Palomar Engineers Magnetic long wire antenna matche has been redesigned for shortwave listeners who listen to a broad frequency range from VLF to HF and others needing to match a long wire antenna to 50/75 ohm coax feed line cable.
Specifications: Frequency: 100 KHz – 30 MHz. Input: 50/75 ohms for coaxial cable. Output: High impedance. Connector: SO-239 (for cable), wingnut/solder lug wire lead (for antenna). Mounting: Stainless steel eyebolt. Size: 2.5” diameter. Case: White PVC sealed weatherproof. External ground bolt with wing nut for external counterpoise or separate ground.
The long wire antenna often has a high impedance in the 500-1000 ohm range and the MLB-2 transforms this high impedance close to efficiently couple the received signal to the receiver. A long wire antenna with a matching balun such as the MLB-2 often has a 12 db (2 “S” units) better signal than a long wire without a matching balun.
Typical Installation Diagram
MLB-1/MLB-2 Typical installation diagram
For best results we recommend that the coax feed line be at least 1/4 wavelength on the lowest operating frequency since the coax braid is used as a counterpoise if you don’t use the external counterpoise terminal on the matching unit. We also recommend a feed line choke at the end of the coax feed line near the radio to prevent RFI common mode current (from neighbor noise sources) from interfering with the radio – check out the info below on feed line chokes.
Also available as a complete ready to hang SWL antenna. (see related products).
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.