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1.5kW ICAS Dual Core High Power 1:1 Antenna Tuner Current Balun or Choke
1.5kW ICAS Dual Core High Power 1:1 Antenna Tuner Current Balun or Choke
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The 1.5 kW ICAS Dual-Core 1:1 Antenna Tuner Balun / Current Choke is designed for balanced open-wire and ladder-line systems using external tuners. It converts an unbalanced tuner output to a balanced line, maintaining true current symmetry and eliminating common-mode RF that can disturb tuner readings or cause RF feedback.
Correct Use of RF.Guru Antenna Tuner Baluns
Baluns in a Nutshell
How Much Choking Do You Really Need — for RX and TX?
Function
This current-balun design provides the correct balanced-to-unbalanced transition for ladder-line-fed antennas. It uses dual 61 mm ferrite cores wound with Teflon-insulated twin lead, each conductor enclosed in an additional Teflon sleeve (24 kV/mm) to withstand extreme voltage stress. The four M6 terminals (two for tuner output, two for balanced line) allow a direct, low-loss connection without coax connectors or SO-239 interfaces.
The balun tolerates wide impedance swings found at tuner outputs and maintains high current isolation across its operating range. It can be used as a standalone choke or cascaded with a second unit for extended coverage across the entire HF spectrum.
Variants
160 – 40 m Low-Band Tuner Balun (1.5 kW ICAS)
Optimized for 1.5 – 15 MHz, delivering excellent common-mode suppression on 160, 80 and 40 meters. Ideal for long doublets or Inverted-L antennas driven through a tuner.
| Band | Choking Impedance (Ω) | Common-Mode Rejection (dB) |
|---|---|---|
| 160 m | ≥ 5 kΩ | ≈ 44 dB |
| 80 m | ≥ 8 kΩ | ≈ 50 dB |
| 40 m | ≥ 3 kΩ | ≈ 40 dB |
30 – 10 m High-Band Tuner Balun (1.5 kW ICAS)
High-frequency version for 30 – 10 m balanced loops and tuner-fed doublets. Provides strong isolation and reduced RF coupling on higher bands.
| 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 |
For full 1.5 – 30 MHz coverage, simply connect both variants in series. Cascading increases isolation and ensures seamless choking performance across the entire HF spectrum.
Mechanical Characteristics
- Four M6 stainless-steel terminals (two for tuner side, two for balanced line)
- Each terminal isolated with Teflon spacers to prevent creepage and surface arcing across the polycarbonate housing
- Dual 61 mm toroidal ferrites for extended thermal and magnetic headroom
- Heat-resistant Teflon twin-lead with 24 kV/mm sleeving
- INOX 316 hardware — more info
- UV-resistant polycarbonate enclosure, IP64 sealed — more info
- Side-mounted terminals maximize creepage distance and lightning resilience
- Weight: approx. 500 g
Construction Highlights
- Dual-core architecture for QRO thermal capacity and broadband response
- High-voltage internal coating to prevent corona and surface tracking
- Fully sealed polycarbonate enclosure with precision silicone gasket
- All performance values are conservative and verified under load
Each balun is evaluated using true common-mode current injection methods under load. Residual current is measured with a precision probe to derive Common-Mode Rejection (CMR in dB). This process complies with EMC industry standards and yields real field-relevant data.
Unlike differential VNA tests, this method measures the actual current suppression on the feedline — the figure that matters for tuner-fed systems.
Mini-FAQ
-
Q: Can I connect it directly to my tuner terminals?
— Yes. The four M6 posts let you connect tuner and ladder line without coax interfaces. -
Q: Are the terminals insulated from the box?
— Yes. Each M6 bolt has a Teflon spacer preventing creepage and arcing over the polycarbonate surface. -
Q: Which variant should I choose?
— Use the 160–40 m version for low-band antennas, the 30–10 m for upper HF loops. -
Q: Can I combine them for all-band use?
— Yes. Cascading both covers 1.5–30 MHz and raises isolation even further. -
Q: Is it safe for outdoor installation?
— Absolutely. The IP64 polycarbonate housing and Teflon hardware ensure long-term weather resistance.
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