Momobeam RFC-LI 4kW Dual Big Core Line Isolator RF Choke Baluns

Momobeam RFC-LI 2kW Dual‑Core Line Isolator RF Choke Baluns are efficient broadband common‑mode current chokes designed to ensure proper current balance and clean transitions between balanced resonant antennas—such as dipoles and Yagi antennas—and unbalanced coaxial feed lines. By delivering excellent suppression of unwanted common‑mode current across a wide frequency range, these RF chokes help maintain optimal antenna performance and protect sensitive station equipment.

Common‑mode currents can cause a variety of station problems, including elevated receiver noise levels, inaccurate SWR measurements, and interference affecting nearby electronic devices or equipment within the shack. The RFC‑LI effectively prevents these issues by stopping common‑mode current from traveling on the outside of the coaxial shield, ensuring cleaner transmit and receive performance under all operating conditions.

RFI-LI Line Isolator Choke Baluns can be installed along 50‑ohm coaxial feedlines in various strategic positions, such as:

- At the antenna feed point, using a suitable high‑power pigtail

- At the base of the tower or near the shack, where they serve as an additional device—complementing the RF Choke at the antenna feed—to further reduce common mode currents traveling on the coaxial shield and generating unwanted noise

- Along the feedline of End‑Fed antennas, where they are also very effective as Feedline Chokes, suppressing common mode current and improving overall system performance

Additional Features and Specifications:

• RF Choke Type: Current Balun / Line Isolator

• Frequency Range: 3-50MHz

• Power Rating: 4kW PEP* / 1000W Digital Modes

• Materials: High quality 5mm coaxial cable with PTFE insulation on a 2.9-inch dual toroid core

• Ratio: 1:1, 50-Ohm

• Termination Type: (2) SO-239 with PTFE

• Common Mode Rejection: Up to 30-50dB

• Insertion Loss: <0.1dB

• Enclosure Type: UV-resistant ABS box with IP65 protection rating

• Dimensions: 4.72 x 4.72in. (12X12cm)

• Weight: 1.20lbs.(0.54kg)

Important: *Digital modes such as FT8 and similar, whose duty cycle is very stressful, we recommend using a power not exceeding 25% of the applicable power of the RF Choke!

A higher applied power could cause irreversible damage!