Momobeam RFC‑DU 3kW RF Choke Baluns provide an excellent balance of currents and ensure a proper transition between balanced resonant antenna systems (with low SWR)—such as dipoles and Yagi antennas—and unbalanced coaxial feedlines. These RF Chokes are highly effective at suppressing common mode current from flowing along the exterior of coaxial feedlines, a condition that can cause several issues, including:

• Increased noise levels

• Inaccurate SWR meter readings

• Interference affecting electronic devices within our shack or near the antenna system

Each unit features two output wires of different colors to clearly identify polarity.

• The light‑colored wire must always connect to the center conductor of the coaxial cable.

• The dark‑colored wire must always connect to the shield braid of the coaxial cable.

Correct polarity identification is important for phased array installations, while it is generally not critical when installing single antennas.

See the "Recommended Parts" section for genuine Momobeam Choke/Balun Mounting Brackets, designed to fit compatible square and round Momobeam antenna booms.

Additional Features and Specifications:

• RF Choke Type: Current Balun

• Frequency Range: 7-54MHz

• Power Rating: 3kW PEP* 750W Digital Modes (2kW on 50MHz)

• Materials: Coaxial cable insulated with Teflon, and surrounded by ferrite beads

• Enclosure Type: UV-resistant PVC

• Ratio: 1:1, 50-Ohm

• Termination Type: SO-239 with PTFE / 3.94-inch (10cm) wires to be soldered to M4 Ring terminals

• Common Mode Rejection: Up to 20dB

• Insertion Loss: <1dB

• Length: 17.72in. (45cm)

• Weight: 0.53lbs.(0.24kg)

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!