.

Band Choking Impedance (Ω) Impedance-Equivalent dB (from |Zc|)
30 m 3.0 kΩ 41.6 dB
20 m 2.5 kΩ 40.0 dB
17 m 2.3 kΩ 39.3 dB
15 m 2.1 kΩ 38.5 dB
12 m 1.9 kΩ 37.6 dB
10 m 1.7 kΩ 36.7 dB
*Impedance-Equivalent (dB) values computed from |ZCM| using a 50 Ω common-mode reference. They express the choke’s intrinsic suppression, not the CM impedance of a real beam or dipole.*

6 m VHF Beam Choke (3 kW ICAS)

VHF-tuned choke for 50–54 MHz beam feedpoints. Measured values are conservative and load-verified.

Band Choking Impedance (Ω) Impedance-Equivalent dB (from |Zc|)
6 m (50–54 MHz) ≈2.0 kΩ ≈38.0 dB
*Impedance-Equivalent (dB) values derived from |ZCM| on a 50 Ω CM reference — representing the choke’s inherent suppression ability, not antenna-specific CM behavior.*

Maximum ICAS/CCS Power Ratings

Connector Type 160–40 m 30–10 m 6–2 m Limiting Factor
PL-259 / UHF ≈2.7 kW ≈1.3 kW ≈0.6 kW Connector
N-Type ≈10 kW ≈5 kW ≈2 kW Coax
7/16 DIN ≈10 kW ≈5 kW ≈2 kW Coax

Construction Highlights

  • Dual-core ferrite structure
  • PL-259 or N-type input
  • Dual M6 stainless balanced outputs
  • INOX 316 eye bolts for mechanical support
  • HV internal coating
  • Polycarbonate enclosure with silicone gaskets
  • Decompression valve
  • All values load-verified
Technical Validation — How We Measure It
All RF.Guru chokes are tested using EMC-standard dual-probe CM measurement: one probe injects controlled CM current, the second measures CM current at the output.

This produces real Common-Mode Rejection (CMR) data — based on actual current reduction — not differential-mode VNA artifacts.

Typical VNAs excite the coax in differential mode and do not measure common-mode behavior. Our EMC rig measures true CM suppression under load, exactly as it appears on beam, dipole, and vertical installations.

Mini-FAQ

  • Q: Best choke for rotary dipoles?
    — The 160–40 m version.
  • Q: Best choke for Yagis?
    — The 30–10 m version.
  • Q: Do you have a 6 m beam choke?
    — Yes, tuned for ≈2 kΩ at 50–54 MHz.
  • Q: Is it weatherproof?
    — Fully sealed, HV-coated, and pressure-equalized.
  • Q: Connector options?
    — PL-259 or N-type input, dual M6 stainless outputs.

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Written by Joeri Van Dooren, ON6URE — RF engineer, antenna designer, and founder of RF.Guru.
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