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RF Guru

9kW High Power Dual Core 1:1 Balun for Wire Antennas

9kW High Power Dual Core 1:1 Balun for Wire Antennas

€206,00 EUR
€206,00 EUR
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Connector
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.

Designed for wire antennas such as dipoles and inverted-V configurations, this high-power current choke provides stable, high-impedance isolation between the radiating wire and the feedline. It features a coax input (PL-259 or N-type) and dual INOX M6 terminals for direct wire attachment, plus dual INOX eye bolts for mechanical support. The enclosure is fully sealed and built for permanent outdoor service.

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

Each choke is rated for high-power ICAS duty cycles, tested beyond legal-limit operation. A rugged polycarbonate enclosure with HV coating, silicone gaskets, and a decompression valve ensures long-term reliability under moisture, salt, and UV exposure. Available with either PL-259 or N-type input connectors.

Variants

160–40 m Dual-Core Current Choke (9 kW ICAS)

Optimized for low-band wire antennas (160–40 m). All values are conservative, verified under 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. 5.0 kΩ → 44.0 dB on 30 m for this choke alone. In series with the 30–10 m choke (≈3.0 kΩ / 41.6 dB) gives ≈8.0 kΩ / 50.1 dB total.

*Impedance-Equivalent (dB) values are computed directly from |ZCM| using a 50 Ω common-mode source reference. Real antennas rarely present 50 Ω in common-mode, so these dB values represent the choke’s intrinsic suppression capability — not the behavior you would see under a specific antenna load. More: Why dB Attenuation Specs on Ham Chokes Are a Mess.*

30–10 m Dual-Core Current Choke (5 kW ICAS)

Upper-HF isolation suitable for EFHW, dipoles, OCF antennas, fan dipoles, and multiband operation. All values are conservative and measured under load.

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 derived directly from measured |ZCM| using a 50 Ω CM source reference. They show the choke’s intrinsic suppression, not the CM impedance of a real antenna system.*

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 stack for thermal & magnetic overhead
  • HV internal coating for corona resistance
  • IP-rated polycarbonate enclosure
  • Pressure-equalizing decompression valve
  • Coax input: PL-259 or N-type
  • Dual M6 stainless output terminals
  • Two INOX 316 eye bolts for strain relief
  • All values verified under load in real antenna setups
Technical Validation — How We Measure It
At RF.Guru Lab, all baluns are evaluated using EMC-standard dual-probe common-mode testing. One probe injects controlled CM current; another probe measures the CM current at the output.

This yields true Common-Mode Rejection (CMR) curves based on actual current reduction — not differential-mode VNA S21 plots.

Most VNA tests stimulate the coax in differential mode, not common-mode. Our EMC method measures real CM suppression under load, matching dipole, EFHW, and inverted-V installations.

Mini-FAQ

  • Q: Can I use the 160–40 m choke on upper-HF?
    — Yes, but |Zc| drops above 30 m. Pair with the 30–10 m choke for full HF coverage.
  • Q: Weatherproof?
    — Fully sealed, HV-coated, and pressure-equalized.
  • Q: Connection scheme?
    — Coax input (PL-259 or N-type), dual M6 wire terminals, dual eye bolts for support.
  • Q: Power rating?
    — 9 kW ICAS (low-band choke), 5 kW ICAS (upper-HF choke).
  • Q: Measurement accuracy?
    — All values are conservative and measured with EMC-grade CM probes.

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