4:1 impedance transformers (Baluns and Unun configurations) are available in kit form or assembled form in a weatherproof Current Unun and Balun Enclosure which we call CUBE Baluns™ and CUBE Ununs™. All 4:1 impedance transformers use ferrite cores and the kit forms can be configured as a balun with balanced output of 200 ohms or as ununs with one side grounded.
4:1 baluns are designed for 50 ohm unbalanced (coax) input to 200 ohm output (either balanced or with one side grounded).
4:1 Baluns are useful between balanced lines for center fed Zepps, Off-center fed (OCF) dipoles with coax, G5RV antennas, full wave loops, NVIS dipoles that are close to ground and have impedance levels near 200 ohms or high impedance feeds for log periodic beams.
4:1 ununs are useful between coax and vertical antennas, monopole verticals or long wires with load impedances near 200 ohms.